Merck & Co. (MRK) 10-K risk factor changes: FY2025 vs FY2024

- Key products generate a significant amount of the Company’s profits and cash flows, and any events that adversely affect the markets for its leading products could have a material adverse effect on the Company’s results of [removed: operations and] [added: operations, cash flows,] financial [removed: condition.][added: condition, and prospects.]

- The Company faces continued pricing pressure with respect to its [removed: products.][added: products in the public and private sectors.]

- Unfavorable or uncertain economic conditions, together with cost-reduction measures being taken by [removed: certain governments,] [added: the U.S. and other countries,] could negatively affect the Company’s operating results.

- The Company has significant global operations, which expose it to additional risks, and any adverse event could have a material adverse effect on the Company’s results of [removed: operations and] [added: operations, cash flows,] financial [removed: condition.][added: condition, and prospects.]

- Climate change or legal, regulatory or market measures to address climate change may negatively affect the Company’s business, results of operations, cash [removed: flows] [added: flows, financial condition,] and prospects.

[removed: In 2024, the Company] [added: - The Company’s business in China] experienced [added: significantly] lower sales of [removed: *Gardasil/Gardasil 9*] [added: *Gardasil/Gardasil* 9] in [removed: China] [added: 2025] and [added: the Company] expects that sales of [removed: *Gardasil/Gardasil 9*] [added: *Gardasil/Gardasil* 9] in China will [removed: decline significantly] [added: not materially increase] in [removed: 2025.][added: 2026.]

- Biologics and vaccines carry unique risks and uncertainties, which could have a material adverse effect on the Company’s future results of [removed: operations and] [added: operations, cash flows,] financial [removed: condition.][added: condition, and prospects.]

- The Company’s products, including products in development, cannot be marketed unless the Company obtains and maintains regulatory [removed: approval.][added: approval or authorization.]

- Developments following regulatory approval [added: or authorization] may adversely affect sales of the Company’s products.

- Adverse outcomes in current or future legal matters could negatively affect [removed: Merck’s] [added: the Company’s] business.

- The Company is increasing its use of artificial intelligence (AI) systems to automate processes, analyze data, and support [removed: decision-making] [added: decision-making,] which poses inherent risks.

Additionally, certain foreign governments have indicated that compulsory licenses to patents may be granted in the case of national emergencies or in other circumstances, which could diminish or eliminate sales and profits from those regions and negatively affect the Company’s results of [removed: operations.][added: operations, cash flows, financial condition, and prospects.]

[removed: Further, court decisions relating to other companies’ patents, potential legislation in both the U.S. and] certain foreign markets relating to patents, as well as regulatory initiatives may result in a more general weakening of intellectual property protection.

If one or more important products lose patent protection in profitable markets, sales of those products are likely to decline significantly as a result of generic [added: or biosimilar] versions of those products becoming available.

The Company’s [added: business, cash flows,] results of [removed: operations] [added: operations, financial position, and prospects] may be adversely affected by the lost sales unless and until the Company has launched commercially successful products that replace the lost sales.

Loss of patent protection for one of the Company’s products typically leads to a significant and rapid loss of sales for that product as lower priced generic [added: or biosimilar] versions [removed: of that drug] become available.

*Bridion* will lose market exclusivity in the U.S. in [added: July] 2026 [removed: (subject to patent litigation discussed below) and] [added: at which time] the Company [removed: expects that sales of *Bridion*] [added: anticipates a significant and rapid decline] in [removed: the] U.S. [removed: will decline substantially thereafter.][added: sales of *Bridion*.]

The Company [added: also] expects to lose market exclusivity in Europe for *Keytruda* in 2031 following compound patent expiration.

Key products generate a significant amount of the Company’s profits and cash flows, and any events that adversely affect the markets for its leading products could have a material adverse effect on the Company’s results of [removed: operations and] [added: operations, cash flows,] financial [removed: condition.][added: condition, and prospects.]

The Company’s ability to generate profits and operating cash flows depends largely upon the continued profitability of the Company’s key products, such as *Keytruda*, *Gardasil/Gardasil* 9, Lynparza, [removed: *Bravecto*,] [added: *Winrevair,*] and [removed: *Bridion*.][added: *Bravecto*.]

In particular, in the aggregate, in [removed: 2024,] [added: 2025,] sales of *Keytruda* represented [removed: 46%] [added: 49%] of the Company’s total sales.

As a result of the Company’s dependence on key products, any event that adversely affects any of these products or the markets for any of these products, such as the [removed: slowing] [added: materially lower] demand for [removed: *Gardasil/Gardasil 9*] [added: *Gardasil/Gardasil* 9] in China which the Company has experienced, could have a significant adverse impact on results of [removed: operations and] [added: operations, cash flows,] financial [removed: condition.][added: condition, and prospects.]

Other events could include loss of patent protection, [added: selection for IRA price setting, lower than expected utilization of *Keytruda Qlex*,] increased costs associated with manufacturing, [removed: generic] [added: generic, biosimilar] or over-the-counter availability of the Company’s product or a competitive product, the discovery of previously unknown side effects, results of post-approval trials, increased competition from the introduction of new, more effective treatments and discontinuation or removal from the market of the product for any reason.

Expected declines in sales of products after the loss of market exclusivity mean that the Company’s future success is dependent on its pipeline of new products, including new products that it may develop [removed: through collaborations and joint ventures and products that it is able to obtain through license or acquisition.]

Therefore, the Company may abandon a product [added: candidate or use] in which it has invested substantial amounts of time and resources.

[removed: Products] [added: Product candidates or uses] that appear promising in development may fail to reach the market or fail to succeed for numerous reasons, including the following:

The Company faces continued pricing pressure with respect to its [removed: products.][added: products in the public and private sectors.]

The Company faces continued pricing pressure globally and, particularly in mature markets, from managed care organizations, government agencies and programs that could negatively affect the Company’s sales [removed: and profit margins.]

“Competition and the Health Care Environment,” in 2023, HHS selected *Januvia* for the first year of the IRA’s price setting program, which [removed: will result] [added: resulted] in a government set price becoming effective on January 1, 2026.

In [removed: January] 2025, HHS [removed: announced that] [added: selected] *Janumet* and *Janumet XR* [removed: have been selected] for government price setting, which will become effective on January 1, 2027.

Furthermore, the Company expects that in [removed: 2026] [added: 2027] HHS will include *Keytruda* in a subsequent selection of products to undergo IRA price setting, with such price to become effective on January 1, [removed: 2028] [added: 2029] and the Company expects that, as a result, U.S. sales of *Keytruda* will decline [added: materially] after that time.

Unfavorable or uncertain economic conditions, together with cost-reduction measures being taken by [removed: certain governments,] [added: the U.S. and other countries,] could negatively affect the Company’s operating results.

In addition, the Company’s sales performance in [removed: 2024] [added: 2025] was negatively affected by other cost-reduction measures taken by governments and other third parties to lower health care costs, including in the U.S., the expansion of the Federal 340B Drug Discount Program.

Although it is the Company’s policy to actively protect its patent rights, [removed: generic] challenges to the Company’s products can arise at any time, and the Company’s patents may not prevent the emergence of generic [added: or biosimilar] competition for its products.

Availability of generic [added: or biosimilar] substitutes for the Company’s drugs may adversely affect its results of operations and cash flows.

In addition, proposals emerge from time to time in the U.S. and other countries for legislation to further encourage the early and rapid approval of generic [added: or biosimilar] drugs.

Any such proposal that is enacted into law could worsen this substantial negative effect on the Company’s [removed: sales,] business, cash flows, results of operations, financial condition and prospects.

Alternatively, in the case of generic [added: or biosimilar] competition, including the generic [added: or biosimilar] availability of competitors’ branded products, they may be equally safe and effective products that are sold at a substantially lower price than the Company’s products.

The Company has significant global operations, which expose it to additional risks, and any adverse event could have a material adverse effect on the Company’s results of [removed: operations and] [added: operations, cash flows,] financial [removed: condition.][added: condition, and prospects.]

Events like these, such as the ongoing war between Russia and Ukraine, and [removed: the] conflict in the Middle East, and/or policy changes with respect to international trade protection measures, could result in material adverse effects on [removed: macroeconomic conditions, currency exchange rates and financial markets, and may adversely affect the Company’s business, results of operations, cash flows and financial condition.]

As a consequence of the reduced sales of *Gardasil/Gardasil* 9, the Company’s business in China declined significantly.

Further, court decisions relating to other companies’ patents, potential legislation in both the U.S. and

The Company expects to discontinue U.S. sales of *Bridion* by the end of 2026.

In addition, *Januvia* and *Janumet* will lose market exclusivity in the U.S. in May 2026 and *Janumet XR* will lose market exclusivity in the U.S. in July 2026.

The Company expects a significant decline in sales of *Januvia* in the first half of 2026 reflecting the impact of government price setting noted above and subsequently, following loss of market exclusivity in May 2026, the Company anticipates it will lose nearly all U.S. sales of *Januvia* and *Janumet*.

Also, the Company expects that sales of *Keytruda* will be materially negatively impacted by biosimilar competition between 2028 and 2029.

As previously disclosed, while two patents in the *Keytruda* composition of matter patent family expire in May and November of 2029, respectively, the Company expects these patents to be the subject of litigation and, thus, biosimilar competition could begin in December 2028 when the primary compound patent expires.

through collaborations and joint ventures and products that it is able to obtain through license or acquisition.

- changes in clinical preferences or standards of care, including competitor innovations, that diminish the value of the product;

and profit margins.

In addition, in January 2026, HHS announced that Lenvima has been selected for government price setting, the set price for which will become effective on January 1, 2028.

Also, as noted above, in December 2025, the Company entered into the MFN Agreement with the U.S. government pursuant to which the Company will provide key products through a direct-to-patient program at affordable prices for eligible patients in the U.S. This currently includes *Januvia*, *Janumet*, and *Janumet XR*, and will be expanded in the future to include enlicitide decanoate pending FDA approval.

The Company also agreed to offer its existing medicines at discounted prices to Medicaid, excluding certain products.

In addition, the Company has agreed that products launched during the term of the MFN Agreement (with certain exceptions) will be subject to “most-favored-nation” pricing in reference to prices for such products in the MFN Countries.

Also, the Company expects that U.S. states will continue their focus on pharmaceutical pricing and may shift to more aggressive price control tools.

In addition, it is possible that as a consequence of the MFN Agreement, certain of the Company’s products may not be launched in the MFN Countries or their launch may be delayed and as a result, the MFN Countries may take actions that adversely impact the Company.

- the imposition of tariffs by the U.S. or other governments;

macroeconomic conditions, currency exchange rates and financial markets, and may adversely affect the Company’s business, results of operations, cash flows, financial condition, and prospects.

New legal and regulatory requirements with respect to climate-related matters, which may differ across jurisdictions, could result in the Company being subject to increased compliance burdens and costs to meet these obligations.

As a consequence of the reduced sales of Gardasil/Gardasil 9, the Company’s business in China declined significantly.

The Company’s business in China experienced significantly lower sales of *Gardasil/Gardasil* 9 in 2025.

Due to above normal inventory levels at the Company’s commercialization partner in China, the Company made a decision to pause shipments to China beginning in February 2025 and has not resumed shipments to date.

The Company will not resume shipments until inventory levels return to normal levels and it cannot predict when shipments to China will resume nor the levels of sales that the Company will achieve and as a result, the Company expects that sales of *Gardasil/Gardasil* 9 in China will not materially increase in 2026.

In June 2025, a nine-valent HPV vaccine produced by a local manufacturer received regulatory approval in China for use in females 9-45 years of age.

In addition, in 2025, sales of the *Bravecto* family of products were

- Biologics and vaccines require long manufacturing lead times, sometimes requiring planning years in advance of demand, which could increase the risk of inventory write-downs if that demand does not materialize.

starting in 2026, and Medicare Part B drugs starting in 2028.

“Competition and the Health Care Environment,” in 2023, HHS selected *Januvia* for the first year of the IRA’s price setting program, which resulted in a government set price becoming effective on January 1, 2026.

In addition, in January 2026, HHS announced that Lenvima has been selected for government price setting, the set price for which will become effective on January 1, 2028.

Furthermore, the Company expects that in 2027 HHS will include *Keytruda* in a subsequent selection of products to undergo IRA price setting, with such price to become effective on January 1, 2029 and the Company expects that, as a result, U.S. sales of *Keytruda* will decline materially after that time.

Changes could also impact the CDC, including how recommendations for immunizations are issued and maintained.

Changes that have been made to the CDC’s recommended immunization schedule which could impact public and private coverage, as well as reduction in state-controlled school immunization requirements, could cause a decline in vaccine uptake.

Alterations to the National Vaccine Injury Compensation Program also could impact how claims against vaccine manufacturers are adjudicated.

The government also has discussed certain policy changes to facilitate market entry of biosimilar products.

The Company’s failure to obtain approval, significant delays in the approval process, or its

Similarly, new information that becomes available about products from other manufacturers may prompt new regulatory reviews of the Company’s products, leading to actions that could negatively affect sales.

routinely examined by various tax authorities.

If the IRS’ challenge to the Company’s transition tax position is ultimately successful, the impact could be material to the Company’s cash flows, results of operations and financial condition.

Unauthorized use of open-source AI tools or generative AI platforms by employees or third parties could result in inadvertent disclosure of confidential information, intellectual property leakage, or regulatory violations.

[Table of Content](#i783cf867b028427ba2fa2dcfd656c4d4_7)[s](#i783cf867b028427ba2fa2dcfd656c4d4_7)

- The Company’s business in China has grown in the past few years, and the importance of China to the Company’s overall pharmaceutical and vaccines business has increased accordingly.

The Company lost market exclusivity for *Bridion* in Europe and Japan in 2023 and 2024, respectively, and the Company has experienced a substantial decline in *Bridion* sales in those markets.

In addition, the Company expects U.S. sales of *Keytruda* to decline beginning in January 2028 upon implementation of government pricing under the IRA, and to further decline upon loss of market exclusivity following expiration of the U.S. compound patent in December 2028.

In 2024, the Company’s oncology portfolio, led by *Keytruda*, represented substantially all of the Company’s revenue growth.

The U.S. government has announced plans to significantly increase tariffs on foreign imports into the U.S., particularly from Canada and Mexico and has already increased tariffs on imports from China.

It is too early for the

Company to assess if, or to what extent, such policies will be implemented or continue to be implemented, and the extent of any measures that have been or will be taken by any impacted countries.

New legal and regulatory requirements are being enacted to prevent, mitigate, or adapt to the implications of a changing climate and its effects on the environment.

These regulations, which may differ across jurisdictions, could result in the Company being subject to new or expanded carbon pricing or taxes, increased compliance costs, restrictions on GHG emissions, investment in new technologies, increased GHG emission disclosure (including costs resulting from mandatory or voluntary reporting, diligence or disclosure) and transparency, recurring investments in data gathering and reporting systems, upgrades of facilities to meet new building codes, and the redesign of utility systems, which could increase the Company’s operating costs, including the cost of electricity and energy used by the Company.

In addition, the Company is subject to expanding mandatory and voluntary reporting, diligence and disclosure requirements, including the EU’s Corporate

For example, the Company is currently experiencing manufacturing delays related to *Varivax* and *ProQuad* which will result in supply constraints in 2025.

The Company’s business in China has grown in the past few years, and the importance of China to the Company’s overall pharmaceutical and vaccines business has increased accordingly.

The Company’s business in China has grown in the past few years, and the importance of China to the Company’s overall pharmaceutical and vaccines business has increased accordingly.

Beginning in mid-2024, the Company observed a significant decline in shipments from its distributor and commercialization partner in China, Chongqing Zhifei Biological Products Co., Ltd. (Zhifei), to disease and control prevention institutions and correspondingly into the points of vaccination, resulting in above normal inventory levels at Zhifei.

Accordingly, the Company shipped less than its contracted doses to Zhifei in the latter part of 2024.

Lower demand in China persisted and, at the end of 2024, overall channel inventory levels in China remained elevated at above normal levels.

Therefore, the Company made a decision to temporarily pause shipments to China beginning in February 2025 through at least the middle of the year and as a result, combined sales of G*ardasil/Gardasil 9* will decline significantly in 2025 compared with 2024.

If the IRS disagrees with the Company’s transition tax position, it may result in a significant tax liability.

The following section of this Form 10-K generally discusses [removed: 2024] [added: 2025] and [removed: 2023] [added: 2024] results and year-to-year comparisons between [removed: 2024] [added: 2025] and [removed: 2023.][added: 2024.]

Discussion of [removed: 2022] [added: 2023] results and year-to-year comparisons between [removed: 2023] [added: 2024] and [removed: 2022] [added: 2023] that are not included in this Form 10-K can be found in Part II, Item 7.

“Management’s Discussion and Analysis of Financial Condition and Results of Operations” in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, [removed: 2023] [added: 2024] filed on February [removed: 26, 2024.][added: 25, 2025.]

The Company sells these human health pharmaceutical products primarily to drug wholesalers and retailers, hospitals, government [removed: agencies] [added: agencies,] and managed health care providers such as health maintenance organizations, pharmacy benefit managers and other institutions.

| *($ in millions except per share amounts)* | | | [removed: 2024] [added: 2025] | | | | | | % Change | | | | | | % Change Excluding Foreign Exchange | | | | | | [removed: 2023] [added: 2024] | | | | | | % Change | | | | | | % Change Excluding Foreign Exchange | | | | | | [removed: 2022] [added: 2023] | | |

| Sales | | | $ | [removed: 64,168] [added: 65,011] | | | | | [removed: 7] [added: 1] | | % | | | | [removed: 10] [added: 2] | | % | | | | $ | [removed: 60,115] [added: 64,168] | | | | | [removed: 1] [added: 7] | | % | | | | [removed: 4] [added: 10] | | % | | | | $ | [removed: 59,283] [added: 60,115] | |

| GAAP | | | $ | [removed: 17,117] [added: 18,254] | | | | | [removed: *] [added: 7] | | [added: %] | | | | [removed: *] [added: 9] | | [added: %] | | | | $ | [removed: 365] [added: 17,117] | | | | | [removed: (97)] [added: *] | | [removed: %] | | | | [removed: (95)] [added: *] | | [removed: %] | | | | $ | [removed: 14,519] [added: 365] | |

| Non-GAAP *(1)* | | | $ | [removed: 19,444] [added: 22,513] | | | | | [removed: *] [added: 16] | | [added: %] | | | | [removed: *] [added: 18] | | [added: %] | | | | $ | [removed: 3,837] [added: 19,444] | | | | | [removed: (80)] [added: *] | | [removed: %] | | | | [removed: (75)] [added: *] | | [removed: %] | | | | $ | [removed: 19,005] [added: 3,837] | |

| GAAP | | | $ | [removed: 6.74] [added: 7.28] | | | | | [removed: *] [added: 8] | | [added: %] | | | | [removed: *] [added: 10] | | [added: %] | | | | $ | [removed: 0.14] [added: 6.74] | | | | | [removed: (98)] [added: *] | | [removed: %] | | | | [removed: (95)] [added: *] | | [removed: %] | | | | $ | [removed: 5.71] [added: 0.14] | |

| Non-GAAP *(1)* | | | $ | [removed: 7.65] [added: 8.98] | | | | | [removed: *] [added: 17] | | [added: %] | | | | [removed: *] [added: 19] | | [added: %] | | | | $ | [removed: 1.51] [added: 7.65] | | | | | [removed: (80)] [added: *] | | [removed: %] | | | | [removed: (75)] [added: *] | | [removed: %] | | | | $ | [removed: 7.48] [added: 1.51] | |

The Company [added: also] continued to return capital to shareholders, primarily through dividends.

[removed: ][added: ]

Worldwide sales were [removed: $64.2] [added: $65.0] billion in [removed: 2024,] [added: 2025,] an increase of [removed: 7%] [added: 1%] compared with [removed: 2023,] [added: 2024,] or [removed: 10%] [added: 2%] excluding the unfavorable effect of foreign exchange.

The sales increase was primarily due to growth in oncology, [removed: cardiovascular] [added: cardiometabolic] and [added: respiratory, diabetes, and] animal health, [removed: partially] [added: largely] offset by declines in [removed: diabetes, virology (driven largely by lower sales of COVID-19 medication *Lagevrio*),] [added: vaccines,] immunology (as Merck’s marketing rights to these products ended in [removed: 2024)] [added: 2024),] and [removed: vaccines.][added: virology (driven largely by lower sales of COVID-19 medication *Lagevrio*).]

Merck continues to execute [removed: value creating] [added: science-led] business development [removed: opportunities focused on innovation] [added: transactions] to augment its robust internal pipeline [added: and portfolio] with compelling external [removed: science.][added: science focused on delivering innovation to patients, long-term growth, and value creation to shareholders.]

Highlights of [removed: 2024] [added: 2025] activity include the following:

*Keytruda* received [removed: approval] [added: approvals] for additional indications in [removed: the U.S. and/or internationally as monotherapy in the therapeutic areas of hepatocellular carcinoma (HCC), melanoma and urothelial carcinoma,] [added: certain markets, including] in combination with chemotherapy in the therapeutic areas of [removed: biliary tract cancer, cervical cancer, endometrial carcinoma,] gastric or gastroesophageal junction (GEJ) [removed: adenocarcinoma,] [added: adenocarcinoma and] malignant pleural [removed: mesothelioma] [added: mesothelioma, in combination with Padcev (enfortumab vedotin) for locally advanced or metastatic urothelial carcinoma] and [removed: non-small-cell lung] [added: for cisplatin-ineligible muscle-invasive bladder] cancer [removed: (NSCLC),] [added: (MIBC),] as well as in combination with [removed: Padcev (enfortunab vedotin-ejfv)] [added: radiotherapy with or without chemotherapy] for [removed: advanced urothelial carcinoma.][added: head and neck squamous cell carcinoma (HNSCC).]

[removed: Also] [added: Additionally,] in [removed: 2024,] [added: 2025,] *Welireg* was approved in [removed: China] [added: the European Union (EU) and Japan] for the treatment of adult patients with certain von Hippel-Lindau (VHL) disease-associated tumors [removed: not requiring immediate surgery.][added: and certain adult patients with renal cell carcinoma (RCC), as well as in the U.S. for certain adult and pediatric patients with pheochromocytoma and paraganglioma.]

- MK-1654, [removed: clesrovimab, is an investigational] [added: *Enflonsia*, a] prophylactic long-acting monoclonal antibody designed to protect infants from [removed: respiratory syncytial virus (RSV)] [added: RSV] disease during their first RSV [removed: season] [added: season, is] under review [removed: by] [added: in] the [removed: FDA.][added: EU and Japan.]

[removed: - Additionally, *Keytruda*] [added: ◦*Keytruda*] is under review in the EU and Japan [removed: for a supplemental indication] [added: in combination with chemotherapy with or without bevacizumab] for the treatment of certain patients with [removed: malignant pleural mesothelioma.][added: platinum-resistant recurrent ovarian cancer.]

[removed: Merck’s] [added: Merck has numerous] Phase 3 oncology programs within these [removed: pillars are as follows:][added: pillars.]

- [removed: MK-1308A,] [added: MK-1308A is] the coformulation of quavonlimab, Merck’s novel investigational [removed: anti-CTLA-4] [added: anti-cytotoxic T-lymphocyte associated protein 4 (CTLA-4)] antibody, in combination with [removed: pembrolizumab] [added: pembrolizumab, being evaluated] for [removed: RCC;][added: the treatment of RCC.]

- V940 (mRNA-4157), [added: intismeran autogene, is] an investigational individualized neoantigen [removed: therapy,] [added: therapy being evaluated] in combination with [removed: *Keytruda*, as an] [added: *Keytruda* for the] adjuvant [added: portion of] treatment in patients with certain types of melanoma and [removed: NSCLC, being developed as part of a collaboration with Moderna, Inc.][added: non-small cell lung cancer (NSCLC).]

- MK-1026, nemtabrutinib, [added: is] an [added: investigational] oral, reversible, non-covalent Bruton’s tyrosine kinase (BTK) inhibitor, [added: being evaluated] for [added: the treatment of] hematological malignancies, including chronic lymphocytic leukemia and small lymphocytic [removed: lymphoma;][added: lymphoma.]

- MK-3543, bomedemstat, [added: is] an investigational orally available lysine-specific demethylase 1 inhibitor [added: being evaluated] for [removed: myeloproliferative disorders;][added: the treatment of certain patients with essential thrombocythemia.]

- MK-5684, opevesostat, [added: is] an investigational cytochrome P450 11A1 (CYP11A1) inhibitor [added: being evaluated] for [added: the treatment of certain patients with] metastatic castration-resistant prostate [removed: cancer;][added: cancer.]

- MK-7339, Lynparza, [added: is an oral poly (ADP-ribose) polymerase (PARP) inhibitor being evaluated] in combination with [removed: *Keytruda*,] [added: *Keytruda*] for [removed: non-small-cell] [added: expanded indications in the therapeutic areas of non-small cell] lung and [removed: small-cell] [added: small cell] lung [removed: cancers; and][added: cancers.]

[removed: - MK-7902, Lenvima,] [added: Lenvima is] being developed as part of a collaboration with Eisai Co., Ltd. [removed: (Eisai), in combination with *Keytruda*, for esophageal cancer.][added: (Eisai).]

- MK-2140, zilovertamab vedotin, [added: is] an [added: investigational] ADC targeting receptor tyrosine kinase-like orphan receptor 1 (ROR1) [added: being evaluated] for [added: the treatment of] hematological malignancies, including diffuse large B cell [removed: lymphoma;][added: lymphoma.]

[removed: - MK-2400, ifinatamab deruxtecan, an ADC being evaluated in patients with relapsed SCLC versus chemotherapy,] [added: Ifinatamab deruxtecan is] being developed as part of a collaboration with Daiichi [removed: Sankyo; and][added: Sankyo.]

- MK-2870, sacituzumab tirumotecan, [added: is] an investigational trophoblast cell-surface antigen 2 (TROP2)-directed [removed: ADC,] [added: ADC] being [removed: developed as part of a collaboration with Kelun-Biotech] [added: evaluated] for [added: certain patients with] breast, cervical, endometrial, [removed: gastric] [added: gastric, non-small cell lung,] and [removed: non-small-cell lung] [added: ovarian] cancers.

Additionally, the Company currently has candidates in Phase 3 clinical development in several other therapeutic [removed: areas:][added: areas.]

- [removed: MK-3000,] [added: MK-3000 is] an investigational, potentially first-in-class tetravalent, tri-specific antibody that acts as an agonist of the Wingless-related integration site signaling pathway, [added: which is in clinical development] for the treatment of diabetic macular [removed: edema and neovascular age-related macular degeneration;][added: edema.]

- MK-0616, enlicitide decanoate, [added: is] an [removed: investigational,] [added: investigational] oral proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor [added: being evaluated] for [added: the treatment of] hypercholesterolemia, including in studies evaluating low-density lipoprotein cholesterol reduction and a cardiovascular outcomes [removed: study;][added: study.]

- MK-7240, tulisokibart, [removed: a] [added: is an investigational] humanized monoclonal antibody directed to tumor necrosis factor-like ligand 1A, a [removed: target associated with both intestinal inflammation] [added: central amplifier of inflammatory pathways] and [removed: fibrosis,] [added: fibrotic mechanisms in inflammatory bowel disease, being evaluated] for [added: the treatment of] Crohn’s disease and ulcerative [removed: colitis; and][added: colitis.]

- MK-4482, *Lagevrio*, [added: is an investigational oral antiviral medicine for the treatment of mild to moderate COVID-19 in adults who are at risk for progressing to severe disease,] which is reflected in Phase 3 development in the U.S. as it remains investigational following [added: FDA] Emergency Use Authorization (EUA) in 2021.

Merck’s capital allocation strategy continues to prioritize investments in its business to drive near- and long-term growth, including investing in the Company’s key growth drivers and [removed: expansive] [added: its broad and diverse] pipeline of novel candidates, [removed: each] [added: enabled in part by the benefits] of [removed: which has potential to address important unmet medical needs.][added: the Company’s multiyear optimization initiative.]

Research and development expenses in [removed: 2024] [added: 2025] reflect increased development spending particularly in the therapeutic areas of [removed: oncology, immunology] [added: ophthalmology, oncology] and [removed: cardiometabolic.][added: immunology.]

[removed: In addition, Merck remains committed to its dividend and will continue to] pursue the most compelling external science and technologies through value-enhancing business development transactions.

[removed: ][added: ]

In 2025, Merck successfully advanced its science-led strategy through new product approvals and launches, strong clinical execution, important data readouts, and the addition of novel innovation through business development efforts.

- Entered into an agreement to acquire Cidara Therapeutics, Inc. (Cidara), a biotechnology company developing drug-Fc conjugate therapeutics, including a long-acting antiviral designed to prevent seasonal and pandemic influenza; this transaction closed in January 2026.

- Acquired Verona Pharma plc (Verona Pharma), a biopharmaceutical company focused on respiratory diseases, through which Merck obtained *Ohtuvayre,* a product approved for the maintenance treatment of chronic obstructive pulmonary disease (COPD).

- Closed an exclusive license agreement for MK-7262 (HRS-5346), an investigational oral small molecule Lipoprotein(a) inhibitor from Jiangsu Hengrui Pharmaceuticals Co., Ltd. (Hengrui Pharma).

- Closed an agreement with Dr. Falk Pharma GmbH (Falk) to acquire sole global rights to MK-8690, an investigational anti-CD30 ligand monoclonal antibody.

During 2025, Merck continued its efforts to address unmet medical needs by launching *Enflonsia* in the U.S. for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in neonates (newborns) and infants born during or entering their first RSV season.

Also in 2025, the Company launched *Keytruda Qlex*, which was approved by the U.S. Food and Drug Administration (FDA) for subcutaneous administration across all solid tumor indications for *Keytruda* in the U.S., and the European Commission (EC) approved a new subcutaneous (SC) route of administration and a new pharmaceutical form (solution for injection) of *Keytruda* (to be marketed as *Keytruda SC*) for use across all *Keytruda* indications for adult patients in Europe.

Additionally, in pulmonary arterial hypertension (PAH), the Company launched an expanded indication for *Winrevair* in the U.S. based on the results of the ZENITH trial.

The Company also received numerous other approvals in oncology.

- MK-8591A, doravirine/islatravir, is an investigational, once-daily, oral two-drug regimen for adults with HIV-1 infection that is virologically suppressed on antiretroviral therapy under review by the FDA.

MK-8591A is also under review in Japan.

- MK-7962, *Winrevair*, an activin signaling inhibitor for the treatment of adults with PAH (World Health Organization \[WHO\] Group 1 pulmonary hypertension), is under review by the FDA in connection with a proposed update to the U.S. product label based on the results of the HYPERION trial.

*•*MK-3475, *Keytruda* (pembrolizumab), is an anti-PD-1 (programmed death receptor-1) therapy available for intravenous administration.

MK-3475A, *Keytruda Qlex*, combines pembrolizumab with berahyaluronidase alfa to enhance dispersion and permeability to enable subcutaneous administration.

*Keytruda* and *Keytruda Qlex* each are approved for the treatment of many cancers and continue to be studied in additional Phase 3 trials.

◦*Keytruda* is also under review in the EU and Japan in combination with Pfizer, Inc.’s (Pfizer) and Astellas’ Padcev as neoadjuvant treatment, then continued after radical cystectomy as adjuvant treatment, for patients with MIBC who are ineligible for cisplatin-based chemotherapy.

◦*Keytruda* and *Keytruda Qlex* are under review by the FDA in combination with Gilead Sciences Inc.’s (Gilead) sacituzumab govitecan (Trodelvy) for the first-line treatment of certain patients with unresectable locally advanced or metastatic triple-negative breast cancer (TNBC) whose tumors express programmed death-ligand 1 (PD‑L1).

- MK-6482, *Welireg,* is Merck’s first-in-class oral hypoxia-inducible factor-2 alpha (HIF-2α) inhibitor.

◦*Welireg*, in combination with *Keytruda* or *Keytruda Qlex*, is under priority review by the FDA for the adjuvant treatment of certain patients with clear cell RCC following nephrectomy.

◦*Welireg*, in combination with MK-7902, Lenvima, an orally available multiple receptor tyrosine kinase inhibitor (TKI), is under review by the FDA for the treatment of certain patients with advanced RCC following previous treatment with a PD-1 or PD-L1 inhibitor.

In 2025, the Company announced positive late-stage results from 18 Phase 3 trials and initiated 21 new Phase 3 trials spanning cardiometabolic and respiratory, immunology, infectious diseases, oncology and ophthalmology.

The Company now has approximately 80 Phase 3 studies underway.

Intismeran autogene is being developed as part of a collaboration with Moderna, Inc. (Moderna).

- MK-1084, calderasib, is an investigational oral selective *KRAS* G12C inhibitor being evaluated with or without *Keytruda* or *Keytruda Qlex* for the treatment of certain patients with colorectal and non-small cell lung cancers.

Calderasib is being developed as part of a collaboration with Taiho Pharmaceutical Co. Ltd. and Astex Pharmaceuticals (UK), a wholly owned subsidiary of Otsuka Pharmaceutical Co., Ltd.

- MK-6482, *Welireg*, is being developed for expanded indications in RCC in combination with *Keytruda* and Lenvima, and in other combinations.

Lynparza is being developed as part of a collaboration with AstraZeneca PLC (AstraZeneca).

*•*MK-1022, patritumab deruxtecan, is an investigational human epidermal growth factor receptor 3 (HER3) directed antibody drug conjugate (ADC) being evaluated in certain patients with breast cancer.

Patritumab deruxtecan is being developed as part of a collaboration with Daiichi Sankyo.

- MK-2400, ifinatamab deruxtecan, is an investigational B7-H3 directed ADC being evaluated in certain patients with esophageal, prostate, and small cell lung cancers.

Sacituzumab tirumotecan is being developed as part of a collaboration with Kelun-Biotech.

- MK-5909, raludotatug deruxtecan, is an investigational CDH6 targeting ADC being evaluated in patients with platinum resistant ovarian cancer.

Raludotatug deruxtecan is being developed as part of a collaboration with Daiichi Sankyo.

- V181 is an investigational quadrivalent vaccine for the prevention of dengue disease caused by any of the four dengue virus serotypes (DENV-1, DENV-2, DENV-3, and DENV-4), regardless of prior dengue exposure.

- MK-8591D is an investigational once-weekly, oral combination of Merck’s islatravir, a nucleoside analog leveraging translocation inhibition, and Gilead’s lenacapavir being evaluated for the treatment of HIV-1 infection in virologically suppressed adults (which remains under a partial clinical hold for any studies that would use islatravir doses higher than the doses considered for the revised clinical programs).

- MK-8527 is an investigational once-monthly, oral nucleoside analog leveraging translocation inhibition, for HIV-1 pre-exposure prophylaxis (PrEP).

- MK-1406 (formerly CD388) is an investigational small molecule neuraminidase inhibitor stably conjugated to a proprietary Fc fragment of a human antibody designed to prevent seasonal and pandemic influenza.

MK-1406 was obtained in connection with the January 2026 acquisition of Cidara.

Merck is developing *Lagevrio* as part of a collaboration with Ridgeback Biotherapeutics LP (Ridgeback).

In addition, Merck remains committed to its dividend and will continue to

Merck’s performance during 2024 was driven by continued demand across its innovative portfolio, including for recently launched products, enabled by the operational and commercial execution of its science-led strategy.

The Company maintained its focus on the pursuit of breakthrough science and innovation, making disciplined investments in compelling science to drive long-term value for patients, customers, and shareholders.

Merck advanced its robust early- and late-phase pipeline which includes growing diversity across new therapeutic areas and modalities and completed several promising business development transactions.

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- Closed an exclusive global license to develop, manufacture and commercialize MK-2010 (LM-299), a novel investigational programmed death receptor-1 (PD-1)/vascular endothelial growth factor (VEGF) bispecific antibody from LaNova Medicines Ltd (LaNova).

- Closed an exclusive global license to develop, manufacture and commercialize MK-4082 (HS-10535), an investigational preclinical oral small molecule GLP-1 receptor agonist from Hansoh Pharma (Hansoh).

- Acquired global rights to MK-1045 (formerly CN201), a novel investigational clinical-stage bispecific antibody for the treatment of B-cell associated diseases from Curon Pharmaceutical (Curon).

- Acquired Eyebiotech Limited (EyeBio), a privately held ophthalmology-focused biotechnology company developing candidates for the prevention and treatment of vision loss.

- Acquired Harpoon Therapeutics, Inc. (Harpoon), a clinical-stage immunotherapy company developing a novel class of T-cell engagers designed to harness the power of the body’s immune system to treat patients suffering from cancer and other diseases.

During 2024, Merck continued its efforts to address unmet medical needs by launching new products with significant patient benefit, including the U.S. launches of *Winrevair*, for the treatment of certain adults with pulmonary arterial hypertension (PAH), and *Capvaxive,* for the prevention of invasive pneumococcal disease and pneumococcal pneumonia in adults.

*Winrevair* was also approved in the EU.

The Company received more than 25 regulatory approvals in major markets in 2024, including the *Winrevair* and *Capvaxive* approvals noted above, along with numerous approvals in oncology.

Lynparza, which is being developed in collaboration with AstraZeneca PLC (AstraZeneca), received approval in China for the treatment of certain adult patients with germline *BRCA*\-mutated, human epidermal growth factor receptor 2 (HER2)-negative high-risk early breast cancer.

- MK-1022, patritumab deruxtecan, is a potential first-in-class HER3 directed DXd antibody drug conjugate (ADC), under review by the U.S. Food and Drug Administration (FDA) for the treatment of adult patients with locally advanced or metastatic epidermal growth factor receptor (EGFR)-mutated NSCLC previously treated with two or more systemic therapies.

In June 2024, the FDA issued a complete response letter (CRL) for the Biologics License Application (BLA) due to findings pertaining to an inspection of a third-party manufacturing facility.

The CRL did not identify any issues with the efficacy or safety data submitted.

Patritumab deruxtecan (HER3-DXd) was discovered by Daiichi Sankyo and is

being jointly developed by Daiichi Sankyo and Merck.

Merck is working with Daiichi Sankyo to address FDA feedback.

- MK-6482*, Welireg,* is under review in Japan both for the treatment of adults with VHL disease and for the treatment of certain adults with previously treated advanced renal cell carcinoma (RCC).

*Welireg* is also under priority review in the U.S. for the treatment of certain patients with advanced, unresectable or metastatic pheochromocytoma and paraganglioma.

- V116, *Capvaxive*, a 21-valent pneumococcal conjugate vaccine designed to help prevent invasive pneumococcal disease and pneumococcal pneumonia caused by certain serotypes in adults, is under review in the EU and Japan.

- MK-7962, *Winrevair*, Merck’s novel activin signaling inhibitor, is under review in Japan for the treatment of adult patients with PAH.

Clesrovimab is also under review in the EU.

During 2024, the Company initiated more than 20 Phase 3 studies spanning cardiometabolic, immunology, infectious diseases, oncology, ophthalmology and vaccines.

- MK-3475, *Keytruda*, in the therapeutic areas of hepatocellular, ovarian and small-cell lung cancers;

- MK-3475A, the subcutaneous coformulation of pembrolizumab in combination with hyaluronidase, being evaluated for comparability with intravenous pembrolizumab in metastatic NSCLC; and

- MK-1084, an investigational oral selective *KRAS* G12C inhibitor, in combination with *Keytruda*, for metastatic NSCLC;

*•*MK-1022, patritumab deruxtecan, being developed in collaboration wtih Daiichi Sankyo, for NSCLC as noted above;

- MK-8591A, a once-daily oral combination of doravirine and islatravir, an investigational nucleoside reverse transcriptase translocation inhibitor, for the treatment of HIV-1 infection (which is on partial clinical hold for higher doses of islatravir than those used in current clinical trials);

- MK-8591D, islatravir in combination with lenacapavir for the treatment of HIV-1 infection (which is on partial clinical hold for higher doses of islatravir than those used in current clinical trials), being developed in collaboration with Gilead Sciences Inc.;

In January 2025, the U.S. Department of HHS, through the CMS, announced that *Janumet* and *Janumet* XR would be in included in the second year of the IRA’s Program, with government price setting to become effective on January 1, 2027.

The devaluation of the Argentine peso contributed approximately 2 percentage points of the negative impact of foreign exchange, which was largely offset by inflation-related price increases consistent with practice in that market.

Also contributing to revenue growth were higher sales in the cardiovascular

franchise, largely attributable to the launch of *Winrevair*, higher sales of certain hospital acute care products, particularly *Prevymis*, as well as higher sales of animal health products.

Lower sales in the immunology franchise due to the return of the marketing rights for *Remicade* and *Simponi* in former Merck territories to Johnson & Johnson on October 1, 2024, and lower sales in the vaccines franchise primarily due to *Gardasil/Gardasil 9* also offset sales growth in 2024.

The devaluation of the Argentine peso contributed approximately 3 percentage points of the negative impact of foreign exchange, which was largely offset by inflation-related price increases consistent with practice in that market.

Global sales of *Keytruda* grew 18% in 2024, or 22% excluding the unfavorable effect of foreign exchange.

The negative impact of foreign exchange was primarily due to the devaluation of the Argentine peso, which was largely offset by inflation-related price increases consistent with practice in that market.

| January 2024 | | | FDA approval in combination with chemoradiotherapy for the treatment of patients with FIGO (International Federation of Gynecology and Obstetrics) 2014 Stage III-IVA cervical cancer, based on the KEYNOTE-A18 trial. | | |

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The Company sells these human health pharmaceutical products primarily to drug wholesalers and retailers, hospitals, government [removed: agencies] [added: agencies,] and managed health care providers such as health maintenance organizations, pharmacy benefit managers and other institutions.

| *($ in millions)* | | | [removed: 2024] [added: 2025] | | | | | | [removed: 2023] [added: 2024] | | | | | | [removed: 2022] [added: 2023] | | |

| Total Sales | | | $ | [removed: 64,168] [added: 65,011] | | | | | $ | [removed: 60,115] [added: 64,168] | | | | | $ | [removed: 59,283] [added: 60,115] | |

| Pharmaceutical | | | [removed: 57,400] [added: 58,142] | | | | | | [removed: 53,583] [added: 57,400] | | | | | | [removed: 52,005] [added: 53,583] | | |

| [removed: *Keytruda*] [added: *Keytruda/Keytruda Qlex*] | | | [removed: 29,482] [added: 31,680] | | | | | | [removed: 25,011] [added: 29,482] | | | | | | [removed: 20,937] [added: 25,011] | | |

| *Gardasil/Gardasil* 9 | | | [removed: 8,583] [added: 5,233] | | | | | | [removed: 8,886] [added: 8,583] | | | | | | [removed: 6,897] [added: 8,886] | | |

| *ProQuad/M-M-R* II*/Varivax* | | | [removed: 2,485] [added: 2,451] | | | | | | [removed: 2,368] [added: 2,485] | | | | | | [removed: 2,241] [added: 2,368] | | |

| *Januvia/Janumet* | | | [removed: 2,268] [added: 2,544] | | | | | | [removed: 3,366] [added: 2,268] | | | | | | [removed: 4,513] [added: 3,366] | | |

| *Bridion* | | | [removed: 1,764] [added: 1,841] | | | | | | [removed: 1,842] [added: 1,764] | | | | | | [removed: 1,685] [added: 1,842] | | |

| Alliance revenue - Lynparza*(1)* | | | [removed: 1,311] [added: 1,450] | | | | | | [removed: 1,199] [added: 1,311] | | | | | | [removed: 1,116] [added: 1,199] | | |

| Alliance revenue - Lenvima*(1)* | | | [removed: 1,010] [added: 1,053] | | | | | | [removed: 960] [added: 1,010] | | | | | | [removed: 876] [added: 960] | | |

| *Vaxneuvance* | | | [removed: 808] [added: 825] | | | | | | [removed: 665] [added: 808] | | | | | | [removed: 170] [added: 665] | | |

| *Prevymis* | | | [removed: 785] [added: 978] | | | | | | [removed: 605] [added: 785] | | | | | | [removed: 428] [added: 605] | | |

| Animal Health | | | [removed: 5,877] [added: 6,354] | | | | | | [removed: 5,625] [added: 5,877] | | | | | | [removed: 5,550] [added: 5,625] | | |

| Livestock | | | [removed: 3,462] [added: 3,896] | | | | | | [removed: 3,337] [added: 3,462] | | | | | | [removed: 3,300] [added: 3,337] | | |

| Companion Animal | | | [removed: 2,415] [added: 2,458] | | | | | | [removed: 2,288] [added: 2,415] | | | | | | [removed: 2,250] [added: 2,288] | | |

| Other Revenues*(2)* | | | [removed: 891] [added: 515] | | | | | | [removed: 907] [added: 891] | | | | | | [removed: 1,728] [added: 907] | | |

*Keytruda* [added: (pembrolizumab)] is an anti-PD-1 (programmed death receptor-1) therapy [added: available for intravenous administration] that has been approved as monotherapy for the treatment of certain patients with cervical cancer, classical Hodgkin lymphoma (cHL), cutaneous squamous cell carcinoma, esophageal or gastroesophageal junction (GEJ) carcinoma, head and neck squamous cell carcinoma (HNSCC), hepatocellular carcinoma (HCC), melanoma, Merkel cell carcinoma, microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) solid tumors (including MSI-H/dMMR colorectal cancer and endometrial carcinoma), [removed: non-small-cell] [added: non-small cell] lung cancer (NSCLC), primary mediastinal large B-cell lymphoma (PMBCL), tumor mutational burden-high (TMB-H) solid tumors, and urothelial cancer including non-muscle invasive bladder cancer.

Additionally, [added: in perioperative settings,] *Keytruda* is approved for patients with certain types of resectable NSCLC in combination with chemotherapy as neoadjuvant treatment, and then continued as a single agent as adjuvant treatment after [removed: surgery.][added: surgery; for certain patients with high-risk early stage triple-negative breast cancer (TNBC) in combination with chemotherapy as neoadjuvant treatment, and then continued as a single agent as adjuvant treatment after surgery; for certain patients with resectable locally advanced HNSCC as a single agent as neoadjuvant treatment, continued as adjuvant treatment in combination with radiotherapy with or without cisplatin chemotherapy and then as a single agent; and for certain patients with muscle invasive bladder cancer (MIBC), in combination with enfortumab vedotin, as neoadjuvant treatment and then continued after cystectomy as adjuvant treatment.]

In addition, *Keytruda* is approved in combination with chemotherapy for the treatment of certain patients with advanced NSCLC, advanced malignant pleural mesothelioma, HNSCC, advanced biliary tract cancer, advanced esophageal cancer, advanced TNBC, and advanced or recurrent endometrial carcinoma; in combination with chemotherapy with or without bevacizumab, and in combination with chemoradiotherapy, for the treatment of certain patients with advanced cervical cancer; in combination with trastuzumab and chemotherapy for the treatment of certain patients with advanced human epidermal growth factor receptor 2 (HER2)-positive gastric or GEJ [removed: adenocarcinoma with programmed death-ligand 1 (PD-L1) (CPS ≥1),] [added: adenocarcinoma,] and in combination with chemotherapy for the treatment of certain patients with advanced HER2-negative gastric or GEJ adenocarcinoma; in combination with axitinib for the treatment of certain patients with advanced RCC; in combination with Lenvima (lenvatinib) for the treatment of certain patients with advanced RCC or advanced endometrial carcinoma; [removed: and] in combination with enfortumab vedotin for certain patients with locally advanced or metastatic urothelial [added: cancer; and in combination with chemotherapy with or without bevacizumab for certain patients with platinum-resistant ovarian] cancer.

*Welireg* (belzutifan) is a medication for the treatment of adult patients with certain von Hippel-Lindau (VHL) disease-associated tumors not requiring immediate surgery, [removed: and] for the treatment of adult patients with advanced RCC following a PD-1 or [removed: PD-L1] [added: programmed death-ligand 1 (PD-L1)] inhibitor and a vascular endothelial growth factor tyrosine kinase [removed: inhibitor.][added: inhibitor (TKI) and for treatment of adult and pediatric patients 12 years and older with certain types of pheochromocytoma or paraganglioma.]

In addition, the Company recognizes alliance revenue related to sales of Lynparza (olaparib), an oral poly (ADP-ribose) polymerase (PARP) inhibitor, for certain types of advanced or recurrent ovarian, early or metastatic breast, metastatic pancreatic, and metastatic castration-resistant prostate cancers; alliance revenue related to sales of Lenvima, an oral receptor [removed: tyrosine kinase inhibitor,] [added: TKI,] for certain types of thyroid cancer, RCC, HCC, in combination with everolimus for certain patients with advanced RCC, and in combination with *Keytruda* for certain patients with advanced endometrial carcinoma or advanced RCC; and alliance revenue related to Reblozyl (luspatercept-aamt) for the treatment of certain types of anemia.

*Gardasil* (Human Papillomavirus Quadrivalent \[Types 6, 11, 16 and 18\] Vaccine, Recombinant)/*Gardasil* 9 (Human Papillomavirus 9-valent Vaccine, Recombinant), vaccines to help prevent certain cancers and diseases caused by certain types of human papillomavirus (HPV); *ProQuad* (Measles, Mumps, Rubella and Varicella Virus Vaccine Live), a pediatric combination vaccine to help protect against measles, mumps, rubella and varicella; *M−M−R* II (Measles, Mumps and Rubella Virus Vaccine Live), a vaccine to help prevent measles, mumps and rubella; *Varivax* [removed: (Varicella Virus Vaccine Live), a vaccine to help prevent chickenpox (varicella); *Vaxneuvance* (Pneumococcal 15-valent Conjugate Vaccine), a vaccine to help prevent invasive pneumococcal disease in individuals 6 weeks of age and older; *RotaTeq* (Rotavirus Vaccine, Live Oral, Pentavalent), a vaccine to help protect against rotavirus gastroenteritis in infants and children; and *Pneumovax* 23 (pneumococcal vaccine polyvalent), a vaccine to help prevent pneumococcal disease.]

*Bridion* (sugammadex), a medication for the reversal of two types of neuromuscular blocking agents used during surgery; *Prevymis* (letermovir) for the prophylaxis of cytomegalovirus (CMV) infection and disease, or of CMV disease, in certain high risk adult and pediatric recipients of an allogeneic hematopoietic stem cell transplant or of a kidney transplant, respectively; [removed: *Dificid* (fidaxomicin) for the treatment of *C. difficile*\-associated diarrhea;] *Zerbaxa* (ceftolozane and tazobactam) for injection, a combination antibacterial and beta-lactamase inhibitor for the treatment of certain bacterial infections; and [removed: *Noxafil* (posaconazole), an antifungal agent] [added: *Dificid* (fidaxomicin)] for the [removed: prevention] [added: treatment] of [removed: certain invasive fungal infections.][added: *C. difficile*\-associated diarrhea.]

[added: MK-7962,] *Winrevair* (sotatercept-csrk), an activin signaling inhibitor [removed: indicated] for the treatment of adults with [removed: pulmonary arterial hypertension (PAH) (World Health Organization \[WHO\]] [added: PAH (WHO] Group [removed: 1)] [added: 1 pulmonary hypertension), is under review by the FDA in connection with a proposed update] to [removed: increase exercise capacity,][added: the U.S. product label based on the results of the Phase 3 HYPERION trial.]

[added: *Winrevair* (sotatercept-csrk), an activin signaling inhibitor indicated for the treatment of adults with pulmonary arterial hypertension (PAH, Group 1 pulmonary hypertension) to] improve [removed: WHO] [added: exercise capacity and World Health Organization (WHO)] functional class [added: (FC),] and reduce the risk of clinical worsening [removed: events;] [added: events including hospitalization for PAH, lung transplantation and death;] Adempas (riociguat), a cardiovascular drug for the treatment of chronic thromboembolic pulmonary hypertension or [removed: pulmonary arterial hypertension] [added: PAH] in certain patients; [removed: and] Verquvo (vericiguat), a medicine to reduce the risk of cardiovascular death and heart failure hospitalization following a hospitalization for heart failure or need for outpatient intravenous diuretics in certain adults with symptomatic chronic heart failure and reduced ejection [removed: fraction.][added: fraction; and *Ohtuvayre* (ensifentrine), an inhaled PDE3/4 inhibitor indicated for the maintenance treatment of chronic obstructive pulmonary disease (COPD) in adults.]

*Lagevrio* (molnupiravir), an investigational oral antiviral COVID-19 medicine available in the U.S. under Emergency Use [removed: Authorization (EUA); *Isentress/Isentress HD*] [added: Authorization; *Isentress/Isentress* HD] (raltegravir), [removed: an HIV] [added: a human immunodeficiency virus (HIV)] integrase inhibitor for use in combination with other antiretroviral agents for the treatment of HIV-1 infection; *Delstrigo* (doravirine/lamivudine/tenofovir disoproxil fumarate), a complete regimen for the treatment of HIV-1 infection in adult patients with no prior antiretroviral treatment history or to replace the current antiretroviral regime in certain patients who are virologically suppressed on a stable antiretroviral regimen; and *Pifeltro* (doravirine), a non-nucleoside reverse transcriptase inhibitor for use in combination with other antiretroviral agents for the treatment of HIV-1 infection in adult patients with no prior antiretroviral treatment history or to replace the current antiretroviral regime in certain patients who are virologically suppressed on a stable antiretroviral regimen.

*Nuflor* (Florfenicol) antibiotic range for use in cattle and swine; *Bovilis*/*Vista* vaccine lines for infectious diseases in cattle, including *Bovilis Cryptium* for protection against Cryptosporidium parvum; *Banamine* (Flunixin meglumine) bovine and swine anti-inflammatory; *Estrumate* (cloprostenol sodium) for the treatment of fertility disorders in cattle; *Matrix* (altrenogest) fertility management for swine; *Resflor* (florfenicol and flunixin meglumine)*,* a combination broad-spectrum antibiotic and non-steroidal anti-inflammatory drug for bovine respiratory disease; *Zuprevo* (tildipirosin) for bovine respiratory disease; *Revalor* (trenbolone acetate and estradiol) to improve production efficiencies in beef cattle; *Safe-Guard* (fenbendazole) de-wormer for cattle; *M+Pac* (Mycoplasma Hyopneumoniae Bacterin) swine pneumonia vaccine; *Porcilis* (Lawsonia intracellularis baterin) and *Circumvent* (Porcine Circovirus Vaccine, Type 2, Killed Baculovirus Vector) vaccine lines for infectious diseases in swine; *Nobilis*/*Innovax* (Live [removed: Marek’s Disease Vector)*,* vaccine lines for poultry; *Paracox* and *Coccivac* coccidiosis vaccines; *Exzolt*, a systemic treatment for poultry red mite infestations; *Slice* (emamectin benzoate) parasiticide and *Imvixa* (lufenuron) for sea lice control in salmon; *Clynav* vaccine for protection against pancreas disease in salmon; *Aquavac* (Avirulent Live Culture)/*Norvax* vaccines against bacterial and viral disease in fish; *Aquaflor* (florfenicol) antibiotic for farm-raised fish; *Flexolt* (fluralaner) against lice in sheep; and *Allflex Livestock Intelligence* solutions for animal identification, monitoring and traceability.]

*Bravecto*, a line of oral, topical and injectable parasitic control products, including the original *Bravecto* (fluralaner) products for dogs and cats that last up to 12 weeks; *Bravecto* (fluralaner) *One-Month*, a monthly product for dogs, *Bravecto* (fluralaner) *Injectable/Quantum*, an injectable product for dogs that lasts up to one-year, [added: *Bravecto TriUNO* (fluralaner/moxidectin/pyrantel), a one month dog product that covers internal] and [added: external parasites, and] *Bravecto Plus* (fluralaner/moxidectin), a two-month product for cats; *Sentinel,* a line of oral parasitic products for dogs including *Sentinel Spectrum* (milbemycin oxime, lufenuron, and praziquantel) and *Sentinel Flavor Tabs* (milbemycin oxime, lufenuron); [added: *Numelvi* (atinvicitinib), a once daily second-generation Janus kinase inhibitor for the treatment of pruritus associated with allergic dermatitis;] *Optimmune* (cyclosporine), an ophthalmic ointment; *Nobivac* vaccine lines for flexible dog and cat vaccination, including *Nobivac NXT* for canine flu and feline leukemia virus; [removed: *GilvetMab*,] [added: Gilvetmab,] an immune checkpoint inhibitor monoclonal antibody conditionally licensed for melanoma and mastocytoma tumors; *Otomax* (gentamicin sulfate, USP; Betamethasone valerate USP; and Clotrimazole USP ointment)/*Mometamax* (gentamicin sulfate, USP, Mometasone Furoate Monohydrate and Clotrimazole, USP, Otic Suspension)/*Mometamax Ultra* (gentamicin sulfate, mometasone furoate monohydrate and posaconazole suspension)/*Posatex* (orbifloxacin, mometasone furoate monohydrate and posaconazole, suspension) ear ointments for acute and chronic otitis; *Caninsulin*/*Vetsulin* (porcine insulin zinc suspension) diabetes mellitus treatment for dogs and cats; *Panacur* (fenbendazole)/*Safeguard* (fenbendazole) broad-spectrum anthelmintic (de-wormer) for use in many animals; *Regumate* (altrenogest) fertility management for horses; *Prestige* vaccine line for horses; *Scalibor* (Deltamethrin)*/Exspot* for protecting against bites [added: from fleas, ticks, mosquitoes and sandflies; and *Sure Petcare* products for companion animal identification and well-being, including the microchip and pet recovery system *Home Again*.]

Set forth below is a summary of significant product approvals received by the Company in [removed: 2024] [added: 2025] and, to date, in [removed: 2025.][added: 2026.]

| May [removed: 2024] [added: 2025] | | | Japan’s Ministry of Health, Labor and Welfare (MHLW) approval in combination with [removed: fluoropyrimidine] [added: trastuzumab] and [removed: platinum-containing] chemotherapy for the first-line treatment of patients with [removed: locally] [added: unresectable,] advanced [removed: unresectable] or [removed: metastatic] [added: recurrent HER2-positive] gastric or GEJ adenocarcinoma, based on the [removed: KEYNOTE-859] [added: KEYNOTE-811] trial. | | | | | |

| May [removed: 2024] [added: 2025] | | | Japan’s MHLW approval in combination with [removed: standard of care chemotherapy (gemcitabine] [added: pemetrexed] and [removed: cisplatin)] [added: platinum chemotherapy] for [removed: the treatment of patients with locally] [added: unresectable,] advanced [removed: unresectable] or [added: recurrent] metastatic [removed: biliary tract cancer,] [added: malignant pleural mesothelioma,] based on the [removed: KEYNOTE-966] [added: IND.227/KEYNOTE-483] trial. | | | | | |

| [removed: September 2024] [added: *Keytruda*] | | | [removed: EC] [added: January 2025 | | | China’s National Medical Products Administration (NMPA)] approval in combination with [removed: Padcev (enfortumab vedotin-ejfv),] [added: enfortumab vedotin,] an antibody-drug [removed: conjugate,] [added: conjugate (ADC),] for the [removed: first-line] treatment of [removed: unresectable] [added: adults with locally advanced] or metastatic urothelial [removed: carcinoma in adults,] [added: carcinoma,] based on the KEYNOTE-A39 trial that was conducted in collaboration with Seagen (now Pfizer [removed: Inc.)] [added: Inc., Pfizer)] and Astellas. | | | [removed: | | |]

| [removed: September 2024] [added: April 2025] | | | [removed: FDA] [added: European Commission (EC)] approval in combination with pemetrexed and platinum chemotherapy for the first-line treatment of adult patients with unresectable [removed: advanced or metastatic] [added: non epithelioid] malignant pleural mesothelioma, based on the IND.227/KEYNOTE-483 trial. | | | | | |

| [removed: November 2024] [added: February 2026] | | | Japan’s MHLW approval [removed: in combination with chemoradiotherapy as treatment] for [removed: patients with] [added: neoadjuvant and adjuvant treatment of] locally advanced [removed: cervical cancer,] [added: HNSCC,] based on the [removed: KEYNOTE-A18] [added: KEYNOTE-689] trial. | | | | | |

| *Capvaxive* | | | [removed: June 2024] [added: March 2025] | | | [removed: FDA] [added: EC] approval for the prevention of invasive pneumococcal disease and pneumococcal pneumonia caused by certain serotypes in individuals 18 years of age and older. | | |

| [removed: *Gardasil*] [added: *Gardasil/Gardasil* 9] | | | January 2025 | | | China’s NMPA approval [added: of *Gardasil*] for use in males 9-26 years of age to help prevent certain HPV-related cancers and diseases. | | |

| [removed: *Lynparza(1)*] [added: Lynparza*(2)*] | | | January 2025 | | | China’s NMPA approval for the adjuvant treatment of adult patients with deleterious or suspected deleterious germline *BRCA*\-mutated, HER2-negative high-risk early breast cancer who have been previously treated with neoadjuvant or adjuvant chemotherapy, based on the OlympiA trial. | | |

| *Welireg* | | | [removed: November 2024] [added: February 2025] | | | [removed: China’s NMPA] [added: EC conditional] approval [added: as monotherapy] for the treatment of adult patients with VHL disease who require therapy for [removed: associated] [added: associated, localized] RCC, central nervous system [removed: hemangioblastomas] [added: hemangioblastomas,] or pancreatic neuroendocrine [removed: tumors.] [added: tumors, and for whom localized procedures are unsuitable, based on the LITESPARK-004 trial.] | | |

| February 2025 | | | EC conditional approval [removed: as monotherapy both] for the treatment of adult patients with [removed: VHL disease who require therapy for associated, localized RCC, central nervous system hemangioblastomas, or pancreatic neuroendocrine tumors, and for whom localized procedures are unsuitable, and for the treatment of adult patients with] advanced clear cell RCC that progressed following two or more lines of therapy that included a PD-1 or PD-L1 inhibitor and at least two [removed: VEGF] [added: vascular endothelial growth factor] targeted [removed: therapies. The EC approval of these two indications is] [added: therapies,] based on [removed: results from] the [removed: LITESPARK-004 and] LITESPARK-005 [removed: trials.] [added: trial.] | | | | | |

| *Winrevair* | | | 1,443 | | | | | | 419 | | | | | | — | | |

| *Capvaxive* | | | 759 | | | | | | 97 | | | | | | — | | |

| *Welireg* | | | 716 | | | | | | 509 | | | | | | 218 | | |

*Keytruda Qlex* (pembrolizumab and berahyaluronidase alfa-pmph) is a subcutaneously-administered fixed combination of pembrolizumab, an anti-PD-1 therapy, and berahyaluronidase alfa, which enhances dispersion and permeability to enable subcutaneous administration of pembrolizumab.

*Keytruda Qlex* is approved in the U.S. in solid tumor indications approved for *Keytruda*.

In some markets, it is approved as a new subcutaneous route of administration and new pharmaceutical form of *Keytruda* and is marketed as *Keytruda SC*.

(Varicella Virus Vaccine Live), a vaccine to help prevent chickenpox (varicella); *Vaxneuvance* (Pneumococcal 15-valent Conjugate Vaccine), a vaccine to help prevent invasive pneumococcal disease in individuals 6 weeks of age and older; *RotaTeq* (Rotavirus Vaccine, Live Oral, Pentavalent), a vaccine to help protect against rotavirus gastroenteritis in infants and children; *Capvaxive* (Pneumococcal 21-valent Conjugate Vaccine), a vaccine to help prevent invasive pneumococcal disease and pneumococcal pneumonia in adults; *Enflonsia* (clesrovimab-cfor), a long acting monoclonal antibody for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in neonates and infants who are born during or entering their first RSV season; and *Pneumovax* 23 (pneumococcal vaccine polyvalent), a vaccine to help prevent pneumococcal disease.

Cardiometabolic and Respiratory

Marek’s Disease Vector)*,* vaccine lines for poultry; *Paracox* and *Coccivac* coccidiosis vaccines; *Exzolt* (fluralaner), a systemic treatment for poultry red mite and northern foul mite infestations; *Exzolt 5%* (fluralaner), for treatment and prevention of ticks, lice, horn flies and New World Screwworm on cattle; *Slice* (emamectin benzoate) parasiticide and *Imvixa* (lufenuron) for sea lice control in salmon; *Clynav* vaccine for protection against pancreas disease in salmon; *Aquavac* (Avirulent Live Culture)/*Norvax* vaccines against bacterial and viral disease in fish; *Aquaflor* (florfenicol) antibiotic for farm-raised fish; *Flexolt* (fluralaner) against lice in sheep; and *Allflex Livestock Intelligence* solutions for animal identification, monitoring and traceability.

| June 2025 | | | U.S. Food and Drug Administration (FDA) approval for the treatment of adult patients with resectable locally advanced HNSCC whose tumors express PD-L1 Combined Positive Score (CPS) ≥ 1 as determined by an FDA-approved test, as a single agent as neoadjuvant treatment, continued as adjuvant treatment in combination with radiotherapy with or without cisplatin and then as a single agent, based on the KEYNOTE-689 trial. | | | | | |

| *Keytruda* | | | June 2025 | | | China’s NMPA approval of *Keytruda* plus Lenvima in combination with transarterial chemoembolization for the treatment of patients with unresectable, non-metastatic HCC, based on the LEAP-012 clinical trial. | | |

| October 2025 | | | EC approval as monotherapy for the treatment of resectable locally advanced HNSCC as neoadjuvant treatment, continued as adjuvant treatment in combination with radiation therapy with or without concomitant cisplatin and then as monotherapy in adults whose tumors express PD-L1 with a CPS ≥ 1, based on the KEYNOTE-689 trial. | | | | | |

| November 2025 | | | FDA approval in combination with Padcev (enfortumab vedotin-ejfv) as neoadjuvant treatment and then continued after cystectomy as adjuvant treatment, for the treatment of adult patients with MIBC who are ineligible for cisplatin-based chemotherapy, based on the KEYNOTE-905 trial conducted in collaboration with Pfizer and Astellas. | | | | | |

| February 2026 | | | China’s NMPA approval for the first-line treatment of certain patients with primary advanced or recurrent endometrial cancer, based on the KEYNOTE-868 (NRG-GY018) trial. | | | | | |

| February 2026 | | | FDA approval in combination with paclitaxel, with or without bevacizumab, for the treatment of adult patients with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal carcinoma whose tumors express PD-L1 (CPS ≥ 1) as determined by an FDA-authorized test, and who have received one or two prior systemic treatment regimens, based on the KEYNOTE-B96 trial. | | | | | |

| *Keytruda Qlex(1)* | | | September 2025 | | | FDA approval across most adult solid tumor indications for *Keytruda.* | | |

| October 2025 | | | FDA approval for the treatment of adult patients with resectable locally advanced HNSCC whose tumors express PD-L1 CPS ≥ 1 as determined by an FDA-approved test, as a single agent as neoadjuvant treatment, continued as adjuvant treatment in combination with radiotherapy with or without cisplatin and then as a single agent, based on the KEYNOTE-689 trial. | | | | | |

| November 2025 | | | EC approval of new subcutaneous route of administration and a new pharmaceutical form of *Keytruda* for all adult indications approved in the European Union (to be marketed as *Keytruda SC*). | | | | | |

| November 2025 | | | FDA approval in combination with Padcev as neoadjuvant treatment and then continued after cystectomy as adjuvant treatment, for the treatment of adult patients with MIBC who are ineligible for cisplatin-based chemotherapy, based on the KEYNOTE-905 trial conducted in collaboration with Pfizer and Astellas. | | | | | |

| February 2026 | | | FDA approval in combination with paclitaxel, with or without bevacizumab, for the treatment of adult patients with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal carcinoma whose tumors express PD-L1 (CPS ≥ 1) as determined by an FDA-authorized test, and who have received one or two prior systemic treatment regimens, based on the KEYNOTE-B96 trial. | | | | | |

| *Enflonsia* | | | June 2025 | | | FDA approval for the prevention of RSV lower respiratory tract disease in neonates (newborns) and infants who are born during or entering their first RSV season | | |

| April 2025 | | | China’s NMPA approval of *Gardasil* 9 for use in males 16-26 years of age to help prevent certain HPV-related cancers and diseases. | | | | | |

| *Gardasil/Gardasil* 9 | | | August 2025 | | | Japan’s MHLW approval of nine-valent HPV vaccine for use in males nine years of age and older (marketed as *Silgard* 9). | | |

| June 2025 | | | Japan’s MHLW approval as monotherapy for the treatment of adult patients with VHL disease-associated tumors, based on the LITESPARK-004 trial. | | | | | |

| June 2025 | | | Japan’s MHLW approval for the treatment of adults with radically unresectable or metastatic RCC that has progressed after chemotherapy, based on the LITESPARK-005 trial. | | | | | |

| *Winrevair* | | | June 2025 | | | Japan’s MHLW approval for the treatment of adults with PAH, based on the STELLAR trial (marketed as *Airwin*). | | |

| *Bravecto Quantum* | | | July 2025 | | | FDA approval for flea and tick treatment and protection in dogs using a once-yearly injectable form of *Bravecto*. | | |

| *Numelvi* | | | July 2025 | | | EC approval of tablets for dogs for the treatment of pruritus associated with allergic dermatitis including atopic dermatitis and treatment of clinical manifestations of atopic dermatitis. | | |

*(1)* Keytruda Qlex *is available in some markets as* Keytruda SC*.*

In May 2025, the U.S. presidential administration issued an executive order intended to encourage or impose the use of “most-favored-nation” pricing to tie U.S. prescription drug prices to prices in selected comparably developed nations.

In July 2025, the Company and other pharmaceutical companies received letters from the U.S. presidential administration with a request to agree to the administration’s “most-favored-nation” drug pricing goals by September 29, 2025.

Further to the letter received from the administration, on December 19, 2025, the Company announced that it had entered into a three-year agreement (the MFN Agreement) with the U.S government that

addressed the four policy goals of the administration’s July letter.

Included within the MFN Agreement is an obligation by the Company to provide key products through a direct-to-patient program at affordable prices for eligible patients in the U.S. This will initially include *Januvia*, *Janumet* and *Janumet XR*, and will be expanded in the future to include enlicitide decanoate pending FDA approval.

The Company also agreed to offer its existing medicines at discounted prices to Medicaid, excluding certain products.

The Company has also agreed that products launched during the term of the MFN Agreement (with certain exceptions) will be subject to “most-favored-nation” pricing in reference to prices for such products in a specified group of countries (MFN Countries).

Finally, the Company agreed to repatriate and share with the Federal government a portion of foreign revenue received by the Company as a result of the government’s successful trade policy efforts.

Additionally, the Company reached an agreement with the U.S. Department of Commerce to delay Section 232 tariffs for three years, enabling the Company to make investments in the U.S. to reshore manufacturing for American patients.

In September 2025, the Advisory Committee on Immunization Practices (ACIP) of the U.S. Centers for Disease Control and Prevention (CDC) voted to recommend that children under the age of four years receive protection from chickenpox (varicella) as a standalone immunization rather than in combination with measles, mumps, and rubella (MMR) vaccination, eliminating a previous shared clinical decision-making recommendation that allowed parents to choose combined MMR and varicella vaccine (MMRV) first-dose administration.

The ACIP also voted to align the Vaccines for Children (VFC) program with this change.

| *Lagevrio* | | | 964 | | | | | | 1,428 | | | | | | 5,684 | | |

| *RotaTeq* | | | 711 | | | | | | 769 | | | | | | 783 | | |

[Table of Content](#i783cf867b028427ba2fa2dcfd656c4d4_7)[s](#i783cf867b028427ba2fa2dcfd656c4d4_7)

*Keytruda* is also approved for certain patients with high-risk early stage triple-negative breast cancer (TNBC) in combination with chemotherapy as neoadjuvant treatment, and then continued as a single agent as adjuvant treatment after surgery.

Cardiovascular

from fleas, ticks, mosquitoes and sandflies; and *Sure Petcare* products for companion animal identification and well-being, including the microchip and pet recovery system *Home Again*.

| *Keytruda* | | | January 2024 | | | U.S. Food and Drug Administration (FDA) approval in combination with chemoradiotherapy for the treatment of patients with FIGO (International Federation of Gynecology and Obstetrics) 2014 Stage III-IVA cervical cancer, based on the KEYNOTE-A18 trial. | | |

| January 2024 | | | FDA full approval for the treatment of patients with HCC secondary to hepatitis B who have received prior systemic therapy other than a PD-1/PD-L1 containing regimen. The conversion from an accelerated to full (regular) approval is based on the KEYNOTE-394 trial. | | | | | |

| February 2024 | | | China’s National Medical Products Administration (NMPA) approval in combination with gemcitabine and cisplatin for the first-line treatment of patients with locally advanced or metastatic biliary tract carcinoma, based on the KEYNOTE-966 trial. | | | | | |

| March 2024 | | | European Commission (EC) approval in combination with platinum-containing chemotherapy as neoadjuvant treatment, and then continued as monotherapy as adjuvant treatment, for resectable NSCLC at high risk of recurrence in adults, based on the KEYNOTE-671 trial. | | | | | |

| June 2024 | | | FDA approval in combination with carboplatin and paclitaxel, followed by *Keytruda* as a single agent, for the treatment of adult patients with primary advanced or recurrent endometrial carcinoma, based on the KEYNOTE-868 trial. | | | | | |

| June 2024 | | | China’s NMPA approval in combination with trastuzumab, fluoropyrimidine and platinum-containing chemotherapy for the first-line treatment of patients with locally advanced unresectable or metastatic HER2 positive gastric or GEJ adenocarcinoma whose tumors express PD-L1 as determined by a fully validated test, based on the KEYNOTE-811 trial. | | | | | |

| September 2024 | | | Japan’s MHLW approval in combination with chemotherapy as a neoadjuvant treatment, then continued as monotherapy as an adjuvant treatment for patients with NSCLC, based on the KEYNOTE-671 trial. | | | | | |

| *Keytruda* | | | September 2024 | | | Japan’s MHLW approval in combination with Padcev for the first-line treatment of patients with radically unresectable urothelial carcinoma, based on the KEYNOTE-A39 trial. | | |

| September 2024 | | | Japan’s MHLW approval as monotherapy in patients with radically unresectable urothelial carcinoma who are not eligible for any platinum-containing chemotherapy, based on the KEYNOTE-052 trial. | | | | | |

| September 2024 | | | China’s NMPA approval for the first-line treatment of adult patients with unresectable or metastatic melanoma, and conversion from conditional to full approval for the second-line treatment of adult patients with unresectable or metastatic melanoma following failure of one prior line of therapy, based on the LEAP-003 trial. | | | | | |

| October 2024 | | | EC approval in combination with chemoradiotherapy for the treatment of FIGO 2014 Stage III-IVA locally advanced cervical cancer in adults who have not received prior definitive therapy, based on the KEYNOTE-A18 trial. | | | | | |

| October 2024 | | | EC approval in combination with carboplatin and paclitaxel followed by *Keytruda* as a single agent for the first-line treatment of primary advanced or recurrent endometrial carcinoma in adults who are candidates for systemic therapy, based on the KEYNOTE-868 trial. | | | | | |

| December 2024 | | | Japan’s MHLW approval in combination with carboplatin and paclitaxel as treatment for adult patients with advanced or recurrent endometrial carcinoma, based on the KEYNOTE-868 trial. | | | | | |

| December 2024 | | | China’s NMPA approval in combination with platinum-containing chemotherapy as neoadjuvant treatment and then continued as monotherapy as adjuvant treatment after surgery for patients with resectable stage II, IIIA, or IIIB NSCLC, based on the KEYNOTE-671 trial. | | | | | |

| December 2024 | | | China’s NMPA approval in combination with chemoradiotherapy for the treatment of patients with FIGO 2014 Stage III-IVA cervical cancer, based on the KEYNOTE-A18 trial. | | | | | |

| January 2025 | | | China’s NMPA approval in combination with Padcev for adult patients with locally advanced or metastatic urothelial cancer, based on the KEYNOTE-A39 trial. | | | | | |

| *Bravecto* | | | January 2024 | | | EC approval of injectable formulation for dogs for the persistent killing of fleas and ticks for 12 months after treatment. | | |

Furthermore,

which it is conducted.

In addition, if a Merck product has the same medical action or composition of another product that is subject to market expansion re-pricing, the Merck product could also be subject to re-pricing unless it meets exception criteria.

The Company’s business in China has grown in the past few years, and the importance of China to the Company’s overall pharmaceutical and vaccines business has increased accordingly.

and patient levels.

The Company is subject to a significant number of privacy and data protection laws and regulations globally, many of which place restrictions on the Company’s ability to collect, transfer, access and use personal data across its business.

There has been increased attention to privacy and data protection issues in both developed and emerging markets with the potential to affect directly the Company’s business, including the EU General Data Protection Regulation (GDPR), which imposes penalties of up to 4% of global revenue.

The GDPR and related implementing laws in individual EU Member States govern the collection and use of personal health data and other personal data in the EU.

The GDPR increased responsibility and liability in relation to personal data that the Company processes.

It also imposes a number of strict obligations and restrictions on the ability to process (which includes collection, analysis and transfer of) personal data, including health data from clinical trials and adverse event reporting.

The GDPR also includes requirements relating to the consent of the individuals to whom the personal data relates, the information provided to the individuals prior to processing their personal data or personal health data, notification of data processing obligations to the national data protection authorities, and the security and confidentiality of the personal data.

Further, the GDPR prohibits the transfer of personal data to countries outside of the EU that are not considered by the EC to provide an adequate level of data protection, including to the U.S., except if the data controller meets very specific requirements.

Following the *Schrems II* decision of the Court of Justice of the EU in 2020, uncertainty has existed as to the permissibility of international data transfers under the GDPR.

In light of the implications of this decision, the Company may face difficulties regarding the transfer of personal data from the EU to third countries.

Since then, the Company entered into the EU-approved Standard Contractual Clauses with its vendors, suppliers, collaboration partners and clinical trial sites in order to facilitate the lawful transfer of personal data from the EU to the U.S. In addition, former President Biden issued Executive Order 14086 in October 2022 to address the data privacy concerns raised in the *Schrems II* decision through introducing, among other measures, further safeguards and oversight of personal data collection by U.S. signals intelligence activities and providing individuals with a redress mechanism in the U.S. for their data protection concerns.

Further certainty for the international transfer of personal data from the EU via the EU-U.S. Data Privacy Framework (successor to the invalidated EU-U.S. Privacy Shield) came about by way of a new EU Adequacy Decision, issued by the EC in July 2023.

However, the new Adequacy Decision has already been contested by privacy advocates and is subject to legal review.

As filed with the Securities and Exchange Commission on February [removed: 25, 2025][added: 24, 2026]

For the Fiscal Year Ended December 31, [removed: 2024][added: 2025]

[removed: ][added: ]

Number of shares of Common Stock ($0.50 par value) outstanding as of January 31, [removed: 2025: 2,526,036,240.][added: 2026: 2,472,392,003.]

Aggregate market value of Common Stock ($0.50 par value) held by non-affiliates on June [removed: 28, 2024] [added: 30, 2025] based on the closing price on June [removed: 28, 2024,] [added: 30, 2025,] the last business day of the registrant’s most recently completed second fiscal quarter: approximately [removed: $313,799,000,000.][added: $198,051,000,000.]

| Proxy Statement for the Annual Meeting of Shareholders to be held May [removed: 27, 2025,] [added: 26, 2026,] to be filed with the Securities and Exchange Commission within 120 days after the close of the fiscal year covered by this report | | | | | | Part III | | |

| Item 1. | | | [removed: [Business](#i783cf867b028427ba2fa2dcfd656c4d4_13)] [added: [Business](#i8a76267127a74bd7861180372b8f2b53_13)] | | | | | | [removed: [1](#i783cf867b028427ba2fa2dcfd656c4d4_13)] [added: [1](#i8a76267127a74bd7861180372b8f2b53_13)] | | |

| Item 1A. | | | [Risk [removed: Factors](#i783cf867b028427ba2fa2dcfd656c4d4_49)] [added: Factors](#i8a76267127a74bd7861180372b8f2b53_49)] | | | | | | [removed: [26](#i783cf867b028427ba2fa2dcfd656c4d4_49)] [added: [26](#i8a76267127a74bd7861180372b8f2b53_49)] | | |

| | | | [Cautionary Factors that May Affect Future [removed: Results](#i783cf867b028427ba2fa2dcfd656c4d4_52)] [added: Results](#i8a76267127a74bd7861180372b8f2b53_52)] | | | | | | [removed: [40](#i783cf867b028427ba2fa2dcfd656c4d4_52)] [added: [41](#i8a76267127a74bd7861180372b8f2b53_52)] | | |

| Item 1B. | | | [Unresolved Staff [removed: Comments](#i783cf867b028427ba2fa2dcfd656c4d4_55)] [added: Comments](#i8a76267127a74bd7861180372b8f2b53_55)] | | | | | | [removed: [41](#i783cf867b028427ba2fa2dcfd656c4d4_55)] [added: [42](#i8a76267127a74bd7861180372b8f2b53_55)] | | |

| Item 1C. | | | [removed: [Cybersecurity](#i783cf867b028427ba2fa2dcfd656c4d4_58)] [added: [Cybersecurity](#i8a76267127a74bd7861180372b8f2b53_58)] | | | | | | [removed: [41](#i783cf867b028427ba2fa2dcfd656c4d4_58)] [added: [42](#i8a76267127a74bd7861180372b8f2b53_58)] | | |

| Item 2. | | | [removed: [Properties](#i783cf867b028427ba2fa2dcfd656c4d4_61)] [added: [Properties](#i8a76267127a74bd7861180372b8f2b53_61)] | | | | | | [removed: [41](#i783cf867b028427ba2fa2dcfd656c4d4_61)] [added: [42](#i8a76267127a74bd7861180372b8f2b53_61)] | | |

| Item 3. | | | [Legal [removed: Proceedings](#i783cf867b028427ba2fa2dcfd656c4d4_64)] [added: Proceedings](#i8a76267127a74bd7861180372b8f2b53_64)] | | | | | | [removed: [42](#i783cf867b028427ba2fa2dcfd656c4d4_64)] [added: [43](#i8a76267127a74bd7861180372b8f2b53_64)] | | |

| Item 4. | | | [Mine Safety [removed: Disclosures](#i783cf867b028427ba2fa2dcfd656c4d4_67)] [added: Disclosures](#i8a76267127a74bd7861180372b8f2b53_67)] | | | | | | [removed: [42](#i783cf867b028427ba2fa2dcfd656c4d4_67)] [added: [43](#i8a76267127a74bd7861180372b8f2b53_67)] | | |

| | | | [Executive Officers of the [removed: Registrant](#i783cf867b028427ba2fa2dcfd656c4d4_70)] [added: Registrant](#i8a76267127a74bd7861180372b8f2b53_70)] | | | | | | [removed: [43](#i783cf867b028427ba2fa2dcfd656c4d4_70)] [added: [44](#i8a76267127a74bd7861180372b8f2b53_70)] | | |

| Item 5. | | | [Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity [removed: Securities](#i783cf867b028427ba2fa2dcfd656c4d4_76)] [added: Securities](#i8a76267127a74bd7861180372b8f2b53_76)] | | | | | | [removed: [44](#i783cf867b028427ba2fa2dcfd656c4d4_76)] [added: [45](#i8a76267127a74bd7861180372b8f2b53_76)] | | |

| Item 6. | | | [removed: [\[Reserved\]](#i783cf867b028427ba2fa2dcfd656c4d4_79)] [added: [\[Reserved\]](#i8a76267127a74bd7861180372b8f2b53_79)] | | | | | | [removed: [45](#i783cf867b028427ba2fa2dcfd656c4d4_79)] [added: [46](#i8a76267127a74bd7861180372b8f2b53_79)] | | |

| Item 7. | | | [Management’s Discussion and Analysis of Financial Condition and Results of [removed: Operations](#i783cf867b028427ba2fa2dcfd656c4d4_82)] [added: Operations](#i8a76267127a74bd7861180372b8f2b53_82)] | | | | | | [removed: [46](#i783cf867b028427ba2fa2dcfd656c4d4_82)] [added: [47](#i8a76267127a74bd7861180372b8f2b53_82)] | | |

| Item 7A. | | | [Quantitative and Qualitative Disclosures About Market [removed: Risk](#i783cf867b028427ba2fa2dcfd656c4d4_124)] [added: Risk](#i8a76267127a74bd7861180372b8f2b53_124)] | | | | | | [removed: [74](#i783cf867b028427ba2fa2dcfd656c4d4_124)] [added: [76](#i8a76267127a74bd7861180372b8f2b53_124)] | | |

| Item 8. | | | [Financial Statements and Supplementary [removed: Data](#i783cf867b028427ba2fa2dcfd656c4d4_127)] [added: Data](#i8a76267127a74bd7861180372b8f2b53_127)] | | | | | | [removed: [75](#i783cf867b028427ba2fa2dcfd656c4d4_127)] [added: [77](#i8a76267127a74bd7861180372b8f2b53_127)] | | |

| | | | (a) | | | [Financial [removed: Statements](#i783cf867b028427ba2fa2dcfd656c4d4_130)] [added: Statements](#i8a76267127a74bd7861180372b8f2b53_130)] | | | [removed: [75](#i783cf867b028427ba2fa2dcfd656c4d4_130)] [added: [77](#i8a76267127a74bd7861180372b8f2b53_130)] | | |

| | | | | | | [Notes to Consolidated Financial [removed: Statements](#i783cf867b028427ba2fa2dcfd656c4d4_145)] [added: Statements](#i8a76267127a74bd7861180372b8f2b53_145)] | | | [removed: [79](#i783cf867b028427ba2fa2dcfd656c4d4_145)] [added: [81](#i8a76267127a74bd7861180372b8f2b53_145)] | | |

| | | | | | | [Report of Independent Registered Public Accounting [removed: Firm](#i783cf867b028427ba2fa2dcfd656c4d4_211)] [added: Firm](#i8a76267127a74bd7861180372b8f2b53_205)] | | | [removed: [131](#i783cf867b028427ba2fa2dcfd656c4d4_211)] [added: [135](#i8a76267127a74bd7861180372b8f2b53_205)] | | |

| Item 9. | | | [Changes in and Disagreements with Accountants on Accounting and Financial [removed: Disclosure](#i783cf867b028427ba2fa2dcfd656c4d4_214)] [added: Disclosure](#i8a76267127a74bd7861180372b8f2b53_208)] | | | | | | [removed: [133](#i783cf867b028427ba2fa2dcfd656c4d4_214)] [added: [137](#i8a76267127a74bd7861180372b8f2b53_208)] | | |

| Item 9A. | | | [Controls and [removed: Procedures](#i783cf867b028427ba2fa2dcfd656c4d4_217)] [added: Procedures](#i8a76267127a74bd7861180372b8f2b53_211)] | | | | | | [removed: [133](#i783cf867b028427ba2fa2dcfd656c4d4_217)] [added: [137](#i8a76267127a74bd7861180372b8f2b53_211)] | | |

| Item 9B. | | | [Other [removed: Information](#i783cf867b028427ba2fa2dcfd656c4d4_223)] [added: Information](#i8a76267127a74bd7861180372b8f2b53_217)] | | | | | | [removed: [134](#i783cf867b028427ba2fa2dcfd656c4d4_223)] [added: [138](#i8a76267127a74bd7861180372b8f2b53_217)] | | |

| Item 9C. | | | [Disclosure Regarding Foreign Jurisdictions that Prevent [removed: Inspections](#i783cf867b028427ba2fa2dcfd656c4d4_226)] [added: Inspections](#i8a76267127a74bd7861180372b8f2b53_220)] | | | | | | [removed: [134](#i783cf867b028427ba2fa2dcfd656c4d4_226)] [added: [138](#i8a76267127a74bd7861180372b8f2b53_220)] | | |

| Item 10. | | | [Directors, Executive Officers and Corporate [removed: Governance](#i783cf867b028427ba2fa2dcfd656c4d4_232)] [added: Governance](#i8a76267127a74bd7861180372b8f2b53_226)] | | | | | | [removed: [135](#i783cf867b028427ba2fa2dcfd656c4d4_232)] [added: [139](#i8a76267127a74bd7861180372b8f2b53_226)] | | |

| Item 11. | | | [Executive [removed: Compensation](#i783cf867b028427ba2fa2dcfd656c4d4_235)] [added: Compensation](#i8a76267127a74bd7861180372b8f2b53_229)] | | | | | | [removed: [135](#i783cf867b028427ba2fa2dcfd656c4d4_235)] [added: [139](#i8a76267127a74bd7861180372b8f2b53_229)] | | |

| Item 12. | | | [Security Ownership of Certain Beneficial Owners and Management and [removed: Related](#i783cf867b028427ba2fa2dcfd656c4d4_238)[ ](#i783cf867b028427ba2fa2dcfd656c4d4_238)[Stockholder Matters](#i783cf867b028427ba2fa2dcfd656c4d4_238)] [added: Related](#i8a76267127a74bd7861180372b8f2b53_232)[ ](#i8a76267127a74bd7861180372b8f2b53_232)[Stockholder Matters](#i8a76267127a74bd7861180372b8f2b53_232)] | | | | | | [removed: [136](#i783cf867b028427ba2fa2dcfd656c4d4_238)] [added: [140](#i8a76267127a74bd7861180372b8f2b53_232)] | | |

| Item 13. | | | [Certain Relationships and Related Transactions, and Director [removed: Independence](#i783cf867b028427ba2fa2dcfd656c4d4_241)] [added: Independence](#i8a76267127a74bd7861180372b8f2b53_235)] | | | | | | [removed: [136](#i783cf867b028427ba2fa2dcfd656c4d4_241)] [added: [140](#i8a76267127a74bd7861180372b8f2b53_235)] | | |

| Item 14. | | | [Principal Accountant Fees and [removed: Services](#i783cf867b028427ba2fa2dcfd656c4d4_244)] [added: Services](#i8a76267127a74bd7861180372b8f2b53_238)] | | | | | | [removed: [136](#i783cf867b028427ba2fa2dcfd656c4d4_244)] [added: [140](#i8a76267127a74bd7861180372b8f2b53_238)] | | |

| Item 15. | | | [Exhibits and Financial Statement [removed: Schedules](#i783cf867b028427ba2fa2dcfd656c4d4_250)] [added: Schedules](#i8a76267127a74bd7861180372b8f2b53_244)] | | | | | | [removed: [137](#i783cf867b028427ba2fa2dcfd656c4d4_250)] [added: [141](#i8a76267127a74bd7861180372b8f2b53_244)] | | |

| Item 16. | | | [Form 10-K [removed: Summary](#i783cf867b028427ba2fa2dcfd656c4d4_262)] [added: Summary](#i8a76267127a74bd7861180372b8f2b53_256)] | | | | | | [removed: [141](#i783cf867b028427ba2fa2dcfd656c4d4_262)] [added: [145](#i8a76267127a74bd7861180372b8f2b53_256)] | | |

| [Part I](#i8a76267127a74bd7861180372b8f2b53_10) | | | | | | | | | | | |

| [Part II](#i8a76267127a74bd7861180372b8f2b53_73) | | | | | | | | | | | |

| | | | [Management’s Report](#i8a76267127a74bd7861180372b8f2b53_214) | | | | | | [137](#i8a76267127a74bd7861180372b8f2b53_214) | | |

| [Part III](#i8a76267127a74bd7861180372b8f2b53_217) | | | | | | | | | | | |

| [Part IV](#i8a76267127a74bd7861180372b8f2b53_241) | | | | | | | | | | | |

| | | | [Signatures](#i8a76267127a74bd7861180372b8f2b53_259) | | | | | | [146](#i8a76267127a74bd7861180372b8f2b53_259) | | |

[Table of Content](#i783cf867b028427ba2fa2dcfd656c4d4_7)[s](#i783cf867b028427ba2fa2dcfd656c4d4_7)

| [Part I](#i783cf867b028427ba2fa2dcfd656c4d4_10) | | | | | | | | | | | |

| [Part II](#i783cf867b028427ba2fa2dcfd656c4d4_73) | | | | | | | | | | | |

| | | | [Management’s Report](#i783cf867b028427ba2fa2dcfd656c4d4_220) | | | | | | [133](#i783cf867b028427ba2fa2dcfd656c4d4_220) | | |

| [Part III](#i783cf867b028427ba2fa2dcfd656c4d4_223) | | | | | | | | | | | |

| [Part IV](#i783cf867b028427ba2fa2dcfd656c4d4_247) | | | | | | | | | | | |

| | | | [Signatures](#i783cf867b028427ba2fa2dcfd656c4d4_265) | | | | | | [142](#i783cf867b028427ba2fa2dcfd656c4d4_265) | | |

Oversight of the information security program [removed: has been] [added: remains fully] integrated into the Company’s overall enterprise risk management [removed: program.][added: framework.]

The Company’s interim CISO has over 22 years of experience in cybersecurity and national security, including distinguished service in the U.S. Army and the National Security Agency.

He holds a Master’s degree in Cyber Intelligence Studies and a Bachelor’s degree in Mathematical Physics, and maintains the Certified Information Systems Security Professional (CISSP) credential.

The CISO has worked in the cybersecurity and national security fields for more than 30 years.

He has a Master of Science in Telecommunications and Computers.

He has served as a board member of the Health Information Sharing and Analysis Center for 10 years.

Principal research facilities outside the U.S. are located in the United Kingdom, [removed: Switzerland and China.]

[removed: Merck’s] [added: The Company’s] manufacturing operations are currently headquartered in Rahway, New Jersey.

The Company also has production facilities for human health products at [removed: six] [added: five] locations in the U.S. and Puerto Rico.

Switzerland and China.

[Table of Content](#i783cf867b028427ba2fa2dcfd656c4d4_7)[s](#i783cf867b028427ba2fa2dcfd656c4d4_7)

Executive Officers of the Registrant (ages as of February 1, [removed: 2025)][added: 2026)]

| Robert M. Davis | | | [removed: 58] [added: 59] | | | Chairman, Chief Executive Officer and President (since December 2022); Chief Executive Officer and President (July 2021-December 2022); Executive Vice President, Global Services, and Chief Financial Officer (April 2016-July 2021) | | |

| Sanat Chattopadhyay | | | [removed: 65] [added: 66] | | | Executive Vice President and President, Merck Manufacturing Division (since March 2016) | | |

| Richard R. DeLuca, Jr. | | | [removed: 62] [added: 63] | | | Executive Vice President and President, Merck Animal Health (since September 2011) | | |

| Chirfi Guindo | | | [removed: 59] [added: 60] | | | Senior Vice President, Chief Marketing Officer, Human Health (since July 2022); Prior to that, Executive Vice President, Head of Global Product Strategy and Commercialization, Biogen Inc. (July 2018-July 2022) | | |

| Betty D. Larson | | | [removed: 49] [added: 50] | | | Executive Vice President and Chief Human Resources Officer (since April 2024); Prior to that, Chief People Officer, GE HealthCare (February 2022-April 2024); Executive Vice President and Chief Human Resources Officer, Becton Dickinson (June 2018-February 2022) | | |

| Dean Li | | | [removed: 62] [added: 63] | | | Executive Vice President, President, Merck Research Laboratories (since January [removed: 2021); Senior Vice President, Discovery Sciences and Translational Medicine, Merck Research Laboratories (November 2017-January] 2021) | | |

| Caroline Litchfield | | | [removed: 56] [added: 57] | | | Executive Vice President and Chief Financial Officer (since April [removed: 2021); Senior Vice President, Corporate Treasurer (January 2018-March] 2021) | | |

| Johannes J. Oosthuizen | | | [removed: 57] [added: 58] | | | Senior Vice President and President Merck U.S. Human Health (since January 2022); Senior Vice President and Head of Global Oncology Commercial (January 2021-December [removed: 2021); Senior Vice President and President of MSD K.K. (July 2016-December 2020)] [added: 2021)] | | |

| Joseph Romanelli | | | [removed: 51] [added: 52] | | | Senior Vice President and President MSD International Human Health (since July 2022); Prior to that, Chief Executive Officer JiXing Pharmaceuticals (July 2021-July 2022); President MSD China (December 2016-July 2021) | | |

| Dalton Smart | | | [removed: 58] [added: 59] | | | Senior Vice President Finance – Global Controller (since December 2023); Vice President, Assistant Controller (September 2023-December 2023); Vice President, Internal Audit (March 2015-September 2023) | | |

| David M. Williams | | | [removed: 56] [added: 57] | | | Executive Vice President, Chief Information and Digital Officer (since August [removed: 2020); Acting Chief Information and Digital Officer (December 2019-August] 2020) | | |

| Jennifer Zachary | | | [removed: 47] [added: 48] | | | Executive Vice President and General Counsel (since April 2018) | | |

On February 2, 2026, the Company announced that Sanat Chattopadhyay, Executive Vice President and President, Merck Manufacturing Division, will retire from the Company, effective July 1, 2026.

The Company announced that Mr. David R.

Maraldo will assume the role as Executive Vice President and President, Merck Manufacturing Division, effective May 1, 2026, at which time Mr. Maraldo will become, and Mr. Chattopadhyay will cease to be, an Executive Officer of the Company.

Mr. Chattopadhyay will remain in a strategic advisory role at the Company until his retirement.

| | | | | | | | | |

| --- | --- | --- | --- | --- | --- | --- | --- | --- |

| David R. Maraldo | | | 49 | | | Senior Vice President, Human Health Operations (since June 2025), Senior Vice President, Global Biologic Operations (February 2022 – June 2025), Vice President, Large Molecule Commercialization (June 2020 – February 2022) | | |

On February 12, 2026, the Company announced that Joseph Romanelli has decided to retire from the Company in the second quarter of 2026.

On February 23, 2026, the Company announced that Brian Foard will join the Company as Executive Vice President, and President Specialty, Pharma & Infectious Diseases, effective March 2, 2026.

Mr. Foard most recently served as Executive Vice President and Head of Specialty Care at Sanofi.

[Table of Content](#i783cf867b028427ba2fa2dcfd656c4d4_7)[s](#i783cf867b028427ba2fa2dcfd656c4d4_7)

| Cristal Downing | | | 56 | | | Executive Vice President and Chief Communications & Public Affairs Officer (since August 2021); Prior to that, Vice President Medical Devices, Global Communications and Public Affairs Johnson & Johnson (December 2020-August 2021); Vice President Financial Communication, Johnson & Johnson (January 2018-December 2020) | | |

As of January 31, [removed: 2025,] [added: 2026,] there were approximately [removed: 85,700] [added: 80,500] shareholders of record of the Company’s Common Stock.

Issuer purchases of equity securities for the three months ended December 31, [removed: 2024] [added: 2025] were as follows:

*(1)* *All shares purchased during the period were made as part of a plan approved by the Board of Directors in [removed: October 2018] [added: January 2025] to purchase up to $10 billion in Merck shares for its [removed: treasury.][added: treasury.*]

The following graph assumes a $100 investment on December 31, [removed: 2019,] [added: 2020,] and reinvestment of all dividends, in each of the Company’s Common Stock, the S&P 500 Index, and a composite peer group of major U.S. and European-based pharmaceutical companies, which are: AbbVie Inc., Amgen Inc., AstraZeneca plc, Bristol-Myers Squibb Company, Johnson & Johnson, Eli Lilly and Company, Gilead Sciences Inc., GlaxoSmithKline plc, Novartis AG, Pfizer Inc., Roche Holding AG, and Sanofi SA.

| | | | End of Period Value | | | | | | [removed: 2024/2019] [added: 2025/2020] CAGR* | | |

| PEER GROUP | | | [removed: 154] [added: 198] | | | | | | [removed: 9%] [added: 15%] | | |

| S&P 500 | | | [removed: 197] [added: 196] | | | | | | 15% | | |

[removed: ][added: ]

| | | | [removed: 2019 | | |] 2020 | | | 2021 | | | 2022 | | | 2023 | | | 2024 | | | [added: 2025 | | |]

* Peer group average was calculated on a market cap weighted basis as of December 31, [removed: 2019.*][added: 2020.*]

| October 1 — October 31 | | | | | | 5,409,085 | | | | | | $86.70 | | | | | | 5,409,085 | | | | | | $8,103 | | |

| November 1 — November 30 | | | | | | 4,098,025 | | | | | | $91.68 | | | | | | 4,098,025 | | | | | | $7,728 | | |

| December 1 — December 31 | | | | | | 4,009,200 | | | | | | $101.51 | | | | | | 4,009,200 | | | | | | $7,321 | | |

| Total | | | | | | 13,516,310 | | | | | | $92.60 | | | | | | 13,516,310 | | | | | | | | |

| MERCK | | | $158 | | | | | | 10% | | |

| MERCK | | | $ | 100.0 | | $ | 101.8 | | $ | 152.1 | | $ | 153.6 | | $ | 144.0 | | $ | 158.1 | |

| PEER GROUP | | | 100.0 | | | 122.5 | | | 130.1 | | | 134.1 | | | 145.5 | | | 198.3 | | |

| S&P 500 | | | 100.0 | | | 128.7 | | | 105.4 | | | 133.0 | | | 166.3 | | | 196.0 | | |

| October 1 — October 31 | | | | | | 2,428,680 | | | | | | $108.45 | | | | | | 2,428,680 | | | | | | $2,620 | | |

| November 1 — November 30 | | | | | | 993,250 | | | | | | $99.29 | | | | | | 993,250 | | | | | | $2,522 | | |

| December 1 — December 31 | | | | | | 1,215,000 | | | | | | $99.51 | | | | | | 1,215,000 | | | | | | $2,401 | | |

| Total | | | | | | 4,636,930 | | | | | | $104.15 | | | | | | 4,636,930 | | | | | | | | |

In January 2025, the Board of Directors approved a plan to purchase up to an additional $10 billion in Merck shares for its treasury.*

[Table of Content](#i783cf867b028427ba2fa2dcfd656c4d4_7)[s](#i783cf867b028427ba2fa2dcfd656c4d4_7)

| MERCK | | | $134 | | | | | | 6% | | |

| MERCK | | | $ | 100.0 | | $ | 92.8 | | $ | 94.5 | | $ | 141.1 | | $ | 142.5 | | $ | 133.6 | |

| PEER GROUP | | | 100.0 | | | 106.5 | | | 130.4 | | | 138.1 | | | 142.0 | | | 153.7 | | |

| S&P 500 | | | 100.0 | | | 118.4 | | | 152.3 | | | 124.7 | | | 157.5 | | | 196.8 | | |

[Table of Content](#i783cf867b028427ba2fa2dcfd656c4d4_7)[s](#i783cf867b028427ba2fa2dcfd656c4d4_7)

The consolidated balance sheet of Merck & Co., Inc. and subsidiaries as of December 31, [removed: 2024] [added: 2025] and [removed: 2023,] [added: 2024,] and the related consolidated statements of income, of comprehensive income (loss), of equity and of cash flows for each of the three years in the period ended December 31, [removed: 2024,] [added: 2025,] the notes to consolidated financial statements, and the report dated February [removed: 25, 2025] [added: 24, 2026] of PricewaterhouseCoopers LLP, independent registered public accounting firm, are as follows:

| | | | [removed: 2024] | | | [added: 2024] | | | [added: | | | | | | | | |] 2023 | | | | | | [removed: 2022] | | |

| Sales | | | $ | [removed: 64,168] [added: 65,011] | | | | | $ | [removed: 60,115] [added: 64,168] | | | | | $ | [removed: 59,283] [added: 60,115] | |

| Cost of sales | | | [removed: 15,193] [added: 16,382] | | | | | | [removed: 16,126] [added: 15,193] | | | | | | [removed: 17,411] [added: 16,126] | | |

| Selling, general and administrative | | | [removed: 10,816] [added: 10,733] | | | | | | [removed: 10,504] [added: 10,816] | | | | | | [removed: 10,042] [added: 10,504] | | |

| Research and development | | | [removed: 17,938] [added: 15,789] | | | | | | [removed: 30,531] [added: 17,938] | | | | | | [removed: 13,548] [added: 30,531] | | |

| Restructuring costs | | | [removed: 309] [added: 889] | | | | | | [removed: 599] [added: 309] | | | | | | [removed: 337] [added: 599] | | |

| Other (income) expense, net | | | [removed: (24)] [added: 151] | | | | | | [removed: 466] [added: (24)] | | | | | | [removed: 1,501] [added: 466] | | |

| | | | [removed: 44,232] [added: 43,944] | | | | | | [removed: 58,226] [added: 44,232] | | | | | | [removed: 42,839] [added: 58,226] | | |

| Income Before Taxes | | | [removed: 19,936] [added: 21,067] | | | | | | [removed: 1,889] [added: 19,936] | | | | | | [removed: 16,444] [added: 1,889] | | |

| Taxes on Income | | | [removed: 2,803] [added: 2,804] | | | | | | [removed: 1,512] [added: 2,803] | | | | | | [removed: 1,918] [added: 1,512] | | |

| Net Income | | | [removed: 17,133] [added: 18,263] | | | | | | [removed: 377] [added: 17,133] | | | | | | [removed: 14,526] [added: 377] | | |

| Less: Net Income Attributable to Noncontrolling Interests | | | [removed: 16] [added: 9] | | | | | | [removed: 12] [added: 16] | | | | | | [removed: 7] [added: 12] | | |

| Net Income Attributable to Merck & Co., Inc. | | | $ | [removed: 17,117] [added: 18,254] | | | | | $ | [removed: 365] [added: 17,117] | | | | | $ | [removed: 14,519] [added: 365] | |

| Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders | | | $ | [removed: 6.76] [added: 7.30] | | | | | $ | [removed: 0.14] [added: 6.76] | | | | | $ | [removed: 5.73] [added: 0.14] | |

| Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders | | | $ | [removed: 6.74] [added: 7.28] | | | | | $ | [removed: 0.14] [added: 6.74] | | | | | $ | [removed: 5.71] [added: 0.14] | |

| Net unrealized [removed: income] (loss) [added: income] on derivatives, net of reclassifications | | | [removed: 266] [added: (347)] | | | | | | [removed: (97)] [added: 266] | | | | | | [removed: (71)] [added: (97)] | | |

| Benefit plan net gain (loss) and prior service credit (cost), net of amortization | | | [removed: 466] [added: 828] | | | | | | [removed: (385)] [added: 466] | | | | | | [removed: 335] [added: (385)] | | |

| Cumulative translation adjustment | | | [removed: (516)] [added: 177] | | | | | | [removed: 89] [added: (516)] | | | | | | [removed: (603)] [added: 89] | | |

| | | | [removed: 216] [added: 658] | | | | | | [removed: (393)] [added: 216] | | | | | | [removed: (339)] [added: (393)] | | |

| Comprehensive Income (Loss) Attributable to Merck & Co., Inc. | | | $ | [removed: 17,333] [added: 18,912] | | | | | $ | [removed: (28)] [added: 17,333] | | | | | $ | [removed: 14,180] [added: (28)] | |

| | | | [removed: 2024] [added: 2025] | | | | | | [added: 2024 | | | | | |] 2023 | | |

| Cash and cash equivalents | | | $ | [removed: 13,242] [added: 14,565] | | | | | $ | [removed: 6,841] [added: 13,242] | |

| Short-term investments | | | [removed: 447] [added: —] | | | | | | [removed: 252] [added: 447] | | |

| Accounts receivable (net of allowance for doubtful accounts of [removed: $89] [added: $97] in [removed: 2024] [added: 2025] and [removed: $88] [added: $89] in [removed: 2023)] [added: 2024)] | | | [removed: 10,278] [added: 11,775] | | | | | | [removed: 10,349] [added: 10,278] | | |

| Inventories (excludes inventories of [removed: $4,193] [added: $5,681] in [removed: 2024] [added: 2025] and [removed: $3,348] [added: $4,193] in [removed: 2023] [added: 2024] classified in Other assets - see Note 7) | | | [removed: 6,109] [added: 6,658] | | | | | | [removed: 6,358] [added: 6,109] | | |

| Other current assets | | | [removed: 8,706] [added: 10,518] | | | | | | [removed: 8,368] [added: 8,706] | | |

| Total current assets | | | [removed: 38,782] [added: 43,516] | | | | | | [removed: 32,168] [added: 38,782] | | |

| Investments | | | [removed: 463] [added: 956] | | | | | | [removed: 252] [added: 463] | | |

| Land | | | [removed: 307] [added: 321] | | | | | | [removed: 326] [added: 307] | | |

| Buildings | | | [removed: 16,360] [added: 17,983] | | | | | | [removed: 14,966] [added: 16,360] | | |

| Machinery, equipment and office furnishings | | | [removed: 18,283] [added: 19,760] | | | | | | [removed: 17,763] [added: 18,283] | | |

| Construction in progress | | | [removed: 7,984] [added: 9,166] | | | | | | [removed: 8,262] [added: 7,984] | | |

| Less: accumulated depreciation | | | [removed: 19,155] [added: 21,914] | | | | | | [removed: 18,266] [added: 19,155] | | |

| | | | [removed: 23,779] [added: $] | [added: 25,316] | | | | | [removed: 23,051] [added: $] | [added: 23,779] | | [added: | | | $ | 23,051 | |]

| Goodwill | | | [removed: 21,668] [added: 21,579] | | | | | | [removed: 21,197] [added: 21,668] | | |

| Other Intangibles, Net | | | [removed: 16,370] [added: 26,681] | | | | | | [removed: 18,011] [added: 16,370] | | |

| Other Assets | | | [removed: 16,044] [added: 18,818] | | | | | | [removed: 11,996] [added: 16,044] | | |

| | | | $ | [removed: 117,106] [added: 136,866] | | | | | $ | [removed: 106,675] [added: 117,106] | |

| Loans payable and current portion of long-term debt | | | $ | [removed: 2,649] [added: 2,589] | | | | | $ | [removed: 1,372] [added: 2,649] | |

| | | | 2025 | | | | | | 2024 | | |

| | | | 47,230 | | | | | | 42,934 | | |

| | | | 25,316 | | | | | | 23,779 | | |

| | | | $ | 136,866 | | | | | $ | 117,106 | |

| Net income attributable to Merck & Co., Inc. | | | — | | | | | | — | | | | | | 18,254 | | | | | | — | | | | | | — | | | | | | — | | | | | | 18,254 | | |

| Treasury stock shares purchased | | | — | | | | | | — | | | | | | — | | | | | | — | | | | | | (5,084) | | | | | | — | | | | | | (5,084) | | |

| Balance December 31, 2025 | | | $ | 1,788 | | | | | $ | 45,029 | | | | | $ | 73,075 | | | | | $ | (4,287) | | | | | $ | (62,999) | | | | | $ | 56 | | | | | $ | 52,662 | |

| Acquisition of Verona Pharma plc, net of cash acquired | | | (10,042) | | | | | | — | | | | | | — | | |

are considered service agreements.

These costs are included in *Other Assets*.

When the collaborative partner is the principal on sales transactions with

H.R. 1 - One Big Beautiful Bill Act (OBBBA) renamed the provision for taxes on foreign earnings from GILTI to net controlled foreign corporation tested income (NCTI).

measurements.

The adoption primarily resulted in incremental disclosures to the Company’s income tax disclosures contained in Note 15.

In September 2025, the FASB issued amended guidance to reduce the complexity of evaluating whether contracts are derivatives by adding a scope exception (which may apply to certain R&D funding arrangements) to exclude from derivative accounting non-exchange-traded contracts with variables (underlyings) that are based on operations or activities specific to one of the parties to the contract.

In December 2025, the FASB issued guidance that includes requirements for recognition of government grants in a Company’s financial statements as well as disclosure requirements, including the nature of the government grant received, the accounting policies used to account for the grant, and significant terms and conditions of the grant.

The guidance is effective for 2029 interim and annual reporting on a modified prospective, modified retrospective or retrospective approach.

Early adoption is permitted as of the beginning of an annual reporting period.

The Company is currently evaluating the impact of adoption on its consolidated financial statements.

In January 2026, Merck acquired Cidara Therapeutics, Inc. (Cidara), a biotechnology company developing drug-Fc conjugate (DFC) therapeutics, for approximately $9.2 billion (including payments to settle share-based equity awards).

Cidara’s lead DFC candidate, MK-1406 (formerly CD388), is a long-acting antiviral designed to prevent seasonal and pandemic influenza.

MK-1406 is currently being evaluated among adult and adolescent participants who are at higher risk of developing complications from influenza.

Merck anticipates the transaction will be accounted for as an asset acquisition since MK-1406 is expected to account for substantially all of the fair value of the gross assets to be acquired (excluding cash and deferred income taxes).

Merck expects to record a charge of approximately $9.0 billion to *Research and development* expenses in the first quarter of 2026 for acquired IPR&D with no alternative future use.

2025 Transactions

In November 2025, Merck reached an agreement with Dr. Falk Pharma GmbH (Falk) to discontinue an existing contract concerning co-development and co-commercialization rights in certain territories for MK-8690 (formerly PRA-052), and for Merck to assume full responsibility for the development program going forward.

MK-8690 is an investigational anti-CD30 ligand monoclonal antibody being evaluated by the Company in an early-stage clinical trial.

Under the terms of the agreement, Merck and Falk have discontinued their collaboration based on their existing co-development contract resulting in Merck having secured global rights to MK-8690.

Falk is also eligible to receive a developmental milestone payment, as well as tiered low-single-digit royalties on sales in certain territories.

In October 2025, Merck acquired Verona Pharma plc (Verona Pharma), a biopharmaceutical company focused on respiratory diseases, for total consideration of $10.4 billion (including payments to settle share-based equity awards).

Through this acquisition, Merck acquired *Ohtuvayre* (ensifentrine), an inhaled phosphodiesterases 3 and 4 (PDE3 and PDE4) inhibitor, which was approved in the U.S. in June 2024 for the maintenance treatment of chronic obstructive pulmonary disease (COPD) in adults.

*Ohtuvayre* is also being evaluated in clinical trials for the treatment of non-cystic fibrosis bronchiectasis.

The transaction was accounted for as an asset acquisition since *Ohtuvayre* accounted for substantially all of the fair value of the gross assets acquired (excluding cash and deferred income taxes).

Merck recorded an intangible asset of $12.1 billion for *Ohtuvayre*, cash of $495 million, inventories of $522 million (including $498 million of step-up to fair value), deferred tax liabilities of $2.7 billion and other net liabilities of $51 million.

The estimated fair value of the *Ohtuvayre* intangible asset was determined using an income approach.

Actual cash flows are likely to be different than those assumed.

The *Ohtuvayre* intangible asset will be amortized over its estimated useful life of nine years, subject to impairment testing.

Also in October 2025, Merck and Blackstone Life Sciences (Blackstone) entered into a funding arrangement under which Blackstone will pay Merck up to $700 million in the fourth quarter of 2026 (which is non-refundable, subject to the termination provisions of the agreement) to fund a portion of the Company’s development costs for MK-2870, sacituzumab tirumotecan (sac-TMT), expected to be incurred throughout 2026.

The funding will be recognized as a reduction to *Research and development* expenses as Merck incurs applicable development costs for the sac-TMT program.

Upon receipt of regulatory approval for an indication in the U.S. for first-line triple-negative-breast cancer (TroFuse-011 trial), Blackstone will be eligible to receive low-to-mid single-digit royalties on net sales of sac-TMT subsequent to such approval across all approved indications in Merck’s marketing territories.

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| | | | 42,934 | | | | | | 41,317 | | |

| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

| Balance January 1, 2022 | | | $ | 1,788 | | | | | $ | 44,238 | | | | | $ | 53,696 | | | | | $ | (4,429) | | | | | $ | (57,109) | | | | | $ | 73 | | | | | $ | 38,257 | |

that is considered a service agreement, which are included in *Other Assets*.

(within *Sales*).

based milestone payments and other reserves, pension and other postretirement benefit plan assumptions, share-based compensation assumptions, restructuring costs, impairments of long-lived assets (including intangible assets and goodwill) and investments, and taxes on income.

*Recently Adopted Accounting Standards —* In August 2023, the Financial Accounting Standards Board (FASB) issued amended guidance that requires a newly formed joint venture to recognize and initially measure its assets and liabilities at fair value upon formation.

The amended guidance includes exceptions to fair value measurement that are consistent with the accounting for business combinations guidance.

In November 2023, the FASB issued guidance intended to improve reportable segment disclosure requirements, primarily through expanded disclosures for significant segment expenses.

The guidance resulted in incremental disclosures to the Company’s segment reporting disclosures.

See Note 18 for further details.

The guidance is effective for 2025 annual reporting.

The guidance will result in incremental disclosures within the footnotes to the Company’s financial statements.

In January 2025, Merck and WuXi Vaccines, a wholly owned subsidiary of WuXi Biologics, entered into a definitive agreement pursuant to which Merck will acquire WuXi Vaccines’ facility in Dundalk, Ireland for a payment of approximately $440 million at closing.

The transaction is expected to close in the first quarter of 2025, subject to the satisfaction of customary closing conditions.

Hansoh is also eligible to receive future contingent

| Goodwill *(2)* | | | | | | 518 | | |

Additionally, a $100 million developmental milestone was triggered and paid in 2024 upon initiation of a Phase 2/3 clinical trial

evaluating MK-3000 for the treatment of diabetic macular edema, which was also recorded as a charge to *Research and development* expenses.

Also in July 2024, Merck notified Kelun-Biotech (a holding subsidiary of Sichuan Kelun Pharmaceutical Co., Ltd.) it was terminating the license and collaboration agreement entered into in July 2022 in which Merck gained exclusive worldwide rights for the development, manufacture and commercialization of an investigational antibody drug conjugate (ADC) MK-1200 (SKB315) for the treatment of solid tumors.

As a result of this termination, which became effective in September 2024, all rights to SKB315 have reverted to Kelun-Biotech.

See Note 4 for additional information related to this collaboration.

Phase 3 clinical trials evaluating tulisokibart for Crohn’s disease and ulcerative colitis are underway.

In July 2024, Merck notified Kelun-Biotech that it was

2022 Transactions

In October 2022, Merck and Royalty Pharma plc (Royalty Pharma) entered into a funding arrangement under which Royalty Pharma paid Merck $50 million to co-fund Merck’s development costs for a Phase 2b trial of MK-8189, an investigational oral phosphodiesterase 10A (PDE10A) inhibitor, which was being evaluated for the treatment of schizophrenia.

As Royalty Pharma was sharing the risk of technical and regulatory success with Merck, the development funding was recognized by Merck as an obligation to perform contractual services.

Accordingly, the payment received was recognized by Merck as a reduction to *Research and development* expenses ratably over the estimated Phase 2b research period.

In 2024, it was determined the Phase 2b clinical trial for MK-8189 as a monotherapy for acute schizophrenia did not meet its primary efficacy endpoint; therefore, further development in schizophrenia, bipolar, and dementia indications has stopped, and the funding arrangement was terminated.

In August 2022, Merck and Orna Therapeutics (Orna), a biotechnology company pioneering a new investigational class of engineered circular RNA (oRNA) therapies, entered into a collaboration agreement to discover, develop, and commercialize multiple programs, including vaccines and therapeutics in the areas of infectious disease and oncology.

In addition, Orna is eligible to receive future contingent payments aggregating up to $440 million in development-related payments, $675 million in regulatory milestones, and $2.4 billion in sales-based milestones associated with the progress of the multiple vaccine and therapeutic programs, as well as royalties ranging from a high-single-digit rate to a low-double-digit rate on any approved products derived from the collaboration.

Merck also invested $100 million in Orna’s Series B preferred shares in 2022.

In July 2022, Merck and Orion Corporation (Orion) announced a global co-development and co-commercialization agreement for Orion’s investigational candidate opevesostat (MK-5684/ODM-208) and other drugs targeting cytochrome P450 11A1 (CYP11A1), an enzyme important in steroid production.

Orion is responsible for the manufacture of clinical and commercial supply of opevesostat.

In addition, the contract provided both parties with an option to convert the initial co-development and co-commercialization agreement into a global exclusive license to Merck, which was mutually exercised in July 2024 (as noted above).

In May 2022, in connection with an existing arrangement, Merck exercised its option to obtain an exclusive license outside of Chinese mainland, Hong Kong, Macau and Taiwan for the development, manufacture and commercialization of Kelun-Biotech’s trophoblast antigen 2 (TROP2)-targeting ADC programs, including its lead compound, sacituzumab tirumotecan (MK-2870/SKB-264), which is currently in Phase 3 clinical development.

Under the terms of the agreement, Merck and Kelun-Biotech are collaborating on certain early clinical development plans,

including evaluating the potential of sacituzumab tirumotecan as a monotherapy and in combination with *Keytruda* for advanced solid tumors.

Additionally, Merck made an additional payment of $25 million upon technology transfer in 2023.

For the fourth quarter of [removed: 2024,] [added: 2025,] there have been no changes in internal control over financial reporting that materially affected, or are reasonably likely to materially affect, the Company’s internal control over financial reporting.

Based on this evaluation, management concluded that internal control over financial reporting was effective as of December 31, [removed: 2024.][added: 2025.]

The effectiveness of the Company’s internal control over financial reporting as of December 31, [removed: 2024,] [added: 2025,] has been audited by PricewaterhouseCoopers LLP, an independent registered public accounting firm, as stated in their report which appears herein.

| [removed: ] [added: ] | | | | | |

| ] [added: Sig..jpg](https://www.sec.gov/Archives/edgar/data/310158/000031015826000063/mrk-20251231_g9.jpg)] | | | | | |

Based on this evaluation, management concluded that internal control over financial reporting was effective as of December 31, 2025.

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During the three months ended December 31, [removed: 2024,] [added: 2025,] none of the Company’s directors or executive officers adopted or terminated [removed: any Rule] [added: a “Rule] 10b5-1 trading [removed: arrangements] [added: arrangement”] or [removed: non-Rule] [added: “non-Rule] 10b5-1 trading [removed: arrangements.][added: arrangement,” as each term is defined in Item 408 of Regulation S-K.]

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Election of Directors of the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May [removed: 27, 2025.][added: 26, 2026.]

Information on executive officers is set forth in Part I of this document on page [removed: [43](#i783cf867b028427ba2fa2dcfd656c4d4_70).][added: [44](#i8a76267127a74bd7861180372b8f2b53_70).]

The required information on compliance with Section 16(a) of the Securities Exchange Act of 1934, if applicable, is incorporated by reference from the discussion under the heading “Stock Ownership Information” of the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May [removed: 27, 2025.][added: 26, 2026.]

Every [removed: Merck] [added: Company] employee is responsible for adhering to business practices that are in accordance with the law and with ethical principles that reflect the highest standards of corporate and individual behavior.

The required information on the identification of the audit committee and the audit committee financial expert is incorporated by reference from the discussion under the heading “Board Meetings and Committees” of the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May [removed: 27, 2025.][added: 26, 2026.]

The required information about the Company’s insider trading policy is incorporated by reference from the discussion under the heading “Insider Trading Policy” of the Company's Proxy Statement for the Annual Meeting of Shareholders to be held on May [removed: 27, 2025.][added: 26, 2026.]

The information required on executive compensation is incorporated by reference from the discussion under the headings “Compensation Discussion and Analysis,” “Summary Compensation Table,” “All Other [removed: Compensation” table,] [added: Compensation”,] “CEO Pay Ratio,” “Pay [removed: versus Performance” table,] [added: Versus Performance”,] “Grants of Plan-Based [removed: Awards” table,] [added: Awards”,] “Outstanding Equity [removed: Awards” table,] [added: Awards”,] “Option Exercises and Stock [removed: Vested” table,] [added: Vested”,] “Pension [removed: Benefits” table,] [added: Benefits”,] “Nonqualified Deferred Compensation” table, and “Potential Payments Upon Termination or a Change in Control”, as well as all footnote information to the [removed: various] [added: applicable] tables, of the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May [removed: 27, 2025.][added: 26, 2026.]

The required information on director compensation is incorporated by reference from the discussion under the heading “Director Compensation” and related [removed: “2024 Schedule] [added: “Schedule] of Director Fees” table and [removed: “2024] [added: “2025] Director Compensation” table of the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May [removed: 27, 2025.][added: 26, 2026.]

The required information under the headings “Compensation and Management Development Committee Interlocks and Insider Participation” and “Compensation and Management Development Committee Report” is incorporated by reference from the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May [removed: 27, 2025.][added: 26, 2026.]

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Information with respect to security ownership of certain beneficial owners and management is incorporated by reference from the discussion under the heading “Stock Ownership Information” of the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May [removed: 27, 2025.][added: 26, 2026.]

The following table summarizes information about the options, warrants and rights and other equity compensation under the Company’s equity compensation plans as of the close of business on December 31, [removed: 2024.][added: 2025.]

*(2)Excludes approximately [removed: 12,232,051] [added: 15,722,346] shares of restricted stock units and [removed: 3,531,246] [added: 3,667,688] performance share units (assuming maximum payouts) under the Merck Sharp & Dohme 2010 and 2019 Incentive Stock Plans.

Also excludes [removed: 153,540] [added: 140,237] shares of phantom stock deferred under the MSD Employee Deferral Program and [removed: 518,423] [added: 439,767] shares of phantom stock deferred under the Merck & Co., Inc. Plan for Deferred Payment of Directors’ Compensation.*

| Equity compensation plans approved by security holders*(1)* | | | | | | 12,476,856*(2)* | | | | | | $ | 87.95 | | | | | 65,539,454 | | |

| Total | | | | | | 12,476,856 | | | | | | $ | 87.95 | | | | | 65,539,454 | | |

| Equity compensation plans approved by security holders*(1)* | | | | | | 12,500,010*(2)* | | | | | | $ | 86.04 | | | | | 74,988,831 | | |

| Total | | | | | | 12,500,010 | | | | | | $ | 86.04 | | | | | 74,988,831 | | |

The required information on transactions with related persons is incorporated by reference from the discussion under the heading “Related Person Transactions” of the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May [removed: 27, 2025.][added: 26, 2026.]

The required information on director independence is incorporated by reference from the discussion under the heading “Independence of Directors” of the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May [removed: 27, 2025.][added: 26, 2026.]

Ratification of Appointment of Independent Registered Public Accounting Firm for [removed: 2025] [added: 2026] beginning with the caption “Pre-Approval Policy for Services of Independent Registered Public Accounting Firm” through “Fees for Services Provided by the Independent Registered Public Accounting Firm” of the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May [removed: 27, 2025.][added: 26, 2026.]

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Consolidated statement of income for the years ended December 31, [removed: 2024, 2023] [added: 2025, 2024] and [removed: 2022][added: 2023]

Consolidated statement of comprehensive income (loss) for the years ended December 31, [removed: 2024, 2023] [added: 2025, 2024] and [removed: 2022][added: 2023]

Consolidated balance sheet as of December 31, [removed: 2024] [added: 2025] and [removed: 2023][added: 2024]

Consolidated statement of equity for the years ended December 31, [removed: 2024, 2023] [added: 2025, 2024] and [removed: 2022][added: 2023]

Consolidated statement of cash flows for the years ended December 31, [removed: 2024, 2023] [added: 2025, 2024] and [removed: 2022][added: 2023]

| 3.1 | | | | | | — | | | | | | [Restated Certificate of Incorporation of Merck & Co., Inc. (November 3, 2009) — Incorporated by reference [removed: to Merck] [added: to](https://www.sec.gov/Archives/edgar/data/310158/000119312509223917/dex31.htm) [Exhibit 3.1 to](https://www.sec.gov/Archives/edgar/data/310158/000119312509223917/dex31.htm) [Merck] & Co., Inc.’s Current Report on Form 8-K filed November 4, 2009 (No. 1-6571)](https://www.sec.gov/Archives/edgar/data/310158/000119312509223917/dex31.htm) | | |

| 3.2 | | | | | | — | | | | | | [By-Laws of Merck & Co., Inc. [removed: (effective March 22, 2022)] [added: (effective](https://www.sec.gov/Archives/edgar/data/310158/000110465924122027/tm2429161d1_ex3-1.htm) [N](https://www.sec.gov/Archives/edgar/data/310158/000110465924122027/tm2429161d1_ex3-1.htm)[ovember 19, 2024](https://www.sec.gov/Archives/edgar/data/310158/000110465924122027/tm2429161d1_ex3-1.htm)[)] — Incorporated by reference [removed: to Merck] [added: to](https://www.sec.gov/Archives/edgar/data/310158/000110465924122027/tm2429161d1_ex3-1.htm) [Exhibit 3.1 to](https://www.sec.gov/Archives/edgar/data/310158/000110465924122027/tm2429161d1_ex3-1.htm) [Merck] & Co., Inc.’s Current Report on Form 8-K [removed: filed March 25, 2022 (No. 1-6571)](https://www.sec.gov/Archives/edgar/data/310158/000031015822000006/exhibit31-byxlawsasamended.htm)] [added: filed](https://www.sec.gov/Archives/edgar/data/310158/000110465924122027/tm2429161d1_ex3-1.htm) [N](https://www.sec.gov/Archives/edgar/data/310158/000110465924122027/tm2429161d1_ex3-1.htm)[ovember](https://www.sec.gov/Archives/edgar/data/310158/000110465924122027/tm2429161d1_ex3-1.htm) [22](https://www.sec.gov/Archives/edgar/data/310158/000110465924122027/tm2429161d1_ex3-1.htm)[, 2024](https://www.sec.gov/Archives/edgar/data/310158/000110465924122027/tm2429161d1_ex3-1.htm) [(No. 1-6571)](https://www.sec.gov/Archives/edgar/data/310158/000110465924122027/tm2429161d1_ex3-1.htm)] | | |

| 4.10 | | | | | | — | | | | | | [removed: [I](https://www.sec.gov/Archives/edgar/data/310158/000162828024025800/exhibit41-8xk.htm)[ndenture,] [added: [Indenture,] dated as of May 30, 2024, among MSD [removed: Net](https://www.sec.gov/Archives/edgar/data/310158/000162828024025800/exhibit41-8xk.htm)[herlands] [added: Netherlands] Capital B.V., Merck & Co., Inc. and U.S. Bank Trust National [removed: Association](https://www.sec.gov/Archives/edgar/data/310158/000162828024025800/exhibit41-8xk.htm)[,] [added: Association,] as [removed: Trustee](https://www.sec.gov/Archives/edgar/data/310158/000162828024025800/exhibit41-8xk.htm) [—](https://www.sec.gov/Archives/edgar/data/310158/000162828024025800/exhibit41-8xk.htm) [Incorporated] [added: Trustee — Incorporated] by reference to Exhibit 4.1 to Merck & Co., [removed: Inc.](https://www.sec.gov/Archives/edgar/data/310158/000162828024025800/exhibit41-8xk.htm)[’](https://www.sec.gov/Archives/edgar/data/310158/000162828024025800/exhibit41-8xk.htm)[s] [added: Inc.’s] Current Report on Form 8-K filed May 30, 2024 (No. 1-6571)](https://www.sec.gov/Archives/edgar/data/310158/000162828024025800/exhibit41-8xk.htm) | | |

| *10.1 | | | | | | — | | | | | | [Merck & Co., Inc. Executive Incentive Plan (as amended and restated effective January 1, 2025)](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm) [added: [](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm)[—](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm) [Incor](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm)[po](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm)[rated by reference to](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm) [Exhibit 10.1 to Merck & Co., Inc](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm)[.](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm)[’](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm)[s](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm) [Form](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm) [10-K Annual Report for the](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm) [fiscal year ended December 31,](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm) [202](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm)[4 filed February 25, 2025](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm) [(No](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm)[.](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm) [1-6571)](https://www.sec.gov/Archives/edgar/data/310158/000162828025007732/exh101-eipplan.htm)] | | |

| *10.4 | | | | | | — | | | | | | [Form of stock option terms for [removed: 2013] [added: 2015] quarterly and annual non-qualified option grants under the Merck & Co., Inc. 2010 Incentive Stock Plan — Incorporated by reference to Exhibit [removed: 10.19] [added: 10.20] to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, [removed: 2012] [added: 2015] filed February [removed: 28, 2013] [added: 26, 2016] (No. [removed: 1-6571)](https://www.sec.gov/Archives/edgar/data/310158/000119312513084618/d438975dex1019.htm)] [added: 1-6571)](https://www.sec.gov/Archives/edgar/data/310158/000031015816000063/ex10202015nqsograntsunderm.htm)] | | |

| [removed: *10.5] [added: *10.8] | | | | | | — | | | | | | [Form of stock option terms for [removed: 2014] [added: 2016] quarterly and annual non-qualified option grants under the Merck & Co., Inc. 2010 Incentive Stock Plan — Incorporated by reference to Exhibit [removed: 10.18] [added: 10.19] to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, [removed: 2014] [added: 2016] filed February [removed: 27, 2015] [added: 28, 2017] (No. [removed: 1-6571)](https://www.sec.gov/Archives/edgar/data/310158/000031015815000005/ex1018stockoptiontermsfor2.htm)] [added: 1-6571)](https://www.sec.gov/Archives/edgar/data/310158/000031015817000010/ex10192016nqsograntsunderm.htm)] | | |

| [removed: *10.6] [added: *10.7] | | | | | | — | | | | | | [Form of stock option terms for [removed: 2015] [added: 2018] quarterly and annual non-qualified option grants under the Merck & Co., Inc. 2010 Incentive Stock Plan — Incorporated by reference to Exhibit [removed: 10.20] [added: 10.12] to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, [removed: 2015] [added: 2017] filed February [removed: 26, 2016] [added: 27, 2018] (No. [removed: 1-6571)](https://www.sec.gov/Archives/edgar/data/310158/000031015816000063/ex10202015nqsograntsunderm.htm)] [added: 1-6571)](https://www.sec.gov/Archives/edgar/data/310158/000031015818000005/ex1012_2018nqsogranttermsu.htm)] | | |

| [removed: *10.7] [added: *10.5] | | | | | | — | | | | | | [Form of stock option terms for 2017 annual non-qualified option grants under the Merck & Co., Inc. 2010 Incentive Stock Plan — Incorporated by reference to Exhibit 10.7 to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, 2022 filed February 24, 2023 (No. 1-6571)](https://www.sec.gov/Archives/edgar/data/310158/000162828023005061/exhibit107-2017annualnqsot.htm) | | |