MRK US Equity☆

mrk-20241231

As filed with the Securities and Exchange Commission on February 25, 2025

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D. C. 20549

_________________________________

FORM 10-K

For the Fiscal Year Ended December 31, 2024

OR

For the transition period from to

Commission File No. 1-6571

Merck & Co., Inc.

126 East Lincoln Avenue

(908) 740-4000

Securities Registered pursuant to Section 12(b) of the Act:

Title of Each Class Trading Symbol(s) Name of Each Exchange on which Registered

Common Stock ($0.50 par value) MRK New York Stock Exchange

1.875% Notes due 2026 MRK/26 New York Stock Exchange

3.250% Notes due 2032 MRK/32 New York Stock Exchange

2.500% Notes due 2034 MRK/34 New York Stock Exchange

1.375% Notes due 2036 MRK 36A New York Stock Exchange

3.500% Notes due 2037 MRK/37 New York Stock Exchange

3.700% Notes due 2044 MRK/44 New York Stock Exchange

3.750% Notes due 2054 MRK/54 New York Stock Exchange

Securities Registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes☒ No ☐

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.Yes ☐ No☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes☒No☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes☒No☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☒

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

Number of shares of Common Stock ($0.50 par value) outstanding as of January 31, 2025: 2,526,036,240.

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

Documents Incorporated by Reference:

Document Part of Form 10-K

Table of Contents

Table of Contents

Page

Part I

Item 1. Business 1

Item 1A. Risk Factors 26

Cautionary Factors that May Affect Future Results 40

Item 1B. Unresolved Staff Comments 41

Item 1C. Cybersecurity 41

Item 2. Properties 41

Item 3. Legal Proceedings 42

Item 4. Mine Safety Disclosures 42

Executive Officers of the Registrant 43

Part II

Item 6. [Reserved] 45

Item 7A. Quantitative and Qualitative Disclosures About Market Risk 74

Item 8. Financial Statements and Supplementary Data 75

(a) Financial Statements 75

Notes to Consolidated Financial Statements 79

Report of Independent Registered Public Accounting Firm 131

Item 9A. Controls and Procedures 133

Management’s Report 133

Item 9B. Other Information 134

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections 134

Part III

Item 10. Directors, Executive Officers and Corporate Governance 135

Item 11. Executive Compensation 135

Item 14. Principal Accountant Fees and Services 136

Part IV

Item 15. Exhibits and Financial Statement Schedules 137

Table of Contents

PART I

Item 1.Business.

Merck & Co., Inc. (Merck or the Company) is a global health care company that delivers innovative health solutions through its prescription medicines, including biologic therapies, vaccines and animal health products. The Company’s operations are principally managed on a product basis and include two operating segments, Pharmaceutical and Animal Health, both of which are reportable segments.

The Pharmaceutical segment includes human health pharmaceutical and vaccine products. Human health pharmaceutical products consist of therapeutic and preventive agents, generally sold by prescription, for the treatment of human disorders. The Company sells these human health pharmaceutical products primarily to drug wholesalers and retailers, hospitals, government agencies and managed health care providers such as health maintenance organizations, pharmacy benefit managers and other institutions. Human health vaccine products consist of preventive pediatric, adolescent and adult vaccines. The Company sells these human health vaccines primarily to physicians, wholesalers, distributors and government entities.

The Animal Health segment discovers, develops, manufactures and markets a wide range of veterinary pharmaceutical and vaccine products, as well as health management solutions and services, for the prevention, treatment and control of disease in all major livestock and companion animal species. The Company also offers an extensive suite of digitally connected identification, traceability and monitoring products. The Company sells its products to veterinarians, distributors, animal producers, farmers and pet owners.

All product or service marks appearing in type form different from that of the surrounding text are trademarks or service marks owned, licensed to, promoted or distributed by Merck, its subsidiaries or affiliates, except as noted. All other trademarks or service marks are those of their respective owners.

Product Sales

Total Company sales, including sales of the Company’s top pharmaceutical products, as well as sales of animal health products, were as follows:

(1)Alliance revenue represents Merck’s share of profits, which are product sales net of cost of sales and commercialization costs.

(2)Other revenues are primarily comprised of miscellaneous corporate revenues, including revenue hedging activities, as well as revenue from third-party manufacturing arrangements.

Pharmaceutical

The Pharmaceutical segment includes human health pharmaceutical and vaccine products. Human health pharmaceutical products consist of therapeutic and preventive agents, generally sold by prescription, for the treatment of human disorders. Human health vaccine products consist of preventive pediatric, adolescent and adult vaccines. Certain of the products within the Company’s franchises are as follows:

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Oncology

Keytruda is an anti-PD-1 (programmed death receptor-1) therapy 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), 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. Keytruda is also approved as monotherapy for the adjuvant treatment of certain patients with melanoma, and for certain patients with renal cell carcinoma (RCC) post-surgery. Keytruda is approved for adjuvant treatment following resection and platinum-based chemotherapy for certain patients with NSCLC. Additionally, 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 surgery. 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. 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 adenocarcinoma with programmed death-ligand 1 (PD-L1) (CPS ≥1), 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; and in combination with enfortumab vedotin for certain patients with locally advanced or metastatic urothelial 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, and for the treatment of adult patients with advanced RCC following a PD-1 or PD-L1 inhibitor and a vascular endothelial growth factor tyrosine kinase inhibitor. 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 tyrosine kinase inhibitor, 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.

Vaccines

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 (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.

Hospital Acute Care

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; 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 Noxafil (posaconazole), an antifungal agent for the prevention of certain invasive fungal infections.

Cardiovascular

Winrevair (sotatercept-csrk), an activin signaling inhibitor indicated for the treatment of adults with pulmonary arterial hypertension (PAH) (World Health Organization [WHO] Group 1) to increase exercise capacity,

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improve WHO functional class and reduce the risk of clinical worsening events; Adempas (riociguat), a cardiovascular drug for the treatment of chronic thromboembolic pulmonary hypertension or pulmonary arterial hypertension in certain patients; 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 fraction.

Virology

Lagevrio (molnupiravir), an investigational oral antiviral COVID-19 medicine available in the U.S. under Emergency Use Authorization (EUA); Isentress/Isentress HD (raltegravir), an 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.

Neuroscience

Belsomra (suvorexant), an orexin receptor antagonist, indicated for the treatment of insomnia, characterized by difficulties with sleep onset and/or sleep maintenance.

Diabetes

Januvia (sitagliptin) and Janumet (sitagliptin/metformin HCl) for the treatment of type 2 diabetes.

Animal Health

The Animal Health segment discovers, develops, manufactures and markets a wide range of veterinary pharmaceuticals, vaccines and health management solutions and services, as well as an extensive suite of digitally connected identification, traceability and monitoring products. Principal products in this segment include:

Livestock Products

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 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.

Companion Animal Products

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, 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); Optimmune (cyclosporine), an ophthalmic ointment; Nobivac vaccine lines for flexible dog and cat vaccination, including Nobivac NXT for canine flu and feline leukemia virus; 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

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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.

For a further discussion of sales of the Company’s products, see Item 7. “Management’s Discussion and Analysis of Financial Condition and Results of Operations” below.

Product Approvals

Set forth below is a summary of significant product approvals received by the Company in 2024 and, to date, in 2025.

Product Date Approval

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(1) Being jointly developed and commercialized in a worldwide collaboration with AstraZeneca.

Competition and the Health Care Environment

Competition

The markets in which the Company conducts its business and the pharmaceutical industry in general are highly competitive and highly regulated. The Company’s competitors include other worldwide research-based pharmaceutical companies, smaller research companies with more limited therapeutic focus, generic drug manufacturers, and animal health care companies. The Company’s operations may be adversely affected by generic and biosimilar competition as the Company’s products mature, as well as technological advances of competitors, industry consolidation, patents granted to competitors, competitive combination products, new products of competitors, the generic availability of competitors’ branded products, and new information from clinical trials of marketed products or post-marketing surveillance. In addition, patent rights are increasingly being challenged by competitors, and the outcome can be highly uncertain. An adverse result in a patent dispute can preclude commercialization of products or negatively affect sales of existing products and could result in the payment of royalties or in the recognition of an impairment charge with respect to intangible assets associated with certain products.

Pharmaceutical competition involves a rigorous search for technological innovations and the ability to market these innovations effectively. With its long-standing emphasis on research and development, the Company is well-positioned to compete in the search for technological innovations. The Company is active in acquiring and marketing products through external alliances, such as licensing arrangements and collaborations, and has been refining its sales and marketing efforts to address changing industry conditions. However, the introduction of new products and processes by competitors may result in price reductions and product displacements, even for products protected by patents. For example, the number of compounds available to treat a particular disease typically increases over time and can result in slowed sales growth or reduced sales of the Company’s products in that therapeutic category.

The highly competitive animal health business is affected by several factors including regulatory and legislative issues, scientific and technological advances, product innovation, the quality and price of the Company’s products as well as competitors’ products, effective promotional efforts and the frequent introduction of generic products by competitors.

Health Care Environment and Government Regulation

Global efforts toward health care cost containment continue to exert pressure on product pricing and market access. Changes to the U.S. health care system as part of health care reform, as well as increased purchasing power of entities that negotiate on behalf of Medicare, Medicaid, and private sector beneficiaries, have contributed to pricing pressure. In several international markets, government-mandated pricing actions have reduced prices of generic and patented drugs. In addition, the Company’s sales performance in 2024 was negatively affected by other cost-reduction measures taken by governments and other third parties to lower health care costs. In the U.S., the Executive Branch and Congress continue to discuss legislation designed to control health care costs, including the cost of drugs. The Company anticipates all of these actions and additional actions in the future will continue to negatively affect sales and profits.

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In addressing global cost containment pressures, the Company engages in public policy advocacy with policymakers and continues to work to demonstrate that its medicines provide value to patients and to those who pay for health care. The Company advocates with government policymakers to encourage a long-term approach to sustainable health care financing that ensures access to innovative medicines and does not disproportionately target pharmaceuticals as a source of budget savings. In markets with historically low rates of health care spending, the Company encourages those governments to increase their investments and adopt market reforms in order to improve their citizens’ access to appropriate health care, including medicines.

Operating conditions have become more challenging under the global pressures of competition, industry regulation and cost containment efforts. Although no one can predict the effect of these and other factors on the Company’s business, the Company continually takes measures to evaluate, adapt and improve the organization and its business practices to better meet customer needs and believes that it is well-positioned to respond to the evolving health care environment and market forces.

United States

The Company faces increasing pricing pressure from managed care organizations, government agencies and programs that could negatively affect the Company’s sales and profit margins, including, through (i) practices of managed care organizations, federal and state exchanges, and institutional and governmental purchasers, and (ii) federal laws and regulations related to Medicare and Medicaid, including the Medicare Prescription Drug, Improvement, and Modernization Act of 2003, the Patient Protection and Affordable Care Act of 2010 (ACA), the American Rescue Plan Act of 2021 (American Rescue Plan Act), and the Inflation Reduction Act of 2022 (IRA). Additionally, increased utilization of the 340B Federal Drug Discount Program and restrictions on the Company’s ability to identify inappropriate discounts are having a negative impact on Company performance.

In the U.S., federal and state governments for many years have pursued methods to reduce the cost of drugs and vaccines for which they pay. For example, federal and state laws require the Company to pay specified rebates for medicines reimbursed by Medicaid and to provide discounts for medicines purchased by certain state and federal entities such as the Department of Defense, Veterans Affairs, Public Health Service entities and hospitals serving a disproportionate share of low income or uninsured patients.

Additionally in the U.S., consolidation and integration among health care entities is a major factor in the competitive marketplace for pharmaceutical products. Health plans and pharmacy benefit managers have been consolidating into fewer, larger entities, thus enhancing their purchasing strength and importance. Private third-party insurers, as well as governments, employ formularies to control costs by negotiating discounted prices in exchange for formulary inclusion. Failure to obtain timely or adequate pricing or formulary placement for Merck’s products or obtaining such placement at unfavorable pricing could adversely affect revenue. In addition to formulary tier co-pay differentials, private health insurance companies and self-insured employers have been increasing the cost-sharing required from beneficiaries, particularly for branded pharmaceuticals and biotechnology products. Private health insurance companies, as well as governments, also are increasingly imposing utilization management tools, such as clinical protocols, requiring prior authorization for a branded product or requiring the patient to first fail on one or more generic products before permitting access to a branded medicine. These same management tools are also used in treatment areas in which the payor has taken the position that multiple branded products are therapeutically comparable. As the U.S. payor market concentrates further, the Company may face greater pricing pressure from private third-party payors.

Legislative Changes

In 2022, Congress passed the IRA, which makes significant changes to how drugs are covered and paid for under the Medicare program, including the creation of financial penalties for drugs whose prices rise faster than the rate of inflation, redesign of the Medicare Part D program to require manufacturers to bear more of the liability for certain drug benefits, which has taken effect in 2025, and government price setting for certain Medicare Part D drugs, starting in 2026, and Medicare Part B drugs starting in 2028. Government price setting may also impact pricing in the private market negatively affecting the Company’s performance. In August 2023, the U.S. Department of Health and Human Services (HHS), through the Centers for Medicare & Medicaid Services (CMS), selected Januvia for the first year of the IRA’s “Drug Price Negotiation Program” (Program). Pursuant to the IRA’s Program, a government price was set for Januvia, which will become effective on January 1, 2026. In January 2025, HHS announced that Janumet and Janumet XR have been selected for government price setting, which will become effective on January 1, 2027. In addition, the Company expects that Keytruda will be selected in 2026 for government price setting, which would become effective on January 1, 2028 and the Company expects that, as a result, U.S. sales of Keytruda will decline after that time. The Company has sued the U.S. government regarding the IRA’s Program (see Item 8 “Financial Statements and Supplementary Data,” Note 10. “Contingencies and Environmental Liabilities” below). Furthermore,

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the Executive Branch and Congress continue to discuss legislation designed to control health care costs, including the cost of drugs.

The long-term implications of the IRA remain uncertain and subject to various factors, including the manner in which HHS decides to implement the statute. Many experts and analysts, both within the industry and outside, have predicted that the law will harm innovation in the pharmaceutical industry and result in fewer new treatments being developed and approved over time. Merck is working to mitigate the potentially harmful effects that the law could have, which could include a detrimental impact on innovation.

In addition, in 2021, Congress passed the American Rescue Plan Act, which included a provision that eliminates the statutory cap on rebates drug manufacturers pay to Medicaid beginning in January 2024. These rebates act as a discount off the list price and eliminating the cap means that manufacturer discounts paid to Medicaid can increase. Prior to this change, manufacturers have not been required to pay more than 100% of the Average Manufacturer Price (AMP) in rebates to state Medicaid programs for Medicaid-covered drugs. As a result of this provision, manufacturers may have to pay state Medicaid programs more in rebates than they received on sales of particular products. This change presents a risk to Merck for drugs that have high Medicaid utilization and rebate exposure that is more than 100% of the AMP.

The Company also faces increasing pricing pressure in the states, which are looking to exert greater influence over the price of prescription drugs. A number of states have passed pharmaceutical price and cost transparency laws. These laws typically require manufacturers to report certain product price information or other financial data to the state. Some laws also require manufacturers to provide advance notification of price increases. The Company expects that states will continue their focus on pharmaceutical pricing and will increasingly shift to more aggressive price control tools such as Prescription Drug Affordability Boards that have the authority to conduct affordability reviews and establish upper payment limits and that Company products may be selected for such reviews. In addition, in 2024, the FDA authorized, for a two-year period, Florida’s application to import prescription drugs from Canada.

Regulatory Changes

The pharmaceutical industry also could be considered a potential source of savings via other legislative and administrative proposals that have been debated but not enacted. These types of revenue generating or cost saving proposals include additional direct price controls.

European Union

Efforts toward health care cost containment remain intense in the European Union (EU). The Company faces competitive pricing pressure resulting from generic and biosimilar drugs. In addition, a majority of countries in the EU attempt to contain drug costs by engaging in reference pricing in which authorities examine pre-determined markets for published prices of drugs. Reference pricing may either compare a product’s prices in other markets (external reference pricing), or compare a product’s price with those of other products in a national class (internal reference pricing). The authorities then use the price data to set new local prices for brand-name drugs, including the Company’s drugs. Reference pricing mechanisms are usually set at the national level and can be changed pursuant to local regulations or guidance.

Some EU Member States have established free-pricing systems, but regulate the pricing for drugs through profit control plans. Others seek to negotiate or set prices based on the cost-effectiveness of a product or an assessment of whether it offers a therapeutic benefit over other products in the relevant class.

The downward pressure on health care costs in general, particularly prescription drugs, has become intense. As a result, increasingly high barriers are being erected to the entry of new products. In some EU Member States, cross-border imports from low-priced markets also exert competitive pressure that may reduce pricing within an EU Member State.

Additionally, EU Member States have the power to restrict the range of pharmaceutical products for which their national health insurance systems provide reimbursement. In the EU, pricing and reimbursement plans vary widely from Member State to Member State. Some EU Member States provide that drug products may be marketed only after a reimbursement price has been agreed. Some EU Member States may require the completion of additional studies that compare the cost-effectiveness of a particular product candidate to already available therapies or a so-called health technology assessment (HTA), in order to obtain reimbursement or pricing approval. The HTA of pharmaceutical products is becoming an increasingly common part of the pricing and reimbursement procedures in most EU Member States. The HTA process, which is currently governed by the national laws of these countries, involves the assessment of the cost-effectiveness, public health impact, therapeutic impact and/or the economic and social impact of use of a given pharmaceutical product in the national health care system of the individual country in

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which it is conducted. Ultimately, an HTA measures the added value of a new health technology compared to existing ones.

The EU Health Technology Assessment Regulation 2021/2282 (HTAR) applies in 2025. This provides for the conduct of an EU level comparative Joint Clinical Assessment (JCA) of a new product versus relevant comparators identified by the EU Member States. JCAs will be carried out in parallel with the review of a marketing authorization application, so that a JCA report is available shortly after the product is authorized. The HTAR applies to all new active substance oncology products and advanced therapy medicinal products, including cell and gene therapies, beginning January 1, 2025; to new active substance orphan medicinal products beginning January 1, 2028; and to all products approved via the centralized procedure beginning in 2030.

EU Member States remain responsible for pricing and reimbursement decisions but must take “due consideration” of JCA reports when making national market access decisions. This means that EU Member State pricing and reimbursement processes are likely to evolve and more EU Member States may use HTAs as part of their decision-making.

The outcome of HTAs regarding specific pharmaceutical products will increasingly influence the pricing and reimbursement status granted to these pharmaceutical products by the market access authorities of individual EU Member States. A negative HTA of one of the Company’s products may mean that the product is not reimbursable or may force the Company to reduce its reimbursement price or offer discounts or rebates.

A negative HTA by a leading and recognized HTA body could also undermine the Company’s ability to obtain reimbursement for the relevant product outside a jurisdiction. For example, EU Member States that have not yet developed HTA mechanisms may rely to some extent on JCAs under the HTAR or an HTA performed in other countries with a developed HTA framework, to inform their pricing and reimbursement decisions. HTA procedures require additional data, reviews and administrative processes, all of which increase the complexity, timing and costs of obtaining product reimbursement and exert downward pressure on available reimbursement.

To obtain reimbursement or pricing approval in some EU Member States, the Company may be required to conduct studies that compare the cost-effectiveness of the Company’s product candidates to other therapies that are considered the local standard of care. There can be no assurance that any EU Member State will allow favorable pricing, reimbursement and market access conditions for any of the Company’s products, or that it will be feasible to conduct additional cost-effectiveness studies, if required.

Japan

In Japan, the pharmaceutical industry is subject to government-mandated annual price reductions of pharmaceutical products and certain vaccines. Furthermore, the government can order re-pricings for specific products if it determines that use of such product will exceed certain thresholds defined under applicable re-pricing rules. 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 next government-mandated price reduction is scheduled to occur in April 2025.

China

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. Continued growth of the Company’s business in China is dependent upon ongoing development of a favorable environment for innovative pharmaceutical products and vaccines, sustained access for the Company’s currently marketed products, and the absence of trade impediments or adverse pricing controls. In recent years, the Chinese government has introduced and implemented a number of structural reforms to accelerate the shift to innovative products and reduce costs. There have been multiple new policies introduced by the government to improve access to new innovation, reduce the complexity of regulatory filings, and accelerate the review and approval process. This has led to a significant increase in the number of new products being approved each year. While the mechanism for drugs being added to the government’s National Reimbursement Drug List (NRDL) evolves, inclusion may require a price negotiation which could impact the outlook in the market for selected brands. A new NRDL was recently completed in which new entries averaged 63% price reductions. While pricing pressure has always existed in China, health care reform has increased this pressure in part due to the acceleration of generic substitution through volume-based procurement (VBP). In 2019, the government implemented the VBP program through a tendering process for mature products which have generic substitutes with a Generic Quality Consistency Evaluation approval. Mature products that have entered into the last five rounds of VBP had, on average, a price reduction of more than 50%. The Company expects VBP to be a semi-annual process that will have a significant impact on mature products moving forward.

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Emerging Markets

The Company’s focus on emerging markets, in addition to China, has continued. Governments in many emerging markets are also focused on constraining health care costs and have enacted price controls and measures impacting intellectual property, including in exceptional cases, threats of compulsory licenses, that aim to put pressure on the price of innovative pharmaceuticals or result in constrained market access to innovative medicine. The Company anticipates that pricing pressures and market access challenges will continue in the future to varying degrees in the emerging markets.

Beyond pricing and market access challenges, other conditions in emerging market countries can affect the Company’s efforts to continue to grow in these markets, including potential political instability, changes in trade sanctions and embargoes, significant currency fluctuation and controls, financial crises, limited or changing availability of funding for health care, credit worthiness of health care partners, such as hospitals, and other developments that may adversely impact the business environment for the Company. Further, the Company may engage third-party agents to assist in operating in emerging market countries, which may affect its ability to realize continued growth and may also increase the Company’s risk exposure.

Regulation

The pharmaceutical industry is also subject to regulation by regional, country, state and local agencies around the world focused on standards and processes for determining drug safety and effectiveness, as well as conditions for sale or reimbursement.

Of particular importance is the FDA in the U.S., which administers requirements covering the testing, approval, safety, effectiveness, manufacturing, labeling, and marketing of prescription pharmaceuticals. In some cases, the FDA requirements and practices have increased the amount of time and resources necessary to develop new products and bring them to market in the U.S. At the same time, the FDA has committed to expediting the development and review of products bearing the “breakthrough therapy” designation, which has accelerated the regulatory review process for medicines with this designation. The FDA has also undertaken efforts to bring generic competition to market more efficiently and in a more timely manner.

The EU has adopted directives and other legislation concerning the classification, approval for marketing, labeling, advertising, manufacturing, wholesale distribution, integrity of the supply chain, pharmacovigilance and safety monitoring of medicinal products for human use. These provide mandatory standards throughout the EU, which may be supplemented or implemented with additional regulations by the EU Member States. In particular, EU regulators may approve products subject to a number of post-authorization conditions. Examples of typical post-authorization commitments include additional pharmacovigilance, the conduct of clinical trials, the establishment of patient registries, physician or patient education and controlled distribution and prescribing arrangements. Non-compliance with post-authorization conditions, pharmacovigilance and other obligations can lead to regulatory action, including the variation, suspension or withdrawal of the marketing authorizations, or other enforcement or regulatory actions, including the imposition of financial penalties. The Company’s policies and procedures are already consistent with the substance of these directives; consequently, it is believed that they will not have any material effect on the Company’s business.

The Company believes that it will continue to be able to conduct its operations, including launching new drugs, in this regulatory environment. (See “Research and Development” below for a discussion of the regulatory approval process.)

Access to Medicines

As a global health care company, Merck’s primary role is to discover and develop innovative medicines and vaccines. The Company also recognizes that, in collaboration with key stakeholders, it has a role to play in helping to ensure that its science advances health care, and its products are accessible and affordable globally. The Company is committed to ensuring a high-quality, safe, reliable, supply of its medicines and vaccines, and to implementing innovative solutions that address barriers to sustainable access to its products.

Merck’s approach is designed to enable it to serve the greatest number of patients today, while meeting the needs of patients in the future. The Company's wide-ranging efforts to expand access to health encompass a set of principles embedded in its business strategies and operations. These principles guide its global approach to addressing significant public health burdens and unmet medical needs. The Company systematically evaluates its pipeline candidates to assess their potential in low and middle-income countries and underserved health care settings. Throughout the life cycle of its products, Merck seeks to evaluate their potential and adapt to changes in the external environment. Collaborating with various stakeholders, including private, governmental, multilateral, and non-profit organizations, the Company seeks to design and deliver sustainable access solutions at the payer, provider,

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and patient levels. Furthermore, the Company incorporates access to health metrics in its scorecard, making it a component of calculating annual incentive pay for the majority of its global employees.

In addition, through social investments, including philanthropic programs and impact investing, Merck is helping to strengthen health systems and build capacity, particularly in communities underserved by health care. The Merck Patient Assistance Program provides certain medicines and adult vaccines for free to people in the U.S. and U.S. territories who do not have prescription drug or health insurance coverage and who, without the Company’s assistance, cannot afford their Merck medicines and vaccines. Globally, Merck has made substantial contributions to access to health through key initiatives, including product donations for humanitarian assistance in low-income countries through the Medical Outreach Program. The Mectizan Donation Program, the longest running disease-specific drug donation program of its kind, supports the elimination of two neglected tropical diseases – onchocerciasis and lymphatic filariasis. Additionally, through Merck for Mothers, the Company provides funding, and scientific and business acumen to help global health partners strengthen health systems, expand access to critical maternal health services, and end preventable deaths from complications of pregnancy and childbirth. Merck also supports the Merck Foundation, an independent grantmaking organization helping to address systemic barriers to access to health care.

Privacy and Data Protection

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. The legislative and regulatory landscape for privacy and data protection continues to evolve. 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.

Failure to comply with the requirements of the GDPR and the related national data protection laws of the EU Member States may result in significant monetary fines and other administrative penalties as well as civil liability claims from individuals whose personal data was processed. Data protection authorities from the different EU Member States may still implement certain variations, enforce the GDPR and national data protection laws differently, and introduce additional national regulations and guidelines, which adds to the complexity of processing personal data in the EU. Guidance developed at both the EU level and at the national level in individual EU Member States concerning implementation and compliance practices is often updated or otherwise revised.

There is, moreover, a growing trend towards required public disclosure of clinical trial data in the EU which adds to the complexity of obligations relating to processing health data from clinical trials. Failing to comply with these obligations could lead to government enforcement actions and significant penalties against the Company, harm to its reputation, and adversely impact its business and operating results. The uncertainty regarding the interplay between

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different regulatory frameworks further adds to the complexity that the Company faces with regard to data protection regulation.

In 2021, China passed the Personal Information Protection Law (PIPL) that aims to standardize the handling of personal information in China. The PIPL currently applies to the processing of personal information of natural persons in China, the processing of personal information outside China where the purpose is to provide products and services in China, and to analyze the activities of individuals in China. While similar to the GDPR, the PIPL contains unique requirements not found in the GDPR. The Company has developed and implemented comprehensive plans to ensure compliance with the PIPL, including plans relating to data localization and cross-border transfers.

Additional laws and regulations enacted in Canada, Europe, Asia, Latin America, the Middle East and 19 states in the U.S. have increased enforcement and litigation activity in the U.S. and other developed markets, as well as increased regulatory cooperation among privacy authorities globally. The Company has adopted a comprehensive global privacy program to manage these evolving requirements and risks and to facilitate the transfer of personal information across international borders.

Distribution

The Company sells its human health pharmaceutical products primarily to drug wholesalers and retailers, hospitals, government agencies and managed health care providers, such as health maintenance organizations, pharmacy benefit managers and other institutions. Human health vaccines are sold primarily to physicians, wholesalers, distributors and government entities. The Company’s professional representatives communicate the effectiveness, safety and value of the Company’s pharmaceutical and vaccine products to health care professionals in private practice, group practices, hospitals and managed care organizations. The Company sells its animal health products to veterinarians, distributors, animal producers, farmers and pet owners.

Raw Materials

The Company obtains raw materials essential to its business from numerous suppliers worldwide. Most of the principal materials the Company uses in its manufacturing operations are available from more than one source. However, the Company obtains certain raw or intermediate materials primarily from only one source. The Company attempts, if possible, to mitigate the potential risk associated with raw materials, components and supplies through inventory and appropriate supplier management.

Patents, Trademarks and Licenses

Patent protection is considered, in the aggregate, to be of material importance to the Company’s marketing of its products in the U.S. and in most major foreign markets. Patents may not only cover a product per se, but also pharmaceutical formulations of a product, processes for making a product, including intermediates useful in those processes, and methods of treatment or other uses of a product. Patent protection for individual products extends for varying periods in accordance with the legal life of patents in individual countries. The protection afforded, which may also vary from country to country, depends upon the type of patent and its scope of coverage.

Patent portfolios developed for products introduced by the Company normally provide varying degrees of market exclusivity. Key patents, which generally cover the product per se, may be subject to a patent term restoration (also known as patent term extension or PTE) of up to five years in the U.S., Japan, and certain other jurisdictions. In Europe, up to five years of extended term may be available in the form of a Supplementary Protection Certificate (SPC). PTEs and SPCs are awarded to offset a portion of the patent term lost during the clinical testing and regulatory review process of a product prior to approval. The Food and Drug Administration Modernization Act includes a Pediatric Exclusivity Provision that may provide an additional six months of market exclusivity (added to the patent term for all Orange Book-listed patents, and to the regulatory data exclusivity term for small molecule and biologic products) in the U.S. for indications of new or currently marketed drugs if certain agreed upon pediatric studies are completed by the applicant. The EU also provides an additional six months of pediatric market exclusivity attached to a product’s SPC term for both small molecule and biologic products. Japan attaches the additional term for pediatric studies to market exclusivity and this extension is unrelated to patent term. In some countries, one or more regulatory exclusivities, including data exclusivity, may provide parallel market protection that is complementary to patent protection and, in some cases, may provide more effective or longer lasting marketing exclusivity than a product’s patent portfolio. In the U.S., the regulatory data/marketing protection term generally runs five years from first marketing approval of a new chemical entity, extended to seven years for an orphan drug indication, and twelve years from first marketing approval of a biological product.

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The table below provides a list of expiration dates, which include any pending PTE and SPC periods where indicated, for the key patent protection in the U.S., the EU, Japan and China for the following marketed products:

Janumet 2026(3) Expired N/A Expired

Janumet XR 2026(3) N/A N/A Expired

Isentress Expired(4) Expired 2026(5) Expired

Bridion 2026 Expired Expired Expired

Gardasil 2028 Expired Expired Expired

Vaxneuvance 2031(14) No Patent(15) No Patent(15) N/A

Welireg 2035 (with pending PTE) N/A N/A N/A

Capvaxive 2038 N/A N/A N/A

Note: Compound patent unless otherwise noted. Certain of the products listed may be the subject of patent litigation. See Item 8. “Financial Statements and Supplementary Data,” Note 10. “Contingencies and Environmental Liabilities” below.

N/A: Currently no marketing approval.

(1)The EU date represents the expiration date for the following four countries: France, Germany, Italy, and Spain (Major EU Markets). If SPC applications have been filed but have not been granted in all Major EU Markets, both the patent expiry date and the SPC expiry date are listed.

(2)The PTE system in Japan allows for a patent to be extended more than once provided the later approval is directed to a different indication from that of the previous approval. This may result in multiple PTE approvals for a given patent, each with its own expiration date.

(3)As a result of settlement agreements related to a patent directed to the specific sitagliptin salt form of the products, exclusivity will extend through May 2026 for Januvia and Janumet, and through July 2026 for Janumet XR.

(4)Generic entry is not anticipated in 2025.

(5)Expiry date reflects granted PTE for the 600 mg tablet in Japan.

(6)Part of a global strategic oncology collaboration with Eisai Co., Ltd.

(7)Eligible for six months pediatric market exclusivity.

(8)The compound patent family contains two additional patents that expire in 2029 due to patent term adjustment resulting from patent office delay. These patents are based on the initial discovery of the active ingredient in Keytruda. While these patents may provide additional protection, the Company expects that they will be the subject of litigation in the future.

(9)Part of a global strategic oncology collaboration with AstraZeneca.

(10)Eligible for 12 years of data exclusivity in the U.S. and 10 years in the EU, which will expire in 2036 and 2034, respectively. Granted patents covering methods of treating pulmonary arterial hypertension with Winrevair, which will expire in 2037 (absent PTE or SPC), may provide additional exclusivity.

(11)Commercialized under a worldwide collaboration with Bayer AG.

(12)The Company has no marketing rights in the U.S.

(13)Data exclusivity has also been granted in the EU and expires in January 2028; eligible for two additional years of market exclusivity based on pediatric studies for an orphan product.

(14)PTE pending but is not included in the listed patent expiry date. Data exclusivity has been granted in the U.S. and expires in July 2033.

(15)Data exclusivity has been granted in the EU and Japan, and expires in December 2031 and September 2030, respectively.

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The Company has the following key U.S. patent protection for drug candidates under review in the U.S. by the FDA:

Under Review in the U.S. Currently AnticipatedYear of Expiration (in the U.S.)

(1)Being developed in a collaboration with Daiichi Sankyo. The FDA issued a Complete Response Letter for the application in June 2024.

The Company also has the following key U.S. patent protection for drug candidates in Phase 3 development:

Phase 3 Drug Candidate Currently AnticipatedYear of Expiration (in the U.S.)

MK-1308A (quavonlimab + pembrolizumab) 2035

MK-3475A (pembrolizumab + hyaluronidase subcutaneous) 2039

(1)On partial clinical hold for higher doses of islatravir than those used in current clinical trials.

(2)Being developed in a collaboration.

(3)Available in the U.S. under Emergency Use Authorization.

(4)Program is in a Phase 2/3 study.

Unless otherwise noted, the patents in the above tables cover the product per se (also known as compound patents). For those drug candidates under review or in development, the key U.S. patents may be subject to a future PTE of up to five years and/or six months of pediatric market exclusivity. In addition, depending on the circumstances surrounding any final regulatory approval of the product, there may be other granted patents or pending patent applications that could have relevance to the product as finally approved.

While the expiration of the compound patent generally results in loss of market exclusivity for the covered pharmaceutical product, other patents may provide additional market exclusivity associated with certain aspects of the product that extends beyond the compound patent expiration, including those derived from the initial discovery of the product’s active ingredient(s) or from product-related innovation that occurs after this initial discovery. These include later-expiring patents directed to (i) processes and intermediates related to methods of manufacture of the active ingredient(s), (ii) use(s) of the product, and (iii) novel compositions and formulations of the product. The effect of product patent expiration on pharmaceutical product sales may also depend upon many other factors such as the nature of the market and the position of the product in it, the growth of the market, the complexities and economics of the process for manufacture of the active ingredient(s) of the product and the requirements of new drug provisions of the Federal Food, Drug and Cosmetic Act or similar laws and regulations in other countries. In addition, in the U.S. and certain other countries, a variety of different regulatory exclusivities that impact market exclusivity may be available under relevant law.

For further information with respect to the Company’s patents, see Item 1A. “Risk Factors” and Item 8. “Financial Statements and Supplementary Data,” Note 10. “Contingencies and Environmental Liabilities” below.

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Worldwide, all of the Company’s important products are sold under trademarks that are considered in the aggregate to be of material importance. Trademark protection continues in some countries as long as used; in other countries, as long as registered. Registration is for fixed terms and can be renewed indefinitely.

Royalty income in 2024 on patent and know-how licenses and other rights amounted to $1.1 billion. Merck also incurred royalty expenses amounting to $1.9 billion in 2024 under patent and know-how licenses it holds.

Research and Development

The Company’s business is characterized by the introduction of new products or new uses for existing products through a strong research and development program. At December 31, 2024, approximately 23,500 people were employed in the Company’s research activities. The Company prioritizes its research and development efforts and focuses on candidates that it believes represent breakthrough science for unmet medical needs that will make a difference for patients and payers.

The Company maintains a number of long-term exploratory and fundamental research programs in biology and chemistry as well as research programs directed toward product development. The Company’s research and development model is designed to increase productivity and improve the probability of success by prioritizing the Company’s research and development resources on candidates the Company believes are capable of providing unambiguous, promotable advantages to patients and payers and delivering the maximum value of its approved medicines and vaccines through new indications and new formulations. Merck is pursuing emerging product opportunities independent of therapeutic area or modality. The Company is committed to ensuring that externally sourced programs remain an important component of its pipeline strategy, with a focus on supplementing its internal research through acquisitions as well as a licensing and external alliance strategy focused on the entire spectrum of collaborations from early research to late-stage compounds, as well as access to new technologies.

The Company’s clinical pipeline includes candidates in multiple disease areas, including cancer, cardiovascular diseases, metabolic diseases, infectious diseases, neurosciences, immunology, ophthalmology, respiratory diseases, and vaccines.

In the development of human health products, industry practice and government regulations in the U.S. and most foreign countries provide for the determination of effectiveness and safety of new chemical compounds through preclinical tests and controlled clinical evaluation. Before a new drug or vaccine may be marketed in the U.S., recorded data on preclinical and clinical experience are included in the New Drug Application (NDA) for a drug or the Biologics License Application (BLA) for a vaccine or biologic submitted to the FDA for the required approval.

Once the Company’s scientists discover a new small molecule compound or biologic that they believe has promise to treat a medical condition, the Company commences preclinical testing with that compound. Preclinical testing includes laboratory testing and animal safety studies to gather data on chemistry, pharmacology, immunogenicity and toxicology. Pending acceptable preclinical data, the Company will initiate clinical testing in accordance with established regulatory requirements. The clinical testing begins with Phase 1 studies, which are designed to assess safety, tolerability, pharmacokinetics, and preliminary pharmacodynamic activity of the compound in humans. If favorable, additional, larger Phase 2 studies are initiated to determine the efficacy of the compound in the affected population, define appropriate dosing for the compound, as well as identify any adverse effects that could limit the compound’s usefulness. In some situations, the clinical program incorporates adaptive design methodology to use accumulating data to decide how to modify aspects of the ongoing clinical study as it continues, without undermining the validity and integrity of the trial. One type of adaptive clinical trial is an adaptive Phase 2a/2b trial design, a two-stage trial design consisting of a Phase 2a proof-of-concept stage and a Phase 2b dose-optimization finding stage. If data from the Phase 2 trials are satisfactory, the Company commences large-scale Phase 3 trials to confirm the compound’s efficacy and safety. Another type of adaptive clinical trial is an adaptive Phase 2/3 trial design, a study that includes an interim analysis and an adaptation that changes the trial from having features common in a Phase 2 study (e.g., multiple dose groups) to a design similar to a Phase 3 trial. An adaptive Phase 2/3 trial design reduces timelines by eliminating activities which would be required to start a separate study. Upon completion of Phase 3 trials, if satisfactory, the Company submits regulatory filings with the appropriate regulatory agencies around the world to have the product candidate approved for marketing. There can be no assurance that a compound that is the result of any particular program will obtain the regulatory approvals necessary for it to be marketed.

Vaccine development follows the same general pathway as for drugs. Preclinical testing focuses on the vaccine’s safety and ability to elicit a protective immune response (immunogenicity). Pre-marketing vaccine clinical trials are typically done in three phases. Initial Phase 1 clinical studies are conducted in normal subjects to evaluate the safety, tolerability and immunogenicity of the vaccine candidate. Phase 2 studies are dose-ranging studies and provide additional data on safety, immunogenicity and/or effectiveness. Finally, Phase 3 trials are conducted in the

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intended population for licensure and provide data on immunogenicity and/or effectiveness, as well as safety, to support applications for regulatory approvals. If successful, the Company submits regulatory filings with the appropriate regulatory agencies.

United States

In the U.S., the FDA review process begins once a complete NDA or BLA is submitted, received and accepted for review by the agency. Within 60 days after receipt, the FDA determines if the application is sufficiently complete to permit a substantive review. The FDA also assesses, at that time, whether the application will be granted a priority review or standard review. Pursuant to the Prescription Drug User Fee Act VII (PDUFA), the FDA review period target for NDAs or original BLAs is either six months, for priority review, or ten months, for a standard review, from the time the application is deemed sufficiently complete. For original efficacy supplements to an NDA or BLA, the FDA review period target is six months, for priority review, or ten months, for a standard review, from the time the supplemental application is received. Once the review timelines are determined, the FDA will generally act upon the application within those timeline goals, unless a major amendment has been submitted (either at the Company’s own initiative or the FDA’s request) to the pending application. If this occurs, the FDA may extend the review period to allow for review of the new information, but by no more than three months. Extensions to the review period are communicated to the Company. The FDA can act on an application either by issuing an approval letter or by issuing a Complete Response Letter (CRL) stating that the application will not be approved in its present form and describing all deficiencies that the FDA has identified. Should the Company wish to pursue an application after receiving a CRL, it can resubmit the application with information that addresses the questions or issues identified by the FDA in order to support approval. Resubmissions are subject to review period targets, which vary depending on the underlying submission type and the content of the resubmission.

The FDA has four program designations — Fast Track, Breakthrough Therapy, Accelerated Approval, and Priority Review — to facilitate and expedite development and review of new drugs to address unmet medical needs in the treatment of serious or life-threatening conditions. The Fast Track designation provides pharmaceutical manufacturers with opportunities for frequent interactions with FDA reviewers during the product’s development and the ability for the manufacturer to do a rolling submission of the NDA/BLA. A rolling submission allows completed portions of the application to be submitted and reviewed by the FDA on an ongoing basis. The Breakthrough Therapy designation provides manufacturers with all of the features of the Fast Track designation as well as intensive guidance on implementing an efficient development program for the product and a commitment by the FDA to involve senior managers and experienced staff in the review. The Accelerated Approval designation allows the FDA to approve a product based on an effect on a surrogate or intermediate endpoint that is reasonably likely to predict a product’s clinical benefit and generally requires the manufacturer to conduct required post-approval confirmatory trials to verify the clinical benefit. The Priority Review designation means that the FDA’s goal is to take action on the NDA/BLA within six months, compared to ten months under standard review. More than one of these special designations can be granted for a given application (i.e., a product designated as a Breakthrough Therapy may also be eligible for Priority Review).

Due to the COVID-19 public health crisis, in 2020, the U.S. Secretary of Health and Human Services (Secretary) exercised statutory authority to determine that a public health emergency existed, and declared those circumstances justified the emergency use of drugs and biological products as authorized by the FDA. In 2023, the Secretary issued an amended determination that a public health emergency or a significant potential for a public health emergency existed, and declared that circumstances continued to justify authorization of emergency use of these products. While in effect, this declaration (as amended) enables the FDA to issue Emergency Use Authorizations (EUAs) permitting distribution and use of specific medical products absent NDA/BLA submission or approval, including products to treat or prevent diseases or conditions caused by the SARS-CoV-2 virus, subject to the terms of any such EUAs. The Company is currently marketing Lagevrio in the U.S. pursuant to an EUA. The FDA must make certain findings to grant an EUA, including that it is reasonable to believe based on the totality of evidence that the drug or biologic may be effective, and that known or potential benefits when used under the terms of the EUA outweigh known or potential risks. Additionally, the FDA must find that there is no adequate, approved and available alternative to the emergency use of the authorized drug or biologic. The FDA may revise or revoke an EUA if the circumstances justifying its issuance no longer exist, the criteria for its issuance are no longer met, or other circumstances make a revision or revocation appropriate to protect the public health or safety.

European Union

The primary method the Company uses to obtain marketing authorization of pharmaceutical products in the EU is through the “centralized procedure.” This procedure is compulsory for certain pharmaceutical products, in particular those using biotechnological processes, and is also available for certain new chemical compounds and products. A company seeking to market an innovative pharmaceutical product through the centralized procedure must file a complete set of safety data and efficacy data as part of a Marketing Authorization Application (MAA) with the

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European Medicines Agency (EMA). After the EMA evaluates the MAA, it provides a recommendation to the EC and the EC then approves or denies the MAA. It is also possible for new chemical products to obtain marketing authorization in the EU through a “mutual recognition procedure” in which an application is made to a single member state and, if the member state approves the pharmaceutical product under a national procedure, the applicant may submit that approval to the mutual recognition procedure of some or all other EU Member States.

Japan

In Japan, the Company submits new drug applications to the PMDA for its pharmaceutical regulatory review. The PMDA is an independent administrative agency which is under the jurisdiction of the Ministry of Health, Labor and Welfare (MHLW). The PMDA considers multiple factors in its review process, including the drug’s safety, efficacy, quality, and manufacturing process in accordance with the Act on Securing Quality, Efficacy and Safety of Products Including Pharmaceuticals and Medical Devices. In addition, there are various other regulations and guidelines issued by the MHLW or the PMDA that must also be complied with in order to secure approval. The length of the PMDA review process can vary, but it typically takes around one year for a new drug to be approved in Japan. The review period may be shortened if the drug candidate is designated by the MHLW as an innovative drug satisfying certain conditions.

China

In China, the Company submits marketing applications to the NMPA for an independent review. The NMPA considers multiple factors in its review process, including the drug‘s safety, efficacy, quality, and manufacturing process. Moreover, the NMPA implements strict regulations to ensure that all drugs meet the same standards as those set by the WHO. The agency establishes stringent safety and efficacy requirements for drug approval. The length of the NMPA review process can vary, but it typically takes around one to two years for a new drug to be approved in China.

Other Markets

Outside of the U.S., the EU, Japan and China, the Company submits marketing applications to national regulatory authorities. Examples of such are Health Canada, Agência Nacional de Vigilância Sanatária in Brazil, Korea Food and Drug Administration in South Korea, and the Therapeutic Goods Administration in Australia. Each country has a separate and independent review process and timeline. In many markets, approval times can be longer as the regulatory authority requires approval in a major market, such as the U.S. or the EU, and issuance of a Certificate of Pharmaceutical Product from that market before initiating their local review process.

Research and Development Update

The Company currently has several candidates under regulatory review in the U.S. and internationally or in late-stage clinical development.

MK-1022, patritumab deruxtecan, is a potential first-in-class HER3 directed DXd antibody drug conjugate (ADC), under review by the FDA for the treatment of adult patients with locally advanced or metastatic EGFR-mutated NSCLC previously treated with two or more systemic therapies. The BLA is based on the primary results from the HERTHENA-Lung01 pivotal Phase 2 trial and data results presented at the IASLC 2023 World Conference on Lung Cancer, which were simultaneously published in the Journal of Clinical Oncology. In June 2024, the FDA issued a CRL for the 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 based on the LITESPARK-004 clinical trial and for the treatment of certain adults with previously treated advanced RCC based on the LITESPARK-005 clinical trial. Additionally, in January 2025, the FDA accepted for priority review a supplemental NDA seeking approval of Welireg for the treatment of adult and pediatric patients (12 years and older) with advanced, unresectable, or metastatic pheochromocytoma and paraganglioma, based on the LITESPARK-015 trial. The FDA set a PDUFA, or target action, date of May 26, 2025.

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. The applications are supported by results from multiple Phase 3 clinical studies evaluating V116 in both vaccine-naïve and vaccine-experienced adult patient populations. In January 2025, the Committee for Medicinal Products for Human Use (CHMP) of the EMA recommended the approval of Capvaxive for active immunization for the prevention of invasive disease and pneumonia caused by certain types of Streptococcus pneumoniae in individuals 18 years of age and older. The CHMP’s recommendation will now be reviewed by the EC for marketing authorization in the EU, and a final decision is expected by the second quarter of 2025.

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MK-7962, Winrevair, Merck’s novel activin signaling inhibitor, is under review in Japan for the treatment of adult patients with PAH based on the Phase 3 STELLAR trial. In November 2024, Merck announced positive topline results from the Phase 3 ZENITH study, evaluating Winrevair in adults with PAH with WHO Group 1 FC III or IV at high risk of mortality. Based on the positive results of an interim analysis, an independent data monitoring committee recommended that the study be stopped early due to overwhelming efficacy. In addition, in January 2025, Merck announced the Phase 3 HYPERION study evaluating Winrevair in newly diagnosed adults with PAH FC II or III at intermediate or high risk of disease progression was also stopped early based on the positive results from the interim analysis of the ZENITH trial and a review of the totality of data from the Winrevair clinical program to date. All participants in both the ZENITH and HYPERION studies will be offered the opportunity to receive Winrevair as part of the open-label, long-term extension study, SOTERIA.

MK-1654, clesrovimab, is an investigational prophylactic long-acting monoclonal antibody designed to protect infants from respiratory syncytial virus (RSV) disease during their first RSV season. In December 2024, the FDA accepted the BLA for clesrovimab and set a PDUFA date of June 10, 2025. Clesrovimab is also under review in the EU.

MK-3475, Keytruda, is an anti-PD-1 therapy approved for the treatment of many cancers that is in clinical development for expanded indications. These studies encompass more than 30 cancer types including: biliary, estrogen receptor positive breast, triple-negative breast, cervical, colorectal, endometrial, esophageal, gastric, glioblastoma, head and neck, hepatocellular, Hodgkin lymphoma, non-Hodgkin lymphoma, non-small-cell lung, small-cell lung, melanoma, malignant pleural mesothelioma, ovarian, prostate, renal, and urothelial, several of which are currently in Phase 3 clinical development. Further trials are being planned for other cancers.

Keytruda is under review in the EU and Japan for the first-line treatment of adult patients with unresectable advanced or metastatic malignant pleural mesothelioma, based on the Phase 2/3 IND.227/KEYNOTE-483 trial. In November 2024, the EMA’s CHMP adopted a positive opinion recommending approval of Keytruda in combination with pemetrexed and platinum chemotherapy for the first-line treatment of adult patients with unresectable non-epithelioid malignant pleural mesothelioma. In December 2024, the Company requested a re-examination from the EMA’s CHMP for an extension of the indication to include approval in combination with pemetrexed and platinum chemotherapy for the first-line treatment of adults and adolescents aged 12 years and older with unresectable advanced or metastatic malignant pleural mesothelioma, based on final results from the KEYNOTE-483 trial.

The Company is diversifying its oncology portfolio and executing on its strategy which is broadly based on three strategic pillars: immuno-oncology, precision molecular targeting and tissue targeting. Merck has numerous Phase 3 oncology programs within these pillars.

Immuno-oncology

•MK-1308A is the coformulation of quavonlimab, Merck’s novel investigational anti-CTLA-4 antibody, in combination with pembrolizumab, being evaluated for the treatment of RCC.

•MK-3475, Keytruda, is being evaluated in the therapeutic areas of hepatocellular, ovarian and small-cell lung cancers.

•MK-3475A is the subcutaneous coformulation of pembrolizumab in combination with hyaluronidase being evaluated for comparability with intravenous pembrolizumab in metastatic NSCLC.

•V940 (mRNA-4157) is an investigational individualized neoantigen therapy being evaluated in combination with Keytruda as an adjuvant treatment in patients with certain types of melanoma. The FDA and EMA granted Breakthrough Therapy designation and Priority Medicines (PRIME) scheme designation, respectively, for V940 (mRNA-4157) in combination with Keytruda for the adjuvant treatment of patients with certain stages of high-risk melanoma following complete resection. V940 (mRNA-4157) is also being evaluated as adjuvant and perioperative treatment for certain patients with NSCLC. V940 is being developed as part of a collaboration with Moderna, Inc.

Precision molecular targeting

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

•MK-1084 is an investigational oral selective KRAS G12C inhibitor being evaluated in combination with Keytruda for the first-line treatment of certain patients with metastatic NSCLC.

•MK-3543, bomedemstat, is an investigational orally available lysine-specific demethylase 1 inhibitor, being evaluated for the treatment of certain patients with essential thrombocythemia. Bomedemstat has FDA

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Orphan Drug and Fast Track Designation for the treatment of essential thrombocythemia and myelofibrosis, Orphan Drug Designation for the treatment of acute myeloid leukemia and PRIME scheme designation by the EMA for the treatment of myelofibrosis.

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

•MK-7339, Lynparza, is an oral PARP inhibitor being evaluated in combination with Keytruda for expanded indications in the therapeutic areas of NSCLC and SCLC. Lynparza is being developed as part of a collaboration with AstraZeneca PLC.

•MK-7902, Lenvima, is an oral receptor tyrosine kinase inhibitor being evaluated in combination with Keytruda for expanded indications in the therapeutic area of esophageal cancer. Lenvima is being developed as part of a collaboration with Eisai Co., Ltd.

Tissue targeting

•MK-1022, patritumab deruxtecan, is being evaluated in the therapeutic area of NSCLC as noted above.

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

•MK-2400, ifinatamab deruxtecan, is an ADC being evaluated in patients with relapsed SCLC versus chemotherapy. MK-2400 is being developed as part of a collaboration with Daiichi Sankyo.

•MK-2870, sacituzumab tirumotecan, is an investigational trophoblast cell-surface antigen 2 (TROP2)-directed ADC being evaluated for certain patients with breast, cervical, endometrial, gastric and non-small-cell lung cancers. The FDA granted Breakthrough Therapy designation to sacituzumab tirumotecan for the treatment of patients with advanced or metastatic nonsquamous NSCLC with EGFR mutations whose disease progressed on or after tyrosine kinase inhibitor and platinum-based chemotherapy. Sacituzumab tirumotecan is being developed as part of a collaboration with Kelun-Biotech.

Additionally, the Company currently has candidates in Phase 3 clinical development in several other therapeutic areas.

•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, which is in clinical development for the treatment of diabetic macular edema and neovascular age-related macular degeneration. MK-3000 was obtained in connection with the July 2024 acquisition of Eyebiotech Limited.

•MK-8591A is a once-daily oral combination of doravirine and islatravir, an investigational nucleoside reverse transcriptase translocation inhibitor (NRTTI), being evaluated for the treatment of HIV infection in previously untreated adults and as a switch in antiretroviral therapy in virologically suppressed adults. MK-8591D is an oral once-weekly combination of islatravir and Gilead Sciences Inc.’s lenacapavir being evaluated for the treatment of HIV infection in virologically suppressed adults. In 2021, the FDA placed clinical holds on the islatravir investigational NDAs based on observations of decreases in total lymphocyte and CD4+ T-cell counts in some participants receiving islatravir in clinical studies. The investigational NDAs for the doravirine/islatravir and the islatravir/lenacapavir once-weekly treatment regimens remain under a partial clinical hold for any studies that would use islatravir doses higher than the doses considered for the revised clinical programs.

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

•MK-7240, tulisokibart, is a humanized monoclonal antibody directed to tumor necrosis factor-like ligand 1A, a target associated with both intestinal inflammation and fibrosis, being evaluated for the treatment of Crohn’s disease and ulcerative colitis.

•MK-4482, Lagevrio, 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. Merck is developing Lagevrio in collaboration with Ridgeback Biotherapeutics LP (Ridgeback). The FDA granted Emergency Use Authorization for Lagevrio in December 2021, which was last reissued in November 2023. Lagevrio is authorized for the treatment of adults with a current diagnosis of mild to moderate COVID-19, and who are at high risk for progression to severe COVID-19, including hospitalization or death, and for whom alternative COVID-19 treatment options approved or authorized by the FDA are not accessible or clinically appropriate. Lagevrio is not approved for any use in the U.S. and is authorized only for the duration of the declaration that circumstances exist justifying the authorization of its emergency use under the Food, Drug and Cosmetic Act, unless the authorization is terminated or revoked sooner. In 2024, an additional Phase 3 clinical trial

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(MOVe-NOW) was initiated to evaluate Lagevrio for the treatment of adults with COVID-19 at high risk for disease progression. MOVe-NOW will build on existing Lagevrio data to assess efficacy in the current COVID-19 environment and support applications for licensure.

The Company also terminated certain of its development programs in 2024.

•MK-7264, gefapixant, is a non-narcotic, oral selective P2X3 receptor antagonist for the treatment of refractory or unexplained chronic cough in adults. In December 2023, the FDA issued a second CRL regarding the resubmission of Merck’s NDA for gefapixant. In the CRL, the FDA concluded that Merck’s application did not meet substantial evidence of effectiveness for treating refractory or unexplained chronic cough. The CRL was not related to the safety of gefapixant. Merck has withdrawn its application for gefapixant from the FDA and does not plan to refile.

•In December 2024, Merck announced the discontinuation of the Phase 3 KeyVibe-003 and KeyVibe-007 trials, which were evaluating MK-7684A, the fixed-dose combination of vibostolimab, an anti-TIGIT antibody, and pembrolizumab, in certain patients with NSCLC, based on the recommendation of an independent data monitoring committee. In a pre-planned analysis, both trials met the pre-specified futility criteria for the primary endpoint of overall survival. Considering the totality of data from the Phase 3 KeyVibe studies, including the efficacy outcomes from KeyVibe-003 and KeyVibe-007, the Company decided to discontinue the Phase 3 KeyVibe-006 trial and other vibostolimab studies.

•Also in December 2024, Merck announced the discontinuation of the clinical development program for favezelimab, an anti-LAG-3 antibody, and will stop enrollment in the Phase 3 KEYFORM-008 trial evaluating the fixed-dose combination of favezelimab and pembrolizumab (MK-4280A) in patients with relapsed or refractory cHL whose disease has progressed following prior anti-PD-1 therapy. The Company made this decision after a thorough evaluation of data from the favezelimab clinical program. Data analyses for the Phase 3 trials are ongoing, and the results will be shared with the scientific community.

•Based on the topline results of the MK-2060 Phase 2 study, Merck will not proceed to Phase 3 clinical development. The Phase 2 study results will be presented at a scientific meeting later in 2025.

•The Phase 2b clinical trial for MK-8189 as a monotherapy for acute schizophrenia did not meet its primary efficacy endpoint and further development in schizophrenia, bipolar, and dementia indications has stopped. Potential alternative indications for MK-8189 are being explored.

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The chart below reflects the Company’s research pipeline as of February 21, 2025. Candidates shown in Phase 3 include the date such candidate entered into Phase 3 development. Candidates shown in Phase 2 include the most advanced compound with a specific mechanism or, if listed compounds have the same mechanism, they are each currently intended for commercialization in a given therapeutic area. Small molecules and biologics are given MK-number designations and vaccine candidates are given V-number designations. Except as otherwise noted, candidates in Phase 1, additional indications in the same therapeutic area (other than with respect to cancer and immunology) and additional claims, line extensions or formulations for in-line products are not shown.

Phase 2

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Phase 3 (Phase 3 entry date) Under Review

Human Capital

As of December 31, 2024, the Company had approximately 75,000 employees worldwide, with approximately 31,000 employed in the U.S., including Puerto Rico, and approximately 15,000 third-party contractors globally. Third-party contractors include the Company’s temporary workers, independent contractors, and freelancers who are viewed as full-time equivalent employees; they exclude outsourced service providers. Approximately 73,000 of the Company’s employees are full-time employees. Globally, women comprise 52% of employees, and in the U.S. individuals from underrepresented ethnic groups comprise 37% of its workforce (the Company defines workforce as its employees). Women comprise 46% of the members of the Board of Directors. Additionally, the Company’s senior management team is made up of 39% women. Approximately 21% of the Company’s employees are represented by various collective bargaining groups. The Company’s voluntary turnover rate was approximately 4.6% and 5.6%, in 2024 and 2023, respectively.

The Company recognizes that its employees are critical to meet the needs of its patients and customers and that its ability to excel depends on the integrity, skill, and collaboration of its employees.

Talent Acquisition

The Company uses a comprehensive approach to ensure recruiting, retention and leadership development goals are systematically executed throughout the Company and that it hires talented leaders with a wide

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range of knowledge, skills, backgrounds and perspectives. In addition, the Company utilizes a comprehensive communications strategy, employee branding and marketing outreach, social media and strategic alliance partnerships to reach a broad pool of talent in its critical business areas. In 2024, the Company hired approximately 7,300 employees across the globe through various channels including the Company’s external career site, direct passive candidate sourcing, employee referrals, universities and other external sources.

Enabling a Collaborative Work Environment

Fostering a collaborative environment is fundamental to the Company’s success and core to future innovation. The Company strives to create an environment of acceptance, engagement and empowerment. The Company seeks to hire and develop the best talent by providing equal opportunity to all people. The Company creates competitive advantages by leveraging practices which help to meet the needs of all our patients worldwide. This includes evaluating social determinants of health when developing commercialization strategies and leveraging employee insights to improve performance.

Compensation and Benefits

The Company provides a valuable suite of compensation and benefits programs that reflect its commitment to attract, retain and motivate its talent, and support its employees and their families in every stage of life. The Company continuously monitors and adjusts its compensation and benefit programs to ensure they are competitive, contemporary, helpful and engaging, and that they support strategic imperatives such as fairness, flexibility, quality, security and affordability. For example, the Company regularly monitors and evaluates its pay practices and policies to ensure that it is paying employees fairly. The Company offers a personal health care concierge service to assist U.S. employees participating in the Company medical plan with their health care needs. Aligned with its business and in support of its cancer care strategy, the Company provides enhanced cancer screening benefits with cash incentives, immediate access to two leading cancer centers of excellence for U.S. employees and high value cancer support resources (e.g., caregiving and mental health) for employees and their families. Globally, the Company implemented a minimum standard of 12 weeks of paid parental leave. In the U.S., the Company’s benefits rank in the top quartile of Fortune 100 companies under the Aon 2024 Benefits Index. The Company has been included in the Seramount (previously the Working Mother) 100 Best Companies ranking for 38 consecutive years and was named a top ten Best Company for Moms in 2024.

Employee Well-being

The Company is committed to helping its employees and their families improve their own health and well-being, whether physical, mental, financial, or social. The Company’s programs ensure quality, competitive value, protection from significant financial hardship and access to tools and resources to support employees and their families in all stages of their career and their lives, earning the Company accolades such as the Business Group on Health’s Best Employers Excellence in Health & Well-being and the CEO Roundtable on Cancer’s Global Gold Standard Employer accreditation in 2024. As part of the Company’s overall culture of well-being, the Company fosters an array of flexible work arrangements and offers onsite services so employees can thrive. For example, in the U.S., these include onsite health care professionals at many major sites, cafeterias committed to healthy menu offerings, onsite childcare, onsite gyms, and the convenient option to bank through an employee credit union.

Engaging Employees

The Company strengthens employee engagement by fostering a safe, positive, and supportive workplace. Merck encourages candid employee feedback through global employee surveys and peer feedback processes. The Company encourages professional networking and collaboration, enabling employees to connect and grow. Additionally, Merck provides community volunteering opportunities, reflecting its commitment to social responsibility. By building strong relationships with its employees, the Company strives to ensure that every voice is heard, fostering an engaging employee experience that drives Merck forward.

Talent Management and Development

As the Company pursues its goal of becoming the world’s premier research-based biopharmaceutical company, there is a consistent focus on the importance of continuously developing its motivated and talented people. The Company is committed to talent growth for all, allowing its employees to move more fluidly across the organization, unlocking an environment that allows them to shape their career pathways via non-linear and wide-ranging opportunities and experience. Merck’s current talent management system supports company-wide performance management, leadership development, talent reviews and succession planning. Annual performance reviews help further the professional development of the Company’s employees and ensure that the Company’s workforce is aligned with the Company’s objectives. The Company seeks to continuously build the skills and capabilities of its workforce to accelerate talent, improve performance and mitigate risk through relevant continuous learning experiences. This includes, but is not limited to, building leadership and management skills, as well as providing technical and functional training to all employees.

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Environmental Matters

Environmental Sustainability

The Company is committed to enabling a safe, sustainable and healthy future and strives to be a strong environmental steward, evolving its efforts in the face of a changing world. The Company’s environmental sustainability strategy has three focus areas:

•Driving operational efficiency;

•Designing new products to minimize environmental impact; and

•Reducing any impacts in the Company’s upstream and downstream value chain.

The Company ensures its ongoing commitment to these areas through thoughtful governance. Its Environmental, Health and Safety Council (EHS Council) is a cross-functional body with leadership representation from each area of the Company’s business and is responsible for overseeing its environmental sustainability strategy, policy, and risk mitigation controls. The EHS Council monitors performance against the Company’s goals and increases transparency on environmental issues within the Company, senior management, and the Board of Directors (the Board). The Global Safety and Environment (GSE) vice president communicates progress on environmental sustainability goals, objectives and other important issues to the Board, senior management and the EHS Council. Additionally, the head of the Environmental Sustainability Center of Excellence is a member of the Environmental, Social and Governance Strategy Management Team, a group of functional experts that advises, shapes, and drives the Company’s long-term sustainability strategy with guidance from an internal cross divisional forum of senior leaders. The Company’s cross-functional Environmental Sustainability Implementation Steering Committee was designated by the EHS Council to oversee the progress of initiatives that support the achievement of the Company’s public goals and provide guidance on resourcing of the Company’s environmental sustainability strategy.

Merck believes that climate change could present risks to its business, as discussed in further detail in Item 1A. “Risk Factors” below under the headings “Climate change or legal, regulatory or market measures to address climate change may negatively affect the Company’s business, results of operations, cash flows and prospects” and “Environmental, social and governance matters may impact the Company’s business and reputation.” Some of the potential impacts of climate change to the Company’s business include increased operating costs due to additional regulatory requirements, physical risks to the Company’s facilities, water limitations and disruptions to its supply chain. These potential risks are integrated into the Company’s business planning, including investment in reducing energy usage, water use and greenhouse gas (GHG) emissions.

The Company has adopted a set of climate goals to help position it to succeed in an increasingly resource-constrained world. These goals address the rising expectations of the Company’s customers, investors, external stakeholders and employees regarding the environmental impact of its operations and supply chain. The Company’s climate goals include reducing Scope 1 and 2 operational GHG emissions 46% by 2030 (from a 2019 baseline), sourcing 100% of its purchased electricity from renewable sources by 2025, and reducing Scope 3 GHG emissions 30% by 2030 (from a 2019 baseline). In 2024, the Company committed to a net-zero target for its GHG emissions across its global operations (Scopes 1, 2 and 3) by 2045, aligned with the guidelines of the Science Based Targets initiative (SBTi). Other environmental sustainability initiatives of the Company include:

•Partnering for progress across the Company’s value chain. The Company is working to reduce its Scope 3 emissions through a robust supplier engagement approach to drive collaboration upstream and downstream in its value chain. By engaging with its suppliers, the Company can identify key ways to reduce its GHG emissions and pinpoint additional tangible benefits for the business.

•Playbooks for a sustainable environment. To help direct and track projects in support of its goals, the Company has developed a series of guidance documents for its global sites. In 2021, the Company launched its Low Carbon Transition Playbook (LCTP), a common platform that includes a gap assessment to help the Company’s global sites evaluate the maturity of their energy programs and help create short- and long-term plans to reduce sites’ carbon intensity and build toward a low-carbon future. Based on learnings from use, the Company issued LCTP 2.0 in 2022 with a capability to facilitate knowledge sharing across sites. In 2022, the Company also created the Waste Diversion Playbook, which takes a similar approach to guide sites on developing a roadmap to their and the Company’s shared 2025 goals on waste diversion, including local waste-diversion strategies and environmentally responsible procurement practices. In 2024, the Company expanded this list with the addition of a Water Conservation Playbook. This approach guides projects consistently across the Company’s global network of sites and enables continuous improvement toward meetings its goals.

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•Realizing the benefits of green and sustainable science. The Company believes that meeting its environmental sustainability goals is intrinsically linked to the creation of innovative, cost-efficient manufacturing processes with low environmental impact. The Company aims to develop efficient and sustainable processes at product launch, with the goal of minimizing material use and waste from its commercial manufacturing. The Company utilizes an innovative “green-by-design” development strategy with a goal to progress from an initial early clinical supply route to a fully optimized and sustainable commercial manufacturing process. In 2024, for the fifth year in a row, the Company received the Peter J. Dunn Award for Green Chemistry and Engineering Impact, an award given by the American Chemical Society in recognition of outstanding implementation of novel green chemistry in the pharmaceutical industry.

•Waste diversion. The Company continuously evaluates its sites’ waste disposal methods to gain a better understanding of its network and changes therein, as well as to identify risks and opportunities in its value chain. Based on its evaluation, the Company implemented programs to divert non-hazardous landfill waste from its two highest landfill-generating sites. The Company remains committed to its 2025 public waste diversion goals of no more than 20% of the Company’s global operational waste sent to landfills or incinerators (without energy recovery) and that 50% of its sites will send zero waste to landfills by 2025.

•Water as a shared resource. As water is a key input to the Company’s manufacturing operations, the Company assesses water risk throughout its network as a standard business practice. Both of the Company’s priority water-stress risk sites have conservation plans in place, and site staff are actively working on water use reduction and recycling improvement projects. These projects are consistent with the Company’s ongoing commitment to achieving its stated goal of maintaining global water use at or below 2015 levels by 2025. The Company’s sites are employing various technologies and techniques aimed at reducing its water footprint and improving operational performance. The Company’s endorsement of the United Nations CEO Water Mandate enables alignment of the Company’s water program with the mandate’s principles. The Company has continued to identify partnerships to help it advance its water stewardship priorities in the areas in which it operates.

The Company continues to review and explore other opportunities to further its environmental strategy and will evaluate potential impacts and commitments.

Management does not believe that expenditures related to these initiatives should have a material adverse effect on the Company’s financial condition, results of operations, liquidity or capital resources for any year.

Environmental Regulation and Remediation

The Company believes that there are no compliance issues associated with applicable environmental laws and regulations that would have a material adverse effect on the Company. The Company is also remediating environmental contamination resulting from past industrial activity at certain of its sites. Expenditures for remediation and environmental liabilities were $4 million in 2024 and are estimated to be $26 million in the aggregate for the years 2025 through 2029. These amounts do not consider potential recoveries from other parties. The Company has taken an active role in identifying and accruing for these costs and, in management’s opinion, the liabilities for all environmental matters that are probable and reasonably estimable have been accrued and totaled $41 million and $42 million at December 31, 2024 and 2023, respectively. Although it is not possible to predict with certainty the outcome of these matters, or the ultimate costs of remediation, management does not believe that any reasonably possible expenditures that may be incurred in excess of the liabilities accrued should exceed approximately $46 million in the aggregate. Management also does not believe that these expenditures should result in a material adverse effect on the Company’s financial condition, results of operations or liquidity for any year.

Geographic Area Information

The Company’s operations outside the U.S. are conducted primarily through subsidiaries. Sales worldwide by subsidiaries outside the U.S. as a percentage of total Company sales was 50% in 2024, 53% in 2023 and 54% in 2022.

The Company’s worldwide business is subject to risks of currency fluctuations, governmental actions and other governmental proceedings abroad. The Company does not regard these risks as a deterrent to further expansion of its operations abroad. However, the Company closely reviews its methods of operations and adopts strategies responsive to changing economic and political conditions.

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Merck has operations in countries located in Latin America, the Middle East, Africa, Eastern Europe and Asia Pacific. Business in these developing areas, while sometimes less stable, offers important opportunities for growth over time.

Available Information

The Company’s Internet website address is merck.com. The Company will make available, free of charge at the “Investors” portion of its website, its Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, and all amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended, as soon as reasonably practicable after such reports are electronically filed with, or furnished to, the U.S. Securities and Exchange Commission (SEC). The address of that website is sec.gov. In addition, the Company will provide without charge a copy of its Annual Report on Form 10-K, including financial statements and schedules, upon the written request of any shareholder to the Office of the Secretary, Merck & Co., Inc., 126 East Lincoln Avenue, Rahway, NJ 07065 U.S.A.

The Company’s corporate governance guidelines and the charters of the Board of Directors’ four standing committees are available on the Company’s website at www.merck.com/company-overview/leadership/board-of-directors/ and all such information is available in print to any shareholder who requests it from the Company.

The Company’s 2023/2024 Impact Report, which provides enhanced sustainability disclosures, is available in the Sustainability section of the Company’s website at www.merck.com. Information in the Company’s Impact Report is not incorporated by reference into this Form 10-K.

Item 1A.Risk Factors.

Summary Risk Factors

The Company is subject to a number of risks that if realized could materially adversely affect its business, results of operations, cash flows, financial condition or prospects. The following is a summary of the principal risk factors facing the Company:

•The Company is dependent on its patent rights, and if its patent rights are invalidated or circumvented, its business could be materially adversely affected.

•As the Company’s products lose market exclusivity, the Company generally experiences a significant and rapid loss of sales from those products.

•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 operations and financial condition.

•The Company’s research and development efforts may not succeed in developing commercially successful products and the Company may not be able to acquire commercially successful products in other ways; consequently, the Company may not be able to replace sales of successful products that lose patent protection.

•The Company’s success is dependent on the successful development and marketing of new products, which are subject to substantial risks.

•The Company faces continued pricing pressure with respect to its products.

•Unfavorable or uncertain economic conditions, together with cost-reduction measures being taken by certain governments, could negatively affect the Company’s operating results.

•The Company faces intense competition from both lower cost generic and biosimilar products and competitors’ 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 operations and financial condition.

•Climate change or legal, regulatory or market measures to address climate change may negatively affect the Company’s business, results of operations, cash flows and prospects.

•Environmental, social and governance matters may impact the Company’s business and reputation.

•Failure to attract and retain highly qualified personnel could affect the Company’s ability to successfully develop and commercialize products.

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•The Company may experience difficulties and delays in manufacturing certain of its products, including vaccines.

•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. In 2024, the Company experienced lower sales of Gardasil/Gardasil 9 in China and expects that sales of Gardasil/Gardasil 9 in China will decline significantly in 2025.

•The Company may not be able to realize the expected benefits of its investments in emerging markets.

•The Company is exposed to market risk from fluctuations in currency exchange rates and interest rates.

•Pharmaceutical products can develop unexpected safety or efficacy concerns.

•Reliance on third-party relationships and outsourcing arrangements could materially adversely affect the Company’s business.

•Negative events in the animal health industry could have a material adverse effect on future results of operations and financial condition of the Company or its Animal Health business.

•Biologics and vaccines carry unique risks and uncertainties, which could have a material adverse effect on the Company’s future results of operations and financial condition.

•The health care industry in the U.S. has been, and will continue to be, subject to increasing regulation and political action.

•The Company’s products, including products in development, cannot be marketed unless the Company obtains and maintains regulatory approval.

•Developments following regulatory approval may adversely affect sales of the Company’s products.

•The Company is subject to a variety of U.S. and international laws and regulations.

•The Company is subject to evolving and complex tax laws, which may result in additional liabilities that may affect results of operations and financial condition.

•Adverse outcomes in current or future legal matters could negatively affect Merck’s business.

•Product liability insurance for products may be limited, cost prohibitive or unavailable.

•The Company is increasingly dependent on sophisticated software applications and computing infrastructure, including the use of cloud-based applications and environments. The Company continues to be a target of cyber-attacks that could lead to a disruption of its worldwide operations, including manufacturing, research and sales operations.

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

•Social media and mobile messaging platforms present risks and challenges.

The above list is not exhaustive, and the Company faces additional challenges and risks. Investors should carefully consider all of the information set forth in this Form 10-K, including the following risk factors, before deciding to invest in any of the Company’s securities.

Risk Factors

The risks below are not the only ones the Company faces. Additional risks not currently known to the Company or that the Company presently deems immaterial may also impair its business operations. The Company’s business, financial condition, results of operations, cash flows or prospects could be materially adversely affected by any of these risks. This Form 10-K also contains forward-looking statements that involve risks and uncertainties. The Company’s results could materially differ from those anticipated in these forward-looking statements as a result of certain factors, including the risks it faces described below and elsewhere. See “Cautionary Factors that May Affect Future Results” below.

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Risks Related to the Company’s Business

The Company is dependent on its patent rights, and if its patent rights are invalidated or circumvented, its business could be materially adversely affected.

Patent protection is considered, in the aggregate, to be of material importance to the Company’s marketing of human health and animal health products in the U.S. and in most major foreign markets. Patents covering products that it has introduced normally provide market exclusivity, which is important for the successful marketing and sale of its products. The Company seeks patents covering each of its products in each of the markets where it intends to sell the products and where meaningful patent protection is available.

Even if the Company succeeds in obtaining patents covering its products, third parties or government authorities may challenge or seek to invalidate or circumvent its patents and patent applications. It is important for the Company’s business to successfully assert and defend the patent rights that provide market exclusivity for its products. The Company is often involved in patent disputes relating to challenges to its patents or claims by third parties of infringement against the Company. The Company asserts and defends its patents both within and outside the U.S., including by filing claims of infringement against other parties. See Item 8. “Financial Statements and Supplementary Data,” Note 10. “Contingencies and Environmental Liabilities” below. In particular, manufacturers of generic or biosimilar pharmaceutical products from time to time file abbreviated NDAs or BLAs with the FDA seeking to market generic/biosimilar forms of the Company’s products prior to the expiration of relevant patents owned or licensed by the Company. The Company normally responds by asserting one or more of its patents with a lawsuit alleging patent infringement. Patent litigation and other challenges to the Company’s patents are costly and unpredictable and may deprive the Company of market exclusivity for a patented product or, in some cases, third-party patents may prevent the Company from marketing and selling a product in a particular geographic area.

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 operations. 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 versions of those products becoming available. The Company’s results of operations may be adversely affected by the lost sales unless and until the Company has launched commercially successful products that replace the lost sales. In addition, if products that were measured at fair value and capitalized in connection with acquisitions experience difficulties in the market that negatively affect product cash flows, the Company may recognize material non-cash impairment charges with respect to the value of those products.

A chart listing the key patent protection for certain of the Company’s marketed products, and U.S. patent protection for candidates in Phase 3 clinical development is set forth above in Item 1. “Business — Patents, Trademarks and Licenses.”

As the Company’s products lose market exclusivity, the Company generally experiences a significant and rapid loss of sales from those products.

The Company depends upon patents to provide it with exclusive marketing rights for its products for some period of time. 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 versions of that drug become available. In the case of products that contribute significantly to the Company’s sales, the loss of market exclusivity can have a material adverse effect on the Company’s business, cash flows, results of operations, financial condition and prospects. 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. Bridion will lose market exclusivity in the U.S. in 2026 (subject to patent litigation discussed below) and the Company expects that sales of Bridion in the U.S. will decline substantially thereafter. 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. The Company expects to lose market exclusivity in Europe for Keytruda in 2031 following compound patent expiration. There may, however, be attempts by one or more companies to challenge the patent or launch a biosimilar product despite the patent in some European jurisdictions following the expiration of data exclusivity in Europe in July 2026.

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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 operations and financial condition.

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, Bravecto,and Bridion. In 2024, the Company’s oncology portfolio, led by Keytruda, represented substantially all of the Company’s revenue growth. In particular, in the aggregate, in 2024, sales of Keytruda represented 46% 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 slowing demand for Gardasil/Gardasil 9 in China which the Company has experienced, could have a significant adverse impact on results of operations and financial condition. Other events could include loss of patent protection, increased costs associated with manufacturing, generic 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. Such events could have a material adverse effect on the sales of any such products.

The Company’s research and development efforts may not succeed in developing commercially successful products and the Company may not be able to acquire commercially successful products in other ways; consequently, the Company may not be able to replace sales of successful products that lose patent protection.

In order to remain competitive, the Company, like other major pharmaceutical companies, must continue to launch new products. 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 through collaborations and joint ventures and products that it is able to obtain through license or acquisition. To accomplish this, the Company commits substantial effort, funds and other resources to research and development, both through its own dedicated resources and through various collaborations with third parties. There is a high rate of failure inherent in the research and development process for new drugs and vaccines. As a result, there is a high risk that funds invested by the Company in research programs will not generate financial returns. This risk profile is compounded by the fact that this research has a long investment cycle. To bring a pharmaceutical compound from the discovery phase to market may take a decade or more and failure can occur at any point in the process, including later in the process after significant funds have been invested.

For a description of the research and development process, see Item 1. “Business — Research and Development” above. Each phase of testing is highly regulated and during each phase there is a substantial risk that the Company will encounter serious obstacles or will not achieve its goals. Therefore, the Company may abandon a product in which it has invested substantial amounts of time and resources. Some of the risks encountered in the research and development process include the following: preclinical testing of a new compound may yield disappointing results; competing products from other manufacturers may reach the market first; clinical trials of a new drug may not be successful; a new drug may not be effective or may have harmful side effects; a new drug may not be approved by the regulators for its intended use; it may not be possible to obtain a patent for a new drug; payers may refuse to cover or reimburse the new product; or sales of a new product may be disappointing.

The Company cannot state with certainty when or whether any of its products now under development will be approved or launched; whether it will be able to develop, license or otherwise acquire compounds, product candidates or products; or whether any products, once launched, will be commercially successful. The Company must maintain a continuous flow of successful new products and successful new indications for existing products sufficient both to cover its substantial research and development costs and to replace sales that are lost as profitable products lose market exclusivity or are displaced by competing products or therapies. Failure to do so in the short term or long term would have a material adverse effect on the Company’s business, results of operations, cash flows, financial condition and prospects.

The Company’s success is dependent on the successful development and marketing of new products, which are subject to substantial risks.

Products that appear promising in development may fail to reach the market or fail to succeed for numerous reasons, including the following:

•findings of ineffectiveness, superior safety or efficacy of competing products, or harmful side effects in clinical or preclinical testing;

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•failure to receive the necessary regulatory approvals, including delays in the approval of new products and new indications, or the anticipated labeling, and uncertainties about the time required to obtain regulatory approvals and the benefit/risk standards applied by regulatory agencies in determining whether to grant approvals;

•failure in certain markets to obtain reimbursement commensurate with the level of innovation and clinical benefit presented by the product;

•lack of economic feasibility due to manufacturing costs or other factors; and

•preclusion from commercialization by the proprietary rights of others.

In the future, if certain pipeline programs are cancelled or if the Company believes that their commercial prospects have been reduced, the Company may recognize material non-cash impairment charges for those programs that were measured at fair value and capitalized in connection with acquisitions or certain collaborations.

Failure to successfully develop and market new products in the short term or long term would have a material adverse effect on the Company’s business, results of operations, cash flows, financial condition and prospects.

The Company faces continued pricing pressure with respect to its products.

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 and profit margins. In the U.S., these include (i) U.S. federal laws and regulations related to Medicare and Medicaid, including the Medicare Prescription Drug Improvement and Modernization Act of 2003, the ACA, and the IRA, (ii) practices of managed care groups and institutional and governmental purchasers, and (iii) state activities aimed at increasing price transparency, including new laws as noted above in Item 1. “Competition and the Health Care Environment.” Changes to the health care system enacted as part of health care reform in the U.S., as well as increased purchasing power of entities that negotiate on behalf of Medicare, Medicaid, and private sector beneficiaries, could result in further pricing pressures. As noted in Item 1. “Competition and the Health Care Environment,” in 2023, HHS selected Januvia for the first year of the IRA’s price setting program, which will result in a government set price becoming effective on January 1, 2026. Government price setting may also impact pricing in the private market, negatively affecting the Company’s performance. In January 2025, HHS announced that Janumet and Janumet XR have been selected for government price setting, which will become effective on January 1, 2027. Furthermore, the Company expects that in 2026 HHS will include Keytruda in a subsequent selection of products to undergo IRA price setting, with such price to become effective on January 1, 2028 and the Company expects that, as a result, U.S. sales of Keytruda will decline after that time. In addition, in the U.S., larger customers have received higher rebates on drugs in certain highly competitive categories. The Company must also compete to be placed on formularies of managed care organizations. Exclusion of a product from a formulary can lead to reduced usage in the managed care organization. The Company is also facing pricing pressure from purchasers of certain vaccines in highly competitive categories.

Outside the U.S., numerous major markets, including the EU, Japan and China have pervasive government involvement in funding health care and, in that regard, fix the pricing and reimbursement of pharmaceutical and vaccine products. Consequently, in those markets, the Company is subject to government decision making and budgetary actions with respect to its products. In Japan, the pharmaceutical industry is subject to government-mandated annual price reductions of pharmaceutical products and certain vaccines. Furthermore, the Japanese government can order re-pricing for specific products if it determines that use of such product will exceed certain thresholds defined under applicable re-pricing rules.

The Company expects pricing pressures to continue in the future.

Unfavorable or uncertain economic conditions, together with cost-reduction measures being taken by certain governments, could negatively affect the Company’s operating results.

The Company’s business may be adversely affected by local and global economic conditions, including with respect to inflation, interest rates, and costs of raw materials and packaging. Uncertainty in global economic and geopolitical conditions may result in a slowdown to the global economy that could affect the Company’s business by reducing the prices that drug wholesalers and retailers, hospitals, government agencies and managed health care providers may be able or willing to pay for the Company’s products or by reducing the demand for the Company’s products, which could in turn negatively impact the Company’s sales and result in a material adverse effect on the Company’s business, cash flows, results of operations, financial condition and prospects.

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As discussed above in Item 1. “Competition and the Health Care Environment,” global efforts toward health care cost containment continue to exert pressure on product pricing and market access worldwide. Changes to the U.S. health care system as part of health care reform, as well as increased purchasing power of entities that negotiate on behalf of Medicare, Medicaid, and private sector beneficiaries, have contributed to pricing pressure. In several international markets, government-mandated pricing actions have reduced prices of generic and patented drugs. In addition, the Company’s sales performance in 2024 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. The Company anticipates all of these actions, and additional actions in the future, will continue to negatively affect sales and profits.

If credit and economic conditions worsen, the resulting economic and currency impacts in the affected markets and globally could have a material adverse effect on the Company’s results.

The Company faces intense competition from both lower cost generic and biosimilar products and competitors’ products.

In general, the Company faces increasing competition from lower-cost generic and biosimilar products. The patent rights that protect its products are of varying strengths and durations. In addition, in some countries, patent protection is significantly weaker than in the U.S. or in the EU. In the U.S. and the EU, political pressure to reduce spending on prescription drugs has led to legislation and other measures that encourage the use of generic and biosimilar products. Although it is the Company’s policy to actively protect its patent rights, generic challenges to the Company’s products can arise at any time, and the Company’s patents may not prevent the emergence of generic competition for its products.

Loss of patent protection for a product typically is followed promptly by generic or biosimilar substitutes, reducing the Company’s sales of that product. Availability of generic 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 drugs. Any such proposal that is enacted into law could worsen this substantial negative effect on the Company’s sales, business, cash flows, results of operations, financial condition and prospects.

Also, the Company’s products face intense competition from competitors’ products. This competition may increase as new products enter the market. In such an event, the competitors’ products may be safer or more effective, more convenient to use, have better insurance coverage or reimbursement levels or be more effectively marketed and sold than the Company’s products. Alternatively, in the case of generic competition, including the generic 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. As a result, if the Company fails to maintain its competitive position, this could have a material adverse effect on its business, cash flows, results of operations, financial condition and prospects. In addition, if products that were measured at fair value and capitalized in connection with acquisitions experience difficulties in the market that negatively impact product cash flows, the Company may recognize material non-cash impairment charges with respect to the value of those 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 operations and financial condition.

The extent of the Company’s operations outside the U.S. is significant. Risks inherent in conducting a global business include:

•changes in medical reimbursement policies and programs and pricing restrictions in key markets;

•multiple regulatory requirements that could restrict the Company’s ability to manufacture and sell its products in key markets;

•trade protection measures and import or export licensing requirements, including the imposition of trade sanctions or similar restrictions by the U.S. or other governments;

•foreign exchange fluctuations;

•diminished protection of intellectual property in some countries; and

•possible nationalization and expropriation.

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

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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. In addition, there may be changes to the Company’s business if there is instability, disruption or destruction in a significant geographic region, regardless of cause, including war, terrorism, riot, civil insurrection or social unrest; and natural or man-made disasters, including famine, flood, fire, earthquake, storm or disease. Events like these, such as the ongoing war between Russia and Ukraine, and the conflict in the Middle East, and/or policy changes with respect to international trade protection measures, could result in material adverse effects on macroeconomic conditions, currency exchange rates and financial markets, and may adversely affect the Company’s business, results of operations, cash flows and financial condition.

Climate change or legal, regulatory or market measures to address climate change may negatively affect the Company’s business, results of operations, cash flows and prospects.

The Company believes that climate change has the potential to negatively affect its business, results of operations, cash flows and prospects. The Company is exposed to physical risks (such as extreme weather conditions, inland flooding or rising sea levels), risks in transitioning to a low-carbon economy (such as additional legal or regulatory requirements, changes in technology, market risk and reputational risk) and social and human effects (such as population dislocations and harm to health and well-being) associated with climate change. These risks can be either acute (short-term) or chronic (long-term).

The adverse impacts of climate change include increased frequency and severity of natural disasters and extreme weather events such as hurricanes, tornados, wildfires (exacerbated by drought), flooding, and extreme heat. Extreme weather, inland flooding and sea-level rise pose physical risks to the Company’s facilities as well as those of its suppliers. Such risks include losses incurred as a result of physical damage to facilities, loss or spoilage of inventory, and business interruption caused by such natural disasters and extreme weather events. Other potential physical impacts due to climate change include reduced access to high-quality water in certain regions and the loss of biodiversity, which could impact future product development. These risks could disrupt the Company’s operations and its supply chain, which may result in increased costs.

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. The Company’s supply chain would likely be subject to these same transitional risks and would likely pass along any increased costs to the Company, which may affect the Company’s ability to procure raw materials or other supplies required for the operation of the Company’s business at the quantities and levels required.

Environmental, social and governance matters may impact the Company’s business and reputation.

Governmental authorities, non-governmental organizations, customers, investors, external stakeholders and employees are sensitive to environmental, social and governance concerns, such as human capital, climate change, water use, recyclability or recoverability of packaging, and plastic waste. The focus on these concerns may lead to new requirements that could result in increased costs associated with developing, manufacturing and distributing the Company’s products, and related reporting obligations. The Company’s ability to compete could also be affected by changing customer preferences and requirements, such as growing demand for validated net zero GHG emission targets and more environmentally friendly products, packaging or supplier practices, or by failure to meet such customer expectations or demand. The Company risks negative shareholder reaction, including from proxy advisory services, as well as damage to its brand and reputation and inability to attract and retain employee talent, if the Company fails to act responsibly, or if the Company is perceived to not be acting responsibly, in key areas, including equitable access to medicines and vaccines, product quality and safety, environmental stewardship, reduction of GHG emissions, support for local communities, corporate governance and transparency, and addressing human capital factors in the Company’s operations. Responding to these considerations as well as any applicable regulatory requirements and implementation of the Company’s goals and initiatives involves risks and uncertainties, requires investments, and depends in part on third-party performance or data that is outside of the Company’s control. In addition, some governmental authorities, non-governmental organizations, and stakeholders may disagree with the Company’s goals and initiatives. If the Company does not meet the evolving and varied regulatory requirements and expectations of its investors, customers and other stakeholders, the Company could experience negative impacts to the Company’s business and results of operations. In addition, the Company is subject to expanding mandatory and voluntary reporting, diligence and disclosure requirements, including the EU’s Corporate

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Sustainability Reporting Directive (CSRD) and potentially the SEC’s climate-related reporting requirements (which are currently stayed), the legislation in California requiring reporting of GHG emissions and climate risk, and similar regulatory requirements in other jurisdictions outside the U.S. These evolving regulatory requirements are likely to result in increased costs and complexities of compliance in order to collect, measure and report on the relevant information.

Failure to attract and retain highly qualified personnel could affect the Company’s ability to successfully develop and commercialize products.

The Company’s success is largely dependent on its continued ability to attract and retain highly qualified scientific, technical and management personnel, as well as personnel with expertise in clinical research and development, governmental regulation and commercialization. Competition for qualified personnel in the pharmaceutical industry, both in the U.S. and internationally, is intense. The Company cannot be sure that it will be able to attract and retain qualified personnel or that the costs of doing so will not materially increase.

The Company may experience difficulties and delays in manufacturing certain of its products, including vaccines.

Merck from time to time experiences difficulties in manufacturing certain of its products, including vaccines. For example, the Company is currently experiencing manufacturing delays related to Varivax and ProQuad which will result in supply constraints in 2025. The Company may, in the future, experience other difficulties and delays in manufacturing its products, such as (i) failure of the Company or any of its vendors or suppliers to comply with Current Good Manufacturing Practices and other applicable regulations and quality assurance guidelines that could lead to manufacturing shutdowns, product shortages and delays in product manufacturing; (ii) delays related to the construction of new facilities or the expansion of existing facilities, including those intended to support future demand for the Company’s products; and (iii) other manufacturing or distribution problems including supply chain delays, shortages in raw materials, changes in manufacturing production sites and limits to manufacturing capacity due to regulatory requirements, changes in types of products produced, or physical limitations that could impact continuous supply. In addition, the Company could experience difficulties or delays in manufacturing its products caused by natural disasters, such as hurricanes. Manufacturing difficulties can result in product shortages, leading to lost sales and reputational harm to the Company.

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. In 2024, the Company experienced lower sales of Gardasil/Gardasil 9 in China and expects that sales of Gardasil/Gardasil 9 in China will decline significantly 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. 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 Gardasil/Gardasil 9 will decline significantly in 2025 compared with 2024. Furthermore, the government's anti-corruption campaign, particularly the increased number of inspections and audits, could substantially increase the administrative burden on health care institutions and health care professionals throughout the whole industry in China and potentially have a negative impact on the Company's sales. In addition to its commercial operations, the Company has significant research and manufacturing operations in China, including working with Chinese entities such as Wuxi Apptech Co., Ltd. If geopolitical tensions were to increase and disrupt the Company’s operations in China, such disruption could result in a material adverse effect on the Company’s product development, sales, business, cash flows, results of operations, financial condition and prospects.

Also, continued growth of the Company’s business in China is dependent upon ongoing development of a favorable environment for innovative pharmaceutical products and vaccines, sustained access for the Company’s currently marketed products, and the absence of trade impediments or adverse pricing controls. As noted above in Item 1. “Competition and the Health Care Environment,” pricing pressure in China has increased as the Chinese government has been taking steps to reduce costs, including implementing health care reform that has led to the acceleration of generic substitution, where available. While the mechanism for drugs being added to the NRDL evolves, inclusion may require a price negotiation which could impact the outlook in the market for selected brands. A

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