What changed in this filing

/stocks — the workspaceLOADING

Item 1. Business

2026-02-24 compared with 2025-02-25 · 416 added, 393 removed, 551 unchanged (59% of the section changed)

17 unchanged sentences

Pharmaceutical 58,142 57,400 53,583

Keytruda 29,482 25,011 20,937

Keytruda/Keytruda Qlex

31,680 29,482 25,011

Gardasil/Gardasil 9

5,233 8,583 8,886

Januvia/Janumet 2,544 2,268 3,366

ProQuad/M-M-R II /Varivax

2,451 2,485 2,368

Januvia/Janumet 2,268 3,366 4,513

Bridion 1,841 1,764 1,842

3 unchanged sentences

1,053 1,010 960

Lagevrio 964 1,428 5,684

RotaTeq 711 769 783

Animal Health 6,354 5,877 5,625

3 unchanged sentences

Other Revenues (2)

891 907 1,728

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

5 unchanged sentences

Certain of the products within the Company’s franchises are as follows:

Table of Content s

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 (pembrolizumab) is an anti-PD-1 (programmed death receptor-1) therapy available for intravenous administration that has been approved as monotherapy for the treatment of certain patients with cervical cancer, classical Hodgkin lymphoma (cHL), cutaneous squamous cell carcinoma, esophageal or gastroesophageal junction (GEJ) carcinoma, head and neck squamous cell carcinoma (HNSCC), hepatocellular carcinoma (HCC), melanoma, Merkel cell carcinoma, microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) solid tumors (including MSI-H/dMMR colorectal cancer and endometrial carcinoma), 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.

Additionally, in perioperative settings, Keytruda is approved for patients with certain types of resectable NSCLC in combination with chemotherapy as neoadjuvant treatment, and then continued as a single agent as adjuvant treatment after surgery;

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

for certain patients with resectable locally advanced HNSCC as a single agent as neoadjuvant treatment, continued as adjuvant treatment in combination with radiotherapy with or without cisplatin chemotherapy and then as a single agent;

and for certain patients with muscle invasive bladder cancer (MIBC), in combination with enfortumab vedotin, as neoadjuvant treatment and then continued after cystectomy as adjuvant treatment.

In addition, Keytruda is approved in combination with chemotherapy for the treatment of certain patients with advanced NSCLC, advanced malignant pleural mesothelioma, HNSCC, advanced biliary tract cancer, advanced esophageal cancer, advanced TNBC, and advanced or recurrent endometrial carcinoma;

in combination with chemotherapy with or without bevacizumab, and in combination with chemoradiotherapy, for the treatment of certain patients with advanced cervical cancer;

in combination with trastuzumab and chemotherapy for the treatment of certain patients with advanced human epidermal growth factor receptor 2 (HER2)-positive gastric or GEJ 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 trastuzumab and chemotherapy for the treatment of certain patients with advanced human epidermal growth factor receptor 2 (HER2)-positive gastric or GEJ adenocarcinoma, and in combination with chemotherapy for the treatment of certain patients with advanced HER2-negative gastric or GEJ adenocarcinoma;

in combination with axitinib for the treatment of certain patients with advanced RCC;

in combination with Lenvima (lenvatinib) for the treatment of certain patients with advanced RCC or advanced endometrial carcinoma;

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 combination with enfortumab vedotin for certain patients with locally advanced or metastatic urothelial cancer;

and in combination with chemotherapy with or without bevacizumab for certain patients with platinum-resistant ovarian cancer.

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

Keytruda Qlex is approved in the U.S.

in solid tumor indications approved for Keytruda .

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

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

In addition, the Company recognizes alliance revenue related to sales of Lynparza (olaparib), an oral poly (ADP-ribose) polymerase (PARP) inhibitor, for certain types of advanced or recurrent ovarian, early or metastatic breast, metastatic pancreatic, and metastatic castration-resistant prostate cancers;

alliance revenue related to sales of Lenvima, an oral receptor 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;

alliance revenue related to sales of Lenvima, an oral receptor TKI, for certain types of thyroid cancer, RCC, HCC, in combination with everolimus for certain patients with advanced RCC, and in combination with Keytruda for certain patients with advanced endometrial carcinoma or advanced RCC;

and alliance revenue related to Reblozyl (luspatercept-aamt) for the treatment of certain types of anemia.

2 unchanged sentences

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);

(Varicella Virus Vaccine Live), a vaccine to help prevent chickenpox (varicella);

Vaxneuvance (Pneumococcal 15-valent Conjugate Vaccine), a vaccine to help prevent invasive pneumococcal disease in individuals 6 weeks of age and older;

RotaTeq (Rotavirus Vaccine, Live Oral, Pentavalent), a vaccine to help protect against rotavirus gastroenteritis in infants and children;

Capvaxive (Pneumococcal 21-valent Conjugate Vaccine), a vaccine to help prevent invasive pneumococcal disease and pneumococcal pneumonia in adults;

Enflonsia (clesrovimab-cfor), a long acting monoclonal antibody for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in neonates and infants who are born during or entering their first RSV season;

and Pneumovax 23 (pneumococcal vaccine polyvalent), a vaccine to help prevent pneumococcal disease.

2 unchanged sentences

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,

Table of Content s

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.

and Dificid (fidaxomicin) for the treatment of C.

difficile -associated diarrhea.

Cardiometabolic and Respiratory

Winrevair (sotatercept-csrk), an activin signaling inhibitor indicated for the treatment of adults with pulmonary arterial hypertension (PAH, Group 1 pulmonary hypertension) to improve exercise capacity and World Health Organization (WHO) functional class (FC), and reduce the risk of clinical worsening events including hospitalization for PAH, lung transplantation and death;

Adempas (riociguat), a cardiovascular drug for the treatment of chronic thromboembolic pulmonary hypertension or PAH in certain patients;

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;

and Ohtuvayre (ensifentrine), an inhaled PDE3/4 inhibitor indicated for the maintenance treatment of chronic obstructive pulmonary disease (COPD) in adults.

Lagevrio (molnupiravir), an investigational oral antiviral COVID-19 medicine available in the U.S.

under Emergency Use 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;

under Emergency Use Authorization;

Isentress/Isentress HD (raltegravir), a human immunodeficiency virus (HIV) integrase inhibitor for use in combination with other antiretroviral agents for the treatment of HIV-1 infection;

Delstrigo (doravirine/lamivudine/tenofovir disoproxil fumarate), a complete regimen for the treatment of HIV-1 infection in adult patients with no prior antiretroviral treatment history or to replace the current antiretroviral regime in certain patients who are virologically suppressed on a stable antiretroviral regimen;

17 unchanged sentences

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;

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;

Exzolt (fluralaner), a systemic treatment for poultry red mite and northern foul mite infestations;

Exzolt 5% (fluralaner), for treatment and prevention of ticks, lice, horn flies and New World Screwworm on cattle;

Slice (emamectin benzoate) parasiticide and Imvixa (lufenuron) for sea lice control in salmon;

6 unchanged sentences

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;

Bravecto (fluralaner) One-Month , a monthly product for dogs, Bravecto (fluralaner) Injectable/Quantum , an injectable product for dogs that lasts up to one-year, Bravecto TriUNO (fluralaner/moxidectin/pyrantel), a one month dog product that covers internal and external parasites, and Bravecto Plus (fluralaner/moxidectin), a two-month product for cats;

Sentinel, a line of oral parasitic products for dogs including Sentinel Spectrum (milbemycin oxime, lufenuron, and praziquantel) and Sentinel Flavor Tabs (milbemycin oxime, lufenuron);

Numelvi (atinvicitinib), a once daily second-generation Janus kinase inhibitor for the treatment of pruritus associated with allergic dermatitis;

Optimmune (cyclosporine), an ophthalmic ointment;

8 unchanged sentences

Prestige vaccine line for horses;

Scalibor (Deltamethrin) /Exspot for protecting against bites

Table of Content s

from fleas, ticks, mosquitoes and sandflies;

Scalibor (Deltamethrin) /Exspot for protecting against bites 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 .

4 unchanged sentences

Product Date Approval

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

FDA full approval for the treatment of patients with HCC secondary to hepatitis B who have received prior systemic therapy other than a PD-1/PD-L1 containing regimen.

The conversion from an accelerated to full (regular) approval is based on the KEYNOTE-394 trial.

China’s National Medical Products Administration (NMPA) approval in combination with enfortumab vedotin, an antibody-drug conjugate (ADC), for the treatment of adults with locally advanced or metastatic urothelial carcinoma, based on the KEYNOTE-A39 trial that was conducted in collaboration with Seagen (now Pfizer Inc., Pfizer) and Astellas.

European Commission (EC) approval in combination with pemetrexed and platinum chemotherapy for the first-line treatment of adult patients with unresectable non epithelioid malignant pleural mesothelioma, based on the IND.227/KEYNOTE-483 trial.

Japan’s Ministry of Health, Labor and Welfare (MHLW) approval in combination with trastuzumab and chemotherapy for the first-line treatment of patients with unresectable, advanced or recurrent HER2-positive gastric or GEJ adenocarcinoma, based on the KEYNOTE-811 trial.

Japan’s MHLW approval in combination with pemetrexed and platinum chemotherapy for unresectable, advanced or recurrent metastatic malignant pleural mesothelioma, based on the IND.227/KEYNOTE-483 trial.

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

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

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

November 2025

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

February 2026

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

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

Japan’s Ministry of Health, Labor and Welfare (MHLW) approval in combination with fluoropyrimidine and platinum-containing chemotherapy for the first-line treatment of patients with locally advanced unresectable or metastatic gastric or GEJ adenocarcinoma, based on the KEYNOTE-859 trial.

Japan’s MHLW approval in combination with standard of care chemotherapy (gemcitabine and cisplatin) for the treatment of patients with locally advanced unresectable or metastatic biliary tract cancer, based on the KEYNOTE-966 trial.

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

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

September 2024

EC approval in combination with Padcev (enfortumab vedotin-ejfv), an antibody-drug conjugate, for the first-line treatment of unresectable or metastatic urothelial carcinoma in adults, based on the KEYNOTE-A39 trial that was conducted in collaboration with Seagen (now Pfizer Inc.) and Astellas.

September 2024

FDA approval in combination with pemetrexed and platinum chemotherapy for the first-line treatment of adult patients with unresectable advanced or metastatic malignant pleural mesothelioma, based on the IND.227/KEYNOTE-483 trial.

September 2024

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

Table of Content s

September 2024

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

September 2024

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

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

February 2026

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

February 2026

Japan’s MHLW approval for neoadjuvant and adjuvant treatment of locally advanced HNSCC, based on the KEYNOTE-689 trial.

Keytruda Qlex (1)

September 2025

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

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

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

FDA approval across most adult solid tumor indications for Keytruda.

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

November 2025

Japan’s MHLW approval in combination with chemoradiotherapy as treatment for patients with locally advanced cervical cancer, based on the KEYNOTE-A18 trial.

December 2024

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

December 2024

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

December 2024

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

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

Bravecto January 2024

EC approval of injectable formulation for dogs for the persistent killing of fleas and ticks for 12 months after treatment.

FDA approval for the prevention of invasive pneumococcal disease and pneumococcal pneumonia caused by certain serotypes in individuals 18 years of age and older.

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

China’s NMPA approval for the adjuvant treatment of adult patients with deleterious or suspected deleterious germline BRCA -mutated, HER2-negative high-risk early breast cancer who have been previously treated with neoadjuvant or adjuvant chemotherapy, based on the OlympiA trial.

Table of Content s

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

November 2025

China’s NMPA approval for the treatment of adult patients with VHL disease who require therapy for associated RCC, central nervous system hemangioblastomas or pancreatic neuroendocrine tumors.

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

February 2026

EC conditional approval as monotherapy both for the treatment of adult patients with VHL disease who require therapy for associated, localized RCC, central nervous system hemangioblastomas, or pancreatic neuroendocrine tumors, and for whom localized procedures are unsuitable, and for the treatment of adult patients with advanced clear cell RCC that progressed following two or more lines of therapy that included a PD-1 or PD-L1 inhibitor and at least two VEGF targeted therapies.

The EC approval of these two indications is based on results from the LITESPARK-004 and LITESPARK-005 trials.

FDA approval for the treatment of adults with PAH (WHO Group 1) to increase exercise capacity, improve WHO functional class (FC), and reduce the risk of clinical worsening events.

EC approval in combination with other PAH therapies, for the treatment of PAH in adult patients with WHO FC II to III, to improve exercise capacity.

EC approval for the prevention of invasive pneumococcal disease and pneumococcal pneumonia caused by certain serotypes in individuals 18 years of age and older.

Japan’s MHLW approval for the prevention of invasive pneumococcal disease and pneumococcal pneumonia caused by certain serotypes in individuals 18 years of age and older.

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

Gardasil/Gardasil 9

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

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

Gardasil/Gardasil 9

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

February 2025

EC conditional approval as monotherapy for the treatment of adult patients with VHL disease who require therapy for associated, localized RCC, central nervous system hemangioblastomas, or pancreatic neuroendocrine tumors, and for whom localized procedures are unsuitable, based on the LITESPARK-004 trial.

February 2025

EC conditional approval for the treatment of adult patients with advanced clear cell RCC that progressed following two or more lines of therapy that included a PD-1 or PD-L1 inhibitor and at least two vascular endothelial growth factor targeted therapies, based on the LITESPARK-005 trial.

FDA approval for the treatment of adult and pediatric patients (12 years and older) with locally advanced, unresectable, or metastatic pheochromocytoma and paraganglioma, based on the LITESPARK-015 trial.

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

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

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

FDA approval of expanded indication in adults with PAH (WHO Group 1 pulmonary hypertension) to improve exercise capacity and WHO FC, and reduce the risk of clinical worsening events, including hospitalization for PAH, lung transplantation and death, based on the ZENITH trial.

EC approval of expanded indication in combination with other PAH therapies for the treatment of PAH in adult patients with WHO FC II, III and IV, based on the ZENITH trial.

Bravecto Quantum

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

EC approval of tablets for dogs for the treatment of pruritus associated with allergic dermatitis including atopic dermatitis and treatment of clinical manifestations of atopic dermatitis.

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

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

2 unchanged sentences

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.

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 availability of generic or biosimilar versions 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.

14 unchanged sentences

The Company anticipates all of these actions and additional actions in the future will continue to negatively affect sales and profits.

Table of Content s

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.

In addressing global cost containment pressures, the Company engages in public policy advocacy with policymakers and continues to work to demonstrate that its medicines and vaccines 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.

5 unchanged sentences

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.

In May 2025, the U.S.

presidential administration issued an executive order intended to encourage or impose the use of “most-favored-nation” pricing to tie U.S.

prescription drug prices to prices in selected comparably developed nations.

In July 2025, the Company and other pharmaceutical companies received letters from the U.S.

presidential administration with a request to agree to the administration’s “most-favored-nation” drug pricing goals by September 29, 2025.

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

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

Included within the MFN Agreement is an obligation by the Company to provide key products through a direct-to-patient program at affordable prices for eligible patients in the U.S.

This will initially include Januvia , Janumet and Janumet XR , and will be expanded in the future to include enlicitide decanoate pending FDA approval.

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

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

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

Additionally, the Company reached an agreement with the U.S.

Department of Commerce to delay Section 232 tariffs for three years, enabling the Company to make investments in the U.S.

to reshore manufacturing for American patients.

In September 2025, the Advisory Committee on Immunization Practices (ACIP) of the U.S.

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

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

The acting CDC Director adopted the recommendation in October 2025.

MMR and varicella vaccines remain recommended and funded through the VFC program for both the first and second doses.

The Company is the only manufacturer in the U.S.

of MMRV vaccine ( ProQuad ) and varicella vaccine ( Varivax ).

The Company anticipates that any negative effect of these recommendations on sales of ProQuad will not be material.

In December 2025, the CDC ended the universal birth-dose recommendation for hepatitis B vaccination, adopting an ACIP recommendation.

For infants born to mothers who test negative for hepatitis B, vaccination is now based on individual decision-making, with the first dose recommended no earlier than 2 months of age.

For infants born to mothers who are hepatitis B–positive or whose status is unknown, the CDC continues to recommend a birth dose of hepatitis B vaccine.

The Company manufactures a hepatitis B vaccine ( Recombivax HB , Hepatitis B Vaccine [Recombinant]) and, subject to a collaboration agreement with Sanofi Pasteur MSD, co-promotes a hexavalent vaccine that includes a hepatitis B component ( Vaxelis, Diphtheria and Tetanus Toxoids and Acellular Pertussis, Inactivated Poliovirus, Haemophilus b Conjugate and Hepatitis B Vaccine).

The Company anticipates that any negative effect of these recommendations on sales of Recombivax HB and Vaxelis will not be material .

In January 2026, the acting CDC Director announced changes to the child and adolescent immunization schedule (January announcement), reducing the number of routinely recommended vaccinations and creating three new categories:

immunizations recommended for all children;

immunizations recommended for certain high-risk groups or populations;

and immunizations based on shared clinical decision-making.

Immunizations recommended for all children include vaccines for measles, mumps, rubella, polio, pertussis, tetanus, diphtheria, Haemophilus influenzae type B (Hib), pneumococcal disease, HPV, and varicella.

Immunizations recommended for certain high-risk groups or populations include RSV, hepatitis A, hepatitis B, and dengue.

Immunizations recommended based on shared clinical decision-making include rotavirus, hepatitis A, and hepatitis B.

The January announcement is the subject of litigation by third parties.

Department of Health and Human Services (HHS) has stated that immunizations for all of the diseases covered by the previous immunization schedule will still be available to anyone who wants them through Affordable Care Act insurance plans and federal insurance programs, including Medicaid, the Children’s Health Insurance Program, and the VFC program.

Additionally, in September 2025, the trade association representing U.S.

health insurers (AHIP) announced that its member health plans would continue to cover all immunizations that had been recommended by the CDC’s ACIP as of September 1, 2025, with no cost-sharing for patients through the end of 2026.

Among the changes in the January announcement was a reduction of the recommended doses for HPV vaccination of adolescents to a single dose.

Gardasil 9 is currently indicated in the U.S.

for a two-dose regimen in adolescents aged 9-14 and a three-dose regimen for those aged 15-45.

Previous CDC recommendations for adolescents followed FDA-approved dosing.

Many countries outside the U.S.

have implemented a reduced dosing schedule for HPV vaccination in certain age groups.

The Company anticipates that any negative effect of these recommendations or reduced dosing schedules on sales of Gardasil / Gardasil 9 will not be material.

Additionally in the U.S., consolidation and integration among health care entities is a major factor in the competitive marketplace for pharmaceutical products.

2 unchanged sentences

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.

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.

payor market concentrates further, the Company may face greater pricing pressure from private third-party payors.

These same management tools are also used in treatment areas in which the payer has taken the position that multiple branded products are therapeutically comparable.

payer market concentrates further, the Company may face greater pricing pressure from private third-party payers.

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.

In 2022, Congress passed the IRA, which made 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.

HHS, through the Centers for Medicare & Medicaid Services (CMS), selected Januvia in 2023 for the first year of the IRA’s “Drug Price Negotiation Program” (Program), and selected Janumet and Janumet XR in 2025 for the second year of the Program.

Pursuant to the IRA’s Program, the government set a price for Januvia , which became effective on January 1, 2026, and set a price for Janumet and Janumet XR , which will become effective on January 1, 2027.

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

Furthermore, the Company expects that Keytruda will be selected in 2027 for government price setting, which would become effective on January 1, 2029, and the Company expects that, as a result, U.S.

sales of Keytruda will decline materially after that time.

The Company has sued the U.S.

1 unchanged sentence

“Contingencies and Environmental Liabilities” below).

Table of Content s

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

Furthermore, 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.

1 unchanged sentence

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 c ap on rebates drug manufacturers pay to Medicaid beginning in January 2024.

In addition, in 2021, Congress passed the American Rescue Plan Act, which included a provision that eliminated the statutory c ap on rebates drug manufacturers pay to Medicaid.

These rebates act as a discount off the list price and eliminating the cap means that manufacturer discounts paid to Medicaid can increase.

15 unchanged sentences

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.

10 unchanged sentences

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

Table of Content s

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.

The EU Health Technology Assessment Regulation 2021/2282 (HTAR) now applies.

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.

12 unchanged sentences

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.

In December 2025, the EU Parliament and the Council reached political agreement on a new directive and a new regulation that will result in a major update to the EU’s pharmaceutical laws.

The final text of the legislation has yet to be released but it will include measures designed to increase availability of medicines across the EU.

In particular, the new legislation is expected to allow a Member State to request that marketing authorization holders supply their medicines in sufficient quantities to meet patient needs in that Member State.

The request must be within one year of marketing authorization.

A failure to commence supplies within four years of marketing authorization can result in a two-year reduction in regulatory exclusivity in that Member State.

If the final text of the legislation includes such provisions, there is a risk that Member States may seek to exploit the threat of loss of exclusivity to further pressure pharmaceutical prices.

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 2026.

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.

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.

The Company’s business in China experienced significant contraction in 2025 due to lower sales of Gardasil/Gardasil 9.

Recovery 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.

2 unchanged sentences

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.

A new NRDL was recently completed in which new entries averaged approximately 60% 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.

Table of Content s

The government has 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 latest rounds of VBP had, on average, a price reduction of more than 50%.

The Company expects that the VBP process will have a significant impact on mature products moving forward.

Emerging Markets

7 unchanged sentences

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.

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.

5 unchanged sentences

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.

consequently, the Company believes 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.

3 unchanged sentences

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.

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 care and 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.

These principles guide its global approach to addressing significant public health burdens.

The Company systematically evaluates its pipeline candidates to assess their potential to address unmet medical needs, particularly in low- and middle-income countries.

The insights from the assessment inform product development and access strategies, with a focus on expanding the availability of the Company’s medicines and vaccines in an economically sustainable manner.

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,

Table of Content s

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.

In addition, through social investments, including philanthropic programs and impact investing, Merck is helping to strengthen health systems and reduce barriers for communities with limited access to quality care.

The Merck Patient Assistance Program provides certain medicines and adult vaccines for free to people in the U.S.

5 unchanged sentences

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

Table of Content s

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.

The Company is subject to numerous privacy and data protection laws and regulations globally.

These laws and regulations, which often vary, may impact how the Company collects, processes and shares data across borders, including in clinical research, manufacturing, and commercial activities, and corporate functions.

The legislative and regulatory landscape for privacy and data protection continues to evolve and enforcement and litigation in this space continue to increase.

In the U.S., the number of state privacy laws to which the Company is subject is increasing, with a particular focus on the regulation of consumer health data and sensitive personal information, often broadly defined.

At the federal level, while there is no single comprehensive federal privacy law, the Federal Trade Commission (FTC) uses several mechanisms to support consumer privacy in the U.S., including Section 5 of the Federal Trade Commission Act, and other sector-specific laws and rules.

The Data Security Program, established by the U.S.

Department of Justice in 2025 in response to Executive Order 14117, introduced new restrictions on certain types of data sharing to prevent foreign adversaries from accessing bulk U.S.

sensitive personal data and U.S.

government-related data.

Failure to comply with these laws and regulations can result in significant monetary fines and other administrative penalties, as well as reputational harm and civil liability claims from individuals whose personal data was processed.

Outside of the U.S., the Company is subject to the General Data Protection Regulation (GDPR) in the EU and related implementing laws in individual EU Member States .

In China, the privacy and data protection framework is complex and imposes stringent compliance requirements on companies, particularly with respect to transferring certain types of personal data outside of China.

The Company also is subject to other privacy and data protection laws and regulations in Europe, Asia, Canada, Central and South America, Africa, and the Middle East.

Although specific obligations vary by region and country, in general, these laws increase the Company’s responsibility and potential liability in relation to processing personal data, including using data globally and moving data across country borders.

Compliance with these laws, which are rapidly evolving in scope and interpretation, introduces significant complexity in Company business operations.

Failure to comply with the requirements of the GDPR and other data related protection frameworks also may result in significant monetary fines, administrative penalties, litigation, and reputational harm.

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.

21 unchanged sentences

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 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.

Table of Content s

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:

3 unchanged sentences

Januvia 2026 (3)

Expired 2025-2026 Expired

Janumet 2026 (3)

Expired N/A Expired

N/A N/A Expired

Isentress Expired (4)

Bravecto 2027

2028-2029 Expired

2031 (with pending PTE) (8)

Gardasil 2028 Expired Expired Expired

2 unchanged sentences

2031 2032-2033 2028

2027 (7) (with pending PTE)

2027-2028 Expired

Belsomra 2029 N/A 2031 N/A

Prevymis 2029

1 unchanged sentence

No Patent (15)

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

Welireg 2035 (with pending PTE) 2034 (patent), 2039 (SPCs)

2039 (with pending PTE)

2035 (with pending PTE) (16)

2038 (patent) (9)(18)

2040 (with pending PTE) (9)

2039 (with pending PTE)

Keytruda Qlex

Compound patent unless otherwise noted.

9 unchanged sentences

(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.

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

(5) As a result of settlement agreements related to an additional product-related patent, generic entry is not expected until July 2030;

however, litigation is ongoing.

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

(7) Eligible for six months pediatric market exclusivity.

(8) Eligible for 12 years of data exclusivity in the U.S.

(expires in 2036), 11 years in the EU (expires in 2035), and 10 years in Japan (expires in 2035).

Granted patents covering methods of treating PAH with Winrevair, which will expire in 2037 (absent PTE or SPC), may provide additional exclusivity.

(9) Composition patent.

(10) The compound patent family contains two additional patents that expire in 2029 due to patent term adjustment resulting from patent office delay.

1 unchanged sentence

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.

(13) Data exclusivity expires in January 2030.

(14) PTE is 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.

Table of Content s

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

(16) Ensifentrine polymorph patent.

(17) The Company has no marketing rights in China.

(18) SPC applications will be filed in 2026.

(19) A patent application is currently pending, which if granted, will expire in 2040.

The Company has the following key U.S.

3 unchanged sentences

Year of Expiration (in the U.S.)

MK-1022 (patritumab deruxtecan) (1)

MK-1654 (clesrovimab)

(1) Being developed in a collaboration with Daiichi Sankyo.

The FDA issued a Complete Response Letter for the application in June 2024.

MK-8591A (doravirine + islatravir)

The Company also has the following key U.S.

2 unchanged sentences

Year of Expiration (in the U.S.)

MK-8591A (doravirine + islatravir) (1)

MK-2400 (ifinatamab deruxtecan) (1)

MK-1022 (patritumab deruxtecan) (1)

MK-1308A (quavonlimab + pembrolizumab)

MK-1026 (nemtabrutinib)

V940 (intismeran autogene) (1)

MK-3543 (bomedemstat)

1 unchanged sentence

MK-8591D (islatravir + lenacapavir) (1)(2)

2037 (with pending PTE for lenacapavir patent)

MK-2140 (zilovertamab vedotin)

MK-4482 Lagevrio (1)(3)

MK-5909 (raludotatug deruxtecan) (1)

MK-2870 (sacituzumab tirumotecan) (1)

MK-3475A (pembrolizumab + hyaluronidase subcutaneous) 2039

MK-0616 (enlicitide decanoate)

MK-7240 (tulisokibart)

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

MK-1084 (calderasib) (1)

(1) Being developed in a collaboration.

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

(3) Available in the U.S.

under Emergency Use Authorization.

(4) Formerly CD388.

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

12 unchanged sentences

“Contingencies and Environmental Liabilities” below.

Table of Content s

Worldwide, all of the Company’s important products are sold under trademarks that are considered in the aggregate to be of material importance.

34 unchanged sentences

Finally, Phase 3 trials are conducted in the

Table of Content s

intended population for licensure and provide data on immunogenicity and/or effectiveness, as well as safety, to support applications for regulatory approvals.

4 unchanged sentences

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.

Pursuant to the Prescription Drug User Fee Act VII (PDUFA), the FDA review period target for original NDAs or 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.

10 unchanged sentences

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.

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, priority review may be granted by the FDA or obtained using a Priority Review Voucher.

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).

Additionally, in 2025, the FDA announced a Commissioner’s National Priority Voucher (CNPV) pilot program, which offers the ability to seek expedited approval for a drug or biologic application or efficacy supplement.

Pilot program eligibility requires alignment with one or more critical national health priorities, which include addressing a health crisis in the U.S., bringing innovative therapies to the American people, addressing a large unmet medical need, promoting domestic manufacturing, and increasing affordability.

The pilot program is intended to enable enhanced communications with the FDA and action on an application within one to two months.

In December 2025, the FDA selected enlicitide decanoate and sacituzumab tirumotecan, investigational candidates that the Company is developing for hypercholesterolemia and certain cancers, respectively, to receive CNPVs;

these candidates are currently in Phase 3 development.

Due to the COVID-19 public health crisis, in 2020, the U.S.

5 unchanged sentences

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.

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.

1 unchanged sentence

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

Table of Content s

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.

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).

In Japan, the Company submits new drug applications to the Pharmaceuticals and Medical Devices Agency (PMDA) for its pharmaceutical regulatory review.

The PMDA is an independent administrative agency which is under the jurisdiction of the 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.

5 unchanged sentences

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 NMPA 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.

8 unchanged sentences

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.

Table of Content s

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.

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

The FDA set a PDUFA, or target action, date of April 28, 2026 for the new drug application, which is based on findings of the Phase 3 MK-8591A-051 and MK-8591A-052 clinical trials.

MK-8591A is also under review in Japan.

MK-8591A is also being evaluated for the treatment of HIV-1 infection in previously untreated adults, and in November 2025, the Company announced positive topline results from the pivotal Phase 3 MK-8591A-053 trial evaluating MK-8591A in this setting.

MK-1654, Enflonsia , a prophylactic long-acting monoclonal antibody designed to protect infants from RSV disease during their first RSV season, is under review in the EU and Japan.

In September 2025, the Committee for Medicinal Products for Human Use (CHMP) of the EMA recommended the approval of Enflonsia for the prevention of RSV lower respiratory tract disease in neonates (newborns) and infants during their first RSV season.

The CHMP recommendation, which is supported by results from the pivotal Phase 2b/3 CLEVER trial and the Phase 3 SMART trial, was sent to the EC for review for marketing authorization in the EU, Iceland, Liechtenstein and Norway.

In October 2025, Merck informed the EMA and other health authorities, including the FDA, that Merck had identified a

data entry issue related to solicited complaints (injection site pain, injection site swelling, injection site erythema, drowsiness, irritability, and/or lost appetite).

On October 31, 2025, the EC informed Merck that it would return the CHMP opinion to the EMA to allow the CHMP to assess Merck’s update.

This step has delayed a final EC decision on the marketing authorization for Enflonsia .

Updates to solicited complaint data were submitted to the EMA, and to the FDA, in December 2025.

The Company believes that these updates do not meaningfully impact the favorable risk-benefit profile of Enflonsia .

Merck remains confident in the robustness of the CLEVER and SMART trials as pivotal studies for Enflonsia and the risk-benefit profile of Enflonsia.

MK-7962, Winrevair (sotatercept-csrk), an activin signaling inhibitor for the treatment of adults with PAH (WHO Group 1 pulmonary hypertension), is under review by the FDA in connection with a proposed update to the U.S.

product label based on the results of the Phase 3 HYPERION trial.

The FDA set a PDUFA date of September 21, 2026.

MK-3475, Keytruda (pembrolizumab), is an anti-PD-1 therapy available for intravenous administration.

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

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

Keytruda is under review in the EU and Japan in combination with chemotherapy with or without bevacizumab for the treatment of certain patients with platinum-resistant recurrent ovarian cancer.

The applications are based on data from the Phase 3 KEYNOTE-B96 trial.

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

The application is based on data from the Phase 3 KEYNOTE-905 trial conducted in collaboration with Pfizer and Astellas.

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

The FDA set PDUFA dates in the second half of 2026 for these applications.

The supplemental BLAs are based on data from the Phase 3 KEYNOTE-D19 trial.

MK-6482, Welireg (belzutifan), Merck’s first-in-class oral hypoxia-inducible factor-2 alpha (HIF-2α) inhibitor, in combination with Keytruda or Keytruda Qlex is under priority review by the FDA for the adjuvant treatment of certain patients with clear cell RCC following nephrectomy.

The FDA set a PDUFA date of June 19, 2026.

The applications for Welireg , Keytruda and Keytruda Qlex are based on data from the Phase 3 LITESPARK-022 trial.

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

The FDA set a PDUFA date of October 4, 2026.

The application is based on data from the Phase 3 LITESPARK-011 trial.

Lenvima is being developed as part of a collaboration with Eisai Co., Ltd.

The Company is diversifying its oncology portfolio and executing on its strategy which is broadly based on three strategic pillars:

2 unchanged sentences

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.

• V940 (mRNA-4157), intismeran autogene, is an investigational individualized neoantigen therapy being evaluated in combination with Keytruda for the adjuvant portion of treatment in patients with certain types of melanoma and NSCLC.

The FDA and EMA granted Breakthrough Therapy designation and Priority Medicines (PRIME) scheme designation, respectively, for intismeran autogene in combination with Keytruda for the adjuvant treatment of patients with certain stages of high-risk melanoma following complete resection.

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

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

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-1026, nemtabrutinib, is an investigational 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, calderasib, is an investigational oral selective KRAS G12C inhibitor being evaluated with or without Keytruda or Keytruda Qlex for the treatment of certain patients with colorectal cancer and NSCLC.

Calderasib is being developed as part of a collaboration with Taiho Pharmaceutical Co.

and Astex Pharmaceuticals (UK), a wholly owned subsidiary of Otsuka Pharmaceutical Co., Ltd.

• 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

Table of Content s

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.

Bomedemstat has FDA 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.

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

• MK-7339, Lynparza, is an oral PARP inhibitor being evaluated in combination with Keytruda for expanded indications in the therapeutic areas of NSCLC and small cell lung cancer (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.

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

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

• MK-2140, zilovertamab vedotin, is an investigational 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 investigational B7-H3 directed ADC being evaluated in certain patients with esophageal, prostate and small cell lung cancers.

In August 2025, ifinatamab deruxtecan was granted Breakthrough Therapy designation by the FDA for the treatment of adult patients with extensive-stage SCLC with disease progression on or after platinum-based chemotherapy.

Ifinatamab deruxtecan 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, non-small cell lung, and ovarian cancers.

The FDA granted Breakthrough Therapy designation to sacituzumab tirumotecan for the treatment of patients with advanced or metastatic nonsquamous NSCLC with epidermal growth factor receptor (EGFR) mutations whose disease progressed on or after TKI and platinum-based chemotherapy.

In 2025, the FDA selected sacituzumab tirumotecan for the CNPV pilot program.

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

A portion of sacituzumab tirumotecan 2026 development costs will be funded by Blackstone Life Sciences.

See Item 8 “Financial Statements and Supplementary Data,” Note 3.

“Acquisitions, Research Collaborations and Licensing Agreements” below.

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

In September 2025, raludotatug deruxtecan was granted Breakthrough Therapy designation by the FDA for the treatment of adult patients with platinum-resistant epithelial ovarian, primary peritoneal, or fallopian tube cancers expressing CDH6 who have received prior treatment with bevacizumab.

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

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

In December 2025, the FDA selected enlicitide decanoate for the CNPV pilot program.

The Company plans to submit an NDA for enlicitide decanoate to the FDA in early 2026.

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

• MK-8591D is an investigational once-weekly, oral combination of Merck’s islatravir, a nucleoside analog leveraging translocation inhibition, and Gilead Sciences Inc.’s lenacapavir being evaluated for the treatment of HIV-1 infection in virologically suppressed adults.

In 2021, the FDA placed a clinical hold on the islatravir/lenacapavir once-weekly treatment regimen based on observations of decreases in total lymphocyte and CD4+ T-cell counts in some participants receiving islatravir in clinical studies;

the islatravir/lenacapavir combination remains under a partial clinical hold for any studies that would use islatravir doses higher than the doses considered for the revised clinical programs.

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

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

MK-1406, which received Breakthrough Therapy designation from the FDA in 2025, was obtained in connection with the January 2026 acquisition of Cidara Therapeutics, Inc.

• MK-7240, tulisokibart, is an investigational humanized monoclonal antibody directed to tumor necrosis factor-like ligand 1A, a central amplifier of inflammatory pathways and fibrotic mechanisms in inflammatory bowel disease, 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).

Merck is developing Lagevrio in collaboration with Ridgeback Biotherapeutics LP.

The FDA granted Emergency Use Authorization for Lagevrio in December 2021, which was last reissued in November 2023.

2 unchanged sentences

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

Table of Content s

(MOVe-NOW) was initiated to evaluate Lagevrio for the treatment of adults with COVID-19 at high risk for disease progression.

In 2024, an additional Phase 3 clinical trial (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.

Table of Content s

Additionally, the Company announced in November 2025 that the Phase 2, proof-of-concept CADENCE trial of Winrevair met the primary endpoint of reduction in pulmonary vascular resistance from baseline at 24 weeks compared to placebo in adults with combined post- and precapillary pulmonary hypertension due to heart failure with preserved ejection fraction.

Based on the pharmacological activity observed in this proof-of-concept study, the Company intends to proceed with Phase 3 development.

The chart below reflects the Company’s research pipeline as of February 20, 2026.

1 unchanged sentence

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.

Small molecules and biologics generally are given MK-number designations and vaccine candidates generally 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, immunology and certain other indications) and additional claims, line extensions or formulations for in-line products are not shown.

Alzheimer’s Disease

Atherosclerosis

MK-1022 (patritumab deruxtecan) (1)

1 unchanged sentence

Hepatocellular

MK-1308 (quavonlimab) (2)

Non-Small Cell Lung

MK-1308A (quavonlimab+pembrolizumab)

MK-1084 (calderasib) (1)

MK-2400 (ifinatamab deruxtecan) (1)

1 unchanged sentence

Hepatocellular

Non-Small Cell Lung

MK-2870 (sacituzumab tirumotecan) (1)

1 unchanged sentence

MK-3475 Keytruda

Advanced Solid Tumors

MK-3475A (pembrolizumab+hyaluronidase subcutaneous)

Cutaneous Squamous Cell

Hematological Malignancies

MK-5890 (boserolimab) (2)

Neoplasm Malignant

MK-3475A Keytruda Qlex

Hematological Malignancies (U.S.)

MK-5684 (opevesostat)

MK-5909 (raludotatug deruxtecan) (1)

Non-Small Cell Lung

Small Cell Lung

MK-6070 (gocatamig) (1)

Small Cell Lung

MK-6482 Welireg

Hepatocellular

MK-7339 Lynparza (1)(3)

Advanced Solid Tumors

Dengue Fever Virus Vaccine

V940 (intismeran autogene) (1)

Chronic Obstructive Pulmonary Diseases

MK-5884A (ensifentrine+glycopyrrolate)

Eye Disorders

HIV-1 Infection

MK-8591B (islatravir+MK-8507) (4)

HIV-1 Pre-Exposure Prophylaxis

MK-8591B (islatravir+ulonivirine)

MK-7240 (tulisokibart)

Axial Spondyloarthritis

Hidradenitis Suppurativa

Rheumatoid Arthritis

Systemic Sclerosis

4 unchanged sentences

MK-7962 Winrevair

Table of Content s

Phase 3 (Phase 3 entry date) Under Review

Antiviral COVID-19

MK-4482 Lagevrio (U.S.) (May 2021) (1)(6)

MK-1022 (patritumab deruxtecan) (1)

Non-Small-Cell Lung (May 2022) (EU)

Breast (July 2025)

MK-1026 (nemtabrutinib)

Hematological Malignancies (March 2023)

MK-1084 (calderasib) (1)

Colorectal (July 2025)

Non-Small Cell Lung (May 2024)

4 unchanged sentences

MK-2400 (ifinatamab deruxtecan) (1)

Esophageal (March 2025)

Prostate (May 2025)

Small Cell Lung (July 2024)

5 unchanged sentences

Non-Small Cell Lung (November 2023)

Ovarian (April 2025)

MK-3475 Keytruda

Hepatocellular (May 2016) (EU)

Ovarian (December 2018)

Small-Cell Lung (May 2017)

MK-3475A (pembrolizumab+hyaluronidase subcutaneous)

Non-Small-Cell Lung (February 2023)

MK-3543 (bomedemstat)

Myeloproliferative Disorders (December 2023)

MK-5909 (raludotatug deruxtecan) (1)

Ovarian (December 2025)

MK-5684 (opevesostat)

3 unchanged sentences

Small Cell Lung (December 2020)

MK-7902 Lenvima (1)(2)

Esophageal (July 2021)

V940 (intismeran autogene) (1)

Melanoma (July 2023)

Non-Small Cell Lung (December 2023)

MK-4482 Lagevrio (U.S.) (May 2021) (1)(2)

Dengue Fever Virus Vaccine

V181 (June 2025)

Diabetic Macular Edema

HIV-1 Infection

MK-8591A (doravirine+islatravir) (February 2020) (5)

MK-8591A (doravirine+islatravir) (February 2020) ( EU )

MK-8591D (islatravir+lenacapavir) (October 2024) (1)(4)

HIV-1 Pre-Exposure Prophylaxis

MK-8527 (July 2025)

Hypercholesterolemia

3 unchanged sentences

Ulcerative Colitis (October 2023)

MK-1406 (September 2025)

New Molecular Entities

MK-1022 (patritumab deruxtecan) (1)(8)

Non-Small-Cell Lung (U.S.)

MK-6482 Welireg

Renal Cell (JPN)

Von Hippel-Lindau (VHL)

Disease (JPN)

Pneumococcal Vaccine Adult

V116 Capvaxive (EU) (JPN)

Pulmonary Arterial Hypertension

MK-7962 Winrevair (JPN)

HIV-1 Infection

MK-8591A (doravirine+islatravir) (U.S.) (JPN)

Respiratory Syncytial Virus

MK-1654 (clesrovimab) (U.S.) (EU)

MK-1654 Enflonsia (EU) (JPN)

Certain Supplemental Filings

MK-3475 Keytruda

• First-Line Unresectable Advanced or Metastatic Malignant Pleural Mesothelioma

• Platinum-Resistant Recurrent Ovarian Cancer

(KEYNOTE-B96) (EU) (JPN)

• Cisplatin-Ineligible Muscle Invasive Bladder Cancer

(KEYNOTE-905) (EU) (JPN)

• First-Line Unresectable Locally Advanced or Metastatic Triple Negative Breast Cancer

(KEYNOTE-D19) (U.S.)

MK-3475A Keytruda Qlex

• First-Line Unresectable Locally Advanced o r Metastatic Triple Negative Breast Cancer

(KEYNOTE-D19) (U.S.)

MK-6482 Welireg

• Advanced, Unresectable, or Metastatic Pheochromocytoma and Paraganglioma

• Clear Cell Renal Cell Carcinoma Following Nephrectomy

(LITESPARK-022) (U.S.) (5)

• Previously Treated Advanced Renal Cell Carcinoma

(LITESPARK-011) (U.S.) (1)

Pulmonary Arterial Hypertension

MK-7962 Winrevair (HYPERION) (U.S.)

(1) Being developed in a collaboration.

(2) Being developed in combination with Keytruda .

(3) Being developed as monotherapy and/or in combination with Keytruda.

(4) FDA lifted clinical hold on December 4, 2024.

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

(2) Available in the U.S.

1 unchanged sentence

(3) Program is in a Phase 2/3 study that commenced in August 2024.

(8) In June 2024, the FDA issued a CRL for the BLA for patritumab deruxtecan.

Merck is working with Daiichi Sankyo to address FDA feedback.

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

(5) Under review for combination use with Keytruda or Keytruda Qlex.

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

Table of Content s

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.

As of December 31, 2025, the Company had approximately 75,000 employees worldwide, including approximately 30,000 people in the U.S., including Puerto Rico, and approximately 15,000 third-party contractors globally.

Third-party contractors include temporary workers, independent contractors, and freelancers who are considered full-time equivalent employees;

outsourced service providers are excluded.

Approximately 73,000 employees are full-time employees.

Approximately 21% of employees worldwide are covered by collective bargaining agreements.

For 2025, the voluntary turnover rate was approximately 4.8%.

The Company’s success depends on the integrity, skill, and collaboration of its employees, who are essential to meeting the needs of patients and customers.

Talent Acquisition, Management and Development

The Company takes a comprehensive approach to recruiting and leadership development to hire and retain qualified leaders with a range of knowledge, skills, backgrounds, and perspectives.

The Company’s communications strategy, employer branding, marketing outreach, social media, and strategic partnerships help it reach talent across its critical business areas.

In 2025, the Company hired approximately 6,800 people globally through its external career site, direct candidate sourcing, employee referrals, universities, and other channels.

As the Company strives to be the world’s premier research-based biopharmaceutical company, it remains focused on

continuously developing the leadership and management skills of its people, building workforce capabilities to accelerate talent, improving performance, and mitigating risk through relevant continuous learning experiences and technical and functional trainings for all employees.

Employee Engagement and Culture

Collaboration is central to the Company’s success and future innovation.

The Company strives to create an environment of respect, engagement, and empowerment, and seeks to hire and develop top talent by providing equal opportunity in all aspects of employment.

The Company believes these practices create a competitive edge by focusing on the needs of patients worldwide and leveraging employee insights to improve performance.

By building strong relationships with its employees, the Company fosters an engaging employee experience that propels the Company forward.

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’s compensation and benefits programs are designed to attract, retain, and motivate talent, and to support employees and their families in every stage of life.

The Company continually monitors and adjusts its compensation and benefits programs to remain competitive, contemporary, helpful, and engaging and to ensure that they are anchored in fairness, flexibility, quality, security, and affordability.

The Company regularly reviews pay practices and policies to help ensure employees are fairly compensated.

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.

employees participating in its medical plan with their health care needs.

In support of the Company’s cancer care strategy, Merck 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, including caregiving and mental health services, for employees and their families.

Globally, the Company has 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’s Most Admired Companies and 100 Best Companies to Work For of companies that participated in the Aon 2025 Benefits Index.

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.

Table of Content s

The Company is committed to helping its employees and their families improve their health and well-being, including physical, mental, financial, and social.

This commitment has earned the Company recognition including the Business Group on Health’s Best Employers Excellence in Health & Well-being.

As part of the Company’s culture of well-being, it offers flexible work arrangements and onsite services to help employees thrive.

In the U.S., these services include onsite health care professionals at many major sites, onsite cafeterias, childcare, gyms, and convenient banking through an employee credit union.

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;

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

The Company is committed to enabling a safe, sustainable, and healthy future, consistent with its purpose to save and improve lives.

In alignment with the Company’s Corporate Strategic Framework and long-standing environmental stewardship efforts, the Company’s environmental sustainability strategy focuses on:

(1) driving operational efficiency, (2) designing new products to minimize environmental impact, and (3) reducing impacts across 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 EHS Council monitors performance against the Company’s environmental sustainability goals and increases transparency on environmental issues within the Company, senior management, and the Board of Directors (the Board).

The Global Safety and Environment 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 Sustainability 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.

The Company believes that climate change could present risks to its business, as discussed in further detail in Item 1A.

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.

1 unchanged sentence

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).

The Company’s climate goals include reducing Scope 1 and 2 operational GHG emissions 46% by 2030 (from a 2019 baseline), continuing to source 100% of its purchased electricity from renewable sources, 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), a third-party organization.

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.

The Company is working to reduce its Scope 3 emissions through a robust supplier engagement approach to reinforce the Company’s expectations, drive partnerships, and raise awareness of the Company’s climate change objectives to accelerate GHG reduction activities.

The Company launched the Sustainability Partner Exchange, an education and partnership series to facilitate dialogue and knowledge-sharing between the Company and its suppliers.

This innovative initiative fosters the exchange of best practices in environmental sustainability, open discussions on common challenges, and cross-industry collaboration to drive decarbonization.

The Company continues to improve upon the accuracy of its Scope 3 GHG data through close collaboration with suppliers to enhance Scope 3 data calculation, collection, and reporting processes.

• 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.

Table of Content s

To help direct and track projects in support of its goals, the Company has developed a suite of playbooks to guide site-level progress.

The Low Carbon Transition Playbook provides a common platform and gap assessment to evaluate energy management program maturity, set short- and long-term plans to reduce carbon intensity, and build a pathway to net zero.

The Waste Diversion and Water Conservation Playbooks help sites build roadmaps to meet Company-wide goals for waste diversion and water efficiency, including local strategies for material and water use and environmentally responsible procurement.

This standardized approach drives consistent project execution across the global network and enables continuous improvement toward the Company’s goals.

The playbooks are updated to include the advent of new technology, the evolution of sustainable processes, and lessons learned from best practice sharing among the sites.

• Realizing the benefits of green and sustainable science .

2 unchanged sentences

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.

The Company received the Peter J.

Dunn Award for Green Chemistry and Engineering Impact for four of the past five years, 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.

Based on its evaluation, the Company implemented programs to divert non-hazardous landfill waste from its four highest landfill-generating sites.

The Company continues its efforts to reduce its global operational waste sent to landfills or incinerators.

• 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 water risk assessment process enables the Company to better prioritize facilities and catchments for water stewardship activities and lays the foundation for potential future water targets in priority locations.

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’s endorsement of the United Nations CEO Water Mandate enables alignment of the Company’s water program with the mandate’s

The Company has continued to identify partnerships to help it advance its water stewardship priorities in the areas in which it operates.

13 unchanged sentences

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.

as a percentage of total Company sales were 44% in 2025, 50% in 2024 and 53% in 2023.

The Company’s worldwide business is subject to risks of currency fluctuations, governmental actions and other governmental proceedings abroad.

1 unchanged sentence

However, the Company closely reviews its methods of operations and adopts strategies responsive to changing economic and political conditions.

Table of Content s

Merck has operations in countries located in Latin America, the Middle East, Africa, Eastern Europe and Asia Pacific.

The Company 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.

3 unchanged sentences

Securities and Exchange Commission (SEC).

The address of that website is sec.gov .

The address of the SEC 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.

3 unchanged sentences

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-K

Item 1. Business