Doravirine/Islatravir

March 12, 2025 11:26 am ET DOR/ISL demonstrated non-inferiority and a similar safety profile to comparator antiretroviral therapies in adults with virologically suppressed HIV-1 RAHWAY, N.J.--(BUSINESS WIRE)-- Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced the presentation of positive results from two pivotal Phase 3 trials of the investigational, once-daily, oral, two-drug regimen of doravirine/islatravir [DOR/ISL (100mg/0.25mg)] in adults with HIV-1 infection that is virologically suppressed on bictegravir/emtricitabine/tenofovir alafenamidei [BIC/FTC/TAF (50mg/200mg/25mg)] in trial MK-8591A-052 ) or antiretroviral therapy [baseline antiretroviral therapy (bART)] in trial MK-8591A-051. In both trials, DOR/ISL met the primary efficacy success criterion for non-inferiority to comparator antiretroviral therapies and primary safety objectives at Week 48. The findings will be shared in late-breaking oral presentations at the 32nd Conference on Retroviruses and Opportunistic Infections (CROI) being held in San Francisco and were featured in a CROI press conference. Merck plans to begin submitting applications for marketing authorization to regulatory agencies by mid-2025. In the double-blind trial MK-8591A-052 (Abstract #204A), results for the primary endpoint (HIV-1 RNA ≥50 copies/mL) showed that 1.5% of participants who switched to DOR/ISL had a viral load of ≥50 copies/mL at Week 48, compared to 0.6% on BIC/FTC/TAF (treatment difference 0.9%, 95% CI -1.9, 2.9). At Week 48, 91.5% of participants who switched to DOR/ISL maintained viral suppression (HIV-1 RNA <50 copies/mL) compared to 94.2% of participants who continued receiving BIC/FTC/TAF (treatment difference -2.6%, 95% CI -7.1, 2.6; secondary endpoint). In the open-label trial MK-8591A-051 (Abstract #204B), results for the primary endpoint (HIV-1 RNA ≥50 copies/mL) showed that 1.4% of participants who received DOR/ISL had a viral load of ≥50 copies/mL at Week 48, compared to 4.9% on bART (treatment difference -3.6%, 95% CI -7.8, -0.8. At Week 48, 95.6% of participants who switched to DOR/ISL maintained viral suppression (HIV-1 RNA <50 copies/mL) compared to 91.9% of participants who continued on bART (treatment difference 3.7%, 95% CI -0.3, 8.9; secondary endpoint). Across both trials, the safety profile of DOR/ISL was generally comparable to the comparator antiretroviral regimens, including BIC/FTC/TAF in MK-8591A-052. At Week 48, the mean percent change in total lymphocyte and CD4 counts were similar for DOR/ISL and comparator regimens. No treatment-emergent resistance to DOR or ISL was observed in either trial. “Despite the availability of multiple daily antiretroviral therapies, the needs of people living with HIV are evolving. Many people living with HIV are older and also managing comorbidities, making it important to have daily treatment options that can help meet each person’s unique health needs,” said Professor Chloe Orkin, Dean for Healthcare Transformation, Queen Mary University of London, United Kingdom. “I’m excited to see that DOR/ISL has potential as a new daily treatment option for people living with HIV who may benefit from this two-drug regimen.” Islatravir, Merck’s investigational nucleoside reverse transcriptase translocation inhibitor (NRTTI), blocks HIV-1 replication by multiple mechanisms including inhibition of reverse transcriptase translocation resulting in immediate chain termination and delayed chain termination from structural changes induced in the viral DNA. “We are excited that DOR/ISL is the first two-drug regimen without an integrase inhibitor to demonstrate comparable efficacy and safety to the three-drug InSTI-based regimen, BIC/FTC/TAF, in a Phase 3 pivotal trial,” said Dr. Eliav Barr, senior vice president, head of global clinical development and chief medical officer, Merck Research Laboratories. “Merck has been a research pioneer in HIV for decades. These data and our work on the longer-acting islatravir-based therapies in our pipeline show our continued commitment to help find new options that address the evolving needs of people living with HIV.” About the Phase 3 data from MK-8591A-052 MK-8591A-052 is a Phase 3, double-blind randomized, active-controlled, clinical trial to evaluate the efficacy and safety of a switch to investigational, oral, once-daily DOR/ISL (100mg/0.25mg) in adults with HIV-1 infection that has been virologically suppressed on BIC/FTC/TAF (50mg/200mg/25mg). The primary efficacy endpoint was the percentage of participants with HIV-1 RNA ≥50 copies/mL at Week 48 (non-inferiority margin 4%). In this trial, 513 adults with HIV-1 who had virologic suppression for three months or more on BIC/FTC/TAF, no history of treatment failure and no known resistance to DOR were randomized (2:1) and switched to DOR/ISL (n= 342) or continued treatment with BIC/FTC/TAF (n=171). The median age of participants was 47 years; 21.4% were assigned female sex at birth, 30.8% were Black or African American, and 22.8% were Hispanic or Latine. The median duration of BIC/FTC/TAF treatment prior to trial enrollment was 3.4 years (IQR 2.0-5.0). Results for the primary efficacy endpoint showed that five participants (1.5%) treated with DOR/ISL and one participant (0.6%) in the BIC/FTC/TAF group had a viral load of ≥50 copies/mL at Week 48, demonstrating non-inferiority of DOR/ISL to BIC/FTC/TAF (treatment difference 0.9%, 95% CI -1.9, 2.9). The superiority criteria were not met. Results for a secondary endpoint, the proportion of individuals with HIV-1 RNA <50 copies/mL at Week 48, showed that participants who switched to treatment with DOR/ISL or continued BIC/FTC/TAF maintained comparable rates of viral suppression at Week 48 (91.5% on DOR/ISL vs. 94.2% on BIC/FTC/TAF (treatment difference -2.6%, 95% CI -7.1, 2.6). No treatment-emergent resistance to DOR or ISL was observed. At Week 48, the mean percent change in total lymphocyte and CD4 counts were similar for DOR/ISL and BIC/FTC/TAF. There were identical rates of discontinuation for protocol-specified decreases in total lymphocyte and/or CD4 counts (two participants (0.6%) in the DOR/ISL group and one participant (0.6%) in the BIC/FTC/TAF group). Drug-related adverse events (AEs) and discontinuations due to drug-related AEs were similar between groups (n=35, 10.2% for DOR/ISL and n=16, 9.4% for BIC/FTC/TAF; n=4, 1.2% for DOR/ISL and n=2, 1.2% for BIC/FTC/TAF, respectively). Rates of toxicity grade 3 or 4 AEs and serious AEs were similar for DOR/ISL and BIC/FTC/TAF (n=25, 7.3% for DOR/ISL and n=13, 7.6% for BIC/FTC/TAF; n=15, 4.4% for DOR/ISL and n=11, 6.4% for BIC/FTC/TAF, respectively). Mean change in weight from baseline to Week 48 was minimal (-0.03 kg for DOR/ISL versus 0.28 kg for BIC/FTC/TAF; difference -0.30 kg, 95% CI -1.13, 0.53). The most common AEs (>6% in either study arm) were arthralgia, COVID-19, nasopharyngitis, and fatigue. One participant on DOR/ISL discontinued due to a drug-related serious AE (immune thrombocytopenia). There were two cases of low-level hepatitis B (HBV) viremia (HBV DNA <50 IU/mL) with no antigenemia or elevated transaminases in the DOR/ISL group and no cases in the BIC/FTC/TAF group; there were no cases of clinical HBV reactivation. About the Phase 3 data from MK-8591A-051 MK-8591A-051 is a Phase 3, open-label randomized, active-controlled, clinical trial evaluating the efficacy and safety of a switch to investigational, oral, once-daily DOR/ISL (100mg/0.25mg) in adults with HIV-1 infection that has been virologically suppressed using ART. The primary efficacy endpoint was percentage of participants with HIV-1 RNA ≥50 copies/mL at Week 48 (non-inferiority margin 4%). In this trial, 551 adults with HIV-1 RNA <50 copies/mL for three months or more on oral 2- or 3-drug ART, with no history of treatment failure and no known virologic resistance to DOR were randomized 2:1 and switched to DOR/ISL (n=366) or continued baseline antiretroviral therapy (bART) (n=185), stratified by bART regimen. The median age of participants was 51 years; 39.7% were assigned female sex at birth, 45.4% Black or African American and 14.5% Hispanic or Latine. At baseline, 64.2% were treated with an InSTI-based regimen, 30.3% with an NNRTI-based regimen, and 5.4% with a protease inhibitor (PI)-based regimen, with median duration on current ART of 3.8 years (IQR 2.0-6.3). Results for the primary efficacy endpoint showed that five participants (1.4%) in the DOR/ISL group and nine participants (4.9%) in the bART group had a viral load of ≥50 copies/mL at Week 48, demonstrating non-inferiority of DOR/ISL to bART (treatment difference -3.6%, 95% CI -7.8, -0.8). Results for a secondary endpoint, the proportion of individuals with HIV-1 RNA <50 copies/mL at Week 48, showed that participants who switched to treatment with DOR/ISL or continued bART maintained comparable rates of viral suppression at Week 48 (95.6% on DOR/ISL vs. 91.9% on bART; treatment difference 3.7%, 95% CI -0.3, 8.9). No treatment-emergent resistance to DOR or ISL was observed. Two participants discontinued DOR/ISL early after virologic failure at Week 4 with multiple resistance-associated mutations that were also present in baseline proviral DNA. These two participants were later found to be not eligible for the trial due to history of prior virologic failure and exclusionary DOR resistance. At Week 48, the mean percent change in total lymphocyte and CD4 counts were similar for DOR/ISL and bART. No participants discontinued treatment due to decrease in total lymphocyte and/or CD4 counts. In this open-label study, drug-related AEs were more commonly reported with DOR/ISL (n=44; 12.0%) than bART (n=9; 4.9%). Rates of toxicity grade 3 or 4 AEs and serious AEs were similar for DOR/ISL and bART (n=39, 10.7% for DOR/ISL and n=18, 9.7% for bART and n=23, 6.3% for DOR/ISL and n=9, 4.9% for bART, respectively). There were no drug-related serious AEs and there were no discontinuations due to serious AEs in the DOR/ISL group; there was one drug-related serious AE and two discontinuations due to serious AEs in the bART group. The most common drug-related AEs were diarrhea (DOR/ISL 3.3%, bART 0%), fatigue (1.9%, 0.5%), dizziness (1.9%, 0.5%), abdominal distention (1.6%, 0%), weight increased (1.6%, 0%), and headache (1.6%, 1.1%). Change in lipid parameters from baseline were similar between treatment groups for all bART strata. Mean change in weight from baseline to Week 48 was 0.94 kg for DOR/ISL and -0.18 kg for bART (difference -1.13 kg, 95% CI 0.31, 1.94). For baseline regimens without EFV or TDF, the difference in weight between DOR/ISL and bART was 0.82 kg (95% CI -0.22, 1.87). There was one case of low-level HBV viremia with no antigenemia or elevated transaminases in the DOR/ISL group and no cases in the bART group; there were no cases of clinical HBV reactivation. Indications and usage for PIFELTRO® (doravirine) and DELSTRIGO® (doravirine, lamivudine, and tenofovir disoproxil fumarate) in the U.S. PIFELTRO is indicated in combination with other antiretroviral (ARV) agents for the treatment of HIV-1 infection in adult patients with no prior ARV treatment history or to replace the current ARV regimen in those who are virologically suppressed (HIV-1 RNA less than 50 copies per mL) on a stable ARV regimen with no history of treatment failure and no known substitutions associated with resistance to doravirine. DELSTRIGO is indicated as a complete regimen for the treatment of HIV-1 infection in adult patients with no prior ARV treatment history or to replace the current ARV regimen in those who are virologically suppressed (HIV-1 RNA less than 50 copies per mL) on a stable ARV regimen with no history of treatment failure and no known substitutions associated with resistance to the individual components of DELSTRIGO. Selected Safety Information Warning: Posttreatment Acute Exacerbation of Hepatitis B Virus (HBV) for DELSTRIGO All patients with HIV-1 should be tested for the presence of HBV before initiating ARV therapy. Severe acute exacerbations of HBV have been reported in people with concomitant HIV-1 and HBV who have discontinued products containing lamivudine or tenofovir disoproxil fumarate (TDF), which are components of DELSTRIGO. Patients coinfected with HIV-1 and HBV who discontinue DELSTRIGO should be monitored with both clinical and laboratory follow-up for at least several months after stopping DELSTRIGO. If appropriate, initiation of anti-HBV therapy may be warranted. Contraindications PIFELTRO and DELSTRIGO are contraindicated when coadministered with drugs that are strong cytochrome P450 (CYP)3A enzyme inducers (including the anticonvulsants carbamazepine, oxcarbazepine, phenobarbital, and phenytoin; the androgen receptor inhibitor enzalutamide; the antimycobacterials rifampin and rifapentine; the cytotoxic agent mitotane; and the herbal product St. John’s wort (Hypericum perforatum)), as significant decreases in doravirine plasma concentrations may occur, which may decrease the effectiveness of DELSTRIGO and PIFELTRO. DELSTRIGO is contraindicated in patients with a previous hypersensitivity reaction to lamivudine. Warnings and Precautions Severe Skin Reactions Severe skin reactions, including Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN), have been reported during the postmarketing experience with doravirine-containing regimens. Discontinue PIFELTRO or DELSTRIGO, and other medications known to be associated with severe skin reactions, immediately if a painful rash with mucosal involvement or a progressive severe rash develops. Clinical status should be closely monitored, and appropriate therapy should be initiated. New or Worsening Renal Impairment Renal impairment, including cases of acute renal failure and Fanconi syndrome, have been reported with the use of TDF. DELSTRIGO should be avoided with concurrent or recent use of a nephrotoxic agent (eg, high-dose or multiple NSAIDs). Cases of acute renal failure after initiation of high-dose or multiple NSAIDs have been reported in people living with HIV with risk factors for renal dysfunction who appeared stable on TDF. Prior to or when initiating DELSTRIGO, and during treatment, assess serum creatinine, estimated creatinine clearance, urine glucose, and urine protein in all patients. In patients with chronic kidney disease, also assess serum phosphorus. Discontinue DELSTRIGO in patients who develop clinically significant decreases in renal function or evidence of Fanconi syndrome. Discontinue DELSTRIGO if estimated creatinine clearance declines below 50 mL/min. Bone Loss and Mineralization Defects In clinical trials in adults living with HIV, TDF was associated with slightly greater decreases in bone mineral density (BMD) and increases in biochemical markers of bone metabolism. Serum parathyroid hormone levels and 1,25 Vitamin D levels were also higher. Cases of osteomalacia associated with proximal renal tubulopathy have been reported with the use of TDF. The effects of TDF-associated changes in BMD and biochemical markers on long-term bone health and future fracture risk in adults are unknown. Immune Reconstitution Syndrome Immune reconstitution syndrome can occur, including the occurrence of autoimmune disorders with variable time to onset, which may necessitate further evaluation and treatment. Drug Interactions Because DELSTRIGO is a complete regimen, coadministration with other antiretroviral medications for the treatment of HIV-1 infection is not recommended. Coadministration of PIFELTRO with efavirenz, etravirine, or nevirapine is not recommended. If DELSTRIGO is coadministered with rifabutin, take one tablet of DELSTRIGO once daily, followed by one tablet of doravirine (PIFELTRO) approximately 12 hours after the dose of DELSTRIGO. If PIFELTRO is coadministered with rifabutin, increase PIFELTRO dosage to one tablet twice daily (approximately 12 hours apart). Consult the full Prescribing Information prior to and during treatment for more information on potential drug-drug interactions. Dosage and Administration/Specific Populations Renal Impairment Because DELSTRIGO is a fixed-dose combination tablet and the dosage of lamivudine and TDF cannot be adjusted, DELSTRIGO is not recommended in patients with estimated creatinine clearance less than 50 mL/min. Adverse Reactions The most common adverse reactions with DELSTRIGO (incidence ≥5%, all intensities) were dizziness (7%), nausea (5%), and abnormal dreams (5%). The most common adverse reactions with PIFELTRO (incidence ≥5%, all intensities) were nausea (7%), dizziness (7%), headache (6%), fatigue (6%), diarrhea (6%), abdominal pain (5%), and abnormal dreams (5%). By week 96 in DRIVE-FORWARD, 2% of adult participants in the PIFELTRO group and 3% in the darunavir+ritonavir (DRV+r) group had adverse events leading to discontinuation of study medication. By week 96 in DRIVE-AHEAD, 3% of adult participants in the DELSTRIGO group and 7% in the efavirenz (EFV)/emtricitabine (FTC)/TDF group had adverse events leading to discontinuation of study medication. In DRIVE-FORWARD, mean changes from baseline at week 48 in LDL-cholesterol (LDL-C) and non-HDL-cholesterol (non-HDL-C) were pre-specified. LDL-C: -4.6 mg/dL in the PIFELTRO group vs 9.5 mg/dL in the DRV+r group. Non-HDL-C: -5.4 mg/dL in the PIFELTRO group vs 13.7 mg/dL in the DRV+r group. The clinical benefits of these findings have not been demonstrated. In DRIVE-AHEAD, mean changes from baseline at week 48 in LDL-C and non-HDL-C were pre-specified. LDL-C: -2.1 mg/dL in the DELSTRIGO group vs 8.3 mg/dL in the EFV/FTC/TDF group. Non-HDL-C: -4.1 mg/dL in the DELSTRIGO group vs 12.7 mg/dL in the EFV/FTC/TDF group. The clinical benefits of these findings have not been demonstrated. In DRIVE-SHIFT, mean changes from baseline at week 24 in LDL-C and non-HDL-C were pre-specified. LDL-C: -16.3 mg/dL in the DELSTRIGO group vs -2.6 mg/dL in the PI + ritonavir group. Non-HDL-C: -24.8 mg/dL in the DELSTRIGO group vs -2.1 mg/dL in the PI + ritonavir group. The clinical benefits of these findings have not been demonstrated. In DRIVE-AHEAD, neuropsychiatric adverse events were reported in the three pre-specified categories of sleep disorders and disturbances, dizziness, and altered sensorium. Twelve percent of adult participants in the DELSTRIGO group and 26% in the EFV/FTC/TDF group reported neuropsychiatric adverse events of sleep disorders and disturbances; 9% in the DELSTRIGO group and 37% in the EFV/FTC/TDF group reported dizziness; and 4% in the DELSTRIGO group and 8% in the EFV/FTC/TDF group reported altered sensorium. The safety of DELSTRIGO in virologically-suppressed adults was based on week 48 data from participants in the DRIVE-SHIFT trial. Overall, the safety profile in virologically-suppressed adult participants was similar to that in participants with no ARV treatment history. Serum ALT and AST Elevations: In the DRIVE-SHIFT trial, 22% and 16% of participants in the immediate switch group experienced ALT and AST elevations greater than 1.25 X ULN, respectively, through 48 weeks on DELSTRIGO. For these ALT and AST elevations, no apparent patterns with regard to time to onset relative to switch were observed. One percent of participants had ALT or AST elevations greater than 5 X ULN through 48 weeks on DELSTRIGO. The ALT and AST elevations were generally asymptomatic, and not associated with bilirubin elevations. In comparison, 4% and 4% of participants in the delayed switch group experienced ALT and AST elevations of greater than 1.25 X ULN through 24 weeks on their baseline regimen. Pregnancy/Breastfeeding There is a pregnancy exposure registry that monitors pregnancy outcomes in individuals exposed to PIFELTRO or DELSTRIGO during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263. Inform individuals with HIV-1 infection of the potential risks of breastfeeding, including: (1) HIV-1 transmission (in HIV-1–negative infants), (2) developing viral resistance (in HIV-1–positive infants), and (3) serious adverse reactions in a breastfed infant similar to those seen in adults. About Islatravir (MK-8591) and Merck’s HIV Research Islatravir (MK-8591) is Merck’s investigational nucleoside reverse transcriptase translocation inhibitor (NRTTI) under evaluation in multiple ongoing early and late-stage clinical trials in combination with other antiretrovirals for the treatment of HIV-1. Trials with islatravir are designed to offer different dosing options as potential daily and once-weekly treatments. In addition to the MK-8591A-051 and MK-8591A-052 trials, ongoing Phase 3 trials of daily DOR/ISL (100mg /0.25mg) include MK-8591A-053 in people with HIV who had not previously received treatment (treatment-naïve), and MK-8591A-054 evaluating open-label DOR/ISL (100 mg/0.25 mg) in individuals who participated in earlier Phase 3 trials of DOR/ISL (100 mg/0.75 mg). For an overview of Merck’s HIV treatment and prevention clinical development program, please click here. Merck’s Commitment to HIV For more than 35 years, Merck has been committed to scientific research and discovery in HIV leading to scientific breakthroughs that have helped change HIV treatment. Our work has been pioneering in the development of new options across multiple drug classes to help those impacted by HIV. Today, we are developing a series of antiviral options designed to help people manage HIV and protect people from HIV, with the goal of reducing the growing burden of infection worldwide. We want to ensure people are not defined by HIV and our work focuses on transformational innovations, collaborations with others in the global HIV community, and access initiatives aimed at the goal of helping to end the HIV epidemic for everyone. About Merck At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn. Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements. Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions. The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2024 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov). Please see Prescribing Information for PIFELTRO (doravirine) at: https://www.merck.com/product/usa/pi_circulars/p/pifeltro/pifeltro_pi.pdf and Patient Information for PIFELTRO at: https://www.merck.com/product/usa/pi_circulars/p/pifeltro/pifeltro_ppi.pdf Please see Prescribing Information for DELSTRIGO (doravirine, lamivudine, and tenofovir disoproxil fumarate) at: https://www.merck.com/product/usa/pi_circulars/d/delstrigo/delstrigo_pi.pdf and Patient Information for DELSTRIGO at: https://www.merck.com/product/usa/pi_circulars/d/delstrigo/delstrigo_ppi.pdf i bictegravir/emtricitabine/tenofovir alafenamide (BIKTARVY) is a registered trademark of Gilead Sciences, Inc. Media Contacts: Julie Cunningham (617) 519-6264 Deb Wambold (215) 779-2234 Investor Contacts: Peter Dannenbaum (732) 594-1579 Ayn Wisler (732) 594-0482

RAHWAY, N.J.--( BUSINESS WIRE )--Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced financial results for the fourth quarter of 2024. “ We delivered strong growth in 2024, reflecting demand for our innovative portfolio, including for KEYTRUDA, which continues to benefit more patients with cancer globally, the successful launch of WINREVAIR and strong performance of our Animal Health business,” said Robert M. Davis, chairman and chief executive officer, Merck. " We’re continuing to progress our pipeline, advance key clinical programs and augment our pipeline through promising business development. Our business remains well positioned thanks to the dedication of our talented global team, and I am more confident than ever in our long-term growth potential.” Financial Summary $ in millions, except EPS amounts Fourth Quarter Year Ended 2024 2023 Change Change Ex-Exchange Dec. 31, 2024 Dec. 31, 2023 Change Change Ex-Exchange Sales $15,624 $14,630 7% 9% $64,168 $60,115 7% 10% GAAP net income (loss) 1 3,743 (1,226) N/M N/M 17,117 365 N/M N/M Non-GAAP net income that excludes certain items 1,2* 4,372 66 N/M N/M 19,444 3,837 N/M N/M GAAP EPS 1.48 (0.48) N/M N/M 6.74 0.14 N/M N/M Non-GAAP EPS that excludes certain items 2* 1.72 0.03 N/M N/M 7.65 1.51 N/M N/M *Refer to table on page 9. N/M - not meaningful Generally Accepted Accounting Principles (GAAP) earnings per share (EPS) assuming dilution was $1.48 for the fourth quarter and $6.74 for the full year of 2024. Non-GAAP EPS was $1.72 for the fourth quarter and $7.65 for the full year of 2024. GAAP and non-GAAP EPS in the fourth quarter of 2024 include a charge of $0.23 per share related to the execution of licensing agreements with LaNova Medicines Ltd. (LaNova) and Hansoh Pharma (Hansoh). GAAP loss per share and non-GAAP EPS in the fourth quarter of 2023 include a charge of $1.69 per share related to a collaboration with Daiichi Sankyo. GAAP and non-GAAP EPS for the full years of 2024 and 2023 include charges of $1.28 and $6.21 per share, respectively, related to certain collaborations, licensing agreements and asset acquisitions. Non-GAAP EPS excludes acquisition- and divestiture-related costs, costs related to restructuring programs, and income and losses from investments in equity securities. Non-GAAP EPS in the fourth quarter and full year of 2024 also exclude a benefit due to a reduction in reserves for unrecognized income tax benefits resulting from the expiration of the statute of limitations for assessments related to certain federal tax return years. Non-GAAP EPS for the full year of 2023 also excludes a charge related to settlements with certain plaintiffs in the Zetia antitrust litigation. Fourth-Quarter Sales Performance The following table reflects sales of the company’s top products and significant performance drivers. Fourth Quarter $ in millions 2024 2023 Change Change Ex-Exchange Commentary Total Sales $15,624 $14,630 7% 9% The negative impact of foreign exchange was primarily due to devaluation of Argentine peso, which was largely offset by inflation-related price increases, consistent with practice in that market. Pharmaceutical 14,042 13,141 7% 8% Increase driven by growth in oncology and cardiovascular, partially offset by declines in diabetes, vaccines, immunology and virology. KEYTRUDA 7,836 6,608 19% 21% Growth driven by continued strong global demand from metastatic indications, including increased uptake in bladder and endometrial cancers, as well as increased global uptake in earlier-stage indications, including triple-negative breast cancer and non-small cell lung cancer (NSCLC). The negative impact of foreign exchange was primarily due to devaluation of Argentine peso, which was largely offset by inflation-related price increases. GARDASIL/GARDASIL 9 1,550 1,871 -17% -18% Decline primarily due to lower demand in China, partially offset by higher demand in most international regions, particularly in Japan. PROQUAD, M-M-R II and VARIVAX 594 545 9% 9% Growth primarily due to higher pricing in the U.S. and higher tenders in certain international markets, partially offset by lower demand in the U.S. JANUVIA/JANUMET 487 787 -38% -36% Decline primarily due to lower pricing in the U.S., as well as ongoing generic competition in many international markets and supply constraints in China. BRIDION 449 429 5% 5% Growth primarily due to higher demand in the U.S., partially offset by generic competition in certain international markets, particularly in Japan and Europe. Lynparza* 365 315 16% 18% Growth primarily due to higher global demand. Lenvima* 255 226 13% 14% Growth primarily due to timing of shipments in certain international markets. PREVYMIS 215 175 23% 23% Growth primarily due to higher demand in most markets, particularly in the U.S. WINREVAIR 200 - - - Represents continued uptake since second-quarter launch in the U.S. VAXNEUVANCE 161 176 -9% -9% Decline primarily driven by lower demand in the U.S. due to competition, partially offset by continued uptake from launches in Europe and the Asia Pacific region. WELIREG 160 72 122% 123% Growth primarily driven by higher demand in the U.S., largely attributable to ongoing uptake of a new indication. SIMPONI - 171 N/M N/M Marketing rights in former Merck territories reverted to Johnson & Johnson on Oct. 1, 2024. Animal Health 1,397 1,278 9% 13% Growth primarily driven by higher pricing for both Livestock and Companion Animal product portfolios, as well as sales related to July 2024 acquisition of Elanco aqua business and higher demand for Livestock products. Approximately 3 percentage points of the negative impact of foreign exchange were due to devaluation of Argentine peso, which were largely offset by inflation-related price increases. Livestock 889 808 10% 14% Growth primarily driven by higher demand for poultry products, sales related to acquisition of Elanco aqua business, as well as higher pricing across the portfolio. Companion Animal 508 470 8% 10% Growth primarily driven by higher pricing across the product portfolio. Sales of BRAVECTO were $209 million and $197 million in current and prior year quarters, respectively, which represented growth of 6%, or 10% excluding impact of foreign exchange. Other Revenues** 185 211 -13% 3% Decline primarily due to impact of revenue-hedging activities and lower revenues from third-party manufacturing arrangements, partially offset by payments received for out-licensing arrangements and higher royalty income. *Alliance revenue for this product represents Merck’s share of profits, which are product sales net of cost of sales and commercialization costs. **Other revenues are comprised primarily of revenues from third-party manufacturing arrangements and miscellaneous corporate revenues, including revenue-hedging activities. N/M – not meaningful Full-Year Sales Performance The following table reflects sales of the company’s top products and significant performance drivers. Year Ended $ in millions Dec. 31, 2024 Dec. 31, 2023 Change Change Ex- Exchange Total Sales $64,168 $60,115 7% 10% Pharmaceutical 57,400 53,583 7% 10% KEYTRUDA 29,482 25,011 18% 22% GARDASIL/GARDASIL 9 8,583 8,886 -3% -2% PROQUAD, M-M-R II and VARIVAX 2,485 2,368 5% 5% JANUVIA/JANUMET 2,268 3,366 -33% -29% BRIDION 1,764 1,842 -4% -3% Lynparza* 1,311 1,199 9% 11% Lenvima* 1,010 960 5% 6% LAGEVRIO 964 1,428 -33% -28% VAXNEUVANCE 808 665 22% 23% PREVYMIS 785 605 30% 33% ROTATEQ 711 769 -8% -7% SIMPONI** 543 710 -24% -23% WELIREG 509 218 133% 133% WINREVAIR 419 - - - Animal Health 5,877 5,625 4% 8% Livestock 3,462 3,337 4% 9% Companion Animal 2,415 2,288 6% 7% Other Revenues*** 891 907 -2% 4% *Alliance revenue for this product represents Merck’s share of profits, which are product sales net of cost of sales and commercialization costs. **Marketing rights in former Merck territories reverted to Johnson & Johnson on Oct. 1, 2024. ***Other revenues are comprised primarily of revenues from third-party manufacturing arrangements and miscellaneous corporate revenues, including revenue-hedging activities. Full-year 2024 pharmaceutical sales grew 7% to $57.4 billion. Excluding the unfavorable impact of foreign exchange, pharmaceutical sales grew 10%. Approximately 2 percentage points of the negative impact of foreign exchange were due to devaluation of the Argentine peso, which were largely offset by inflation-related price increases, consistent with practice in that market. Pharmaceutical sales growth was primarily driven by higher sales in oncology, particularly KEYTRUDA and WELIREG, as well as increased alliance revenue from Reblozyl and Lynparza. Higher sales in the cardiovascular franchise, reflecting the successful launch of WINREVAIR, as well as higher sales of certain hospital acute care products, particularly PREVYMIS, also drove revenue growth in 2024. Pharmaceutical sales growth in 2024 was partially offset by lower sales of JANUVIA and JANUMET, primarily reflecting lower pricing in the U.S. and generic competition in many international markets, lower sales of the COVID-19 medication LAGEVRIO, lower sales of GARDASIL/GARDASIL 9 and lower sales of SIMPONI and REMICADE, reflecting the transfer of marketing rights in former Merck territories back to Johnson & Johnson. Full-year 2024 Animal Health sales grew 4% to $5.9 billion. Excluding the unfavorable impact of foreign exchange, Animal Health sales grew 8%. Approximately 2 percentage points of the negative impact of foreign exchange were due to devaluation of the Argentine peso, which were largely offset by inflation-related price increases, consistent with practice in that market. Full-year sales growth was primarily driven by higher pricing across both the Companion Animal and Livestock product portfolios, and higher demand for poultry and swine products, as well as sales related to the acquisition of the Elanco aqua business. Sales of BRAVECTO were $1.1 billion in 2024, which represented growth of 6%, or 8% excluding the impact of foreign exchange. Fourth-Quarter and Full-Year Expense, EPS and Related Information The table below presents selected expense information. $ in millions GAAP Acquisition- and Divestiture- Related Costs 3 Restructuring Costs (Income) Loss From Investments in Equity Securities Non- GAAP 2 Fourth Quarter 2024 Cost of sales $3,828 $701 $121 $- $3,006 Selling, general and administrative 2,864 29 16 - 2,819 Research and development 4,585 12 (1) - 4,574 Restructuring costs 51 - 51 - - Other (income) expense, net 126 (31) - 152 5 Fourth Quarter 2023 Cost of sales $3,911 $454 $117 $- $3,340 Selling, general and administrative 2,804 24 29 - 2,751 Research and development 9,628 790 - - 8,838 Restructuring costs 255 - 255 - - Other (income) expense, net 78 (35) - (61) 174 $ in millions GAAP Acquisition- and Divestiture- Related Costs 3 Restructuring Costs (Income) Loss From Investments in Equity Securities Certain Other Items Non- GAAP 2 Year Ended December 31, 2024 Cost of sales $15,193 $2,409 $495 $- $ - $12,289 Selling, general and administrative 10,816 117 83 - - 10,616 Research and development 17,938 72 1 - - 17,865 Restructuring costs 309 - 309 - - - Other (income) expense, net (24) (79) - 45 - 10 Year Ended December 31, 2023 Cost of sales $16,126 $2,018 $211 $- $- $13,897 Selling, general and administrative 10,504 86 122 - - 10,296 Research and development 30,531 819 1 - - 29,711 Restructuring costs 599 - 599 - - - Other (income) expense, net 466 (47) - (279) 573 219 GAAP Expense, EPS and Related Information Gross margin was 75.5% for the fourth quarter of 2024 compared with 73.3% for the fourth quarter of 2023. The increase was primarily due to the favorable effects of product mix (including lower royalty rates related to KEYTRUDA and GARDASIL/GARDASIL 9) and foreign exchange, partially offset by higher manufacturing-related costs (including inventory write-offs) and higher amortization of intangible assets. Gross margin was 76.3% for the full year of 2024 compared with 73.2% for the full year of 2023. The increase was primarily due to the favorable effects of product mix (including lower royalty rates related to KEYTRUDA and GARDASIL/GARDASIL 9) and foreign exchange, partially offset by higher amortization of intangible assets, as well as higher restructuring costs (primarily reflecting asset impairment charges) and higher manufacturing-related costs (including inventory write-offs). Selling, general and administrative (SG&A) expenses were $2.9 billion in the fourth quarter of 2024, an increase of 2% compared with the fourth quarter of 2023. The increase was primarily due to higher promotional and selling costs, partially offset by the favorable impact of foreign exchange and lower restructuring costs. Full-year 2024 SG&A expenses were $10.8 billion, an increase of 3% compared with full-year 2023. The increase was primarily due to higher administrative, promotional, selling and acquisition-related costs, partially offset by the favorable impact of foreign exchange and lower restructuring costs. Research and development (R&D) expenses were $4.6 billion in the fourth quarter of 2024, a decrease of 52% compared with the fourth quarter of 2023. R&D expenses were $17.9 billion for the full year of 2024, a decrease of 41% compared with the full year of 2023. The declines in both the fourth quarter and full year of 2024 were primarily due to lower charges for business development activity, lower intangible asset impairment charges, and the favorable impact of foreign exchange, partially offset by increased compensation and benefit costs and higher clinical development spending. Other (income) expense, net, was $126 million of expense in the fourth quarter of 2024 compared with $78 million of expense in the fourth quarter of 2023. The unfavorability was primarily due to net losses from investments in equity securities compared with net income from investments in equity securities in the prior year quarter, partially offset by lower foreign exchange losses and lower net interest expense. Other (income) expense, net, was $24 million of income in the full year of 2024 compared with $466 million of expense in the full year of 2023, primarily due to a $572.5 million charge in 2023 related to settlements with certain plaintiffs in the Zetia antitrust litigation. The favorability was also due to $170 million of income related to the expansion of an existing development and commercialization agreement with Daiichi Sankyo, as well as lower foreign exchange losses in 2024. Other (income) expense, net, in the full year of 2024 was unfavorably affected by lower net income from investments in equity securities and higher net interest expense compared with 2023. The effective tax rates of 10.2% and 14.1% for the fourth quarter and full year of 2024, respectively, include a 6.2 percentage point favorable impact and a 2.6 percentage point favorable impact, respectively, due to a reduction in reserves for unrecognized income tax benefits, resulting from the expiration of the statute of limitations for assessments related to certain federal tax return years. GAAP EPS was $1.48 for the fourth quarter of 2024 compared with a loss per share of $0.48 for the fourth quarter of 2023, primarily driven by lower charges for business development transactions, operational strength in the business, lower intangible asset impairment charges, and a benefit from the expiration of the statute of limitations for assessments related to the 2020 federal tax return year. GAAP EPS was $6.74 for the full year of 2024 compared with EPS of $0.14 for the full year of 2023. The increase was primarily driven by lower charges for business development transactions, operational strength in the business, lower intangible asset impairment charges, a benefit from the expiration of the statute of limitations for the 2020 and 2019 federal tax return years, and a charge in the prior year for settlements with certain plaintiffs in the Zetia antitrust litigation, partially offset by the unfavorable effect of foreign exchange. Non-GAAP Expense, EPS and Related Information Non-GAAP gross margin was 80.8% for the fourth quarter of 2024 compared with 77.2% for the fourth quarter of 2023. Non-GAAP gross margin was 80.8% for the full year of 2024 compared with 76.9% for the full year of 2023. The non-GAAP gross margin improvements in both the fourth quarter and full year of 2024 were primarily due to the favorable effects of product mix (including lower royalty rates related to KEYTRUDA and GARDASIL/GARDASIL 9) and foreign exchange, partially offset by higher manufacturing-related costs (including inventory write-offs). Non-GAAP SG&A expenses were $2.8 billion in the fourth quarter of 2024, an increase of 2% compared with the fourth quarter of 2023. Non-GAAP SG&A expenses were $10.6 billion for the full year of 2024, an increase of 3% compared with the full year of 2023. The increases were primarily due to higher promotional and selling costs and, for the full year, higher administrative costs, partially offset by the favorable impact of foreign exchange. Non-GAAP R&D expenses were $4.6 billion in the fourth quarter of 2024, a decrease of 48% compared with the fourth quarter of 2023. Non-GAAP R&D expenses were $17.9 billion for the full year of 2024, a decrease of 40% compared with the full year of 2023. The declines in both the fourth quarter and full year of 2024 were primarily due to lower charges for business development activity and the favorable impact of foreign exchange, partially offset by increased compensation and benefit costs and higher clinical development spending. Non-GAAP other (income) expense, net, was $5 million of expense in the fourth quarter of 2024 compared with $174 million of expense in the fourth quarter of 2023. The favorability was primarily due to lower foreign exchange losses and lower net interest expense. Non-GAAP other (income) expense, net, was $10 million of expense in the full year of 2024 compared with $219 million of expense in the full year of 2023. The favorability was primarily due to $170 million of income related to the expansion of an existing development and commercialization agreement with Daiichi Sankyo, as well as lower foreign exchange losses in 2024, partially offset by higher net interest expense. The non-GAAP effective tax rate was 16.2% for the fourth quarter and 16.8% for the full year of 2024. Non-GAAP EPS was $1.72 for the fourth quarter of 2024 compared with $0.03 for the fourth quarter of 2023. Non-GAAP EPS was $7.65 for the full year of 2024 compared with EPS of $1.51 for the full year of 2023. The increase in both periods was primarily driven by lower charges for business development transactions and operational strength in the business. The unfavorable effect of foreign exchange partially offset the increase in the full year. A reconciliation of GAAP to non-GAAP net income (loss) and earnings (loss) per share is provided in the table that follows. Fourth Quarter Year Ended $ in millions, except EPS amounts 2024 2023 Dec. 31, 2024 Dec. 31, 2023 EPS GAAP EPS $1.48 $(0.48) $6.74 $0.14 Difference 0.24 0.51 0.91 1.37 Non-GAAP EPS that excludes items listed below 2 $1.72 $0.03 $7.65 $1.51 Net Income (Loss) GAAP net income (loss) 1 $3,743 $(1,226) $17,117 $365 Difference 629 1,292 2,327 3,472 Non-GAAP net income that excludes items listed below 1,2 $4,372 $66 $19,444 $3,837 Excluded Items: Acquisition- and divestiture-related costs 3 $711 $1,233 $2,519 $2,876 Restructuring costs 187 401 888 933 Loss (income) from investments in equity securities 152 (61) 45 (279) Charge for Zetia antitrust litigation settlements - - - 573 Decrease to net income/increase to net loss before taxes 1,050 1,573 3,452 4,103 Estimated income tax (benefit) expense 4 (421) (281) (1,125) (631) Decrease to net income/increase to net loss $629 $1,292 $2,327 $3,472 Pipeline and Portfolio Highlights Merck made important advancements in its broad, diverse pipeline, meeting significant regulatory and clinical milestones throughout the fourth quarter. In oncology, Merck announced positive topline results from the pivotal Phase 3 MK-3475A-D77 trial evaluating the noninferiority of subcutaneous pembrolizumab and berahyaluronidase alfa, in combination with chemotherapy, versus intravenous (IV) KEYTRUDA administered with chemotherapy, for the first-line treatment of adult patients with metastatic NSCLC. Subcutaneous pembrolizumab and berahyaluronidase alfa has the potential to improve the patient experience and increase access for patients and health care providers compared to IV administration. Merck presented new data across multiple hematologic malignancies at the American Society of Hematology Annual Meeting and Exposition in December 2024, including promising Phase 2 data for its investigational antibody-drug conjugate zilovertamab vedotin for the treatment of patients with previously untreated diffuse large B-cell lymphoma. With more than 20 abstracts presented, the data showcased Merck’s continued progress in advancing clinical research for its expanding and diverse hematology pipeline. Merck also achieved several key regulatory milestones in the U.S., Europe, Japan and China. Highlights include the U.S. Food and Drug Administration (FDA) granting Breakthrough Therapy designation to sacituzumab tirumotecan (sac-TMT) for the treatment of certain patients with previously treated advanced or metastatic nonsquamous NSCLC with epidermal growth factor receptor (EGFR) mutations. Additionally, Merck received new approvals for KEYTRUDA-based regimens in Japan and China, as well as for WELIREG and Lynparza in China. In vaccines and infectious diseases, the FDA accepted the Biologics License Application (BLA) for clesrovimab, an investigational prophylactic long-acting monoclonal antibody designed to protect infants from respiratory syncytial virus (RSV) disease during their first RSV season and set a Prescription Drug User Fee Act (PDUFA) date of June 10, 2025. This regulatory milestone marks important progress toward having clesrovimab available in time for the 2025-26 RSV season. The filing was based on results from the pivotal Phase 2b/3 study of clesrovimab in infants for the prevention of RSV that was presented at ID Week 2024. In addition, Merck announced topline results from two pivotal Phase 3 trials of the investigational, once-daily, oral, two-drug, single-tablet regimen of doravirine/islatravir (DOR/ISL) in adults with virologically suppressed HIV-1 infection, in line with Merck’s commitment to help address the needs of people living with HIV. In January 2025, Merck also received expanded approval in China for GARDASIL. It is now the first HPV vaccine approved in China for the prevention of certain HPV-related cancers and diseases in males 9-26 years of age. In addition, the European Union’s (EU) Committee for Medicinal Products for Human Use (CHMP) recommended the approval of CAPVAXIVE for pneumococcal vaccination in adults, with a final decision for EU approval expected in the second quarter of 2025. In cardiovascular disease, Merck announced positive topline results from the Phase 3 ZENITH study, evaluating WINREVAIR in adults with pulmonary arterial hypertension (PAH) with World Health Organization (WHO) Group 1 functional class (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 with 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. Merck continued to execute on its business development strategy. The company announced the closing of an exclusive global license for MK-2010, a novel investigational PD-1/VEGF bispecific antibody from LaNova. Merck also entered into an exclusive global license agreement with Hansoh to evaluate MK-4082, an investigational preclinical oral small molecule glucagon-like peptide (GLP-1) receptor agonist. Notable recent news releases on Merck’s pipeline and portfolio are provided in the table that follows. Oncology FDA Granted Breakthrough Therapy Designation to sac-TMT for the Treatment of Certain Patients With Previously Treated Advanced or Metastatic Nonsquamous NSCLC With EGFR Mutations (Read Announcement) FDA Granted Priority Review to Merck’s Application for WELIREG for the Treatment of Patients With Advanced Pheochromocytoma and Paraganglioma (Read Announcement) Merck Received Positive EU CHMP Opinion for WELIREG as Treatment for Adult Patients With Certain Types of Von Hippel-Lindau (VHL) Disease-Associated Tumors and for Certain Previously Treated Adult Patients With Advanced RCC, Based on Results From Phase 2 LITESPARK-004 and Phase 3 LITESPARK-005 Trials (Read Announcement) Merck Received Positive EU CHMP Opinion for KEYTRUDA Plus Chemotherapy as First-Line Treatment for Adult Patients With Unresectable Non-Epithelioid Malignant Pleural Mesothelioma, Based on Results From Phase 2/3 IND.227/KEYNOTE-483 Trial (Read Announcement) KEYTRUDA Approved in China in Combination With Chemotherapy as Neoadjuvant Treatment, Then Continued as Monotherapy After Surgery as Adjuvant Treatment for Patients With Resectable Stage II, IIIA or IIIB NSCLC, Based on Results From Phase 3 KEYNOTE-671 Trial (Read Announcement) WELIREG Approved in China for Treatment of Adult Patients With Certain Types of VHL Disease-Associated Tumors, Based on Results From Phase 2 LITESPARK-004 Trial (Read Announcement) Merck Announced Phase 3 MK-3475A-D77 Trial of Subcutaneous Pembrolizumab With Berahyaluronidase Alfa Met Primary Endpoints (Read Announcement) Merck Announced Phase 3 KEYLYNK-001 Trial Met Primary Endpoint of Progression-Free Survival in Patients With Advanced Epithelial Ovarian Cancer (Read Announcement) Lynparza Demonstrated Clinically Meaningful Prolonged Survival Benefit in Early Breast Cancer, Based on Results From Phase 3 OlympiA Trial (Read Announcement) Investigational Zilovertamab Vedotin in Combination With R-CHP Demonstrated Complete Response Rate of 100% at 1.75 MG/KG Dose in Previously Untreated Patients With Diffuse Large B-Cell Lymphoma, Based on Results From Phase 2 WaveLINE-007 Trial (Read Announcement) Vaccines Merck Announced FDA Acceptance of BLA for Clesrovimab (MK-1654), an Investigational Long-Acting Monoclonal Antibody Designed to Protect Infants From RSV Disease During Their First RSV Season; FDA Set PDUFA Date of June 10, 2025 (Read Announcement) Merck Received Expanded Approval of GARDASIL for Males in China (Read Announcement) Merck Received Positive EU CHMP Opinion for CAPVAXIVE for Pneumococcal Vaccination in Adults (Read Announcement) Merck Presented New Data From GARDASIL 9 Studies Reinforcing Importance of Gender-Neutral HPV Vaccination in Adults Up to Age 45 at International Papillomavirus Conference 2024 (Read Announcement) Cardiovascular Merck Announced Pivotal Phase 3 ZENITH Trial Evaluating WINREVAIR Met Primary Endpoint at Interim Analysis (Read Announcement) Merck Announced Decision to Stop Phase 3 HYPERION Trial Evaluating WINREVAIR Early and Move to Final Analysis (Read Announcement) Infectious Diseases Merck Announced Topline Results From Pivotal Phase 3 Trials Evaluating Investigational, Once-Daily, Oral, Two-Drug, Single-Tablet Regimen of Doravirine/Islatravir (DOR/ISL) for the Treatment of Adults With Virologically Suppressed HIV-1 Infection (Read Announcement) Full-Year 2025 Financial Outlook The following table summarizes the company’s full-year financial outlook. Full Year 2025 Sales * $64.1 billion to $65.6 billion Non-GAAP Gross margin 2 Approximately 82.5% Non-GAAP Operating expenses 2** $25.4 billion to $26.4 billion Non-GAAP Other (income) expense, net 2 $300 million to $400 million expense Non-GAAP Effective tax rate 2 16.0% to 17.0% Non-GAAP EPS 2*** $8.88 to $9.03 Share count (assuming dilution) Approximately 2.53 billion *The company does not have any non-GAAP adjustments to sales. **Includes $300 million for an anticipated milestone payment to LaNova associated with the technology transfer for MK-2010 expected to be completed in 2025. Outlook does not assume any additional significant potential business development transactions. ***Includes expected one-time charge of approximately $0.09 per share related to the $300 million milestone payment to LaNova upon completion of the technology transfer for MK-2010. Merck has not provided a reconciliation of forward-looking non-GAAP gross margin, non-GAAP operating expenses, non-GAAP other (income) expense, net, non-GAAP effective tax rate and non-GAAP EPS to the most directly comparable GAAP measures, given it cannot predict with reasonable certainty the amounts necessary for such a reconciliation, including intangible asset impairment charges, legal settlements, and income and losses from investments in equity securities either owned directly or through ownership interests in investment funds, without unreasonable effort. These items are inherently difficult to forecast and could have a significant impact on the company’s future GAAP results. Merck anticipates full-year 2025 sales to be between $64.1 billion and $65.6 billion, including a negative impact of foreign exchange of approximately 2% at mid-January 2025 exchange rates. This sales range reflects a decision to temporarily pause shipments of GARDASIL/GARDASIL 9 into China beginning February 2025 through at least mid-year. Merck’s full-year non-GAAP effective income tax rate is expected to be between 16.0% and 17.0%. Merck expects full-year 2025 non-GAAP EPS to be between $8.88 and $9.03, including a negative impact of foreign exchange of approximately $0.35 per share. This range includes an expected one-time charge of $300 million, or approximately $0.09 per share, related to a milestone payment to LaNova, which will be recognized upon completion of the technology transfer for MK-2010. In 2024, non-GAAP EPS of $7.65 was negatively impacted by a net charge of $1.28 per share related to certain asset acquisitions, licensing agreements and collaborations. Consistent with past practice, the financial outlook does not assume additional significant potential business development transactions. Earnings Conference Call Investors, journalists and the general public may access a live audio webcast of the earnings conference call on Tuesday, Feb. 4, at 9 a.m. ET via this weblink . A replay of the webcast, along with the sales and earnings news release, supplemental financial disclosures, and slides highlighting the results, will be available at www.merck.com . All participants may join the call by dialing (800) 369-3351 (U.S. and Canada Toll-Free) or (517) 308-9448 and using the access code 9818590. About Merck At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter) , Facebook , Instagram , YouTube and LinkedIn . Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements. Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions. The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2023 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site ( www.sec.gov ). Appendix Generic product names are provided below. Pharmaceutical BRIDION (sugammadex) CAPVAXIVE (Pneumococcal 21-valent Conjugate Vaccine) GARDASIL ( Human Papillomavirus Quadrivalent [Types 6, 11, 16 and 18] Vaccine, Recombinant ) GARDASIL 9 (Human Papillomavirus 9-valent Vaccine, Recombinant) JANUMET (sitagliptin and metformin HCl) JANUVIA (sitagliptin) KEYTRUDA (pembrolizumab) LAGEVRIO (molnupiravir) Lenvima (lenvatinib) Lynparza (olaparib) M-M-R II (Measles, Mumps and Rubella Virus Vaccine Live) PREVYMIS ( letermovir ) PROQUAD (Measles, Mumps, Rubella and Varicella Virus Vaccine Live) Reblozyl (luspatercept) REMICADE (infliximab) ROTATEQ (Rotavirus Vaccine, Live, Oral, Pentavalent) SIMPONI (golimumab) VARIVAX (Varicella Virus Vaccine Live) VAXNEUVANCE ( Pneumococcal 15-valent Conjugate Vaccine ) WELIREG ( belzutifan ) WINREVAIR (sotatercept-csrk) Animal Health BRAVECTO (fluralaner) 1 Net income (loss) attributable to Merck & Co., Inc. 2 Merck is providing certain 2024 and 2023 non-GAAP information that excludes certain items because of the nature of these items and the impact they have on the analysis of underlying business performance and trends. Management believes that providing this information enhances investors’ understanding of the company’s results because management uses non-GAAP results to assess performance. Management uses non-GAAP measures internally for planning and forecasting purposes and to measure the performance of the company along with other metrics. In addition, annual employee compensation, including senior management’s compensation, is derived in part using a non-GAAP pretax income metric. This information should be considered in addition to, but not as a substitute for or superior to, information prepared in accordance with GAAP. For a description of the non-GAAP adjustments, see Table 2a attached to this release. 3 Reflects expenses related to business combinations, including the amortization of intangible assets, intangible asset impairment charges, and expense or income related to changes in the estimated fair value measurement of liabilities for contingent consideration. Also includes integration, transaction and certain other costs associated with acquisitions and divestitures, as well as amortization of intangible assets related to collaborations and licensing arrangements. 4 Includes the estimated tax impacts on the reconciling items based on applying the statutory rate of the originating territory of the non-GAAP adjustments, as well as a $260 million benefit and a $519 million benefit in the fourth quarter and full year of 2024, respectively, due to reductions in reserves for unrecognized income tax benefits resulting from the expiration of the statute of limitations for assessments related to certain federal tax return years. The benefit recognized in the fourth quarter of 2024 relates to the 2020 federal tax return year and the benefit for the full year of 2024 relates to both the 2020 and 2019 federal tax return years. MERCK & CO., INC. CONSOLIDATED STATEMENT OF OPERATIONS - GAAP (AMOUNTS IN MILLIONS, EXCEPT PER SHARE FIGURES) (UNAUDITED) Table 1 GAAP % Change GAAP % Change 4Q24 4Q23 Full Year 2024 Full Year 2023 Sales $ 15,624 $ 14,630 7% $ 64,168 $ 60,115 7% Costs, Expenses and Other Cost of sales 3,828 3,911 -2% 15,193 16,126 -6% Selling, general and administrative 2,864 2,804 2% 10,816 10,504 3% Research and development 4,585 9,628 -52% 17,938 30,531 -41% Restructuring costs 51 255 -80% 309 599 -48% Other (income) expense, net 126 78 62% (24 ) 466 * Income (Loss) Before Taxes 4,170 (2,046 ) * 19,936 1,889 * Income Tax Provision (Benefit) 425 (821 ) 2,803 1,512 Net Income (Loss) 3,745 (1,225 ) * 17,133 377 * Less: Net Income Attributable to Noncontrolling Interests 2 1 16 12 Net Income (Loss) Attributable to Merck & Co., Inc. $ 3,743 $ (1,226 ) * $ 17,117 $ 365 * Earnings (Loss) per Common Share Assuming Dilution (1) $ 1.48 $ (0.48 ) * $ 6.74 $ 0.14 * Average Shares Outstanding Assuming Dilution (1) 2,537 2,533 2,541 2,547 Tax Rate 10.2 % 40.1 % 14.1 % 80.0 % * 100% or greater (1) Because the company recorded a net loss in the fourth quarter of 2023, no potential dilutive common shares were used in the computation of loss per common share assuming dilution as the effect would have been anti-dilutive. MERCK & CO., INC. FOURTH QUARTER AND FULL YEAR 2024 GAAP TO NON-GAAP RECONCILIATION (AMOUNTS IN MILLIONS, EXCEPT PER SHARE FIGURES) (UNAUDITED) Table 2a GAAP Acquisition and Divestiture Related Costs (1) Restructuring Costs (2) (Income) Loss from Investments in Equity Securities Certain Other Items Adjustment Subtotal Non-GAAP Fourth Quarter Cost of sales $ 3,828 701 121 822 $ 3,006 Selling, general and administrative 2,864 29 16 45 2,819 Research and development 4,585 12 (1) 11 4,574 Restructuring costs 51 51 51 – Other (income) expense, net 126 (31) 152 121 5 Income Before Taxes 4,170 (711) (187) (152) (1,050) 5,220 Income Tax Provision (Benefit) 425 (111) (3) (17) (3) (33) (3) (260) (4) (421) 846 Net Income 3,745 (600) (170) (119) 260 (629) 4,374 Net Income Attributable to Merck & Co., Inc. 3,743 (600) (170) (119) 260 (629) 4,372 Earnings per Common Share Assuming Dilution $ 1.48 (0.23) (0.07) (0.04) 0.10 (0.24) $ 1.72 Tax Rate 10.2% 16.2% Full Year Cost of sales $ 15,193 2,409 495 2,904 $ 12,289 Selling, general and administrative 10,816 117 83 200 10,616 Research and development 17,938 72 1 73 17,865 Restructuring costs 309 309 309 – Other (income) expense, net (24) (79) 45 (34) 10 Income Before Taxes 19,936 (2,519) (888) (45) (3,452) 23,388 Income Tax Provision (Benefit) 2,803 (461) (3) (135) (3) (10) (3) (519) (4) (1,125) 3,928 Net Income 17,133 (2,058) (753) (35) 519 (2,327) 19,460 Net Income Attributable to Merck & Co., Inc. 17,117 (2,058) (753) (35) 519 (2,327) 19,444 Earnings per Common Share Assuming Dilution $ 6.74 (0.81) (0.30) (0.01) 0.21 (0.91) $ 7.65 Tax Rate 14.1% 16.8% Only the line items that are affected by non-GAAP adjustments are shown. Merck is providing certain non-GAAP information that excludes certain items because of the nature of these items and the impact they have on the analysis of underlying business performance and trends. Management believes that providing non-GAAP information enhances investors’ understanding of the company’s results because management uses non-GAAP measures to assess performance. Management uses non-GAAP measures internally for planning and forecasting purposes and to measure the performance of the company along with other metrics. In addition, annual employee compensation, including senior management’s compensation, is derived in part using a non-GAAP pretax income metric. The non-GAAP information presented should be considered in addition to, but not as a substitute for or superior to, information prepared in accordance with GAAP. (1) Amounts included in cost of sales primarily reflect expenses for the amortization of intangible assets. Amounts included in selling, general and administrative expenses reflect integration, transaction and certain other costs related to acquisitions and divestitures. Amounts included in research and development expenses primarily reflect the amortization of intangible assets. Additionally, research and development expenses for the full year includes Animal Health intangible asset impairment charges. Amounts included in other (income) expense, net, primarily reflect royalty income and a decrease in the estimated fair value measurement of liabilities for contingent consideration related to the prior termination of the Sanofi-Pasteur MSD joint venture. (2) Amounts primarily include employee separation costs, accelerated depreciation and asset impairments associated with facilities to be closed or divested related to activities under the company's formal restructuring programs. (3) Represents the estimated tax impacts on the reconciling items based on applying the statutory rate of the originating territory of the non-GAAP adjustments. (4) Represents benefits recorded in the fourth quarter and full year due to reductions in reserves for unrecognized income tax benefits resulting from the expiration of the statute of limitations for assessments related to federal income tax return years. The benefit recognized in the fourth quarter relates to the 2020 federal tax return year and the benefit recognized for the full year relates to both the 2020 and 2019 federal tax return years. MERCK & CO., INC. FRANCHISE / KEY PRODUCT SALES (AMOUNTS IN MILLIONS) (UNAUDITED) Table 3 2024 2023 4Q Full Year 1Q 2Q 3Q 4Q Full Year 1Q 2Q 3Q 4Q Full Year Nom % Ex-Exch % Nom % Ex-Exch % TOTAL SALES (1) $15,775 $16,112 $16,657 $15,624 $64,168 $14,487 $15,035 $15,962 $14,630 $60,115 7 9 7 10 PHARMACEUTICAL 14,006 14,408 14,943 14,042 57,400 12,721 13,457 14,263 13,141 53,583 7 8 7 10 Oncology Keytruda 6,947 7,270 7,429 7,836 29,482 5,795 6,271 6,338 6,608 25,011 19 21 18 22 Alliance Revenue – Lynparza (2) 292 317 337 365 1,311 275 310 299 315 1,199 16 18 9 11 Alliance Revenue – Lenvima (2) 255 249 251 255 1,010 232 242 260 226 960 13 14 5 6 Welireg 85 126 139 160 509 42 50 54 72 218 122 123 133 133 Alliance Revenue – Reblozyl (3) 71 90 100 110 371 43 47 52 70 212 58 58 75 75 Vaccines (4) Gardasil/Gardasil 9 2,249 2,478 2,306 1,550 8,583 1,972 2,458 2,585 1,871 8,886 -17 -18 -3 -2 ProQuad/M-M-R II/Varivax 570 617 703 594 2,485 528 582 713 545 2,368 9 9 5 5 Vaxneuvance 219 189 239 161 808 106 168 214 176 665 -9 -9 22 23 RotaTeq 216 163 193 139 711 297 131 156 185 769 -25 -25 -8 -7 Pneumovax 23 61 59 68 74 263 96 92 140 85 412 -12 -12 -36 -34 Hospital Acute Care Bridion 440 455 420 449 1,764 487 502 424 429 1,842 5 5 -4 -3 Prevymis 174 188 208 215 785 129 143 157 175 605 23 23 30 33 Dificid 73 92 96 79 340 65 76 74 87 302 -9 -9 13 13 Zerbaxa 56 62 64 70 252 50 54 53 61 218 14 16 16 18 Noxafil 56 45 41 36 177 60 55 51 46 213 -23 -17 -17 -8 Cardiovascular Winrevair 70 149 200 419 - - - - Alliance Revenue - Adempas/Verquvo (5) 98 106 102 109 415 99 68 92 108 367 1 1 13 13 Adempas (6) 70 72 72 73 287 59 65 65 66 255 11 9 12 14 Virology Lagevrio 350 110 383 121 964 392 203 640 193 1,428 -37 -37 -33 -28 Isentress/Isentress HD 111 89 102 92 394 123 136 119 105 483 -13 -7 -18 -14 Delstrigo 56 60 65 69 249 44 50 54 54 201 28 29 24 26 Pifeltro 42 39 42 40 163 34 38 37 33 142 20 20 15 15 Neuroscience Belsomra 46 53 78 45 222 56 63 58 54 231 -17 -17 -4 1 Immunology Simponi 184 172 189 543 180 180 179 171 710 N/M N/M -24 -23 Remicade 39 35 41 114 51 48 45 43 187 N/M N/M -39 -36 Diabetes (7) Januvia 419 405 278 232 1,334 551 511 581 547 2,189 -58 -56 -39 -36 Janumet 251 224 204 255 935 329 354 255 240 1,177 7 11 -21 -16 Other Pharmaceutical (8) 576 573 644 713 2,510 626 560 568 576 2,333 25 25 8 10 ANIMAL HEALTH 1,511 1,482 1,487 1,397 5,877 1,491 1,456 1,400 1,278 5,625 9 13 4 8 Livestock 850 837 886 889 3,462 849 807 874 808 3,337 10 14 4 9 Companion Animal 661 645 601 508 2,415 642 649 526 470 2,288 8 10 6 7 Other Revenues (9) 258 222 227 185 891 275 122 299 211 907 -13 3 -2 4 N/M - Not Meaningful Sum of quarterly amounts may not equal year-to-date amounts due to rounding. (1) Only select products are shown. (2) Alliance Revenue represents Merck’s share of profits, which are product sales net of cost of sales and commercialization costs. (3) Alliance Revenue represents royalties. (4) Total Vaccines sales were $3,424 million, $3,656 million, $3,675 million and $2,693 million in the first, second, third and fourth quarter of 2024, respectively, and $3,133 million, $3,557 million, $4,002 million and $2,962 million in the first, second, third and fourth quarter of 2023, respectively. (5) Alliance Revenue represents Merck's share of profits from sales in Bayer's marketing territories, which are product sales net of cost of sales and commercialization costs. (6) Net product sales in Merck's marketing territories. (7) Total Diabetes sales were $745 million, $715 million, $592 million and $546 million in the first, second, third and fourth quarter of 2024, respectively, and $950 million, $951 million, $924 million and $876 million in the first, second, third and fourth quarter of 2023, respectively. (8) Includes Pharmaceutical products not individually shown above. (9) Other Revenues are comprised primarily of revenues from third-party manufacturing arrangements and miscellaneous corporate revenues, including revenue-hedging activities. Other Revenues related to the receipt of upfront and milestone payments for out-licensed products were $61 million, $15 million, $15 million and $15 million in the first, second, third and fourth quarter of 2024, respectively, and $51 million, $3 million and $65 million in the first, second and third quarter of 2023, respectively.