Contingencies	3 Months Ended
Mar. 31, 2025
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Contingencies The Company is involved in various claims and legal proceedings of a nature considered normal to its business, including product liability, intellectual property, commercial litigation, and securities litigation, as well as certain additional matters including governmental and environmental matters. In the opinion of the Company, it is unlikely that the resolution of these matters will be material to the Company’s financial condition, results of operations or cash flows. Given the nature of the litigation discussed below and the complexities involved in these matters, the Company is unable to reasonably estimate a possible loss or range of possible loss for such matters until the Company knows, among other factors, (i) what claims, if any, will survive dispositive motion practice, (ii) the extent of the claims, including the size of any potential class, particularly when damages are not specified or are indeterminate, (iii) how the discovery process will affect the litigation, (iv) the settlement posture of the other parties to the litigation and (v) any other factors that may have a material effect on the litigation. The Company records accruals for contingencies when it is probable that a liability has been incurred and the amount can be reasonably estimated. These accruals are adjusted periodically as assessments change or additional information becomes available. Generally, for product liability claims, a portion of the overall accrual is actuarially determined and considers such factors as past experience, number of claims reported and estimates of claims incurred but not yet reported. Individually significant contingent losses are accrued when probable and reasonably estimable. Legal defense costs expected to be incurred in connection with a loss contingency are accrued when probable and reasonably estimable. The Company’s decision to obtain insurance coverage is dependent on market conditions, including cost and availability, existing at the time such decisions are made. The Company has evaluated its risks and has determined that the cost of obtaining product liability insurance outweighs the likely benefits of the coverage that is available and, as such, has no insurance for most product liabilities. Product Liability Litigation Dr. Scholl’s Foot Powder As previously disclosed, Merck is a defendant in product liability lawsuits in the U.S. arising from consumers’ alleged exposure to talc in Dr. Scholl’s foot powder, which Merck acquired through its merger with Schering-Plough Corporation and sold as part of the divestiture of Merck’s consumer care business to Bayer in 2014. In these actions, plaintiffs allege that they were exposed to asbestos-contaminated talc and developed mesothelioma as a result. As of March 31, 2025, approximately 500 cases were pending against Merck in various state courts. Gardasil/Gardasil 9 As previously disclosed, Merck is a defendant in product liability lawsuits in the U.S. involving Gardasil (Human Papillomavirus Quadrivalent [Types 6, 11, 16 and 18] Vaccine, Recombinant) and Gardasil 9 (Human Papillomavirus 9-valent Vaccine, Recombinant). As of March 31, 2025, approximately 245 cases were filed and pending against Merck in either federal or state court. In these actions, plaintiffs allege, among other things, that they suffered various personal injuries after vaccination with Gardasil or Gardasil 9, with postural orthostatic tachycardia syndrome (POTS) as a predominate alleged injury. In August 2022, the U.S. Judicial Panel on Multidistrict Litigation ordered that Gardasil/Gardasil 9 product liability cases pending in federal courts nationwide be transferred to Judge Robert J. Conrad in the Western District of North Carolina for coordinated pre-trial proceedings. In February 2024, the multidistrict litigation (Gardasil MDL) was reassigned to Judge Kenneth D. Bell. On March 11, 2025, the court granted Merck’s motion for summary judgment in 16 bellwether cases on implied preemption grounds; plaintiffs have filed a Notice of Appeal to the Fourth Circuit. The parties’ letter submissions on next steps in the Gardasil MDL proceeding in light of the court’s decision were submitted on April 8, 2025. On March 21, 2025, plaintiff’s co-lead counsel in the Gardasil MDL filed a seven-plaintiff complaint in New Jersey state court. On March 24, 2025, Merck removed the case to federal court and has requested that the U.S. Judicial Panel on Multidistrict Litigation transfer the case to the Gardasil MDL. Plaintiffs have opposed transfer to the Gardasil MDL and have moved to have the case remanded to New Jersey state court. On January 28, 2025, a trial commenced in California state court. Plaintiff claims that she suffers from POTS and fibromyalgia as a result of her Gardasil vaccinations. On February 14, 2025, after several weeks of trial and an opportunity to litigate plaintiff’s claims before a jury, plaintiff’s counsel approached Merck and proposed that the jury be discharged and the case adjourned. Merck agreed, subject to an explicit stipulation that Merck would provide no financial or other consideration in exchange for the agreement to adjourn. The case has thus been adjourned until a new trial date of September 15, 2025. Merck is vigorously defending this case and believes that evidence presented in court will show that Gardasil had no role in causing any of plaintiff’s conditions. As previously disclosed, there are fewer than 15 product liability cases pending outside the U.S. Governmental Proceedings As previously disclosed, from time to time, the Company’s subsidiaries in China receive inquiries regarding their operations from various Chinese governmental agencies. Some of these inquiries may be related to matters involving other multinational pharmaceutical companies, as well as Chinese entities doing business with such companies. The Company’s policy is to cooperate with these authorities and to provide responses as appropriate. As previously disclosed, from time to time, the Company receives inquiries and is the subject of preliminary investigation activities from competition and other governmental authorities in markets outside the U.S. These authorities may include regulators, administrative authorities, and law enforcement and other similar officials, and these preliminary investigation activities may include site visits, formal or informal requests or demands for documents or materials, inquiries or interviews and similar matters. Certain of these preliminary inquiries or activities may lead to the commencement of formal proceedings. Should those proceedings be determined adversely to the Company, monetary fines and/or remedial undertakings may be required. Securities Litigation As previously disclosed, in February 2025, a putative class action was filed against Merck and certain of its officers in the U.S. District Court for the District of New Jersey purportedly on behalf of all purchasers of Merck common stock between February 2022 and February 2025. Plaintiff alleges that Merck violated federal securities laws by making materially false and misleading statements and material omissions regarding demand for Gardasil/Gardasil 9 in China. Plaintiff seeks unspecified monetary damages, pre-judgment and post-judgment interest, and fees and costs. Commercial and Other Litigation Zetia Antitrust Litigation As previously disclosed, Merck, MSD, Schering Corporation, Schering-Plough Corporation, and MSP Singapore Company LLC (collectively, the Merck Defendants) were defendants in a number of lawsuits filed in 2018 on behalf of direct and indirect purchasers of Zetia (ezetimibe) alleging violations of federal and state antitrust laws, as well as other state statutory and common law causes of action. The cases were consolidated in a federal multidistrict litigation (Zetia MDL) before Judge Rebecca Beach Smith in the Eastern District of Virginia. In April 2023, the Merck Defendants reached settlements with the direct purchaser and retailer plaintiffs and a settlement with the indirect purchaser class that the court approved in October 2023. As previously disclosed, in 2020 and 2021, United HealthCare Services, Inc. (United HealthCare), Humana Inc. (Humana), Centene Corporation and others (Centene), and Kaiser Foundation Health Plan, Inc. (Kaiser) (collectively, the Insurer Plaintiffs), each filed a lawsuit in a jurisdiction outside of the Eastern District of Virginia against the Merck Defendants and others, making similar allegations as those made in the Zetia MDL, as well as additional allegations about Vytorin. These cases were transferred to the Eastern District of Virginia to proceed with the Zetia MDL. In December 2023, the U.S. Judicial Panel on Multidistrict Litigation remanded the four Insurer Plaintiff cases to the transferor courts in the Northern District of California (Kaiser), the District of Minnesota (United HealthCare), and the District of New Jersey (Humana and Centene). The Merck Defendants filed motions to dismiss in each of the Insurer Plaintiff cases. On December 30, 2024, the district court in the District of New Jersey granted in part and denied in part the motions to dismiss in the Humana and Centene cases and, on January 29, 2025, Humana and Centene filed amended complaints. On March 5, 2025, the Merck Defendants filed motions to dismiss the amended complaints. On March 24, 2025, the Merck Defendants filed a third-party complaint against AmerisourceBergen Drug Corp., AmerisourceBergen Corp., and Cencora, Inc., seeking indemnification for Humana’s direct purchaser claims. On February 25, 2025, the district court in the District of Minnesota granted in part and denied in part the motion to dismiss in the United HealthCare case. On March 11, 2025, the Merck Defendants filed an answer and affirmative defenses in response to United HealthCare’s complaint. On March 24, 2025, the Merck Defendants filed a third-party complaint against Cardinal Health, Inc., Cardinal Health 110, LLC, and Cardinal Health 112, LLC, seeking indemnification for certain of United HealthCare’s direct and indirect purchaser claims. On March 18, 2025, the district court in the Northern District of California granted in part and denied in part the motion to dismiss in the Kaiser case. The court granted Kaiser leave to amend its complaint. Patent Litigation From time to time, generic and biosimilar manufacturers of pharmaceutical products file abbreviated New Drug Applications (ANDAs) and Biologics License Applications, respectively, with the U.S. Food and Drug Administration (FDA) seeking to market generic and biosimilar forms of the Company’s products prior to the expiration of relevant patents owned by the Company. To protect its patent rights, the Company may file patent infringement lawsuits against such generic and biosimilar companies. Similar lawsuits defending the Company’s patent rights may exist in other countries. The Company intends to vigorously defend its patents, which it believes are valid, against infringement by companies attempting to market products prior to the expiration of such patents. As with any litigation, there can be no assurance of the outcomes, which, if adverse, could result in significantly shortened periods of exclusivity for these products and, with respect to products acquired through acquisitions accounted for as business combinations, potentially significant intangible asset impairment charges. Bridion — As previously disclosed, between January and November 2020, the Company received multiple Paragraph IV Certification Letters under the Hatch-Waxman Act notifying the Company that generic drug companies had filed applications to the FDA seeking pre-patent expiry approval to sell generic versions of Bridion (sugammadex) Injection. In March, April and December 2020, the Company filed patent infringement lawsuits in the U.S. District Courts for the District of New Jersey and the Northern District of West Virginia against those generic companies. All actions in the District of New Jersey were consolidated. The West Virginia case was jointly dismissed with prejudice in August 2022 in favor of proceeding in New Jersey. The remaining defendants in the New Jersey action have stipulated to infringement of the asserted claims and withdrew all remaining claims and defenses other than a defense seeking to shorten the patent term extension (PTE) of the sugammadex patent to December 2022. The U.S. District Court for the District of New Jersey held a one-day trial in December 2022 on this remaining PTE calculation defense. The court ordered a post-trial briefing on this defense and held closing arguments in February 2023. In June 2023, the U.S. District Court for the District of New Jersey ruled in Merck’s favor. The court held that Merck’s calculation of PTE for the sugammadex patent covering the compound is not invalid and that the U.S. Patent & Trademark Office correctly granted a full five-year extension. Also in June 2023, the U.S. District Court for the District of New Jersey issued a final judgment prohibiting the FDA from approving any of the pending or tentatively approved generic applications until January 27, 2026, except for any subsequent agreements between defendants and Merck or further order by the court. In July 2023, the defendants filed a notice of appeal with the U.S. Court of Appeals for the Federal Circuit. Oral argument took place on February 4, 2025. While the New Jersey action was pending, the Company settled with five generic companies providing that these generic companies can bring their generic versions of Bridion to the market in January 2026 (which may be delayed by any applicable pediatric exclusivity) or earlier under certain circumstances. The Company agreed to stay the lawsuit filed against two generic companies, which in exchange agreed to be bound by a judgment on the merits of the consolidated action in the District of New Jersey. One of the generic companies in the consolidated action requested dismissal of the action against it and the Company did not oppose this request, which was subsequently granted by the court. The Company does not expect this company to bring its generic version of Bridion to the market before July 27, 2026. In February 2024, the Company received another Paragraph IV Certification Letter under the Hatch-Waxman Act notifying the Company that Hikma Pharmaceuticals USA Inc. (Hikma) had filed an application to the FDA seeking pre-patent expiry approval to sell a generic version of Bridion Injection. In March 2024, the Company filed a patent infringement lawsuit in the U.S. District Court for the District of New Jersey against Hikma, postponing FDA approval of the Hikma generic drug for 30 months or until expiration of the sugammadex patent (January 27, 2026) and any potentially applicable pediatric exclusivity or an adverse court decision, if any, whichever may occur earlier. Expiration of the patent, and any potentially applicable pediatric exclusivity, will occur earlier than expiry of the 30-month stay. On April 16, 2024, the district court stayed the case during the pendency of the Federal Circuit appeal noted above. On March 13, 2025, the Federal Circuit affirmed the district court’s decision, holding that the patent term extension granted to the sugammadex patent covering Bridion was not invalid and that the patent is entitled to its full five-year patent term extension. The FDA has now granted Bridion six months of pediatric exclusivity. Thus, the Federal Circuit’s decision secures Bridion’s exclusivity in the U.S. through July 27, 2026. Januvia, Janumet, Janumet XR — As previously disclosed, the FDA granted pediatric exclusivity with respect to Januvia (sitagliptin), Janumet (sitagliptin/metformin HCI), and Janumet XR (sitagliptin and metformin HCl extended-release), which provides a further six months of exclusivity in the U.S. beyond the expiration of all patents listed in the FDA’s Orange Book. Adding this exclusivity to the term of the key patent protection extended exclusivity on these products to January 2023. However, Januvia, Janumet, and Janumet XR contain sitagliptin phosphate monohydrate and the Company has another patent covering certain phosphate salt and polymorphic forms of sitagliptin that expires in May 2027, including pediatric exclusivity (salt/polymorph patent). As previously disclosed, beginning in 2019, a number of generic drug companies filed ANDAs seeking approval of generic forms of Januvia and Janumet along with paragraph IV certifications challenging the validity of the salt/polymorph patent. The Company responded by filing infringement suits which have all been settled. The Company has settled with a total 26 generic companies providing that these generic companies can bring their generic versions of Januvia and Janumet to the market in the U.S. in May 2026 or earlier under certain circumstances, and their generic versions of Janumet XR to the market in July 2026 or earlier under certain circumstances. In March 2021, the Company filed a patent infringement lawsuit in the U.S. District Court for the District of Delaware against Zydus Worldwide DMCC, Zydus Pharmaceuticals (USA) Inc., and Cadila Healthcare Ltd. (collectively, Zydus). In that lawsuit, the Company alleged infringement of the salt/polymorph patent based on the filing of Zydus’s NDA seeking approval of a form of sitagliptin that is a different from than that used in Januvia. In December 2022, the parties reached settlement that included dismissal of the case without prejudice enabling Zydus to seek final approval of a non-automatically substitutable product. In January 2023, the Company received a Paragraph IV Certification Letter under the Hatch-Waxman Act notifying the Company that Zydus filed an ANDA seeking approval of sitagliptin/metformin HCl tablets and certifying that no valid or enforceable claim of any of the patents listed in FDA’s Orange Book for Janumet will be infringed by the proposed Zydus product. In March 2023, the parties reached settlement enabling Zydus to seek final approval of a non-automatically substitutable product containing a different form of sitagliptin than that used in Janumet. In November 2023, the Company received a Paragraph IV Certification Letter under the Hatch-Waxman Act notifying the Company that Zydus filed an ANDA seeking approval of sitagliptin/metformin HCl Extended Release tablets. In January 2024, the parties reached settlement enabling Zydus to seek final approval of a non-automatically substitutable version containing a different form of sitagliptin than that used in Janumet XR. As a result of these settlement agreements related to the later expiring 2027 salt/polymorph patent directed to the specific sitagliptin salt form of the products, the Company expects that Januvia and Janumet will not lose market exclusivity in the U.S. until May 2026 and Janumet XR will not lose market exclusivity in the U.S. until July 2026, although Zydus has received FDA approval for a non-automatically substitutable form of sitagliptin that differs from the form in the Company’s sitagliptin products. In March 2024, the Company received another Paragraph IV Certification Letter under the Hatch-Waxman Act from Azurity Pharmaceuticals, Inc. (Azurity) asserting that a different sitagliptin product subject to its ANDA does not infringe the salt/polymorph patent. In May 2024, Merck filed a civil action in the U.S. District Court of Delaware alleging infringement. The case was dismissed without prejudice in July 2024. Following the dismissal, the Company granted Azurity a covenant not to assert the salt/polymorph patent against the Azurity product that is the subject of such ANDA. Supplementary Protection Certificates (SPCs) for Janumet expired in April 2023 for the majority of European countries. Prior to expiration, generic companies sought revocation of the Janumet SPCs in a number of European countries. In February 2022, a Finnish court referred certain questions to the Court of Justice of the European Union that could impact the validity of the Janumet SPCs in Europe. A decision was rendered in December 2024. The decision provides guidance on points of law and does not directly apply to the Janumet SPCs. Thus, additional proceedings in certain countries where generic companies were prevented from launching products during the SPC period may be necessary to determine whether the SPCs are valid and if not, whether damages are appropriate. Those countries include Belgium, Czech Republic, Ireland, Finland, France, Slovakia and Switzerland. If the Janumet SPCs are ultimately upheld, the Company has reserved its rights related to the pursuit of damages for those countries where a generic launched prior to expiry of the Janumet SPC. In October 2023, the Company filed a patent infringement lawsuit against Sawai Pharmaceuticals Co., Ltd. and Medisa Shinyaku Co., Ltd (collectively, Defendants) in the Tokyo District Court seeking an injunction to stop the manufacture, sale and offer for sale of the Defendants’ sitagliptin dihydrogen phosphate product, while the Company’s patents and patent term extensions are in force. The lawsuit is in response to the Defendants’ application for marketing authorization to sell a generic sitagliptin dihydrogen phosphate product, in the anhydrate form, which was approved in August 2023. Merck asserts that the Defendants’ activity infringes a patent term extension associated with Merck’s patent directed to the sitagliptin compound patent. Keytruda — As previously disclosed, in November 2022, the Company filed a complaint against The Johns Hopkins University (JHU) in the U.S. District Court of Maryland. This action concerns patents emerging from a joint research collaboration between Merck and JHU regarding the use of pembrolizumab, which Merck sells under the trade name Keytruda. Merck and JHU partnered to design and conduct a clinical study administering Keytruda to cancer patients having tumors that had the genetic biomarker known as microsatellite instability-high (MSI-H). After the conclusion of the study, JHU secured U.S. patents citing the joint research study. Merck alleges that JHU has breached the collaboration agreement by filing and obtaining these patents without informing or involving Merck and then licensing the patents to others. Merck therefore brought this action for breach of contract, declaratory judgment of noninfringement, and promissory estoppel. JHU answered the complaint in April and May 2023, denying Merck’s claims, and counterclaiming for willful infringement of nine issued U.S. patents, including a demand for damages. Between November 30, 2023, and March 13, 2024, the Company filed inter partes review petitions with the United States Patent Trial and Appeal Board (PTAB), challenging the validity of all nine patents asserted in the case. Between June 2024 and October 2024, the PTAB instituted a review of all nine asserted patents. In July 2024, the district court granted Merck’s motion to stay the case in its entirety pending the outcome of the PTAB proceeding instituted in June 2024. Subcutaneous Pembrolizumab — Halozyme, Inc. has publicly alleged that certain patents in its modified hyaluronidase (MDASE) portfolio cover the Company’s subcutaneous pembrolizumab candidate, which is currently under review by the FDA. In November 2024, the Company began filing a series of post grant review (PGR) petitions before the PTAB alleging that certain patents in the MDASE portfolio are invalid. On April 24, 2025, Halozyme, Inc. filed a complaint in the U.S. District Court for the District of New Jersey alleging that the Company’s activities related to subcutaneous pembrolizumab infringe or will infringe 15 patents belonging to the MDASE portfolio, 11 of which are the subject of the Company’s already filed PGR petitions. The PTAB will likely issue a decision regarding the institution of the Company’s first filed petition in early June 2025. Lynparza — As previously disclosed, in December 2022, AstraZeneca Pharmaceuticals LP received a Paragraph IV Certification Letter under the Hatch-Waxman Act notifying AstraZeneca that Natco Pharma Limited (Natco) has filed an application to the FDA seeking pre-patent expiry approval to sell generic versions of Lynparza (olaparib) tablet. In February 2023, AstraZeneca and the Company filed a patent infringement lawsuit in the U.S. District Court for the District of New Jersey against Natco. This lawsuit, which asserts one or more patents covering olaparib, automatically stays FDA approval of the generic application until June 2025 or until an adverse court decision, if any, whichever may occur earlier. In 2024, AstraZeneca and the Company filed additional patent infringement lawsuits in the U.S. District Court for the District of New Jersey against Natco asserting additional patents covering olaparib. In December 2023, AstraZeneca Pharmaceuticals LP received a second Paragraph IV Certification Letter under the Hatch-Waxman Act notifying AstraZeneca that Sandoz Inc. has filed an application to the FDA seeking pre-patent expiry approval to sell generic versions of Lynparza (olaparib) tablet. In February 2024, AstraZeneca and the Company filed a patent infringement lawsuit in the U.S. District Court for the District of New Jersey against Sandoz. This lawsuit, which asserts one or more patents covering olaparib, automatically stays FDA approval of the generic application until June 2026 or until an adverse court decision, if any, whichever may occur earlier. In 2024, AstraZeneca and the Company filed additional patent infringement lawsuits in the U.S. District Court for the District of New Jersey against Sandoz asserting additional patents covering olaparib. In May 2024, AstraZeneca Pharmaceuticals LP received a third Paragraph IV Certification Letter under the Hatch-Waxman Act notifying AstraZeneca that Cipla USA, Inc. and Cipla Limited (collectively, Cipla) filed an application to the FDA seeking pre-patent expiry approval to sell generic versions of Lynparza (olaparib) tablet. In June 2024, AstraZeneca and the Company filed a patent infringement lawsuit in the U.S. District Court for the District of New Jersey against Cipla. This lawsuit, which asserts one or more patents covering olaparib, automatically stays FDA approval of the generic application until November 2026 or until an adverse court decision, if any, whichever may occur earlier. In 2024, AstraZeneca and the Company filed additional patent infringement lawsuits in the U.S. District Court for the District of New Jersey against Cipla asserting additional patents covering olaparib. In November 2024, AstraZeneca Pharmaceuticals LP received another Paragraph IV Certification Letter under the Hatch-Waxman Act notifying AstraZeneca that Zydus Pharmaceuticals (USA) Inc. filed an application to the FDA seeking pre-patent expiry approval to sell generic versions of Lynparza (olaparib) tablet. In November 2024, AstraZeneca and the Company filed a patent infringement lawsuit in the U.S. District Court for the District of New Jersey against Zydus. This lawsuit, which asserts one or more patents covering olaparib, automatically stays FDA approval of the generic application until May 2027 or until an adverse court decision, if any, whichever may occur earlier. In 2024, AstraZeneca and the Company filed an additional patent infringement lawsuit in the U.S. District Court for the District of New Jersey against Zydus asserting an additional patent covering olaparib. Other Litigation There are various other pending legal proceedings involving the Company, principally product liability and intellectual property lawsuits. While it is not feasible to predict the outcome of such proceedings, in the opinion of the Company, either the likelihood of loss is remote or any reasonably possible loss associated with the resolution of such proceedings is not expected to be material to the Company’s financial condition, results of operations or cash flows either individually or in the aggregate. Legal Defense Reserves Legal defense costs expected to be incurred in connection with a loss contingency are accrued when probable and reasonably estimable. Some of the significant factors considered in the review of these legal defense reserves are as follows: the actual costs incurred by the Company; the development of the Company’s legal defense strategy and structure in light of the scope of its litigation; the number of cases being brought against the Company; the costs and outcomes of completed trials; and the most current information regarding anticipated timing, progression, and related costs of pre-trial activities and trials in the associated litigation. The amount of legal defense reserves as of March 31, 2025 and December 31, 2024 of approximately $230 million and $225 million, respectively, represents the Company’s best estimate of the minimum amount of defense costs to be incurred in connection with its outstanding litigation; however, events such as additional trials and other events that could arise in the course of its litigation could affect the ultimate amount of legal defense costs to be incurred by the Company. The Company will continue to monitor its legal defense costs and review the adequacy of the associated reserves and may determine to increase the reserves at any time in the future if, based upon the factors set forth, it believes it would be appropriate to do so.

The Company is involved in various claims and legal proceedings of a nature considered normal to its business, including product liability, intellectual property, commercial litigation, and securities litigation, as well as certain additional matters including governmental and environmental matters. In the opinion of the Company, it is unlikely that the resolution of these matters will be material to the Company’s financial condition, results of operations or cash flows.

Given the nature of the litigation discussed below and the complexities involved in these matters, the Company is unable to reasonably estimate a possible loss or range of possible loss for such matters until the Company knows, among other factors, (i) what claims, if any, will survive dispositive motion practice, (ii) the extent of the claims, including the size of any potential class, particularly when damages are not specified or are indeterminate, (iii) how the discovery process will affect the litigation, (iv) the settlement posture of the other parties to the litigation and (v) any other factors that may have a material effect on the litigation.

The Company records accruals for contingencies when it is probable that a liability has been incurred and the amount can be reasonably estimated. These accruals are adjusted periodically as assessments change or additional information becomes available. Generally, for product liability claims, a portion of the overall accrual is actuarially determined and considers such factors as past experience, number of claims reported and estimates of claims incurred but not yet reported. Individually significant contingent losses are accrued when probable and reasonably estimable. Legal defense costs expected to be incurred in connection with a loss contingency are accrued when probable and reasonably estimable.

The Company’s decision to obtain insurance coverage is dependent on market conditions, including cost and availability, existing at the time such decisions are made. The Company has evaluated its risks and has determined that the cost of obtaining product liability insurance outweighs the likely benefits of the coverage that is available and, as such, has no insurance for most product liabilities.

As previously disclosed, Merck is a defendant in product liability lawsuits in the U.S. arising from consumers’ alleged exposure to talc in Dr. Scholl’s foot powder, which Merck acquired through its merger with Schering-Plough Corporation and sold as part of the divestiture of Merck’s consumer care business to Bayer in 2014. In these actions, plaintiffs allege that they were exposed to asbestos-contaminated talc and developed mesothelioma as a result. As of March 31, 2025, approximately 500 cases were pending against Merck in various state courts.

As previously disclosed, Merck is a defendant in product liability lawsuits in the U.S. involving Gardasil (Human Papillomavirus Quadrivalent [Types 6, 11, 16 and 18] Vaccine, Recombinant) and Gardasil 9 (Human Papillomavirus 9-valent Vaccine, Recombinant). As of March 31, 2025, approximately 245 cases were filed and pending against Merck in either federal or state court. In these actions, plaintiffs allege, among other things, that they suffered various personal injuries after vaccination with Gardasil or Gardasil 9, with postural orthostatic tachycardia syndrome (POTS) as a predominate alleged injury.

In August 2022, the U.S. Judicial Panel on Multidistrict Litigation ordered that Gardasil/Gardasil 9 product liability cases pending in federal courts nationwide be transferred to Judge Robert J. Conrad in the Western District of North Carolina for coordinated pre-trial proceedings. In February 2024, the multidistrict litigation (Gardasil MDL) was reassigned to Judge Kenneth

D. Bell. On March 11, 2025, the court granted Merck’s motion for summary judgment in 16 bellwether cases on implied preemption grounds; plaintiffs have filed a Notice of Appeal to the Fourth Circuit. The parties’ letter submissions on next steps in the Gardasil MDL proceeding in light of the court’s decision were submitted on April 8, 2025.

On March 21, 2025, plaintiff’s co-lead counsel in the Gardasil MDL filed a seven-plaintiff complaint in New Jersey state court. On March 24, 2025, Merck removed the case to federal court and has requested that the U.S. Judicial Panel on Multidistrict Litigation transfer the case to the Gardasil MDL. Plaintiffs have opposed transfer to the Gardasil MDL and have moved to have the case remanded to New Jersey state court.

On January 28, 2025, a trial commenced in California state court. Plaintiff claims that she suffers from POTS and fibromyalgia as a result of her Gardasil vaccinations. On February 14, 2025, after several weeks of trial and an opportunity to litigate plaintiff’s claims before a jury, plaintiff’s counsel approached Merck and proposed that the jury be discharged and the case adjourned. Merck agreed, subject to an explicit stipulation that Merck would provide no financial or other consideration in exchange for the agreement to adjourn. The case has thus been adjourned until a new trial date of September 15, 2025. Merck is vigorously defending this case and believes that evidence presented in court will show that Gardasil had no role in causing any of plaintiff’s conditions.

As previously disclosed, from time to time, the Company’s subsidiaries in China receive inquiries regarding their operations from various Chinese governmental agencies. Some of these inquiries may be related to matters involving other multinational pharmaceutical companies, as well as Chinese entities doing business with such companies. The Company’s policy is to cooperate with these authorities and to provide responses as appropriate.

As previously disclosed, from time to time, the Company receives inquiries and is the subject of preliminary investigation activities from competition and other governmental authorities in markets outside the U.S. These authorities may include regulators, administrative authorities, and law enforcement and other similar officials, and these preliminary investigation activities may include site visits, formal or informal requests or demands for documents or materials, inquiries or interviews and similar matters. Certain of these preliminary inquiries or activities may lead to the commencement of formal proceedings. Should those proceedings be determined adversely to the Company, monetary fines and/or remedial undertakings may be required.

As previously disclosed, in February 2025, a putative class action was filed against Merck and certain of its officers in the U.S. District Court for the District of New Jersey purportedly on behalf of all purchasers of Merck common stock between February 2022 and February 2025. Plaintiff alleges that Merck violated federal securities laws by making materially false and misleading statements and material omissions regarding demand for Gardasil/Gardasil 9 in China. Plaintiff seeks unspecified monetary damages, pre-judgment and post-judgment interest, and fees and costs.

As previously disclosed, Merck, MSD, Schering Corporation, Schering-Plough Corporation, and MSP Singapore Company LLC (collectively, the Merck Defendants) were defendants in a number of lawsuits filed in 2018 on behalf of direct and indirect purchasers of Zetia (ezetimibe) alleging violations of federal and state antitrust laws, as well as other state statutory and common law causes of action. The cases were consolidated in a federal multidistrict litigation (Zetia MDL) before Judge Rebecca Beach Smith in the Eastern District of Virginia. In April 2023, the Merck Defendants reached settlements with the direct purchaser and retailer plaintiffs and a settlement with the indirect purchaser class that the court approved in October 2023.

As previously disclosed, in 2020 and 2021, United HealthCare Services, Inc. (United HealthCare), Humana Inc. (Humana), Centene Corporation and others (Centene), and Kaiser Foundation Health Plan, Inc. (Kaiser) (collectively, the Insurer Plaintiffs), each filed a lawsuit in a jurisdiction outside of the Eastern District of Virginia against the Merck Defendants and others, making similar allegations as those made in the Zetia MDL, as well as additional allegations about Vytorin. These cases were transferred to the Eastern District of Virginia to proceed with the Zetia MDL.

In December 2023, the U.S. Judicial Panel on Multidistrict Litigation remanded the four Insurer Plaintiff cases to the transferor courts in the Northern District of California (Kaiser), the District of Minnesota (United HealthCare), and the District of New Jersey (Humana and Centene). The Merck Defendants filed motions to dismiss in each of the Insurer Plaintiff cases.

On December 30, 2024, the district court in the District of New Jersey granted in part and denied in part the motions to dismiss in the Humana and Centene cases and, on January 29, 2025, Humana and Centene filed amended complaints. On March 5, 2025, the Merck Defendants filed motions to dismiss the amended complaints. On March 24, 2025, the Merck Defendants filed a third-party complaint against AmerisourceBergen Drug Corp., AmerisourceBergen Corp., and Cencora, Inc., seeking indemnification for Humana’s direct purchaser claims.

On February 25, 2025, the district court in the District of Minnesota granted in part and denied in part the motion to dismiss in the United HealthCare case. On March 11, 2025, the Merck Defendants filed an answer and affirmative defenses in response to United HealthCare’s complaint. On March 24, 2025, the Merck Defendants filed a third-party complaint against

From time to time, generic and biosimilar manufacturers of pharmaceutical products file abbreviated New Drug Applications (ANDAs) and Biologics License Applications, respectively, with the U.S. Food and Drug Administration (FDA) seeking to market generic and biosimilar forms of the Company’s products prior to the expiration of relevant patents owned by the Company. To protect its patent rights, the Company may file patent infringement lawsuits against such generic and biosimilar companies. Similar lawsuits defending the Company’s patent rights may exist in other countries. The Company intends to vigorously defend its patents, which it believes are valid, against infringement by companies attempting to market products prior to the expiration of such patents. As with any litigation, there can be no assurance of the outcomes, which, if adverse, could result in significantly shortened periods of exclusivity for these products and, with respect to products acquired through acquisitions accounted for as business combinations, potentially significant intangible asset impairment charges.

Bridion — As previously disclosed, between January and November 2020, the Company received multiple Paragraph IV Certification Letters under the Hatch-Waxman Act notifying the Company that generic drug companies had filed applications to the FDA seeking pre-patent expiry approval to sell generic versions of Bridion (sugammadex) Injection. In March, April and December 2020, the Company filed patent infringement lawsuits in the U.S. District Courts for the District of New Jersey and the Northern District of West Virginia against those generic companies. All actions in the District of New Jersey were consolidated. The West Virginia case was jointly dismissed with prejudice in August 2022 in favor of proceeding in New Jersey. The remaining defendants in the New Jersey action have stipulated to infringement of the asserted claims and withdrew all remaining claims and defenses other than a defense seeking to shorten the patent term extension (PTE) of the sugammadex patent to December 2022. The U.S. District Court for the District of New Jersey held a one-day trial in December 2022 on this remaining PTE calculation defense. The court ordered a post-trial briefing on this defense and held closing arguments in February 2023.

In June 2023, the U.S. District Court for the District of New Jersey ruled in Merck’s favor. The court held that Merck’s calculation of PTE for the sugammadex patent covering the compound is not invalid and that the U.S. Patent & Trademark Office correctly granted a full five-year extension. Also in June 2023, the U.S. District Court for the District of New Jersey issued a final judgment prohibiting the FDA from approving any of the pending or tentatively approved generic applications until January 27, 2026, except for any subsequent agreements between defendants and Merck or further order by the court.

While the New Jersey action was pending, the Company settled with five generic companies providing that these generic companies can bring their generic versions of Bridion to the market in January 2026 (which may be delayed by any applicable pediatric exclusivity) or earlier under certain circumstances. The Company agreed to stay the lawsuit filed against two generic companies, which in exchange agreed to be bound by a judgment on the merits of the consolidated action in the District of New Jersey. One of the generic companies in the consolidated action requested dismissal of the action against it and the Company did not oppose this request, which was subsequently granted by the court. The Company does not expect this company to bring its generic version of Bridion to the market before July 27, 2026.

In February 2024, the Company received another Paragraph IV Certification Letter under the Hatch-Waxman Act notifying the Company that Hikma Pharmaceuticals USA Inc. (Hikma) had filed an application to the FDA seeking pre-patent expiry approval to sell a generic version of Bridion Injection. In March 2024, the Company filed a patent infringement lawsuit in the U.S. District Court for the District of New Jersey against Hikma, postponing FDA approval of the Hikma generic drug for 30 months or until expiration of the sugammadex patent (January 27, 2026) and any potentially applicable pediatric exclusivity or an adverse court decision, if any, whichever may occur earlier. Expiration of the patent, and any potentially applicable pediatric exclusivity, will occur earlier than expiry of the 30-month stay. On April 16, 2024, the district court stayed the case during the pendency of the Federal Circuit appeal noted above.

On March 13, 2025, the Federal Circuit affirmed the district court’s decision, holding that the patent term extension granted to the sugammadex patent covering Bridion was not invalid and that the patent is entitled to its full five-year patent term extension. The FDA has now granted Bridion six months of pediatric exclusivity. Thus, the Federal Circuit’s decision secures Bridion’s exclusivity in the U.S. through July 27, 2026.

Januvia, Janumet, Janumet XR — As previously disclosed, the FDA granted pediatric exclusivity with respect to Januvia (sitagliptin), Janumet (sitagliptin/metformin HCI), and Janumet XR (sitagliptin and metformin HCl extended-release), which provides a further six months of exclusivity in the U.S. beyond the expiration of all patents listed in the FDA’s Orange Book. Adding this exclusivity to the term of the key patent protection extended exclusivity on these products to January 2023. However, Januvia, Janumet, and Janumet XR contain sitagliptin phosphate monohydrate and the Company has another patent covering certain phosphate salt and polymorphic forms of sitagliptin that expires in May 2027, including pediatric exclusivity (salt/polymorph patent).

The Company responded by filing infringement suits which have all been settled. The Company has settled with a total 26 generic companies providing that these generic companies can bring their generic versions of Januvia and Janumet to the market in the U.S. in May 2026 or earlier under certain circumstances, and their generic versions of Janumet XR to the market in July 2026 or earlier under certain circumstances.

In March 2021, the Company filed a patent infringement lawsuit in the U.S. District Court for the District of Delaware against Zydus Worldwide DMCC, Zydus Pharmaceuticals (USA) Inc., and Cadila Healthcare Ltd. (collectively, Zydus). In that lawsuit, the Company alleged infringement of the salt/polymorph patent based on the filing of Zydus’s NDA seeking approval of a form of sitagliptin that is a different from than that used in Januvia. In December 2022, the parties reached settlement that included dismissal of the case without prejudice enabling Zydus to seek final approval of a non-automatically substitutable product.

In January 2023, the Company received a Paragraph IV Certification Letter under the Hatch-Waxman Act notifying the Company that Zydus filed an ANDA seeking approval of sitagliptin/metformin HCl tablets and certifying that no valid or enforceable claim of any of the patents listed in FDA’s Orange Book for Janumet will be infringed by the proposed Zydus product. In March 2023, the parties reached settlement enabling Zydus to seek final approval of a non-automatically substitutable product containing a different form of sitagliptin than that used in Janumet. In November 2023, the Company received a Paragraph IV Certification Letter under the Hatch-Waxman Act notifying the Company that Zydus filed an ANDA seeking approval of sitagliptin/metformin HCl Extended Release tablets. In January 2024, the parties reached settlement enabling Zydus to seek final approval of a non-automatically substitutable version containing a different form of sitagliptin than that used in Janumet XR.

As a result of these settlement agreements related to the later expiring 2027 salt/polymorph patent directed to the specific sitagliptin salt form of the products, the Company expects that Januvia and Janumet will not lose market exclusivity in the U.S. until May 2026 and Janumet XR will not lose market exclusivity in the U.S. until July 2026, although Zydus has received FDA approval for a non-automatically substitutable form of sitagliptin that differs from the form in the Company’s sitagliptin products.

In March 2024, the Company received another Paragraph IV Certification Letter under the Hatch-Waxman Act from Azurity Pharmaceuticals, Inc. (Azurity) asserting that a different sitagliptin product subject to its ANDA does not infringe the salt/polymorph patent. In May 2024, Merck filed a civil action in the U.S. District Court of Delaware alleging infringement. The case was dismissed without prejudice in July 2024. Following the dismissal, the Company granted Azurity a covenant not to assert the salt/polymorph patent against the Azurity product that is the subject of such ANDA.

Supplementary Protection Certificates (SPCs) for Janumet expired in April 2023 for the majority of European countries. Prior to expiration, generic companies sought revocation of the Janumet SPCs in a number of European countries. In February 2022, a Finnish court referred certain questions to the Court of Justice of the European Union that could impact the validity of the Janumet SPCs in Europe. A decision was rendered in December 2024. The decision provides guidance on points of law and does not directly apply to the Janumet SPCs. Thus, additional proceedings in certain countries where generic companies were prevented from launching products during the SPC period may be necessary to determine whether the SPCs are valid and if not, whether damages are appropriate. Those countries include Belgium, Czech Republic, Ireland, Finland, France, Slovakia and Switzerland. If the Janumet SPCs are ultimately upheld, the Company has reserved its rights related to the pursuit of damages for those countries where a generic launched prior to expiry of the Janumet SPC.

In October 2023, the Company filed a patent infringement lawsuit against Sawai Pharmaceuticals Co., Ltd. and Medisa Shinyaku Co., Ltd (collectively, Defendants) in the Tokyo District Court seeking an injunction to stop the manufacture, sale and offer for sale of the Defendants’ sitagliptin dihydrogen phosphate product, while the Company’s patents and patent term extensions are in force. The lawsuit is in response to the Defendants’ application for marketing authorization to sell a generic sitagliptin dihydrogen phosphate product, in the anhydrate form, which was approved in August 2023. Merck asserts that the Defendants’ activity infringes a patent term extension associated with Merck’s patent directed to the sitagliptin compound patent.

Keytruda — As previously disclosed, in November 2022, the Company filed a complaint against The Johns Hopkins University (JHU) in the U.S. District Court of Maryland. This action concerns patents emerging from a joint research collaboration between Merck and JHU regarding the use of pembrolizumab, which Merck sells under the trade name Keytruda. Merck and JHU partnered to design and conduct a clinical study administering Keytruda to cancer patients having tumors that had the genetic biomarker known as microsatellite instability-high (MSI-H). After the conclusion of the study, JHU secured U.S. patents citing the joint research study. Merck alleges that JHU has breached the collaboration agreement by filing and obtaining these patents without informing or involving Merck and then licensing the patents to others. Merck therefore brought this action for breach of contract, declaratory judgment of noninfringement, and promissory estoppel. JHU answered the complaint in April and May 2023, denying Merck’s claims, and counterclaiming for willful infringement of nine issued U.S. patents, including a demand for damages. Between November 30, 2023, and March 13, 2024, the Company filed inter partes review petitions with the United States Patent Trial and Appeal Board (PTAB), challenging the validity of all nine patents asserted in the case. Between June 2024 and October 2024, the PTAB instituted a review of all nine asserted patents. In July 2024, the district court granted Merck’s motion to stay the case in its entirety pending the outcome of the PTAB proceeding instituted in June 2024.

Subcutaneous Pembrolizumab — Halozyme, Inc. has publicly alleged that certain patents in its modified hyaluronidase (MDASE) portfolio cover the Company’s subcutaneous pembrolizumab candidate, which is currently under review by the FDA. In November 2024, the Company began filing a series of post grant review (PGR) petitions before the PTAB alleging that certain patents in the MDASE portfolio are invalid. On April 24, 2025, Halozyme, Inc. filed a complaint in the U.S. District Court for the District of New Jersey alleging that the Company’s activities related to subcutaneous pembrolizumab infringe or will

Lynparza — As previously disclosed, in December 2022, AstraZeneca Pharmaceuticals LP received a Paragraph IV Certification Letter under the Hatch-Waxman Act notifying AstraZeneca that Natco Pharma Limited (Natco) has filed an application to the FDA seeking pre-patent expiry approval to sell generic versions of Lynparza (olaparib) tablet. In February 2023, AstraZeneca and the Company filed a patent infringement lawsuit in the U.S. District Court for the District of New Jersey against Natco. This lawsuit, which asserts one or more patents covering olaparib, automatically stays FDA approval of the generic application until June 2025 or until an adverse court decision, if any, whichever may occur earlier. In 2024, AstraZeneca and the Company filed additional patent infringement lawsuits in the U.S. District Court for the District of New Jersey against Natco asserting additional patents covering olaparib.

In December 2023, AstraZeneca Pharmaceuticals LP received a second Paragraph IV Certification Letter under the Hatch-Waxman Act notifying AstraZeneca that Sandoz Inc. has filed an application to the FDA seeking pre-patent expiry approval to sell generic versions of Lynparza (olaparib) tablet. In February 2024, AstraZeneca and the Company filed a patent infringement lawsuit in the U.S. District Court for the District of New Jersey against Sandoz. This lawsuit, which asserts one or more patents covering olaparib, automatically stays FDA approval of the generic application until June 2026 or until an adverse court decision, if any, whichever may occur earlier. In 2024, AstraZeneca and the Company filed additional patent infringement lawsuits in the U.S. District Court for the District of New Jersey against Sandoz asserting additional patents covering olaparib.

In May 2024, AstraZeneca Pharmaceuticals LP received a third Paragraph IV Certification Letter under the Hatch-Waxman Act notifying AstraZeneca that Cipla USA, Inc. and Cipla Limited (collectively, Cipla) filed an application to the FDA seeking pre-patent expiry approval to sell generic versions of Lynparza (olaparib) tablet. In June 2024, AstraZeneca and the Company filed a patent infringement lawsuit in the U.S. District Court for the District of New Jersey against Cipla. This lawsuit, which asserts one or more patents covering olaparib, automatically stays FDA approval of the generic application until November 2026 or until an adverse court decision, if any, whichever may occur earlier. In 2024, AstraZeneca and the Company filed additional patent infringement lawsuits in the U.S. District Court for the District of New Jersey against Cipla asserting additional patents covering olaparib.

In November 2024, AstraZeneca Pharmaceuticals LP received another Paragraph IV Certification Letter under the Hatch-Waxman Act notifying AstraZeneca that Zydus Pharmaceuticals (USA) Inc. filed an application to the FDA seeking pre-patent expiry approval to sell generic versions of Lynparza (olaparib) tablet. In November 2024, AstraZeneca and the Company filed a patent infringement lawsuit in the U.S. District Court for the District of New Jersey against Zydus. This lawsuit, which asserts one or more patents covering olaparib, automatically stays FDA approval of the generic application until May 2027 or until an adverse court decision, if any, whichever may occur earlier. In 2024, AstraZeneca and the Company filed an additional patent infringement lawsuit in the U.S. District Court for the District of New Jersey against Zydus asserting an additional patent covering olaparib.

There are various other pending legal proceedings involving the Company, principally product liability and intellectual property lawsuits. While it is not feasible to predict the outcome of such proceedings, in the opinion of the Company, either the likelihood of loss is remote or any reasonably possible loss associated with the resolution of such proceedings is not expected to be material to the Company’s financial condition, results of operations or cash flows either individually or in the aggregate.

Legal defense costs expected to be incurred in connection with a loss contingency are accrued when probable and reasonably estimable. Some of the significant factors considered in the review of these legal defense reserves are as follows: the actual costs incurred by the Company; the development of the Company’s legal defense strategy and structure in light of the scope of its litigation; the number of cases being brought against the Company; the costs and outcomes of completed trials; and the most current information regarding anticipated timing, progression, and related costs of pre-trial activities and trials in the associated litigation. The amount of legal defense reserves as of March 31, 2025 and December 31, 2024 of approximately $230 million and $225 million, respectively, represents the Company’s best estimate of the minimum amount of defense costs to be incurred in connection with its outstanding litigation; however, events such as additional trials and other events that could arise in the course of its litigation could affect the ultimate amount of legal defense costs to be incurred by the Company. The Company will continue to monitor its legal defense costs and review the adequacy of the associated reserves and may determine to increase the reserves at any time in the future if, based upon the factors set forth, it believes it would be appropriate to do so.