Plaintiff
13 cases as plaintiff.
Merck Sharp & Dohme LLC is the international trade name for Merck & Co., Inc., a prominent American multinational pharmaceutical company. Known as MSD outside the United States and Canada, the company is headquartered in Rahway, New Jersey, and was founded in 1891 as a U.S. subsidiary before becoming independent in 1917. Merck & Co., Inc. is a publicly traded company on the New York Stock Exchange under the ticker symbol MRK. As of December 31, 2025, it employed approximately 75,000 people and reported an annual revenue of $65.01 billion for fiscal year 2025.
Merck is a research-intensive biopharmaceutical company that discovers, develops, manufactures, and markets a broad range of innovative products for human and animal health. Its major product lines include prescription medicines, vaccines, and biologic therapies. Key therapeutic areas encompass oncology, with flagship drugs like Keytruda, as well as vaccines such as Gardasil, and treatments for infectious diseases, cardiometabolic disorders, and immunology. The company also maintains a significant Animal Health division.
In terms of patent litigation, Merck Sharp & Dohme LLC primarily appears as a plaintiff in Patent Trial and Appeal Board (PTAB) proceedings, with one tracked case. This indicates an operating company actively seeking to challenge the validity of competitor patents. Concurrently, Merck Sharp & Dohme Corp. is a defendant in a co-pending district court litigation (Halozyme Inc. v. Merck Sharp & Dohme Corp., D.N.J., Case No. 2:25-cv-03179), where it is accused of infringing patents related to its subcutaneous (SC) formulation of Keytruda. The district court litigation has been temporarily suspended pending the outcome of the PTAB reviews.
A notable case reflecting Merck's litigation posture is Merck Sharp & Dohme LLC v. Halozyme Inc. at the PTAB, initiated in November 2024. In this proceeding, Merck is challenging multiple patents owned by Halozyme, Inc. directed to modified PH20 hyaluronidase polypeptides, which are relevant to Merck's Keytruda Qlex™ subcutaneous formulation. Recent PTAB decisions have favored Merck in some of these challenges, finding certain Halozyme patents invalid, which could significantly influence the related district court infringement suit.
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Merck Sharp & Dohme LLC filed an Inter Partes Review (IPR) petition challenging the validity of the patent owned by Halozyme Inc. before the PTAB. The case is currently pending.
An inter partes review petition filed by Merck Sharp & Dohme LLC challenging US patent 11058757, which was not instituted by the PTAB.
This is a pending post-grant review (PGR) proceeding before the Patent Trial and Appeal Board, initiated by Merck Sharp & Dohme LLC against Halozyme Inc., asserting US patent 12371685.
Merck Sharp & Dohme LLC filed a post-grant review petition challenging U.S. Patent No. 12,077,791. The Director denied discretionary denial and institution was granted; the proceeding remains in merits briefing with no final written decision.
Merck filed a petition for post-grant review challenging all claims 1–40 of U.S. Patent 12,091,692 B2. The PTAB instituted review on October 10, 2025, on written description, enablement, and obviousness grounds. A motion to terminate based on an alleged undisclosed real party-in-interest remains pending.
Merck Sharp & Dohme LLC petitioned for post-grant review of US 12,037,618. The PTAB instituted review on November 13, 2025, on claims 3, 4, 6, and 34-40 based on written description and enablement, with obviousness also pleaded. Patent Owner's Response was filed January 15, 2026.
Merck Sharp & Dohme LLC filed a post-grant review challenging US 12,104,185 B2. The PTAB instituted trial on October 1, 2025, and the proceeding remains pending; Halozyme statutorily disclaimed claims 5-6.
Post-grant review petition filed by Merck Sharp & Dohme LLC challenging US 12,049,652. The PTAB instituted review on October 1, 2025 on written description and enablement grounds; no final written decision was located.
Merck Sharp & Dohme LLC filed a post-grant review petition challenging claims 1-40 of US 12,054,758 B2. The Board instituted the PGR on October 16, 2025, and the trial remains ongoing with no final written decision yet.
Merck filed a post-grant review challenging claims of the '520 patent on obviousness, written description, and enablement grounds. The PTAB instituted review on written description and enablement, and later reportedly issued a Final Written Decision finding the challenged claims unpatentable while rejecting Merck's novelty challenge; Halozyme may appeal to the Federal Circuit.
This is a Post-Grant Review (PGR) proceeding filed by Merck Sharp & Dohme LLC against Halozyme Inc. regarding US Patent 12123035.
Merits action asserting '708 claim 3 for infringement and challenging claims 1, 2, 3, and 19 for validity. After a five-day bench trial, the court found Mylan's ANDA products infringe claim 3 (Doc. 204, Oct. 26, 2022); Mylan appealed.
Complaint expressly pleads infringement of the '708 patent arising from ANDA No. 216886 (generic JANUVIA) and Prinston's notice letter dated July 1, 2022; settled.