Patent 8377903

Litigation summary

Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.

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No PTAB proceedings on file. This patent has not been challenged through Inter Partes Review, Post-Grant Review, or Covered Business Method review at the USPTO. The absence is itself a signal — well-asserted patents eventually attract IPRs.

Cases on file (3)

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Specific litigation cases in our database that name US patent 8377903. The free-form analysis below may also discuss cases beyond this list.

Litigation summary

Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.

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U.S. Patent 8,377,903 has been involved in several significant litigation cases, primarily concerning its validity related to cladribine dosing regimens for treating multiple sclerosis.

Here's a summary of known litigation:

  • Case 1: Merck Serono SA v. TWI Pharmaceuticals Inc.

    • Plaintiff(s): Merck Serono SA
    • Defendant(s): TWI Pharmaceuticals Inc.
    • Jurisdiction: United States Court of Appeals for the Federal Circuit (CAFC), appealing a decision from a lower tribunal (likely a district court or PTAB).
    • Case Number: 25-1464
    • Filing Date: February 19, 2025
    • Outcome/Current Status: The Federal Circuit affirmed the lower tribunal's ruling of unpatentability for US8377903B2 on October 30, 2025. This means the patent is invalid and unenforceable. Merck Serono's options for further appeal are limited.

  • Case 2: Merck KGaA v. Hopewell Pharma Ventures, Inc.

    • Plaintiff(s): Merck KGaA
    • Defendant(s): Hopewell Pharma Ventures, Inc.
    • Jurisdiction: Delaware District Court, affirmed by the Federal Circuit.
    • Case Number: 1:22-cv-01365 (D. Del.)
    • Filing Date: The duration of the case was from October 2022 to January 2026.
    • Outcome/Current Status: The Delaware District Court entered final judgment on January 29, 2026, in favor of Hopewell Pharma Ventures, Inc., invalidating claims of US8377903 (among other patents) as obvious. This ruling was driven by a precedential Federal Circuit decision.

  • Case 3: Merck v. Apotex

    • Plaintiff(s): Merck (likely Merck KGaA or Merck Serono SA)
    • Defendant(s): Apotex Inc. and Apotex Corp.
    • Jurisdiction: Federal Circuit (as the controlling decision from Merck Serono v. Hopewell was cited, indicating a federal court ruling).
    • Filing Date: Not explicitly stated, but the outcome was reported on February 2, 2026.
    • Outcome/Current Status: The court entered judgment entirely in favor of Apotex, declaring claims 17, 19, 20, and 22–27 of the '903 patent (among others) invalid as obvious. All of Merck's infringement claims were dismissed.

It is important to note that while some sources initially indicated "no publicly documented litigation specific to U.S. Patent 8,377,903", more recent and specific search results from PatSnap and Unified Patents clearly detail these cases, providing more current and accurate information.

Generated 6/25/2026, 6:45:34 AM