Keytruda Organ Failure

Plaintiffs allege Merck & Co.'s PD-1 inhibitor Keytruda (pembrolizumab) causes severe immune-mediated organ failure—including acute kidney injury, myocarditis, cardiomyopathy, pneumonitis, colitis, and hepatitis—through inadequate warnings and failure to disclose elevated risks from internal 2016-2019 data. Litigation remains decentralized with no MDL established as of March 2026; cases proceed as individual product liability actions in state and federal courts. Merck halted two Phase 3 trials (KEYNOTE-867 and KEYNOTE-630) in August 2024 after interim analysis showed no survival benefit and higher rates of adverse events including death.

No MDL established for Keytruda organ failure claims as of March 2026. Product liability litigation proceeds as decentralized individual actions in state and federal courts alleging immune-mediated organ injuries including myocarditis, cardiomyopathy, and acute kidney injury. FDA label (Rev. 11/2025) carries warnings for severe or fatal immune-mediated adverse reactions affecting any organ system.

Approximately 2,799 patients in pooled FDA safety database; 19% discontinuation rate in largest NSCLC monotherapy cohort. No MDL or centralized litigation docket identified as of March 2026; state-specific SOL windows apply for individual immune-mediated adverse reaction claims including myocarditis, cardiomyopathy, and acute kidney injury. FDA label revisions November 2025 and January 2024 expand immune-mediated adverse reaction warnings to 'any organ system or tissue' with fatality risk.

• Arkansas

  Wrongful death lawsuit filed Sept. 24, 2025, alleging fatal acute cardiomyopathy, acute kidney injury, and myocarditis from Keytruda; strict products liability and negligence claims. Source: LegalClarity (June 2026)

• California

  Two-year SOL from injury discovery date applies; 17 independent medical review cases upheld, 10 overturned for Keytruda coverage denials per state regulator records. Source: ICIJ (April 2026)

• Texas

  Six final complaint resolutions reviewed by state insurance regulator; three coverage denials reversed upon regulatory review. Source: ICIJ (April 2026)

• New Jersey

  Halozyme patent litigation v. Merck pending in federal court regarding Keytruda subcutaneous formulation; no product liability MDL established. Source: LegalClarity (June 2026)

• Clinical Trial Sites — KEYNOTE-042 (NSCLC)

  1,251 previously untreated Stage III/metastatic patients; 19% permanent discontinuation rate (121/636), serious adverse reactions ≥2% included pneumonitis, pneumonia, death of unknown cause. Source: FDA Label 125514s188 (Nov. 2025); Merck HCP safety data (2025)

• Clinical Trial Sites — KEYNOTE-051 (Pediatric)

  173 pediatric patients aged 6 months to <18 years with cHL, PMBCL, or solid tumors; immune-mediated adverse reactions observed in pediatric population. Source: FDA Label 125514s188

• Allogeneic HSCT Treatment Centers (Nationwide)

  FDA warning for fatal and serious complications in patients receiving allogeneic hematopoietic stem cell transplantation before or after PD-1 blockade; GVHD and hyperacute graft-versus-host disease documented. Source: FDA Label 125514s188 Section 5.3

• Oncology Infusion Centers — Community and Academic (Nationwide)

  IV pembrolizumab administration sites; immune-mediated pneumonitis 3.4% in pooled trials, infusion-related reactions requiring monitoring per 30-minute infusion protocol. Source: FDA Label 125514s188; pooled safety database of 2,799 patients