Amgen Drug Reviewed Amid Deaths

Why It Matters

The safety alerts and regulatory challenges could erode Tavneos’s market momentum, jeopardizing Amgen’s revenue stream and raising broader questions about data integrity in biotech approvals.

Key Takeaways

• 20 deaths reported among 8,500 Japanese patients on Tavneos.
• FDA proposes withdrawing Tavneos approval due to alleged trial data manipulation.
• Amgen must request hearing by June 1, submit data by June 29.
• European Medicines Agency also reviewing Tavneos safety and efficacy.
• Tavneos generated $459 million in 2025 sales despite safety concerns.

Pulse Analysis

Tavneos, marketed by Amgen after its 2022 acquisition of ChemoCentryx, targets rare autoimmune vasculitis by inhibiting complement component C5a. The drug quickly became a revenue driver, posting $459 million in sales for 2025, and is often used alongside standard immunosuppressants. Its commercial promise, however, is now clouded by safety concerns that have surfaced in key markets, prompting a reassessment of its risk‑benefit profile among clinicians and investors alike.

In Japan, Kissei Pharmaceutical, the local licensee, reported 20 fatalities among roughly 8,500 patients receiving Tavneos, citing severe liver dysfunction and bile‑duct loss. Although a direct causal link remains unproven, regulators imposed an emergency warning label and temporarily halted new prescriptions. After negotiations with the Ministry of Health, the label was reinstated, allowing sales to resume under stricter monitoring. The incident underscores the heightened vigilance required for drugs treating life‑threatening conditions where adverse events can quickly attract regulatory action.

Across the Atlantic, the U.S. FDA’s Center for Drug Evaluation and Research has sent Amgen a formal notice proposing to withdraw the drug’s 2021 approval. The agency alleges that Phase 3 trial data were manipulated to overstate efficacy, and it notes that liver toxicity was flagged in the original submission. Amgen faces a tight timeline—requesting a hearing by June 1 and providing supporting data by June 29—or it may have to pull Tavneos from the market entirely. Simultaneously, the European Medicines Agency has opened its own review, signaling that the drug’s global trajectory hinges on Amgen’s ability to address these safety and data‑integrity concerns.