In May 2021, the US Food and Drug Administration released a briefing document on an experimental medication for a rare autoimmune form of vasculitis that often damages the kidneys and lungs. The agency was undecided on approval and wanted an independent advisory committee to weigh in. Questions centered on whether the drug was meaningfully better than existing therapies. Participants in the study, conducted by the California biotechnology company Chemo Centryx, showed slightly higher rates of symptom remission after one year, but the FDA said the results were hard to interpret because the study design was less than optimal.
Many patients and some physicians nonetheless saw a potentially helpful medication that might lessen reliance on steroids, which are highly effective but often cause severe side effects. The advisory committee narrowly recommended approval, and the FDA granted it on October 7, 2021. The drug, marketed as Tavneos, reached clinics. A year later, Amgen acquired Chemo Centryx. The drug costs $220,000 per year according to Drugs.com, and sales reached nearly half a billion dollars in fiscal year 2025.
The sales have continued despite a long-running investor lawsuit that uncovered what the FDA now believes is evidence that Chemo Centryx employees manipulated data in the pivotal trial. In April of this year, the FDA proposed withdrawing Tavneos from the US market, citing reports of serious, sometimes fatal, liver injury and arguing the drug lacks "substantial evidence" that it works. The New England Journal of Medicine retracted the trial paper this summer, the drug was removed from the European Union market, and the United Kingdom announced it will follow suit. A $69 million settlement hearing is expected October 29.
In the United States, the outcome is far from settled. Amgen insists the drug works as advertised and submitted a 104-page document to the FDA in July. Some academic experts agree it is an important option, while others warn that the case highlights the FDA's struggle to regulate drugs of uncertain efficacy and raises questions about safeguards when a small company runs a pivotal trial.
Source: Ars Technica · Summarized by HeadlinesBriefing