A $220,000 Drug Built on Disputed Data

Tavneos generated nearly half a billion dollars in 2025 sales. Now regulators on three continents say the trial that approved it may have been manipulated.

By The Breakthroughist Desk

In fiscal year 2025, sales of Tavneos — a vasculitis drug priced at $220,000 per year — reached nearly half a billion dollars. [1][2]

The cascade began with a shareholder lawsuit. [1] The company never disclosed the original results, nor the fact that it had revisited the data, to the agency. The New England Journal of Medicine subsequently retracted the paper describing the trial. [1]

The MHRA concluded that "the study can no longer be relied upon to demonstrate the efficacy of Avacopan Vifor." [1]

The dispute crystallises a tension that sits at the heart of rare-disease regulation: small companies carry existential stakes in a single trial, approval systems depend on sponsor honesty, and patients caught in the middle face choices that no regulatory timeline can neatly resolve.

[1] Whether the FDA agrees — and whether it has the procedural will to act — may take months more to determine, while patients and physicians wait for certainty that the data was supposed to have already provided.