The FDA is moving toward market withdrawal for ChemoCentryx’ Tavneos (avacopan), after new information surfaced that the agency says undermines evidence of effectiveness. The dispute centers on allegations that unblinded study personnel manipulated results from the pivotal trial and that the original analysis was not disclosed to FDA. The regulatory posture escalates earlier European scrutiny, with the European CHMP initiating an investigation into data integrity. Together, the actions signal heightened tolerance thresholds for clinical trial conduct in rare-disease immunology. The situation matters for investors and clinicians because Tavneos had been established as a complement C5a receptor antagonist used alongside standard immunosuppressants in vasculitis. If withdrawal proceeds, it will affect treatment access and pricing power for a marketed biologics-adjacent small-molecule option.