Tavneos Faces UK Withdrawal Amid Efficacy Concerns

Tavneos, a rare-disease drug used to treat adults with severe forms of ANCA-associated vasculitis, is facing withdrawal from the U.K. market after regulators suspended its use for new patients. The Medicines and Healthcare Products Regulatory Agency (MHRA) has set a path towards revoking Tavneos' authorization in March 2027.

The MHRA cited concerns over the reliability of efficacy data from a pivotal study supporting the drug, according to Amgen. The company acquired ChemoCentryx, the developer of Tavneos, for $3.7 billion in 2022, but CSL Vifor holds the U.K. marketing authorization and is leading interactions with the MHRA.

Amgen reported $150 million in Tavneos sales during Q2, up 36% year over year, while full-year 2025 sales reached $459 million, up 62%. The company disagrees with the regulator's decision, stating that it believes the MHRA's interpretation does not fully recognize the broader evidence supporting Tavneos.

Tavneos is also facing regulatory scrutiny in the United States, where the FDA has proposed withdrawing the drug due to concerns over efficacy and safety issues, including serious liver injury. Amgen submitted additional analyses in July and requested a hearing as it seeks to preserve the drug's U.S. approval.