Britain’s medicines regulator has suspended the use and sale of Amgen’s rare-disease therapy Tavneos in new patients, citing concerns over the reliability of data from the principal clinical trial supporting its approval.
In the U.K., the drug is marketed as Avacopan Vifor by CSL Vifor. It is used alongside other therapies to treat extreme autoimmune disorders that cause inflammation in small blood vessels and can result in kidney and lung damage.
The regulator determined that problems with the trial data meant the study could no longer reliably establish either Tavneos’ effectiveness or whether its benefits were greater than the risks it posed. The agency intends to withdraw the drug’s U.K. authorization on March 1, 2027.
People who are already receiving Tavneos will be allowed to remain on treatment for another six months while their physicians assess alternative options. The regulator also advised patients against stopping the therapy without first speaking with a specialist.
ChemoCentryx originally developed Tavneos before Amgen acquired the company for $3.7 billion four years ago. Amgen retains U.S. rights to the drug, while CSL Vifor holds commercialization rights in several markets outside the U.S., including the U.K.
The European Commission withdrew Tavneos’ approval in August after regulators reached similar conclusions about the reliability of the pivotal trial data. In the U.S., the FDA has also proposed removing the drug from the market, pointing to insufficient evidence of effectiveness and inaccurate statements in the original regulatory application.
Amgen is contesting the proposed U.S. withdrawal and has provided regulators with more than 70 studies covering over 2,200 patients.
An independent assessment found that Tavneos produced results comparable to steroid-based treatment at both 26 and 52 weeks but failed to establish superiority at the 52-week mark. Separately, the U.S. FDA has associated Tavneos with 76 reports of serious liver injury, including eight fatalities.
Tavneos originally secured European approval in 2022 for use against two kinds of ANCA-associated vasculitis: active granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). The treatment is administered alongside either Roche’s Rituxan (rituximab) or the chemotherapy drug cyclophosphamide.
However, the Phase 3 Advocate trial that supported Tavneos’ initial approvals in both Europe and the U.S. has subsequently become a major source of regulatory concern for the drug and the companies that took ownership of the therapy after Amgen acquired its original developer, ChemoCentryx.
In regulatory documents released Thursday, the Committee for Medicinal Products for Human Use (CHMP) provided additional details behind its recommendation to withdraw Tavneos from the European market. The committee said a review conducted this year had uncovered serious violations of good clinical practice involving the handling of primary endpoint data from the pivotal study.
The CHMP specifically raised concerns that members of the study sponsor’s team gained access to unblinded efficacy results after the database had initially been locked. According to the committee, this access revealed that the trial had failed to demonstrate superiority at the critical 52-week assessment.
Amgen’s Tavneos has faced a major regulatory setback in the United Kingdom after the Medicines and Healthcare products Regulatory Agency (MHRA) concluded that data from the pivotal clinical study supporting its authorization could no longer be relied upon to demonstrate efficacy.
Amgen’s Tavneos Suspension in the UK
Amgen’s Tavneos, marketed in the UK as Avacopan Vifor by CSL Vifor, is used alongside other treatments for adults with severe active granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA). These rare autoimmune diseases can cause inflammation of small blood vessels and potentially damage vital organs.
The MHRA said concerns about the integrity and reliability of the pivotal study changed its assessment of the medicine’s benefit-risk balance. As a result, Amgen’s Tavneos will no longer be available for new patients in the UK.
Amgen’s Tavneos Impact on Patients
Patients already receiving Amgen’s Tavneos in the UK can continue treatment during a managed withdrawal period while healthcare professionals consider suitable alternatives. The MHRA plans to revoke the UK authorization on March 1, 2027. Patients are advised not to stop treatment without consulting their specialist.
