The U.K. Medicines and Healthcare products Regulatory Agency has suspended the use, supply and sale of Avacopan Vifor for new patients, concluding that available evidence no longer supports a positive benefit-risk balance for the rare autoimmune-disease treatment.
The decision took effect Sept. 1, 2026. Existing patients may continue receiving the medicine during a six-month managed withdrawal period while they transition to other treatment options. The MHRA intends to revoke the product’s U.K. marketing authorization on March 1, 2027, and said the marketing authorization holder has guaranteed supply through the transition period.
Avacopan Vifor, previously called Tavneos, is authorized in the U.K. with rituximab or cyclophosphamide for adults with severe, active granulomatosis with polyangiitis, or GPA, and microscopic polyangiitis, or MPA. Both are rare autoimmune conditions that affect small blood vessels.
The regulator’s review was prompted by information that questioned the integrity and reliability of data from the pivotal study supporting the medicine’s authorization. After assessing available evidence, consulting the Commission on Human Medicines and considering feedback from patients and health-care professionals, the MHRA concluded the study could no longer be relied on to demonstrate efficacy.
Health-care professionals should not start Avacopan Vifor in new patients and should review existing patients as soon as possible to consider alternative care, the agency said. Patients should not stop therapy without first consulting their specialist clinician.
The decision follows an April 27, 2026, announcement that the FDA’s Center for Drug Evaluation and Research proposed withdrawing approval of Tavneos in the United States. The agency’s proposal also stemmed from concerns involving the reliability of data supporting the drug’s clinical benefit.
Amgen, which markets Tavneos, said in a May 15 statement that it disagreed with the FDA’s proposed withdrawal and planned to pursue available regulatory processes. The company said it believed Tavneos’ benefit-risk profile remained favorable for patients with GPA and MPA.
The MHRA said existing risk-minimization measures remain in effect for patients continuing treatment. These include liver-function monitoring, with recently increased recommended testing frequency, as well as white-blood-cell monitoring and assessments for serious infections.
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