The Medicines and Healthcare products Regulatory Agency has opened a formal review of avacopan, marketed as Avacopan Vifor and previously known as Tavneos. In its notice, the MHRA said the review was prompted by information that raises questions about the integrity and reliability of data from the pivotal clinical study that underpinned the product's licence approval. For regulators, that places the focus not only on the medicine's known safety profile, but also on whether the evidence base used at authorisation remains sufficient to support the product's overall benefit-risk balance. The review is therefore centred on the quality of the underlying evidence as well as the medicine's continuing place in treatment.
According to the MHRA, avacopan is indicated in combination with a rituximab or cyclophosphamide regimen for adults with severe, active granulomatosis with polyangiitis or microscopic polyangiitis. These are rare autoimmune diseases affecting small blood vessels, and treatment decisions are typically made in specialist settings where disease severity, infection risk and organ involvement require close management. That clinical context matters. Any regulatory reassessment of a medicine used in severe disease has practical consequences for prescribing teams, hospital pharmacists and patients already established on therapy, particularly where treatment is delivered alongside other potent immunomodulatory medicines.
The review is being conducted under Section 68 of the Human Medicines Regulations 2012. As the MHRA sets out, that provision allows the licensing authority to revoke, vary or suspend a UK marketing authorisation where the application, or the material supplied with it, is incorrect or no longer supports a positive benefit-risk balance for the product. In policy terms, Section 68 is a post-authorisation safeguard. Its use signals that the regulator considers the evidential foundation of the licence serious enough to require formal scrutiny. It does not, on the MHRA's own notice, amount to an immediate withdrawal of the medicine from use, but it does place the authorisation under active review.
The agency has also stated that the existing risk-minimisation advice in the product information remains in force while the review is under way. That includes monitoring liver function and white blood cell count, alongside assessment for serious infections. For healthcare professionals, the immediate position is therefore continuity with caution. Prescribers are not being told to stop using the medicine across the board, but they are being reminded to consider carefully the individual benefits and risks for each patient while the regulator reassesses the evidence supporting the product.
For patients, the MHRA's message is equally clear: treatment should not be stopped without consultation with a healthcare professional. That reflects a standard regulatory approach where a review is live but no new restriction has yet been imposed. Abrupt discontinuation could itself create clinical risk, particularly in severe inflammatory disease managed through specialist care pathways. The practical effect is that clinicians retain responsibility for case-by-case decision-making, informed by the current product information and the patient's condition. Patients, meanwhile, are being directed back into managed clinical supervision rather than informal changes to treatment.
The MHRA has said that the outcome of the review, including any new advice for healthcare professionals and patients, will be communicated once the process is complete. Until then, the government's position is that current prescribing safeguards continue to apply and that benefit-risk judgements should be made carefully at individual level. The notice also repeats the standard pharmacovigilance instruction that suspected adverse reactions should be reported through the Yellow Card scheme. Taken together, the announcement shows the UK medicines regulator using an established statutory mechanism to test whether a licensed product's evidential basis still supports continued authorisation, while keeping existing safeguards in place during the review.