The Medicines and Healthcare products Regulatory Agency has opened a review of avacopan, marketed as Avacopan Vifor and previously known as Tavneos. According to the MHRA notice, the review was triggered by information that raises questions about the integrity and reliability of data from the pivotal clinical study that supported the medicine's licence. The product is authorised, in combination with a rituximab or cyclophosphamide regimen, for adults with severe, active granulomatosis with polyangiitis or microscopic polyangiitis. Both are rare autoimmune diseases affecting small blood vessels, which means the review concerns a medicine used in a specialist treatment setting.
The regulator's immediate question is whether the new information changes what the key study showed about avacopan's effectiveness, and whether that in turn alters the overall benefit–risk balance for the product. The MHRA has not announced an immediate suspension, but it is re-examining the evidential basis on which the UK licence rests. That distinction matters. This is not presented as a blanket instruction to stop prescribing at once. It is a formal review of whether the clinical evidence submitted in support of the authorisation remains reliable enough to support continued approval on current terms.
The government notice says the review is being conducted under regulation 68 of the Human Medicines Regulations 2012. Under that provision, the licensing authority may vary, suspend or revoke a UK marketing authorisation if an application, or material supplied with it, is incorrect, or no longer supports a positive benefit–risk balance. In practical terms, regulation 68 gives the MHRA a clear statutory route to act if the supporting evidence is found wanting. The possible outcomes therefore extend beyond updated advice and could, if the review justifies it, include changes to the terms of the authorisation itself.
For now, the existing risk-minimisation measures remain unchanged. The MHRA says the current product information continues to apply, including monitoring liver function and white blood cell count, as well as assessing patients for serious infections. For prescribing teams, the immediate position is continuity rather than disruption. Existing safeguards stay in force while the review proceeds, and the regulator has not indicated any interim removal of the medicine from routine specialist use within its authorised indication.
The agency has also reminded healthcare professionals to weigh the individual benefits and risks carefully when considering avacopan during the review period. In specialist practice, that places renewed emphasis on patient-level assessment, particularly where disease severity, infection risk or prior treatment history may affect the choice between available regimens. For patients, the MHRA's advice is direct: treatment should not be stopped without first consulting a healthcare professional. That message is intended to reduce the risk of unsupervised treatment changes in conditions that can be serious and difficult to manage.
The next step will be the publication of the review outcome, together with any fresh advice for clinicians and patients. Until then, the regulatory position is one of continued use under existing precautions, combined with formal scrutiny of the study data that underpinned approval. The notice also repeats the standard reporting route for suspected adverse reactions through the Yellow Card scheme. For the wider medicines policy system, the episode is a reminder that post-authorisation oversight does not end once a product reaches the market; the regulator can revisit the basis of approval where the reliability of submitted evidence comes into question.