This medicine can cause serious liver damage. 20 people died according to its manufacturer. It remains available in pharmacies in France.
A drug manufactured in Japan and marketed in several countries, including France which is causing concern. In a letter dated May 15, its manufacturer, the Kissei Pharmaceutical laboratory, asked doctors “to refrain from prescribing this medication to new patients and to inform patients currently under treatment of the risks of liver dysfunction” going up to “encourage them to think carefully before continuing treatment”. In question: twenty deaths reported in patients treated with this drug. “Severe damage appears especially in the first three months” warns the laboratory. What medicine is this?
The processing in question has been under “reinforced” surveillance by European authorities since the beginning of 2026, as well as by American authorities. On January 30, the European Medicines Agency (EMA) announced that it had launched a review “due to concerns regarding the consistency of data from the collaborative international phase III clinical trial”reports the Japanese laboratory. This trial is the one that allowed the marketing authorization of the treatment. On March 31, the United States Medicines Agency (FDA) reported serious cases of liver damage in patients. On April 27, its Center for Drug Evaluation and Research (CDER) announced plans to withdraw the drug’s marketing authorization in the United States. New information would have revealed the absence of demonstration of effectiveness of the treatment and the presence “material inaccuracies” in the authorization request file. Clearly, this medication may not be as effective as advertised. Worse, it would be dangerous. This brings to mind the list of 89 medications to avoid according to Prescrire.
The treatment in question? Tavneos whose active ingredient is avacopan. It works by blocking an immune system protein called the C5a receptor. This protein participates in the excessive inflammation observed in a rare disease: ANCA-associated vasculitis. It is an autoimmune disease in which the immune system attacks small blood vessels, especially in the kidneys, lungs or sinuses. Tavneos is usually prescribed with other immunosuppressive treatments such as rituximab or cyclophosphamide. Its interest is to reduce the doses of corticosteroids, which often cause many side effects. It has been authorized in France since January 11, 2022 and available only by prescription.
At this stage, the National Medicines Safety Agency (ANSM) has not communicated about Tavneos and has not issued any specific recommendations for French patients who take it. In France, the drug is indicated in the treatment of two severe forms of vasculitis in adults: granulomatosis with polyangiitis and microscopic polyangiitis. Their overall prevalence in France is estimated at around 100 cases per million inhabitants, or around 6,000 to 7,000 people potentially affected.
