Tavneos Lawsuit

About Tavneos

Tavneos (avacopan) is a prescription oral medication approved by the FDA on October 7, 2021, for the adjunctive treatment of severe active anti-neutrophil cytoplasmic autoantibody-associated vasculitis (ANCA-associated vasculitis) in adults. This includes two specific conditions: granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) — rare autoimmune diseases that cause inflammation and damage to small blood vessels throughout the body.

The drug is a selective complement C5a receptor (C5aR) inhibitor, meaning it blocks a specific protein involved in the inflammatory cascade that drives vasculitis. It was the first orally administered drug in its class and was designed to be used alongside standard therapy such as rituximab or cyclophosphamide. The medication was positioned as an alternative to long-term glucocorticoid (steroid) use, which carries its own significant side effects.

Tavneos was originally developed by ChemoCentryx, Inc., a biopharmaceutical company based in San Carlos, California. In August 2022, Amgen announced a roughly $3.7 billion acquisition of ChemoCentryx, completing the deal in October 2022. Amgen now manufactures and markets Tavneos.

Since its approval, Tavneos has been prescribed to over 8,000 patients in the United States. However, serious postmarketing safety concerns — particularly severe liver injury and questions about the integrity of the clinical trial data used to gain FDA approval — have cast significant doubt on the drug's safety profile and whether it should remain on the market.

Health Risks & Liver Injury

The FDA has identified 76 global postmarketing cases of drug-induced liver injury (DILI) likely caused by Tavneos. The scope and severity of these injuries is alarming: 74 of the 76 cases resulted in serious outcomes, 54 patients required hospitalization, and 8 patients died. The median time from starting Tavneos to the onset of liver injury was approximately 46 days.

Among the most concerning findings are 7 biopsy-confirmed cases of vanishing bile duct syndrome (VBDS), a rare and potentially fatal condition in which the bile ducts within the liver are progressively destroyed and disappear. All 7 VBDS patients required hospitalization, and 3 of those cases were fatal. Most VBDS cases occurred within 60 to 90 days of starting Tavneos.

Hepatotoxicity was actually identified as a serious adverse reaction during premarket clinical trials and was included in the original product labeling. However, the severity and frequency of postmarketing liver injury cases — particularly the emergence of VBDS, which was not observed in clinical trials — prompted the FDA to take action.

Of the 76 reported liver injury cases, 66 occurred in Japan, with the remainder reported in other countries including the United States and Canada. The FDA has recommended that patients taking Tavneos receive liver panel testing every 2 weeks during the first month of treatment, monthly for the next 5 months, and then as clinically indicated thereafter.

FDA Action & Clinical Trial Data Integrity

The FDA's response to Tavneos has been unusually aggressive. In January 2026, the FDA requested that Amgen voluntarily withdraw Tavneos from the U.S. market. Amgen declined, stating it stands by the drug's benefit-risk profile. In March 2026, the FDA issued a formal Drug Safety Communication alerting patients and healthcare professionals about the serious liver injury cases.

Then, on April 29-30, 2026, the FDA published a notice in the Federal Register formally proposing withdrawal of the Tavneos New Drug Application (NDA). The FDA's proposal is based on two grounds: concerns about untrue statements of material fact in the original NDA submission, and a lack of substantial evidence of effectiveness due to data integrity problems with the pivotal ADVOCATE clinical trial.

The data integrity concerns center on an expert report filed in related securities litigation. That report alleged that ChemoCentryx's initial statistical analysis of the Phase 3 ADVOCATE trial — which enrolled roughly 330 patients across 20 countries — showed that Tavneos did not achieve statistically significant superiority on its primary endpoint of sustained disease remission. After this initial failure, unblinded company personnel reportedly selected 9 patients for "readjudication" after the study database had been locked. The outcomes for 5 of those patients were changed from "not in sustained remission" to "sustained remission," which flipped the overall trial result from not statistically significant to statistically significant.

The original failed analysis and the unblinded selection process were allegedly never disclosed to the FDA during the approval process. The European Medicines Agency (EMA) has also begun reviewing Tavneos over similar data integrity concerns. As of May 2026, Tavneos remains on the market while Amgen considers whether to request a formal hearing before the FDA Commissioner.

Settlements & Verdicts

Tavneos personal injury litigation is in its earliest stages. Law firms across the country are actively investigating and accepting cases, but no major settlements or jury verdicts have been announced. No multidistrict litigation (MDL) or class action has been established yet.

Settlement values in Tavneos cases will likely depend on factors such as the severity of liver injury, whether surgery or transplant was required, duration of hospitalization, medical expenses, lost income, and pain and suffering. Wrongful death cases carry additional damages. A qualified attorney can assess the potential value of your specific case during a free review.

How to File a Tavneos Claim

Filing a Tavneos lawsuit through LegalCove is straightforward and costs nothing upfront. Attorneys in our network work on a contingency fee basis, meaning you only pay if your case results in compensation.