FDA Alleges Manipulated Data in Approval of Amgen’s Autoimmune Drug

FDA Intensifies Calls for Amgen to Remove Tavneos, Citing Data Manipulation

The FDA has escalated its campaign against Amgen’s autoimmune therapy Tavneos, raising serious allegations about the integrity of clinical data that led to the drug’s approval nearly five years ago. The agency now claims the drug’s pivotal study results were manipulated to make the treatment appear effective.

“New information that only became known to CDER [Center for Drugs Evaluation and Research] more than three years after approval shows that unblinded study personnel manipulated the results of the pivotal clinical study so the drug looked effective when the original analysis did not support that conclusion,” the FDA said in a statement released Monday.

While making these significant allegations, the FDA did not provide specific evidence supporting its claims. The agency further accused Amgen of regulatory violations by failing to disclose the original analysis in its application, stating that CDER “can no longer conclude that there is, or has ever been, a valid demonstration that Tavneos is effective.”

Amgen has defended its position, with a company spokesperson telling BioSpace: “Patient safety guides every decision we make. We remain confident in TAVNEOS as a safe and effective medicine, supported by years of clinical data and real-world evidence. Our perspective on the benefit-risk profile of TAVNEOS differs from the Agency’s. We will evaluate next steps and respond to the FDA, while keeping patient needs and support at the forefront.”

The oral complement blocker received FDA approval in October 2021 for treating severe active anti-neutrophil cytoplasmic autoantibody-associated vasculitis (ANCA vasculitis), a group of rare autoimmune inflammatory diseases that damage blood vessels. Tavneos was originally developed by ChemoCentryx before Amgen acquired the company in 2022 for $3.7 billion.

This latest announcement marks a significant escalation in tensions between the FDA and Amgen over Tavneos. The FDA first called for the drug’s withdrawal in January after discovering problems with how ChemoCentryx re-adjudicated the primary endpoint in the pivotal study supporting the drug’s application. Amgen refused this initial request.

The situation worsened in March when the FDA issued a safety alert highlighting 76 cases of liver injury and eight deaths in patients taking Tavneos. These safety signals, detected through post-marketing surveillance, showed “reasonable evidence of a causal association” with the drug, according to the agency.

While Amgen has acknowledged liver toxicity as a known risk associated with Tavneos—information that appears in the product’s label—the FDA contends that the cases outlined in its safety alert, particularly those with fatal outcomes, “represent new safety concerns.”

In its most recent statement, the FDA reiterated its mounting concerns about Tavneos’s safety profile. Despite the strengthened rhetoric and serious allegations, the agency has not yet taken formal action to force Amgen to remove the product from the market. For now, Tavneos remains available to patients and prescribers.

The dispute highlights growing tensions between pharmaceutical companies and regulatory authorities over drug safety and efficacy standards. For the rare disease community affected by ANCA vasculitis, the situation creates uncertainty about treatment options. ANCA vasculitis affects approximately 10 to 20 people per million annually in the United States, and treatments for this condition are limited.

Industry analysts note that this case could have broader implications for how clinical trial data is reviewed and validated during the approval process. The FDA’s unusual public criticism of data integrity raises questions about potential reforms to prevent similar situations in the future.

The ongoing dispute also underscores the challenges pharmaceutical companies face when acquiring smaller biotech firms and inheriting their product portfolios. Amgen’s $3.7 billion acquisition of ChemoCentryx in 2022 was largely driven by Tavneos’s market potential, which now faces significant regulatory headwinds.

As this situation develops, patient advocacy groups are closely monitoring the impact on treatment access while awaiting further evidence and potential resolution between Amgen and the FDA.