An independent research firm is reviewing data on Amgen’s Tavneos as the company prepares for a hearing later this month with the FDA which could determine whether the rare disease treatment remains on the market.
In February, the California drugmaker brought on the Duke Clinical Research Institute (DCRI) to review data from the phase 3 Advocate study, according to a letter sent earlier this month by Amgen to the FDA. The study paved the way for the 2021 approval of Tavneos
Early this year, Amgen refused a request by the FDA to stop selling Tavneos. Then six weeks ago, the agency applied more pressure when the Center for Drug Evaluation and Research (CDER) proposed to withdraw the approval of the oral medicine, saying new information indicates the trial results were “manipulated” to facilitate its green light.
ChemoCentryx was the prior owner of the drug before Amgen bought out the California biotech for $3.7 billion in 2022. The approval was the first in the 25-year history of ChemoCentryx.
CBER contends that Tavneos is not effective and that its application for approval to treat ANCA-associated vasculitis included untrue statements. In addition, CDER noted in its April letter (PDF) that it is “increasingly concerned about the safety of Tavneos,” pointing to cases of serious drug-induced liver injury (DILI).
In March, the FDA warned of the risks that could accompany use of Tavneos. Between its approval and through October, 2024, 76 cases of DILI with “reasonable evidence” of a causal association to Tavneos were reported to the FDA Adverse Event Reporting System (FAERS). Nearly all the reported cases resulted in a serious outcome, including hospitalization in 54 patients and death in eight, the FDA said.
Throughout the ordeal, Amgen has insisted that the benefits of Tavneos outweigh the risks. The drug, which is used in combination with glucocorticoids and other standard-of-care therapy, is approved for adults with severe anti-neutrophil cytoplasmic antibody-associated (ANCA) vasculitis.
The autoimmune disorder can lead to organ failure and is often fatal if not treated. With a high variability in symptoms, identifying the disease is difficult. More than 1 in 10 patients die within a year of diagnosis.
Tavneos had momentum in the market last year, drumming up sales of $462 million, an increase of 62% versus 2024. But with the recent warnings, the tide appears to be shifting as first-quarter sales were $119 million, a 22% decline sequentially.
When the FDA sent its April letter, the agency gave the company a choice of pulling the drug off the market or requesting a hearing. Amgen chose the latter, with the proceeding set for June 29. The company will submit the DCRI review leading up to the hearing.
In its letter, Amgen said that there are “few available treatment options” for ANCA and that patients who have used the drug “deserve an opportunity to make their voices heard.”
Concerns about the Advocate trial have been mounting for years, with the FDA flagging them ahead of a pr-approval advisory committee meeting back in 2021. Even though Tavneos won its FDA nod—with a narrower label than anticipated—investors filed a lawsuit in 2022 alleging that ChemoCentryx knew about the FDA’s concerns but downplayed them.
As the legal feud progressed, additional evidence emerged last year pointing to a larger data integrity issue in the trial. Despite this, Amgen was victorious defending itself in its investor lawsuit, which was dismissed eight months ago. A California judge agreed with the company’s argument that the FDA’s approval of a drug “precludes a securities fraud plaintiff from showing that a defendant’s favorable interpretation of the drug’s clinical trial data was fraudulent.”