Sponsors of the pivotal study behind Amgen’s rare disease drug Tavneos saw unblinded findings for the drug and re-adjudicated data from nine patients to make the drug seem effective, according to European regulators.
After quietly pulling the marketing authorization for Amgen’s rare disease drug Tavneos last week, European regulators have released their reasoning behind the decision, flagging “serious breaches” in proper clinical trial guidelines for the drug’s pivotal program.
In particular, study personnel from ChemoCentryx—which developed Tavneos before being acquired by Amgen in 2022 for $3.7 billion—were able to see unblinded efficacy data after the study’s database had been locked “and detected that superiority at week 52 had not been demonstrated,” the European Medicines Agency said in a regulatory document posted Thursday.
“Thereafter, 9 patients were re-adjudicated based on knowledge of treatment outcomes, after which the primary analysis was rerun resulting in a change from a non-significant to a statistically significant result for superiority at week 52,” the agency continued. Not only were these changes not shared with regulators, the clinical study report that the sponsor filed “specifically stated that the unblinding process outlined in the protocol has been followed.”
The European regulator was unable to isolate the impact of this “breach” to just certain parts of Tavneos’ data package, forcing the agency to conclude that the study as a whole was unreliable and that results provided at the time of the drug’s application were “incorrect and misleading.” Given these findings, the agency “could not identify any feasible condition” where Tavneos would have a positive risk-benefit profile.
These assessments formed part of the European Commission’s decision last week to revoke Tavneos’ marketing authorization, according to a release by CSL Vifor, which owns marketing rights to the drug in the region.
Tavneos, approved for certain forms of ANCA-associated vasculitis in 2021, is under similar scrutiny from the FDA. In January, the U.S. regulator asked Amgen to voluntarily pull Tavneos from the market, citing similar problems with the drug’s pivotal study. The pharma refused, kicking off a tense back-and-forth with the regulator.
In April, the FDA renewed its request, claiming that the sponsor of Tavneos’ pivotal trial manipulated the study to make the drug look effective despite original data showing otherwise. In June, the New England Journal of Medicine retracted the paper for the Tavneos study over study integrity issues.
Amgen has since requested a hearing with the FDA, submitting a new data analysis package and patient testimony to support the clinical profile of Tavneos and its value for people with the disease.
Despite the drama, Tavneos sales continue to grow. Revenue from the drug increased 36% year-over-year to $150 million, Amgen reported in its second quarter earnings earlier this month.
