Nov. 14, 2013
Approval of Tasimelteon Would Set Dangerous Precedent, Public Citizen Tells FDA Advisory Committee
Last-Minute, Highly Unorthodox Changes to Clinical Trial Protocol for New Sleep Medicine Threaten to Undermine Integrity of Approval Process for New Drugs
WASHINGTON, D.C. – The uncertainties generated by last-minute changes to the clinical trial protocol for the new sleep medicine tasimelteon raise serious questions about the drug’s effectiveness and, if it is approved, about the U.S. Food and Drug Administration’s (FDA’s) standards for approving new drugs, Public Citizen said today in testimony to the agency’s Peripheral and Central Nervous Systems Drugs Advisory Committee.
Approximately 10 percent of the blind cannot perceive light, which often causes their circadian rhythms, and thus their sleep patterns, to periodically deviate from a normal 24-hour day. Tasimelteon would be the first drug approved to treat the estimated 100,000 blind patients with this condition, known as non-24 hour disorder.
However, the development process for tasimelteon casts considerable doubt on whether the drug is truly effective for this disorder. In a highly unusual move, almost two years into the trial and after data on most subjects had already been collected, the manufacturer of the drug, Vanda Pharmaceuticals, Inc., proposed a complete switch of the trial’s original primary endpoint for assessing the drug’s effectiveness because it claimed that it could not recruit enough subjects into the study. By the end of the trial, the FDA and the company had not agreed upon the primary effectiveness endpoint or the statistical plan used to analyze the data.
Clinical trials are designed to test a pre-specified hypothesis. Changing the analytical plan midway through a trial raises the potential for false positive findings. That tasimelteon is a new drug being tested for a new indication further increases the chances that the drug might erroneously be deemed effective.
“The way in which the data on tasimelteon were generated and analyzed raises far more questions than answers,” said Dr. Sammy Almashat, researcher with Public Citizen’s Health Research Group. “Approval of this drug, given the magnitude of post-hoc changes so close to the end of the study, would set an ominous precedent for future new drug development programs.”
Read Public Citizen’s testimony here.