Federal regulators are human, and, like everyone else, they make mistakes. The public reasonably expects that, upon discovering a significant mistake, regulators will take appropriate action to correct it.
But the Food and Drug Administration (FDA) recently chose a different course of action upon realizing that it erred when approving the labeling for a drug intended for treating only blind people. Rather than simply correcting the labeling error, the FDA blundered by issuing a second approval letter that expanded the approved use of the drug beyond treatment of blind patients.
In 2013, Vanda Pharmaceuticals sought FDA approval for tasimelteon (Hetlioz) as an orphan drug, which is a medication for a very specific group of patients who have a rare medical condition. Fewer clinical trial data are required to approve orphan drugs than are needed for other medications.
Vanda requested approval of tasimelteon specifically for treatment of individuals with a rare sleep disorder known as non-24-hour sleep-wake disorder (non-24) -- and who are totally blind, with no perception of light. The relevant clinical trials were conducted only in such individuals. Non-24 is a chronic sleep disorder that occurs when individuals are unable to synchronize their internal body clock to the 24-hour light-dark cycle.
At least 26 FDA review documents, signed by 42 agency officials prior to tasimelteon's approval, explicitly stated that Vanda was seeking approval for use in totally blind patients. According to the original approval letter issued on Jan. 31, 2014, the FDA approved tasimelteon for treatment of "Non-24-hour sleep-wake disorder in blind patients without light perception." That same day, the agency issued a press release touting the drug's approval for treatment of non-24 in "totally blind individuals."
But because of an apparent major oversight by the FDA, the description of tasimelteon's approved use in the product label did not match the one found in the original approval letter. The label omitted the phrase "in blind patients without light perception," effectively expanding tasimelteon's approval to anyone diagnosed with non-24 -- widening the pool of potential users beyond patients who are totally blind.
At some time after the initial approval, the FDA realized its mistake. However, rather than simply correcting the label, the FDA compounded its original mistake by issuing a second approval letter that stated the error was in the original approval letter -- not the drug label. The second letter modified the description of the medication's approved use to match the one found in the erroneous label.
In so doing, the FDA has violated the legal standard required for drug approval. The relevant clinical trial data presented to the agency in Vanda's application did not include studies of subjects with non-24 who were not blind. Because of its failures in this matter, the FDA has allowed a potentially dangerous medication to be given to people for whom substantial evidence of the drug's safety and effectiveness is lacking.
Moreover, the exclusion of the reference to totally blind individuals in the label ultimately will facilitate off-label uses in nonblind individuals who have sleep disorders other than non-24.
On June 11, Public Citizen petitioned the agency to immediately correct the description of the approved use on the tasimelteon label to limit it to totally blind patients suffering from non-24, and then inform both patients and doctors of the change. Public Citizen also submitted a public records request seeking all documents related to the FDA's actions in this matter, including all pertinent communications with Vanda.
The FDA's retroactive decision to expand the approved use of tasimelteon to nonblind individuals, rather than simply requiring that the label be corrected, represents an unprecedented and disturbing failure on the part of the agency. It is imperative that the FDA fixes its error and explains its actions surrounding the approval of tasimelteon.