FDA Rejection of MDMA-Assisted Therapy for PTSD Divides Psychedelic Stakeholders
The US Food and Drug Administration (FDA) last week rejected the new drug application (NDA) from Lykos Therapeutics for midomafetamine (MDMA) capsules for the treatment of post-traumatic stress disorder (PTSD) in conjunction with psychotherapy, determining that “it could not be approved based on the data submitted to date.”
While Lykos did not release the contents of the complete response letter (CRL) it received from the FDA, the drug manufacturer noted that it echoed the concerns raised during the FDA Advisory Committee meeting on June 4, 2024, and requested an additional Phase 3 trial be conducted.
Chief among those concerns is the “functional unblinding” of patients receiving MDMA capsules versus placebo; due to the psychoactive effects of the drug, patients could easily deduce which capsule they received. FDA officials also expressed dissatisfaction with a “striking lack” of documentation on drug abuse potential as well as other long-term health risks.
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Despite these misgivings, Lykos and other supporters say that the positive data from the two Phase 3 trials submitted as part of the NDA far outweigh lingering questions and concerns. Together, the trials enrolled around 200 people and showed that after 3 therapy sessions with MDMA, just over 70% of participants no longer met the diagnostic criteria for PTDS, whereas just 48% of those receiving placebo showed similar gains. Data from both trials were published in Nature Medicine.
"The FDA request for another study is deeply disappointing," said Lykos CEO Amy Emerson. "While conducting another phase 3 study would take several years, we still maintain that many of the requests that had been previously discussed with the FDA…can be addressed with existing data, post-approval requirements or through reference to the scientific literature."
The rejection has sparked a wide array of reactions from supporters and opponents alike, with some expressing complete dismay at the decision while others celebrate it as an opportunity.
“The FDA’s decision is disgraceful,” said Heroic Hearts Project in a statement cited by NPR. “This is the epitome of bureaucratic red tape—and the result is people will keep dying.” Veterans have been among the most vocal proponents for approval, experiencing much higher rates of PTSD than the general population. It is estimated that nearly 13 million Americans suffer from PTSD.
From other perspectives, the rejection may ultimately lead to the later approval of more effective drug-assisted therapies. “I believe the field of psychedelic research in general requires more large-scale, controlled, and rigorous trials,” David Yaden, a psychedelics researcher at Johns Hopkins University, told Science. “Data from another phase 3 trial ‘would be valuable for policymakers, regulators, and the public.’”
Additional psychedelic therapies under study include ongoing phase 3 trials conducted by Compass Pathways and the Usona Institute, all of which are examining psilocybin’s potential to treat depression.
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