The U.S. Food and Drug Administration (FDA) has issued a complete response letter for MDMA-assisted psychotherapy (MDMA-AT) for treating post-traumatic stress disorder (PTSD) in which it calls for an additional phase 3 trial to further evaluate its safety and efficacy. As Psychiatric Times reported, this decision puts on hold what could have been a landmark approval for the treatment of PTSD with MDMA, also known as midomafetamine.

Despite the setback, Lykos Therapeutics, the company behind the MDMA-AT treatment, remains determined. Lykos has expressed confidence that the FDA's concerns could be addressed using "existing data, post...