Compass shows safety in first psilocybin trial for PTSD, but efficacy data still to come

Readers with a keen interest in the decades-long development of psychedelic-assisted therapy could be forgiven for thinking Christmas has come early. Less than a week after the first-ever request for approval of an MDMA treatment landed on the FDA’s desk, Compass Pathways has reported phase 2 safety data from the first clinical trial of psilocybin in post-traumatic stress disorder (PTSD).

Psilocybin is the psychoactive ingredient in magic mushrooms, and Compass has been evaluating the safety and tolerability of its candidate, dubbed COMP360, in patients with PTSD. In a post-market release Dec. 19, the company reported on 22 participants in the first 24 hours after they received a 25 mg dose of the drug.

“The initial data readout … indicated that COMP360 was well-tolerated and the safety profile was as expected, with no treatment-emergent serious adverse events recorded,” the biotech said.

“Safety is of paramount importance when developing potential new treatments, so we are pleased to see these positive safety signals,” Compass’ Chief Medical Officer Guy Goodwin said in the release. “These results are consistent with findings from other studies and add to the growing body of evidence to demonstrate the potential of COMP360 in difficult-to-treat mental health conditions.”

There will be a longer wait for efficacy data, however. Compass is monitoring the patients for 12 weeks after the dosing, with further safety data as well as information on whether the drug improved the participants' PTSD expected in the spring.

The trial is being conducted on both sides of the Atlantic, namely at Icahn School of Medicine at Mount Sinai in New York City, as well as at Sunstone Therapies in Maryland and The Institute of Psychiatry, Psychology & Neuroscience at King’s College London.

“PTSD is a very distressing condition and existing treatments are not always effective. It’s encouraging to see these initial safety results for COMP360 psilocybin treatment in this patient population and we look forward to a more detailed analysis of the study next year,” James Rucker, a consultant psychiatrist who is leading the trial in London, said in the release.

PTSD is also the indication that the Multidisciplinary Association for Psychedelic Studies (MAPS) is pursuing for its MDMA medicine. The organization submitted its application to the FDA at the start of last week, marking a groundbreaking moment in the field of psychedelic research as it became the first new drug submission of a psychedelic-assisted therapy.

Compass has ambitions for psilocybin beyond PTSD. The biotech already has two phase 3 trials on the go for single-dose and repeat-dose regimens of the drug in treatment-resistant depression. Those studies are due to read out in summer 2024 and mid-2025, respectively, and follow positive phase 2 results two years ago. There’s also a phase 2 trial in anorexia nervosa.