Compass Pathways Says Open-Label Phase 2 Study Shows Single 25 Mg COMP360 Psilocybin Dose Was Well Tolerated, With No Serious Adverse Events Observed, And Indicated Both Rapid And Durable Improvement In Symptoms From Baseline Observed Out To 12 Weeks Following Single Administration

Author: Benzinga Newsdesk | September 02, 2025 06:35am

Compass Pathways plc (NASDAQ:CMPS), a biotechnology company dedicated to accelerating patient access to evidence-based innovation in mental health, today announced the publication of results from an open-label Phase 2 study evaluating the safety and tolerability of a single-dose of 25 mg of investigational COMP360 synthetic psilocybin treatment in 22 patients with post-traumatic stress disorder (PTSD). The Phase 2 study findings, previously disclosed in May 2024, show that COMP360 was well tolerated and indicated both rapid and durable improvement in symptoms from baseline observed out to 12 weeks following a single administration. The international Phase 2 study was conducted across three sites in the U.K. and the U.S.

Phase 2 Primary and Key Secondary Endpoints

• Administration was well tolerated, with no serious adverse events observed. There were no treatment-emergent serious adverse events. The most common treatment-emergent adverse events included headache (n=11 or 50.0%), nausea (n=8 or 36.4%), crying (n=6 or 27.3%), fatigue (n=6 or 27.3%), and visual hallucinations (n=5 or 22.7%).
• Durable improvement in symptoms from baseline observed out to 12 weeks following a single administration. Improvement in mean CAPS-5 total score from a baseline of 47.5 was observed (29.9 point reduction at week 4 and 29.5 point reduction at week 12).
• Improvement over time in Sheehan Disability Scale (SDS) measure of functional impairment over 12 weeks. From a mean SDS total score of 22.7 at baseline, there was a 11.7 point reduction at week 4 and a 14.4 point reduction at week 12.
• High and sustained rates of response and remission relative to baseline, with early onset of symptom improvement. Response, as defined by patients experiencing a ≥ 15-point reduction from baseline on CAPS-5 total score, was 81.8% at week 4 and 77.3% at week 12. Remission, as defined by CAPS-5 total score of ≤ 20, was 63.6% at week 4 and 54.5% at week 12.

 

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