COMPASS Pathways (CMPS) Study result summary

Key study results and clinical insights

• COMP360 demonstrated rapid and durable efficacy in treatment-resistant depression (TRD), with effects evident the day after administration and sustained through 26 weeks, especially with one or two doses three weeks apart; results were consistent across two large Phase 3 trials (COMP005 and COMP006).

• In the COMP006 trial, 39% of patients in the 25 mg arm achieved a clinically meaningful reduction in depression scores at week 6, with many maintaining response through week 26; nearly 25% reached remission at 26 weeks, and nearly 30% of week 6 responders achieved remission after retreatment.

• The addition of a second dose increased response rates, with some non-remitters at week 6 becoming remitters after redosing.

• The duration of the current depressive episode was the strongest predictor of non-response in TRD.

• COMP360 is the first classic psychedelic to show rapid, durable, and reproducible effects in highly chronic TRD.

Safety and tolerability

• COMP360 was generally well tolerated, with most adverse events being transient and occurring on the day of dosing; common events included nausea, headache, anxiety, and visual hallucinations.

• Serious adverse events were low and similar across treatment arms (6.3% in 1 mg, 5.7% in 25 mg over 26 weeks), with no new safety signals identified.

• No imbalance in suicidality was observed across arms.

• The safety profile was consistent with previous studies.

Patient population and study design

• COMP006 enrolled a highly chronic TRD population, with participants experiencing current depressive episodes averaging over three years and more than six lifetime episodes.

• The trial included 581 dosed participants across North America and Europe, with three arms (1 mg, 10 mg, 25 mg) and two fixed doses three weeks apart, plus a blinded 26-week follow-up and optional redosing.

• Most participants were psychedelic-naive, aiding study blinding.

• The design allowed for real-world flexibility, with additional doses at physician discretion based on response.

• COMP006 consisted of three parts: Part A (blinded through 9 weeks), Part B (blinded through week 26), and Part C (open-label from week 26 to 52).