LONDON and NEW YORK — September 9, 2026
Compass Pathways plc announced positive topline 52-week open-label results from Part C of the Phase 3 COMP005 trial evaluating COMP360, the company’s synthetic proprietary formulation of psilocybin, in patients with treatment-resistant depression (TRD). The findings showed additional reductions in depressive symptoms following another 25 mg dose, with participants originally randomized to the 25 mg arm achieving an average 13-point reduction in MADRS score from baseline at Week 52. The data also showed that participants originally assigned to placebo experienced a meaningful response after receiving their first 25 mg COMP360 dose in Part C. Across participants who received a 25 mg open-label dose, 40%-45% achieved response and approximately 30% achieved remission during the six weeks following treatment. Compass said the safety profile remained consistent with earlier trial stages, with no new safety findings. The company continues to advance its rolling NDA submission, with final submission expected in Q4 2026 and a potential commercial launch targeted for the first half of 2027, subject to FDA approval.
Additional COMP360 Dose Extends Treatment Benefit
The COMP005 Part C findings provide further evidence that repeated COMP360 dosing may deepen and extend antidepressant benefit in TRD. The Phase 3 trial enrolled 258 participants in the United States and evaluated a single 25 mg dose against placebo in Part A, followed by an opportunity for additional dosing in Part B and open-label treatment in Part C. Approximately 70% of participants continued beyond Week 26. Among participants initially randomized to 25 mg who entered Part C, approximately 80% received another open-label 25 mg dose. These participants experienced additional meaningful reductions in MADRS scores throughout Part C, reaching an average 13-point reduction from baseline at Week 52. Compass said the results suggest that a second or third dose may further deepen clinical response and extend durability toward one year. Participants initially randomized to placebo who received their first 25 mg dose in Part C also showed a meaningful average 10-point MADRS reduction by the end of Part C, reinforcing the potential for rapid and durable activity following a single dose..
Response and Remission Rates Strengthen Clinical Profile
The response and remission findings add another important dimension to COMP360’s emerging clinical profile in difficult-to-treat depression. Among all participants receiving a 25 mg dose during open-label Part C, regardless of whether it represented their first, second or third treatment, 40%-45% response rates were observed between Day 1 and Week 6. Approximately 30% of participants achieved remission during the same period based on the trial’s predefined MADRS criteria. Compass highlighted the results as potentially relevant to future real-world use because they demonstrate continued benefit following intermittent administration rather than daily treatment. The company is developing COMP360 around a treatment model intended to move beyond the frequent dosing required by many existing depression therapies. Safety in Part C remained consistent with Parts A and B, and the company reported no new safety signals, supporting continued progression of the program toward regulatory review.
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Compass Pathways Prepares COMP360 for Regulatory Review
The new 52-week data strengthen Compass Pathways’ broader strategy to establish COMP360 as a potentially durable treatment option for patients with TRD. The company is advancing two pivotal Phase 3 trials, COMP005 and COMP006, with COMP006 evaluating fixed doses of 25 mg, 10 mg and 1 mg in 581 dosed participants across North America and Europe and allowing multiple treatments over a 52-week period. At the same time, Compass is progressing its rolling NDA submission, with final submission on track for Q4 2026 and a potential U.S. launch in the first half of 2027 if approved. The company believes the combination of rapid onset, substantial symptom reduction and durability with relatively few treatments could differentiate COMP360 from daily or frequent pharmacological approaches to TRD. With one-year COMP005 data showing continued clinical benefit, meaningful response and remission rates and a consistent safety profile, Compass Pathways is moving COMP360 closer to a potential regulatory and commercial milestone in treatment-resistant depression.
Source: Compass Pathways,press release
