Compass Pathways plc (NASDAQ: CMPS) just gave investors a reason to smile. On Wednesday, the company shared topline 52-week results from the Part C phase of its Phase 3 COMP005 trial, and the stock responded by jumping more than 11%.

The study evaluates COMP360, a proprietary synthetic formulation of psilocybin, for treatment-resistant depression. The new data suggests that the therapy's benefits aren't just a flash in the pan; they appear to stick around for the long haul.

Long-Term Efficacy and Trial Structure

The trial enrolled 258 participants. In Part A, participants received either a 25 mg dose or a placebo through Week 6. Part B then evaluated a second dose of the initial assignment through Week 26. About 70% of participants continued into the open-label Part C, which spanned Weeks 26 to 52.

Among those initially randomized to the 25 mg arm, roughly 80% received an open-label dose during Part C, marking their second or third total dose. This group achieved an average 13-point reduction on the MADRS scale (a standard measure of depression severity) from baseline at Week 52. That's a meaningful drop, and it suggests that supplemental dosing can deepen responses and extend efficacy out to a full year.

Rapid Onset and Safety Results

But what about the folks who started on placebo? About 90% of them entered Part C and received their first 25 mg COMP360 dose. By the end of Part C, this cohort registered an average 10-point MADRS score drop from baseline. That's a strong signal that even a single administration can produce rapid and durable effects.

Across all Part C participants who received a 25 mg dose, researchers observed response rates of 40% to 45% and remission rates of approximately 30% at all time points in the six weeks following dosing. Safety findings in Part C were consistent with earlier phases, showing a generally well-tolerated profile with no new safety signals.

FDA Filing Underway

Compass said its rolling New Drug Application submission and review are underway, with completion expected in the fourth quarter. Subject to FDA approval, the company is targeting a commercial launch in the first half of 2027. COMP360 already holds FDA Breakthrough Therapy designation for treatment-resistant depression, which could help expedite the review process.

Compass Pathways Price Action

Shares of Compass Pathways were up 11.32% at $15.63 at the time of publication on Wednesday, according to market data.