Executives from Compass Pathways (NASDAQ:CMPS) discussed recent Phase 3 results for its COMP360 psilocybin program in treatment-resistant depression (TRD), highlighting statistically significant improvements in depression scores, signs of durability through 26 weeks in a subset of patients, and what the company described as an encouraging safety profile.
Phase 3 trial designs and top-line efficacy highlights
Management reviewed two Phase 3 studies: COMP005, a placebo-controlled trial evaluating a single 25 mg administration of COMP360 with a primary endpoint at six weeks, and COMP006, a three-arm study evaluating 10 mg and 25 mg doses, with two administrations given three weeks apart and a six-week primary endpoint.
In COMP006 Part A (the primary endpoint period), the company reported statistically significant separation at every time point starting the day after administration through week six. At week six, executives cited a 3.8-point difference on MADRS between the 25 mg group and a 1 mg active comparator.
What the company said about repeat dosing and durability through 26 weeks
Beyond the six-week endpoint, management discussed longer-term follow-up from COMP005 Part B, which extends to week 26 and allows for up to one retreatment while maintaining blinding (patients originally assigned to 25 mg would receive 25 mg again; placebo would receive placebo again).
Executives said the 26-week data indicated that a subset of patients maintained clinically meaningful benefit with one or two treatments through at least six months. They pointed to outcomes among patients meeting a “clinically meaningful benefit” threshold of at least a 25% reduction in MADRS, adding that among those who received a second administration, 40% subsequently entered remission.
When asked whether a second dose primarily deepens response among existing responders or brings in additional responders, management said patient-level analyses were not yet available to make that distinction. However, they said the data supported a benefit from a second administration, whether given on the fixed three-week schedule used in COMP006 or on the variable interval used in COMP005 Part B (between weeks 10 and 14).
The company also described an overlay comparison of the first six weeks of COMP005 and COMP006, saying the 25 mg curve appeared “remarkably consistent” from baseline through week three and then showed further benefit after the second administration at week three in COMP006.
Looking ahead, executives said they would expect a similar pattern of durability in COMP006 as data mature, including for patients who receive a third administration during the Part B period. They also noted that the company has only shown results out to 26 weeks so far and referenced a 52-week Part C follow-up still to come.
Management also cited consistency across the program, saying the primary endpoint has been consistent across three trials, and that long-term follow-up from the Phase 2b study—though smaller—showed a similar six-month pattern among responders. They said COMP005 replicates that in a larger population and argued that this consistency “bodes well” for COMP006.
Responder thresholds and clinical meaning
Executives defended the use of a 25% MADRS reduction as a marker of clinical meaningfulness, stating it was based on published “crosswalk” work in an esketamine (Spravato) dataset linking changes in MADRS with other measures such as the Clinical Global Impressions-Severity (CGI-S), PHQ-9, and Sheehan Disability Scale. They said a one-point change on CGI-S is generally accepted and corresponds to roughly a six-point improvement in MADRS.
Using an average baseline MADRS around 32, management calculated that a six-point improvement is about 19%, and said a 25% threshold sits “comfortably above that,” suggesting an “outsized effect” on quality of life that would be noticeable to clinicians and patients.
They also compared responder rates across trials using the same 25% threshold, saying COMP005 showed roughly 25% of patients achieving that level of reduction, while COMP006 was “almost 40%.” Management suggested the second dose could be contributing both to deeper responses and to a higher proportion of responders, though emphasized that more detailed analysis is pending.
10 mg dose: interest from clinicians, but focus remains on 25 mg
Executives acknowledged clinician interest in a 10 mg option, particularly given that the 10 mg arm in COMP006 appeared to perform differently than in Phase 2, where it behaved “like placebo,” according to the interviewer.
However, management said the 10 mg dose showed statistical significance in only one of the company’s three trials that included it, and also did not meet what they described as a clinical relevance threshold at six weeks. They said the company’s FDA filing and planned launch are centered on the 25 mg dose. They added that the 10 mg dose is being explored in a PTSD trial.
FDA interactions, secondary endpoints, and expectations for REMS
On regulatory strategy, executives described a “very good relationship” with the FDA’s Division of Psychiatry and said the same review team has followed the program throughout development. They emphasized that the company has not taken shortcuts, citing the size and design of its Phase 3 trials and noting that more than 1,000 patients have been treated with COMP360 across studies. They also referenced supporting work across toxicology, safety, and chemistry, manufacturing, and controls (CMC).
Management addressed the company’s prior application for an FDA Commissioner’s voucher, saying it became “highly politicized” and remains unclear in process and benefit. They said they are “quite happy” with their current position, noting that the dataset discussed has been submitted to the FDA, a meeting was requested and granted, and discussions have been collaborative. They also said that because of the program’s pace and the FDA’s encouragement to submit data on a rolling basis, a voucher would not meaningfully accelerate timelines. Executives reiterated the company’s intent to pursue approval “the right way.”
On data reporting, management said the company has many secondary endpoints—including patient-reported outcomes (PROs), quality-of-life measures, and functional scales—that have not yet been fully analyzed or shared, in part due to prioritization of datasets needed for FDA interactions. They said a “richer set of data” will be disseminated through multiple channels and that the company is preparing a conference strategy for the fall. Executives also reiterated expectations for additional COMP006 Part B data in early Q3, with the possibility that some secondary outcomes could be included.
On safety monitoring and a potential Risk Evaluation and Mitigation Strategy (REMS), management said longitudinal follow-up is consistent with chronic disease management in psychiatry. They said they have been directed by the FDA to look at the Spravato REMS as a reference point and described commercial delivery as likely comparable in practice, with a licensed healthcare provider on site and a prescriber available, rather than the granular in-room requirements used in clinical trial protocols. They also pointed to existing infrastructure at Spravato sites, noting thousands of locations already provide multi-hour monitored treatments, often using multiple rooms and team-based staffing models, sometimes supplemented by in-room checks and camera monitoring.
About Compass Pathways (NASDAQ:CMPS)
Compass Pathways (NASDAQ: CMPS) is a clinical-stage biotechnology company focused on the development and commercialization of psilocybin therapy for mental health disorders. Founded in 2016 and headquartered in London with additional offices in the United States, Compass Pathways is pioneering the use of synthetic psilocybin combined with psychotherapy to address treatment-resistant depression. The company’s flagship program is a Phase IIb clinical trial evaluating COMP360, its proprietary psilocybin formulation, which has received Breakthrough Therapy designation from the U.S.
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