What New 26-Week COMP006 Data Mean for TRD, With Boadie Dunlop, MD

New 6-month data from Compass Pathways' phase 3 COMP006 trial show that patients with treatment-resistant depression (TRD) who responded but did not remit after a single dose of COMP360 psilocybin continued to gain benefit through week 26, with nearly 30% reaching remission following a second dose.^1,2 In an interview with HCPLive, investigator Boadie Dunlop, MSC, professor and chair of psychiatry and health behavior at the Medical College of Georgia at Augusta University, discussed the findings and their clinical context.

What The 26-Week Data Add to Earlier COMP005 Findings

COMP005 and COMP006 are the 2 phase 3 trials evaluating COMP360 for TRD, each designed as 52-week studies split into Part A, Part B, and Part C. Participants had current depressive episodes lasting > 3 years on average and > 6 lifetime depressive episodes.

Dunlop noted the trials are similar in design, and the newly reported week 26 outcomes are consistent between them: patients who had a partial benefit after the acute phase but were not in remission continued to improve, with many reaching remission by week 26.¹ He cautioned that granular data beyond the press release are not yet available.

Durability of Response Between Week 6 and Week 26

In COMP006, 39% of participants in the 25-mg arm achieved a clinically meaningful MADRS reduction of 25% or more by week 6, a response reported as maintained on average through week 26.¹ However, this falls short of remission.

“Getting 25% improvement in 39% of people at week 9 of treatment is…a meaningful effect,” Dunlop said. “Until it's published, it's hard to say specifically how much of a benefit or how many people are likely to benefit from the treatment.”

The Role of a Second Dose and Predicting Who Benefits

Nearly 30% of week 6 responders who had not yet remitted went on to remit after retreatment in Part B.¹ Dunlop called patient-level prediction of retreatment benefit "one of the million-dollar questions” still unanswered. He pointed to conflicting evidence from other psychedelic and ketamine research on optimal dosing intervals, noting that in COMP006, a gap of ≥ 6 weeks between doses appeared encouraging.

Serious Adverse Events Across Dose Arms

Serious adverse events occurred in 6.3% of the 1-mg arm and 5.7% of the 25-mg arm through 26 weeks, a difference Dunlop characterized as not clinically meaningful.¹ He said the finding supports confidence that most patients will tolerate COMP360 well when administered in a carefully controlled medical setting.

“It’s important to recognize that these studies [are] being done in very highly specialized centers with a lot [of] people with experience with these treatments and with a lot of support around them,” Dunlop said. “We're going to have to be very mindful and watchful as treatments move into the general practice setting [to see] whether or not serious adverse events increase in those settings.”

Compass Pathways plans to submit a New Drug Application (NDA) to the US Food & Drug Administration (FDA) in Q4.

Editor’s note: Reported disclosures for Dunlop include Otsuka Pharmaceutical Development & Commercialization and LivaNova USA.

References

1. Compass Pathways. Compass Pathways Announces Six-Month Data From Second Phase 3 Trial Confirming Rapid And Durable Profile. Compass Pathways. July 7, 2026. Accessed July 16, 2026. https://ir.compasspathways.com/News--Events-/news/news-details/2026/Compass-Pathways-Announces-Six-Month-Data-from-Second-Phase-3-Trial-Confirming-Rapid-and-Durable-Profile/default.aspx

2. Derman C. COMP360 Psilocybin Sustains Depression Benefit Through 26 Weeks. HCPLive. Published on July 7, 2026. Accessed on July 16, 2026. https://www.hcplive.com/view/comp360-psilocybin-sustains-depression-benefit-26-weeks