Compass Pathways Posts 26-Week Phase 3 COMP360 Data, Eyes H1 2027 TRD Launch

Q: Why did Compass Pathways' stock fall despite positive long-term data for its promising new depression therapy?

Compass Pathways’ shares likely fell because the 26-week update, while positive, did not materially change the investment case the way the earlier Phase 3 readout did. The key value-driving event had already happened in February, when COMP006 met its primary endpoint and showed a statistically significant week-6 benefit versus the 1 mg control. That news sent the stock up sharply because it reduced core clinical risk. By contrast, the July 7 release mainly added longer-term follow-up from Part B, where patients could be retreated and were also allowed to start oral antidepressants. Those design features made the durability data harder for investors to interpret as a clean stand-alone proof of COMP360’s long-term effect. Investors also remain focused on risks beyond efficacy. Psychedelic drug approvals still face unusual regulatory and commercial scrutiny, especially after the FDA’s 2024 rejection of MDMA-assisted therapy for PTSD. For Compass, questions remain around blinding in psilocybin trials, how retreatment will be viewed, how the therapy will be delivered at scale, and whether insurers will reimburse a monitored in-clinic treatment model. There may also have been a classic “sell the news” reaction. The long-term data were broadly expected, and the company is already targeting an H1 2027 launch with an NDA package nearing completion. When expectations are high, even good data can trigger profit-taking if they are seen as confirmatory rather than transformative.

3 articles · Updated · Psychedelic Alpha · Jul 7

26-week topline results from Part B of Compass Pathways’ COMP006 Phase 3 trial extend follow-up on COMP360 psilocybin in treatment-resistant depression, closing out the company’s Phase 3 program.
581 patients were enrolled in the larger study, which tested 1 mg, 10 mg and 25 mg doses given three weeks apart, with blinded follow-up from weeks 9 to 26.
Compass had already reported in February that COMP006 met its primary endpoint, showing a 3.8-point MADRS advantage at week 6 for 25 mg versus 1 mg.
Part B allowed eligible patients to be retreated at the same dose used in Part A and also permitted the start of an oral antidepressant during the follow-up period.
The company said the dataset supports plans to pursue a first-half 2027 launch for COMP360 in TRD.