Six Months In, Compass Pathways' Psilocybin Data Clears the Bar Lykos Couldn't

Compass Pathways says its synthetic psilocybin, COMP360, kept 39% of treatment-resistant depression patients in meaningful remission-range symptom relief six months after two doses. That’s the company’s own headline number, and it isn’t the interesting part. The interesting part is that they’re reporting six months at all.

Durability, not response rate, is the only number in psychedelic medicine worth taking seriously right now.

Here’s the actual data, straight from Compass’s July 7 disclosure and not yet independently peer-reviewed: in the 581-person COMP006 trial, 39% of the 296 people who got a 25mg dose hit a clinically meaningful drop in depression severity (MADRS score) by week 6, and that benefit held on average through week 26. Nearly 30% of those responders went into full remission after a second dose. Serious adverse events landed around 5.7% to 6.3% across arms, with nothing new flagged. The primary endpoint — a 3.8-point MADRS gap between the 25mg arm and a 1mg “comparator” arm — hit p<0.001. All of that is company-reported, from a press release, ahead of publication in a peer-reviewed journal. Treat it as a company’s claim about its own asset, not a finding the field has independently checked.

That caveat matters more here than usual, because this exact field has been burned by exactly this kind of overclaiming. When Lykos Therapeutics brought MDMA-assisted therapy for PTSD to the FDA in 2024, the agency rejected it, citing functional unblinding — patients who feel a psychedelic dose know it, so “durable” results are tangled up with expectancy effects that placebo-controlled design can’t fully separate out. Compass hasn’t solved that problem; it’s designed around it, using a 1mg dose as an active comparator instead of a true placebo, because nobody can blind a 25mg trip. The six-month readout is a genuinely harder thing to fake than a six-week one. It is not proof the underlying blinding problem is gone.

Treatment-resistant depression and substance use disorder travel together constantly — SUD roughly doubles the odds of TRD, and TRD is a major driver of relapse. A therapy that holds for six months instead of six weeks is the difference between a bridge and a stopgap for people whose depression and using are locked together. That’s also why Compass’s own stock dropped 8.3% on the day this “good news” dropped — the market read a 39% response rate as underwhelming even with durability attached, a signal that’s arguably more independent than anything in the press release itself.

A rolling NDA is underway, final submission is targeted for Q4 2026, and a commercial launch is projected for H1 2027 — contingent on both FDA approval and DEA rescheduling of a Schedule I compound, two separate bets Compass hasn’t won yet. Read more in our psychedelics and empathogens hub and the rest of our technology and innovation coverage.

Six months is a start, not a finish line. This field has earned the right to be doubted until the data comes from someone other than the company selling it.