Whenever psilocybin and Phase 3 appear in the same headline, the internet has a tendency to skip several steps.
Phase 3 becomes “approved.” Approved becomes “legal.” Legal becomes “mushroom therapy is arriving next Tuesday.” Somewhere in the process, a clinical-development milestone turns into a small parade.
What COMPASS Pathways has actually accomplished with COMP360 is significant enough that it does not need the parade.
The company now has two positive pivotal Phase 3 trials of COMP360, its proprietary synthetic psilocybin formulation for treatment-resistant depression (TRD). The first, COMP005, was also the first Phase 3 study of a classic psychedelic to report efficacy data. That is a genuine first for the field. It is not FDA approval, and it is not a blanket verdict on every mushroom, every dose of psilocybin, or every condition currently being attached to psychedelic medicine.
Those distinctions are where the interesting story begins.
The 258-person trial that crossed the Phase 3 line
COMP005 enrolled 258 adults with treatment-resistant depression across 32 U.S. sites. In the blinded six-week portion of the study, participants were randomized to receive either a single 25 mg dose of COMP360 or placebo.
At the primary endpoint, COMPASS reported a mean 3.6-point difference on the Montgomery-Åsberg Depression Rating Scale (MADRS) favoring the 25 mg group, with a p-value below .001. In plain English: the trial met its prespecified primary efficacy endpoint, and the result was highly statistically significant.
That June 2025 result mattered because COMP005 was the first classic psychedelic Phase 3 trial to report efficacy data.
But one pivotal trial is not the same thing as a complete regulatory package.
COMPASS also ran COMP006, a larger randomized Phase 3 trial involving 581 dosed participants across North America and Europe. That study compared two fixed doses of 25 mg COMP360, given three weeks apart, with 10 mg and 1 mg comparator groups. At six weeks, the 25 mg arm again met the primary endpoint, with a reported 3.8-point advantage over the 1 mg group and a p-value below .001.
Two positive pivotal studies are substantially more important than one exciting headline. They begin to answer the question regulators care about most: can the effect be reproduced in large, controlled studies?
What exactly is COMP360?
This is one of the places where psychedelic coverage becomes sloppy very quickly.
COMP360 is not a bag of dried Psilocybe cubensis. It is a specific, synthetic, proprietary formulation of psilocybin being developed under a defined clinical protocol for a defined indication.
If it is eventually approved, the FDA approval would apply to that drug product, for the approved population, dose and conditions of use. It would not transform every psilocybin-containing mushroom into an FDA-approved antidepressant by association.
That sounds obvious when written plainly. It becomes surprisingly non-obvious after the phrase “psilocybin passes Phase 3” has ricocheted around social media for a few hours.
The same caution applies to the diagnosis. COMPASS is studying people with treatment-resistant depression—a serious form of depression that has not responded adequately to prior treatments. The trials are not evidence that every person experiencing depression should take psilocybin, nor are they a license to generalize the results to anxiety, addiction, PTSD or whatever condition happens to be trending beside a mushroom emoji.
What about the one-year data?
In September 2026, COMPASS reported 52-week topline results from the open-label Part C of COMP005. Among participants who continued into that phase and received COMP360, the company reported additional reductions in depression scores, response rates around 40–45% during the six weeks after open-label dosing, and remission rates of roughly 30% across those post-dose timepoints.
That is encouraging. It is also open-label follow-up, which means participants and investigators knew COMP360 was being administered. Open-label data can tell us useful things about durability and repeated dosing, but it does not carry the same evidentiary weight as the randomized, blinded comparison that established the primary endpoint.
This is an important habit to keep as psychedelic medicine matures: “promising” and “proven” are not synonyms, even when the promising result happens to be extremely interesting.
Phase 3 still does not mean FDA approval
COMPASS has a rolling New Drug Application submission and review underway and has said it expects to complete the submission in the fourth quarter of 2026. FDA review comes next.
The agency can approve the application. It can ask for more information. It can impose conditions. It can delay a decision. It can say no.
Regulators remain annoyingly resistant to manifestation.
PsychonautDream recently looked at the broader regulatory backdrop in The FDA Is Building a Rulebook for Psychedelics: What Actually Changed in 2026. That distinction matters here: the FDA now has final guidance specifically addressing psychedelic clinical investigations, but a regulatory framework is not an approval. Each product still has to earn its way through the process with its own evidence.
The drug is only part of the treatment
Even if COMP360 reaches approval, another question immediately appears: what exactly is being approved into the real world?
Psychedelic clinical sessions are not ordinary prescriptions in which a patient swallows a pill at breakfast and goes to work. They involve screening, preparation, hours of supervised dosing, a controlled environment and follow-up. The surrounding context matters enough that the FDA’s psychedelic-drug guidance specifically addresses issues created by the acute psychoactive experience.
Music is one small example. In many modern psychedelic trials, carefully selected music is part of the session environment—not because a playlist has been proven to cure depression, but because the subjective experience is unusually sensitive to setting. We explored that question in Music in Psychedelic Therapy: How Sound Shapes the Experience.
That leads to the problem psychedelic medicine is about to spend a lot more time discussing: infrastructure.
Who supervises treatment? How are practitioners trained? How many clinics can realistically deliver hours-long sessions? What will insurers cover? What happens outside major metropolitan areas? How will scheduling rules work if a psilocybin drug is approved while psilocybin remains federally controlled?
The laboratory can prove efficacy without answering any of those questions.
Healthcare cannot.
So how big a deal is COMPASS Phase 3?
Pretty big.
A classic psychedelic has moved through two large pivotal Phase 3 trials for treatment-resistant depression and produced positive primary efficacy results. The first involved 258 participants and was the first classic psychedelic Phase 3 study to report efficacy data. The second involved 581 participants and replicated the core finding in a different dosing design.
A rolling NDA is underway.
That would have sounded wildly optimistic during most of the decades when modern psychedelic research barely existed.
But the most interesting change may be the kind of question we are now asking.
For years the psychedelic renaissance was dominated by:
Can this possibly work?
The question is becoming:
If it works well enough for approval, how do we actually deliver it?
Less mystical.
Much harder.
And, for psychedelic medicine, a sign that the conversation has moved considerably closer to healthcare than hype.
This article is for informational purposes only and does not constitute medical advice or a recommendation to use psychedelic substances. COMP360 remains investigational and has not been approved by the FDA.