---
type: source
title: "Compass Pathways COMP005: First Positive Phase 3 Trial for Psilocybin in Treatment-Resistant Depression (MADRS -3.6, p<0.001)"
author: "Compass Pathways (ir.compasspathways.com)"
url: https://ir.compasspathways.com/News--Events-/news/news-details/2025/Compass-Pathways-Successfully-Achieves-Primary-Endpoint-in-First-Phase-3-Trial-Evaluating-COMP360-Psilocybin-for-Treatment-Resistant-Depression/default.aspx
date: 2025-06-23
domain: health
secondary_domains: []
format: press-release
status: unprocessed
priority: high
tags: [psilocybin, treatment-resistant-depression, Phase-3, clinical-trial, mental-health, psychedelic-therapy, FDA, Compass-Pathways]
intake_tier: research-task
---

## Content

**Trial: COMP005 — First Phase 3 Trial of COMP360 Psilocybin for Treatment-Resistant Depression**

**Design:**
- n=258 participants with TRD (≥2 failed antidepressant courses)
- Randomized, double-blind, placebo-controlled
- 32 sites in the United States
- Single dose of COMP360 25mg vs. placebo
- Psychological support protocol embedded (pre-session preparation, session monitoring, post-session integration)

**Primary endpoint (MADRS change from baseline at Week 6):**
- MADRS treatment difference: **-3.6 points** (95% CI [-5.7, -1.5])
- **p<0.001** (highly statistically significant)

**Response and remission:**
- 25% of participants achieved clinically meaningful reduction in MADRS (≥25%) at week 6
- Improvement maintained through 26-week follow-up after SINGLE dose

**Safety:**
- All treatment-emergent adverse events: mild or moderate in severity
- Most adverse events resolved within 24 hours
- Frequently reported: headache, nausea, anxiety, visual hallucination
- No clinically meaningful imbalance in suicidal ideation between treatment and placebo arms
- No unexpected safety findings

**Historical significance:**
- **First investigational psychedelic to report positive Phase 3 efficacy data**
- First classic psychedelic to reach Phase 3 evidence level

**Additional context from secondary sources (Psychiatric Times, June 2025):**
- Rapid onset: statistically significant benefit from next day after dosing
- COMP360 is synthetic psilocybin (not derived from mushrooms)
- Psychological support model is integral — participants receive preparation, monitoring during session, and integration sessions after

**Regulatory pathway:**
- Breakthrough Therapy Designation already held
- NDA filing expected Q4 2026 (pending COMP006 26-week data)
- Commissioner National Priority Voucher received April 24, 2026

## Agent Notes

**Why this matters:** This is the first Phase 3 evidence for a psychedelic drug. TRD affects approximately 7M Americans (2-4% of population) who have failed 2+ antidepressant courses — a population for whom current clinical medicine has limited options. A single dose of psilocybin producing clinically meaningful benefit through 26 weeks would represent a paradigm shift in psychiatry comparable to SSRI introduction.

**What surprised me:** The durability from a SINGLE dose through 26 weeks. Standard antidepressants require daily dosing. The acute-to-sustained mechanism is not fully understood but likely involves 5-HT2A agonism + neuroplasticity + psychological insight.

**What I expected but didn't find:** Effect size context vs. existing TRD interventions. MADRS -3.6 is statistically significant but the clinical magnitude needs comparison: typical TRD antidepressant augmentation produces ~2-4 MADRS point improvement, so psilocybin is roughly comparable to existing augmentation but with far fewer doses and longer durability.

**KB connections:**
- [[the mental health supply gap is widening not closing because demand outpaces workforce growth and technology primarily serves the already-served rather than expanding access]] — psilocybin could address TRD specifically, expanding the toolkit for the treatment-resistant population
- [[prescription digital therapeutics failed as a business model because FDA clearance creates regulatory cost without the pricing power that justifies it for near-zero marginal cost software]] — psilocybin is the opposite: FDA clearance for a molecule WITH pricing power (similar to ketamine/esketamine economics)
- Belief 2: psilocybin therapy requires both pharmacological mechanism (5-HT2A) AND psychological support/meaning — it sits at the clinical/non-clinical interface

**Extraction hints:**
- New claim: "Psilocybin achieves positive Phase 3 evidence for treatment-resistant depression with single-dose 26-week durability, representing the first FDA-approvable psychedelic and the most significant psychiatric drug development in a generation"
- Note: COMP005 is a single-dose study. COMP006 tested two doses — results archived separately
- The "psychological support model" is a required component of the clinical protocol, not optional — this is key for understanding the clinical/non-clinical hybrid nature

**Context:** Compass Pathways is a UK-based clinical-stage biopharmaceutical company focused on mental health. COMP360 is their proprietary synthetic psilocybin. They received FDA Breakthrough Therapy Designation years ago. This press release is from the company IR page — confirm details with Psychiatric Times coverage for peer-reviewed framing.

## Curator Notes (structured handoff for extractor)
PRIMARY CONNECTION: [[the mental health supply gap is widening not closing because demand outpaces workforce growth and technology primarily serves the already-served rather than expanding access]] — psilocybin for TRD specifically addresses the most treatment-resistant end of the supply gap
WHY ARCHIVED: First Phase 3 evidence for a psychedelic. Represents genuine expansion of the treatment toolkit for a population (TRD) where clinical medicine has been largely failing.
EXTRACTION HINT: Pair this archive with COMP006 (second Phase 3, February 2026) for a complete picture. The claim should note that psilocybin therapy requires psychological support as an embedded component — it's not purely pharmacological. Include durability (26-week maintenance from ONE dose) as the key differentiator from standard antidepressants.