COMP360 · program
Psilocybin (COMP360) for Anorexia nervosa
Indications for COMP360: Treatment-resistant depression · Phase 3 Post-traumatic stress disorder · Phase 2/3 Major depressive disorder · Phase 2 Anorexia nervosa · Phase 2
A Phase 2 proof-of-concept program evaluating COMP360 psilocybin therapy (25 mg vs 1 mg, with psychological support) in anorexia nervosa, an indication with no approved pharmacological treatment. The single multi-centre, double-blind, randomised, controlled trial (NCT05481736), run across UK and US sites, completed in November 2024 with 32 participants enrolled. As of mid-2026 no topline results have been publicly disclosed; Compass's reported priorities are the TRD (lead) and PTSD programs.
Development timeline
- mixedPhase 2 anorexia PoC (NCT05481736, n=32): encouraging improvement in eating-disorder symptoms sustained through 12 weeks on 25mg, but underpowered with heavy control-arm dropout↗
- NCT05481736 reached primary completion / overall completion (actual). 32 participants enrolled. No topline results disclosed as of mid-2026.
- Phase 2 proof-of-concept trial NCT05481736 started (first participant period); randomised 25mg vs 1mg COMP360 with psychological support, primary endpoint EDE global score at Week 4. Launch announced 28 Jul 2022.↗
Readouts
- 2025-08-01ReportedTopline datamixedNCT05481736
Phase 2 anorexia PoC (NCT05481736, n=32): encouraging improvement in eating-disorder symptoms sustained through 12 weeks on 25mg, but underpowered with heavy control-arm dropout ↗
Clinical trials in Anorexia nervosa
NCT05481736Phase 2Completedn=32
Efficacy and Safety of COMP360 Psilocybin Therapy in Anorexia Nervosa: a Proof-of-concept Study
pendingprimaryChange from baseline in EDE (Eating Disorder Examination) global score at Week 4 (25mg vs 1mg)
Primary endpoint of the Phase 2 proof-of-concept study. Trial reached completion (18 Nov 2024) but no results have been posted to ClinicalTrials.gov and no topline press release was found as of 25 Jun 2026.
Formulations
| Formulation | Route | Regimen | Pharmacokinetics |
|---|---|---|---|
| COMP360 oral capsule (25 mg)Immediate-release solid oral capsule (synthetic crystalline psilocybin), administered once with psychological support 25 mg single oral dose (also studied at 1 mg and 10 mg comparator doses) | Oral | Single dose | t½ 3 h · Tmax 2 h · F 52.7% |
Mechanism of action
Psilocybin is a prodrug rapidly converted in vivo to psilocin (4-OH-DMT), the active serotonergic agent. Effects are driven primarily by 5-HT2A partial agonism, with additional agonism at 5-HT2C, 5-HT1A and 5-HT2B and weaker activity at TAAR1. Reported affinities vary widely across assays.
| Target | Action | Affinity |
|---|---|---|
| 5-HT2AprimaryHTR2A | Partial agonist | pEC50 7.6ⓘ |
| 5-HT1AHTR1A | Agonist | —ⓘ |
| 5-HT2BHTR2B | Agonist | pKi 8.33ⓘ |
| 5-HT2CHTR2C | Agonist | pKi 6.85ⓘ |
| TAAR1TAAR1 | Agonist | Ki 1.4 nMⓘ |
← Full COMP360 compound page (identity, identifiers, all indications)
Sources
- 5-HT2A/2C/1A and TAAR1 in the head-twitch response (psilocybin) — Int. J. Mol. Sci.
- Compass Pathways Announces Pricing of $150 Million Public Offering (Exhibit 99.1 to Form 8-K) — COMPASS Pathways plc (SEC EDGAR)
- Compass Pathways Establishes Strategic Collaboration with Radial to Innovate Patient Experience and Inform Potential Delivery Model of COMP360 — COMPASS Pathways plc
- COMPASS Pathways launches phase II clinical trial of psilocybin therapy in anorexia nervosa — Compass Pathways IR
- Compass Pathways plc Annual Report on Form 10-K for fiscal year 2025 (Phase 2 Trial in Anorexia) — Compass Pathways
- Efficacy and Safety of COMP360 Psilocybin Therapy in Anorexia Nervosa: a Proof-of-concept Study (NCT05481736) — ClinicalTrials.gov
- Form 8-K, Items 1.01/2.03 — Third Amendment to Loan and Security Agreement with Hercules Capital, Inc. — COMPASS Pathways plc (SEC EDGAR)
- psilocin — IUPHAR/BPS Guide to Pharmacology (Ligand 11291) — IUPHAR/BPS
- psilocin — Ligand Activity Charts — IUPHAR/BPS
- Psilocybin — Wikipedia