COMP360 · program

Psilocybin (COMP360) for Anorexia nervosa

Phase 2CompletedCOMPASS Pathways plc (CMPS)

Indications for COMP360: Treatment-resistant depression · Phase 3 Anorexia nervosa · Phase 2 Post-traumatic stress disorder · Phase 2/3 Major depressive disorder · 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.

Data current as of

Development timeline

Phase 2Oct 2022 – Nov 2024
  1. UpcomingPhase 2 anorexia nervosa proof-of-concept (NCT05481736) completed Nov 2024; topline EDE result not yet disclosed.
  2. 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

  • after primary completion (Nov 2024)DelayedTopline dataNCT05481736

    Phase 2 anorexia nervosa proof-of-concept (NCT05481736) completed Nov 2024; topline EDE result not yet disclosed.

Clinical trials in Anorexia nervosa

NCT05481736Phase 2Completedn=32

Efficacy and Safety of COMP360 Psilocybin Therapy in Anorexia Nervosa: a Proof-of-concept Study

Started Oct 2022· Primary completion Nov 2024· 📍 5 sites across 3 countries (United States, Ireland, United Kingdom)

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

FormulationRouteRegimenPharmacokinetics
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)
OralSingle doset½ 3 h · Tmax 2 h · F 52.7%

Mechanism of action (compound-wide)

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.

TargetActionAffinity
5-HT2AprimaryHTR2APartial agonistpEC50 7.6ⓘ
5-HT1AHTR1AAgonist—ⓘ
5-HT2BHTR2BAgonistpKi 8.33ⓘ
5-HT2CHTR2CAgonistpKi 6.85ⓘ
TAAR1TAAR1AgonistKi 1.4 nMⓘ

← Full COMP360 compound page (identity, identifiers, all indications)

Sources

  1. 5-HT2A/2C/1A and TAAR1 in the head-twitch response (psilocybin) — Int. J. Mol. Sci.
  2. COMPASS Pathways launches phase II clinical trial of psilocybin therapy in anorexia nervosa — Compass Pathways IR
  3. Efficacy and Safety of COMP360 Psilocybin Therapy in Anorexia Nervosa: a Proof-of-concept Study (NCT05481736) — ClinicalTrials.gov
  4. psilocin — IUPHAR/BPS Guide to Pharmacology (Ligand 11291) — IUPHAR/BPS
  5. psilocin — Ligand Activity Charts — IUPHAR/BPS
  6. Psilocybin — Wikipedia