MM120 · program
Lysergide D-tartrate (MM120 / LSD) for Attention-deficit/hyperactivity disorder
Indications for MM120: Generalized anxiety disorder · Phase 3 Major depressive disorder · Phase 3 Post-traumatic stress disorder · Phase 3 Attention-deficit/hyperactivity disorder · Discontinued
MM120 (lysergide / LSD; DT120) for attention-deficit/hyperactivity disorder — a deliberately tracked NEGATIVE program. The single Phase 2a proof-of-concept study (NCT05200936, study code MMED007) tested a low-dose 'microdosing' regimen (20 ug twice weekly for 6 weeks) and MISSED its primary endpoint: the change in Adult ADHD Investigator Symptom Rating Scale (AISRS) at 6 weeks did not differ from placebo (LSD -7.1 vs placebo -8.9 points; p=0.7145). Repeated low-dose LSD was safe/tolerable but showed no efficacy advantage. Results were published in JAMA Psychiatry (June 2025). MindMed (now Definium Therapeutics) did not advance MM120 to Phase 3 in ADHD, focusing instead on generalized anxiety disorder (lead) and major depressive disorder; the ADHD program is treated as discontinued.
Development timeline
- FinancingDefinium Therapeutics closes upsized $805M public equity offering (~$758M net) funding DT120 program↗
- missedPhase 2a microdosing trial fails: repeated low-dose MM120 (LSD) no better than placebo for adult ADHD (AISRS p=0.7145)↗
- Licensing dealCatalent grants MindMed exclusive license to Zydis ODT technology for MM-120 (lysergide)↗
- Phase 2a proof-of-concept ADHD study (NCT05200936 / MMED007) completed (study completion date 2023-12-04; primary completion 2023-11-06).
Readouts
- 2025-03-19ReportedFull resultsmissedNCT05200936
Phase 2a microdosing trial fails: repeated low-dose MM120 (LSD) no better than placebo for adult ADHD (AISRS p=0.7145) ↗
Clinical trials in Attention-deficit/hyperactivity disorder
NCT05200936MMED007Phase 2Completedn=53
Safety and Efficacy of Repeated Low Dose d-Lysergic Acid Diethylamide (LSD) D-tartrate (MM120) as Treatment for ADHD in Adults: a Multi-center, Randomized, Double-blind, Placebo-controlled Phase 2a Proof of Concept Trial
missedprimaryChange from baseline in Adult ADHD Investigator Symptom Rating Scale (AISRS) total score at 6 weeks — LSD -7.1 points (95% CI -10.1 to -4.0) vs placebo -8.9 points (95% CI -12.0 to -5.8); AISRS ~37.4->29.6 (LSD) vs ~37.3->29.0 (placebo) (0.7145)
Primary endpoint MISSED. Repeated low-dose MM120 (LSD; 20 ug twice weekly x6 weeks) was not more efficacious than placebo in reducing adult ADHD symptoms on the AISRS at 6 weeks; both arms improved similarly. LSD was psychologically well tolerated and safe in an outpatient setting with no severe adverse effects, but showed no therapeutic advantage over placebo.
Mechanism of action
LSD acts across serotonin receptor subtypes; the company describes MM120 as a 5-HT2A partial agonist (IUPHAR classifies LSD as a full 5-HT2A agonist). Antidepressant effects attributed primarily to 5-HT2A agonism.
| Target | Action | Affinity |
|---|---|---|
| 5-HT2AprimaryHTR2A | Partial agonist | pKi 9.4ⓘ |
| 5-HT1AHTR1A | Agonist | pKi 9ⓘ |
| 5-HT2CHTR2C | Agonist | pKi 8.2ⓘ |
← Full MM120 compound page (identity, identifiers, all indications)
Sources
- Definium Therapeutics, Inc. Announces Closing of $805 Million Upsized Public Offering, Including Full Exercise of the Underwriters' Option to Purchase Additional Shares — Definium Therapeutics, Inc.
- Lysergide (LSD), Ligand 17 — IUPHAR/BPS
- MindMed Announces Exclusive License Agreement With Catalent for Its Patented Zydis Fast-Dissolve Technology for Use with MM-120 — MindMed / Definium Therapeutics
- MindMed Rebrands to Definium Therapeutics, Advancing a Leading Late-Stage Psychiatry Pipeline with Three Phase 3 Readouts Expected in 2026 — Definium Therapeutics
- Safety and Efficacy of Low Dose MM120 for ADHD Proof of Concept Trial (NCT05200936 / MMED007) — ClinicalTrials.gov
- Safety and Efficacy of Repeated Low-Dose LSD for ADHD Treatment in Adults: A Randomized Clinical Trial — JAMA Psychiatry (Mueller L, et al. 2025;82(6):555-562)