Phase 2b Study Explores Efficacy of MM-120 for the Treatment of GAD


Experts shared the study results in a poster presentation at the 2024 ASCP Annual Meeting.




Sarah Karas, PhD, and colleagues shared the results from a recent phase 2b study of MM-120 (D-lysergic acid diethylamide D-tartrate) for the treatment of generalized anxiety disorder (GAD) in a poster presentation at the 2024 American Society of Clinical Psychopharmacology (ASCP) Annual Meeting. Karas is associate director of development at Mind Medicine.

According to Karas and colleagues, the study was conducted across multiple centers and included 198 adults aged 18 to 74 years, who had all been diagnosed with moderate to severe GAD, as indicated by a Hamilton Anxiety Rating Scale (HAM-A) score of 20 or higher. The participants were randomized into 5 groups to receive either a placebo or 1 of 4 doses of MM-120: 25 µg, 50 µg, 100 µg, or 200 µg.1

According to the investigators, the results of the study were promising, particularly for the 100 µg and 200 µg doses of MM-120. The 100 µg dose showed the highest clinical activity. At week 4, participants receiving this dose had a reduction of 7.6 points in their HAM-A scores compared with those who had received a placebo (-21.34 vs -13.75; P=0.0004).1

The investigators observed clinical improvements as early as 2 days post-treatment, as measured by the Clinical Global Impressions–Severity (CGI-S) scale. By this point, CGI-S scores had improved by 1.8 points in the 100 µg MM-120 group compared with 0.7 points in the placebo group (P=0.0001), with benefits persisting through the fourth week (P < 0.01).1

Approximately 77.5% of the 100 µg MM-120 group experienced a clinical response, defined as at least a 50% improvement in HAM-A scores, compared with 30.77% in the placebo group. Furthermore, 50% of those treated with 100 µg of MM-120 achieved remission (HAM-A score ≤7) versus 17.95% of the placebo group. The results also showed significant reductions in depression symptoms, as measured by the Montgomery-Asberg Depression Rating Scale, with the 100 µg MM-120 group showing greater improvement than the placebo group (-5.73; P < 0.05).1

However, treatment-emergent adverse events were noted in 97.5% of participants in the 100 µg MM-120 group compared with 56.4% in the placebo group. These events were mostly mild to moderate and occurred on the day of dosing. Common treatment-emergent adverse events included illusion, hallucination, euphoric mood, anxiety, abnormal thinking, headache, nausea, fatigue, dilated pupils, increased blood pressure, and excessive sweating. No deaths were reported.1

The investigators concluded that, “These findings suggest a rapid, robust, and durable clinical response to MM-120 in patients with GAD,” also noting that further research is necessary to fully understand the long-term safety and effects of MM-120.

The US Food and Drug Administration granted Breakthrough Designation to MM-120 for the treatment of GAD in March 2024,2 and positive topline phase 2b study results were reported for MM-120 in December 2023.3

GAD reportedly affects 6.8 million adults in the United States, although only 43.2% of individuals with GAD receive treatment.4 Explore the following and more expert discussions on GAD and other stress and anxiety disorders in Psychiatric Times®:

GAD: A Neglected Diagnosis With a New Investigational Treatment

Positive Topline Results Announced for Phase 2b Clinical Trial of GAD Treatment

First Participant Enrolled in Phase 3 Trial of Fasedienol for Social Anxiety Disorder

FDA Panel Votes Against MDMA-Assisted Therapy

The Role of Psychedelics in Psychiatry: A Conversation With Rachel Dalthorp, MD, MHSA

Navigating New Treatments for PTSD

How do you identify, treat, and manage GAD and other stress and anxiety disorders in your patients? Write to us now at to be part of the Psychiatric Times June content series on stress and anxiety.


1. Karas S, Silva R, Conant C, et al. Rapid and durable response to a single dose of MM120 (lysergide) in generalized anxiety disorder: a dose-optimization study. Poster presentation. 2024 American Society of Clinical Psychopharmacology Annual Meeting. May 29, 2024.

2. Kuntz L. FDA grants breakthrough designation to MM-120 for generalized anxiety disorder. Psychiatric Times. March 7, 2024. Accessed June 6, 2024.

3. O’Brien E. Positive topline results announced for phase 2b clinical trial of GAD treatment. Psychiatric Times. December 14, 2023. Accessed June 6, 2024.

4. Mishra AK, Varma AR. A comprehensive review of the generalized anxiety disorderCureus. 2023;15(9):e46115.

Recent Videos
brain depression
nicotine use
brain schizophrenia
eating disorder brain
© 2024 MJH Life Sciences

All rights reserved.