AtaiBeckley (ATAI) Study result summary

Study background, design, and objectives

• Exploratory, randomized, double-blind, placebo-controlled Phase 2a trial evaluated oral R-MDMA (EMP-01) in 70–71 adults with moderate-to-severe social anxiety disorder (SAD) across seven UK sites, focusing on safety, tolerability, feasibility, and initial efficacy without psychotherapy.

• Participants received two in-clinic doses of EMP-01 (225 mg) or placebo, 28 days apart, with endpoints at Day 43.

• Baseline characteristics were well balanced, and central raters ensured rigor and consistency in clinical measures.

• High retention and adherence: 70 received at least one dose, 69 completed Day 43 assessments.

• The study aimed to identify early efficacy signals and establish a safety profile in a real-world SAD population.

Safety and tolerability

• EMP-01 demonstrated a favorable and manageable safety profile, with only mild or moderate adverse events and no severe or serious treatment-emergent adverse events or suicidal intent/behavior.

• Three participants discontinued due to mild/moderate adverse events, mainly related to predefined vital sign criteria or pre-existing suicidal ideation.

• Most common adverse events included nausea, headache, fatigue, dizziness, decreased appetite, and typical psychedelic effects like sensory disturbance and euphoria.

• Subjective effects were robustly psychedelic but resolved within six hours on average.

• Most adverse events resolved without intervention.

Efficacy outcomes

• EMP-01 showed a least squares mean treatment difference of 11.85 points on the LSAS versus placebo at Day 43 (Hedges' g = 0.45; p = 0.036), indicating clinically meaningful improvement.

• Improvements were observed across both LSAS Fear and Avoidance subdomains, with consistent benefits across all subscales.

• Nearly 49% of EMP-01 patients were CGI-I responders (score ≤2) at Day 43, versus 14–15% for placebo, yielding a number needed to treat (NNT) of 2.95.

• Efficacy was achieved after two doses in six weeks, matching or exceeding standard of care timelines and comparable to 8–12 weeks of daily SSRI/SNRI therapy.

• Placebo response was in line with historical SAD trials, and central raters helped mitigate unblinding.