Definium Therapeutics' DT120 Shows Positive Phase 3 Results for Major Depression, Stock Jumps

Definium said the Phase 3 Emerge study’s primary endpoint (MADRS at week 6) included an 8.1-point placebo-adjusted improvement, reported by the company alongside the LS mean difference of -8.1 points versus placebo.
The company reported very rapid separation from placebo: by week 1, the placebo-adjusted LS mean reduction in MADRS total score was -14.2 points.
Among the key secondary measures, Definium highlighted statistically significant improvements in Clinical Global Impressions (CGI) severity scores.
Definium said most treatment-emergent adverse events were transient and occurred on the day of dosing, with 99% classified as mild to moderate.
Beyond the Emerge trial, Definium’s broader late-stage program includes four Phase 3 trials (two for MDD and two for generalized anxiety disorder), and DT120 ODT has received FDA Breakthrough Therapy Designation for GAD.
Definium Therapeutics reported positive topline results from its Phase 3 Emerge trial of DT120, a single-dose pill for major depressive disorder, on June 22. Patients taking the 100-microgram tablet saw a 13.3-point drop in depression scores at week 6, compared to just 5.2 points for placebo — an 8.1-point placebo-adjusted difference, according to Psychiatric Times.
The stock surged more than 30% in pre-market trading on the news, according to Benzinga. The results mark the first positive Phase 3 data for a psychedelic-adjacent antidepressant taken at home, without clinical supervision.
The Emerge trial used the Montgomery-Åsberg Depression Rating Scale, or MADRS — a standard 60-point tool doctors use to measure depression severity. A lower score means fewer symptoms. By week 6, DT120 patients improved 8.1 points more than placebo patients. That gap held through week 12, according to TipRanks.
The most striking finding was speed. By week 1, DT120 patients already showed a placebo-adjusted improvement of 14.2 points — one of the fastest separations from placebo ever recorded in an MDD trial. The company also reported statistically significant gains on Clinical Global Impressions scores, a key secondary measure, Psychiatric Times reported.
DT120 is an orally disintegrating tablet — it dissolves under the tongue. Unlike SSRIs, which patients take daily for weeks before feeling better, DT120 is designed as a single dose. CEO Dr. Aris Xanthos said the drug represents "a paradigm shift in psychiatry, moving away from chronic maintenance toward rapid, sustained symptomatic relief."
The safety data was clean. In 99% of cases, side effects were mild to moderate. Most adverse events were brief and happened on the day of dosing. Discontinuation rates were below 4% — on par with placebo. Importantly, the company found zero increase in suicidal ideation, a key concern for fast-acting psychiatric drugs, according to Benzinga.
Emerge is just one part of a bigger program. Definium is running four Phase 3 trials — two for MDD and two for generalized anxiety disorder. The FDA has already granted DT120 Breakthrough Therapy Designation for GAD, a status that speeds up the review process, TipRanks reported.
The company plans to hold an End-of-Phase 3 meeting with the FDA in Q3 2026 to discuss a potential New Drug Application for MDD. If approved, DT120 would compete in a market serving an estimated 21 million American adults with MDD. Its at-home ODT format is a key advantage over intranasal rivals like Johnson & Johnson's Spravato, which requires clinical supervision.
Definium shares jumped more than 30% in pre-market trading after the announcement, adding roughly $215 million in market value within hours, according to TS2 Tech. Analysts called the week-1 data especially compelling. Jefferies analyst Roger Song described the rapid separation from placebo as the "Holy Grail" of MDD treatment.
But not everyone is bullish. Some analysts warned that Definium's cash only lasts through Q1 2027, making a dilutive stock offering likely before any NDA submission. The positive data may be a lifeline the company needed to raise more capital — but investors are watching how fast the company can burn through it on the road to approval, according to Stock Titan.
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