Definium Soars As Much As 50% After LSD-Based Depression Drug Meets Late-Stage Clinical Trial Goal

Definium Therapeutics shares surged as much as 54% on Monday, reaching $37.90 in morning trading as investors reacted positively to developments in the biotech company's research pipeline and potential strategic opportunities.

Definium Therapeutics said its LSD-based depression drug, DT120, met the main goal of a mid-stage trial, reducing depression scores by 8.1 points more than placebo after six weeks, according to Reuters.

Patients showed improvement within one week after a single dose, with benefits remaining at 12 weeks. Analysts had said a 4–5 point placebo-adjusted improvement would be a strong result.

DT120, a psychedelic that activates serotonin receptors, was generally well tolerated, with mostly mild side effects occurring on dosing day and no serious safety concerns.

The trial included 149 adults with major depressive disorder, a condition affecting about 21 million U.S. adults. Recent U.S. policy has also encouraged faster development of psychedelic-based mental health treatments.

We noted back in April that psychedelic stocks were going "mainstream", pointing them out as one of the more interesting policy-driven biotech themes, arguing that a supportive regulatory backdrop could become a meaningful catalyst for the sector.

Since then, momentum has accelerated. The FDA unveiled new measures to speed research into psychedelic treatments for serious mental health conditions, while President Trump signed an executive order directing federal agencies to expand access to promising emerging therapies. The moves could accelerate development timelines for treatments targeting depression, PTSD, addiction, and other difficult-to-treat disorders.