Definium reports positive Phase 3 results for single-dose DT120 in generalized anxiety disorder

Definium Therapeutics announced that its LSD-based pill, DT120, met its primary goal in a 214-patient Phase 3 trial, significantly reducing generalized anxiety disorder symptoms over 12 weeks. The single-dose treatment showed benefits within two days with mild side effects. This marks Definium's second late-stage success in two months, boosting premarket shares by over 20% amid a supportive U.S. regulatory environment for psychedelics.

DT120 Phase 3 anxiety results

• ▪Following the announcement of the DT120 trial results, Definium Therapeutics' shares rose more than 20% in premarket trading on August 12, 2026.
• ▪Definium Therapeutics announced on August 12, 2026, that its LSD-based experimental pill, DT120, significantly reduced anxiety symptoms in a late-stage study of 214 patients with generalized anxiety disorder.
• ▪In the 214-patient trial, patients receiving a single 100-microgram dose of DT120 showed an 11.6-point drop on a standard anxiety rating scale at week 12, compared to a 6.2-point drop for those on a placebo.
• ▪The placebo-adjusted difference of 5.4 points in the DT120 trial was statistically significant and clinically meaningful, according to Definium Therapeutics.
• ▪The anxiety-reducing benefit of DT120 emerged as early as two days after dosing and lasted throughout the 12-week study.
• ▪The anxiety trial represents Definium Therapeutics' second late-stage success for DT120, following a positive readout in a depression study in June 2026.

Psychedelic medicine regulatory environment

• ▪In April 2026, U.S. President Donald Trump signed an executive order directing federal agencies to speed up access to research and treatments based on psychedelic drugs for serious mental health conditions.
• ▪Regulatory and investor enthusiasm for psychedelic-based therapies has helped Definium Therapeutics' shares more than triple in value in 2026 prior to the August 12 announcement.

Generalized anxiety disorder treatment

• ▪Generalized anxiety disorder is commonly treated with antidepressants, anti-anxiety medicines, and psychotherapy.
• ▪No new drug has been approved for generalized anxiety disorder in nearly two decades, according to Cleveland Clinic psychiatrist Brian Barnett, who worked on the DT120 study.
• ▪Generalized anxiety disorder affects approximately 26 million U.S. adults and is characterized by persistent and excessive worry that interferes with daily life.

DT120 single-dose administration protocol

• ▪Most side effects of DT120 in the trial were mild to moderate and temporary, occurring mainly on the day of dosing, with no increase in suicidal thoughts.
• ▪Unlike most anxiety medicines that are taken regularly, DT120 is designed to be administered as a single dose during a monitored dosing session.

DT120 mechanism of action

• ▪DT120 works by acting on brain receptors involved in mood and perception.
• ▪Definium Therapeutics describes DT120 as a proprietary, pharmaceutically optimized LSD pill.
• ▪DT120 is a fast-dissolving tablet of lysergide, the chemical name for LSD, and belongs to a class of compounds known as psychedelic medicines.

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