Definium's LSD-based DT120 cuts anxiety in second late-stage trial

Definium Therapeutics said on Monday that its LSD-based treatment reduced symptoms of generalized anxiety disorder (GAD) in a late-stage trial, marking a second successful study of the therapy for the condition.

A single 100-microgram dose of DT120, a fast-dissolving tablet of lysergide — the chemical name for the psychedelic drug LSD — lowered scores on an anxiety scale by 9.8 points after 12 weeks, compared with a 4.7-point decline among patients who received a placebo, the company said.

The trial enrolled 245 patients, who were assigned to receive either 100 micrograms of DT120, a lower 50-microgram dose, or placebo. The lower-dose arm was included to reduce functional unblinding, a limitation of clinical trials in which participants can accurately guess their treatment assignment because of distinctive side effects or unmistakable drug experiences. Even so, patients in both dose groups were able to correctly identify whether they had received the drug rather than placebo, CEO Robert Barrow said.

Definium said the benefits of the treatment appeared as early as the second day and were sustained through week 12. The higher dose showed greater efficacy than the 50-microgram dose, which Barrow said gives the company an easier discussion with regulators.

DT120 had also significantly reduced anxiety symptoms in the first trial, the company said in August. Barrow said having two studies confirm the drug's efficacy will raise its chances of approval, noting that roughly a dozen programs have previously attempted and failed to win approval for GAD.

GAD, characterized by persistent and excessive worry that can interfere with daily life, affects about 26 million adults in the United States and is commonly treated with antidepressants, anti-anxiety medicines and psychotherapy. Psychedelic drugs can temporarily alter perception, mood and thinking.

Regulatory and investor enthusiasm for psychedelic-based therapies has helped Definium's shares nearly triple this year. The company expects to file a marketing application with the U.S. Food and Drug Administration in the first half of 2027.