Biotech Definium reports another phase III success for anxiety disorder therapy

Shares of Definium Therapeutics, a biotech specializing in psychedelic medicine, gained 3.5% on Monday after the company reported positive late-stage trial results for an LSD tablet in patients with generalized anxiety disorder and announced plans to file for approval of the drug. The stock has already tripled since the beginning of the this year.

Definium Therapeutics rose 3.5% on the Nasdaq on Monday to $40.25 per share. In premarket trading Tuesday, they were up another roughly 1.2% as of this writing.

The company reported positive results from a phase III trial of DT120, a drug it is developing to treat psychiatric disorders. The study evaluated the drug in patients with generalized anxiety disorder. This marked the second successful phase III trial of the drug specifically for this condition and the third overall, following positive results in major depressive disorder.

Definium describes DT120 as its proprietary and pharmaceutically optimized formulation of the psychedelic LSD, which temporarily alters perception, cognition, and emotion.

The DT120 trial, called Panorama, met its primary endpoint, Definium stated: the drug delivered around twice the improvement seen with placebo on the Hamilton Anxiety Rating Scale, a clinical tool used to assess the severity of anxiety symptoms. According to the company, patients’ scores improved by an average of 9.8 points on the 56-point HAM-A scale 12 weeks after treatment. The placebo group improved by only 4.7 points. The drug also acted quickly, Definium noted, with improvement observed as early as the second day after treatment.

A distinguishing feature of DT120 is that a single dose could potentially sustain a response for months, eliminating the need for patients to take a pill every day, said Scott Aaronson, chief science officer at the Institute for Advanced Diagnostics and Therapeutics at Sheppard Pratt, who participated in the trial. His comments were included in Definium’s statement. Patients with generalized anxiety disorder often struggle to find a medication they can tolerate, while daily dosing creates additional burdens, including weight changes and sedation, and some classes of medication can cause dependence, Aaronson noted.

Following the series of successful trials, Definium intends to file a new drug application with the U.S. Food and Drug Administration in the first half of 2027. A meeting with the FDA is scheduled for the fourth quarter of this year.

The U.S. Drug Enforcement Administration currently classifies LSD, or lysergic acid diethylamide, as a Schedule I controlled substance, a category for drugs with no currently accepted medical use and a high potential for abuse. That classification could be changing, however. In April, President Trump signed an executive order aimed at accelerating patient access to treatments for serious mental illnesses. The FDA subsequently announced a series of regulatory measures to support their development, including issuing guidance on “psychedelic drugs,” including substances that act on serotonin 2A receptors and alter perception. LSD belongs to this class.

The trial results were better than Wall Street had expected, RBC Capital Markets analyst Brian Abrahams said, according to Barron’s. In his view, Definium’s latest data could significantly reduce regulatory risk, unlock considerable growth potential for the company, and allow it to file for approval of the drug for two indications: generalized anxiety disorder and major depressive disorder.

Definium shares have tripled year to date. Wall Street analysts are bullish on Definium, with 17 “buy” ratings and one “overweight,” according to MarketWatch data. The average target price is $71.59 per share, implying 78% upside from Monday’s close.