Definium Therapeutics Reports Positive Phase 3 Results for LSD-Based Pill in Generalized Anxiety Disorder

Shares of Definium Therapeutics climbed by double digits in early trading Wednesday after the psychedelics developer announced that its lead asset, DT120, achieved positive topline results in another late-stage clinical trial. The study, dubbed VOYAGE, evaluated the orally disintegrating tablet (ODT) formulation of pharmaceutical-grade LSD in patients with generalized anxiety disorder (GAD).

Definium has been working to establish its synthetic LSD product as a potential treatment across multiple psychiatric conditions. In June, the company reported that a single dose of DT120 significantly reduced symptoms of major depressive disorder (MDD) in the Phase 3 EMERGE study. That trial also indicated the drug was generally safe and fast-acting. Leerink Partners analyst Marc Goodman described those findings as “about as good as we could have hoped for,” and projected eventual sales of $1.5 billion to $2 billion in MDD alone.

The latest data extend the drug's positive track record into GAD. Definium's VOYAGE study used a well-established 56-point scale that captures the emotional, cognitive, and physical manifestations of anxiety—including worrying thoughts, sleep difficulties, depressed mood, restlessness, muscle tension, and nausea. According to the company, patients who received a single dose of DT120 experienced a mean reduction of 11.6 points on that scale at 12 weeks post-administration.

That improvement was 5.4 points greater than the change observed in the placebo arm. It also exceeded the five-point treatment difference that Wall Street analysts had anticipated, according to Jefferies analyst Andrew Tsai.

All key secondary endpoints were met as well. Drug-treated patients showed measurable changes as early as the second day after dosing, and those effects persisted throughout the core study period.

Paul Matteis, an analyst at Stifel, characterized the outcome as a “clean win” for Definium. Shareholders appeared to concur: the company's stock traded up 15% to just above $47 per share at Wednesday's market open, before settling around $43 by mid-morning.

“While success here was mostly expected, we were pleased to see” efficacy data that were rapid and consistent with earlier testing, as well as “continued robust durability,” Matteis wrote in a client note.

Rob Barrow, Definium's CEO, said in a statement that this “unprecedented efficacy” should “raise the bar for what patients and clinicians expect from GAD treatments and reinforces our belief that DT120 has the potential to redefine care for the millions of patients in need.”

The trial did not raise any new safety concerns. Notably, there were no signals of suicidal ideation or behavior. After dosing, patients were monitored for up to eight hours. Definium reported that the average time for a patient on DT120 to meet an “end-of-session checklist,” which evaluates psychological and physical state, was 6.4 hours in the first portion of the study. By the eight-hour cutoff, 92% of participants had met the checklist criteria.

A second Phase 3 trial testing DT120 for GAD is scheduled to release data in September. In the coming year, Definium expects to report high-level results from another major depression study and to initiate a late-stage investigation in post-traumatic stress disorder (PTSD). That pipeline “sets up a compelling catalyst path for the company as they seek to bring LSD to market with rapid label expansion opportunities shortly behind,” Matteis wrote.

Evercore ISI analyst Gavin Clark-Gartner models $2 billion in peak annual sales for DT120 in GAD, plus $2 billion from major depression and $1 billion from PTSD.