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One Dose, Anxiety Improvement Lasts 12 Weeks: DT120 Phase 3 Trial Meets Endpoints
Definium’s orally disintegrating lysergide formulation significantly reduced generalized anxiety symptoms with a single 100-microgram dose in a 214-person trial; the results add late-stage evidence for psychedelic drug therapy, but full safety data, the reliability of blinding, and long-term effects remain to be disclosed.
Treating generalized anxiety disorder usually means taking medication every day and repeatedly weighing efficacy, side effects, and adherence. Definium Therapeutics’ Phase 3 Voyage trial tested a very different strategy: administering DT120 only once and observing whether symptom improvement could be sustained through 12 weeks. The company said the trial met its primary endpoint and all key secondary endpoints.
Voyage enrolled 214 adults, who were randomly assigned to receive a single 100-microgram dose of DT120 or placebo in a 12-week double-blind comparison. According to the ClinicalTrials.gov registration, the primary endpoint was the change from baseline in total Hamilton Anxiety Rating Scale (HAM-A) score at Week 12; this clinician-rated scale is commonly used to measure the severity of anxiety symptoms.
Definium reported that the DT120 group improved by 5.4 points more than the placebo group at Week 12, with a statistical test result of p<0.0001 and a Cohen’s d effect size of 0.81. This indicates that the difference between the two groups was not only statistically significant but may also have been clinically meaningful; however, whether it translates into substantive improvements in patients’ daily functioning and quality of life will require more complete secondary endpoint data.
DT120 is an orally disintegrating formulation made with lysergide tartrate; lysergide, also known as LSD, acts in part by partially activating serotonin 5-HT2A receptors. Materials previously submitted by the company to the U.S. Securities and Exchange Commission show that the product uses Zydis rapid-dissolution technology, intended to provide a standardized and controllable method of drug delivery rather than relying on a conventional oral formulation.
The company said the trial identified no new safety signals, but only summary results have been released so far, without details on the types or severity of adverse events, treatment discontinuations, or acute perceptual and psychological reactions. Because drugs with pronounced subjective effects may allow participants or researchers to guess treatment assignments, whether blinding was maintained will also affect interpretation of the placebo-controlled results.
The trial registration shows that the 12-week double-blind period is followed by a 40-week extension, which will help determine whether the effects of a single treatment persist, whether repeat dosing is needed, and whether risks emerge later. As of May 1, 2026, no results had been posted on the registry page, so current assessments of efficacy and safety are based primarily on the company’s topline data and still require support from complete data and peer review.
The results take DT120 past a critical Phase 3 efficacy threshold and also support the possibility of replacing long-term daily medication with a limited number of interventions. However, one successful trial is not enough to answer every question concerning approval and clinical implementation; regulators will still examine reproducibility, long-term safety, the treatment setting, and risk management before determining whether this single-dose model can become a new option for generalized anxiety disorder.