Definium Therapeutics’ DT120 Meets Phase III Goals in GAD Study

Key Points

• DT120 ODT met all primary and key secondary endpoints in Definium Therapeutics’ Phase III Voyage study for generalized anxiety disorder, delivering a 5.4-point placebo-adjusted HAM-A improvement at week 12 with a 0.81 effect size.
• The treatment showed rapid, durable benefits: improvements separated from placebo by week one, while remission, response and mild-or-better symptom rates were substantially higher than with placebo. Interim extension data also indicated sustained effects and further improvement after retreatment.
• Definium reported that DT120 was generally well tolerated, with no serious adverse events, deaths or drug-related suicide signal in the treatment group. The company is preparing for potential FDA filing discussions, with upcoming results potentially supporting applications for both GAD and major depressive disorder.

Definium Therapeutics NASDAQ: DFTX reported positive top-line results from Voyage, its Phase III study evaluating a single 100 mcg dose of DT120 ODT for generalized anxiety disorder, or GAD. The company said the trial met its primary endpoint and all key secondary endpoints, showing rapid and durable improvements in anxiety symptoms through 12 weeks.

Voyage enrolled 214 participants, randomized equally between DT120 and placebo. The study’s 12-week double-blind, placebo-controlled portion was followed by a 40-week extension in which participants could receive up to four open-label DT120 doses if symptoms returned to a predefined level. Participants discontinued background antidepressant and anxiolytic medications before enrollment, and the trial did not include psychotherapy.

Primary Endpoint and Efficacy Results

The primary endpoint was the change from baseline in the Hamilton Anxiety Rating Scale, or HAM-A, total score at week 12. According to the company, DT120 produced an 11.6-point mean improvement from baseline and a 5.4-point placebo-adjusted improvement at week 12, with a Cohen’s d effect size of 0.81 and a P value of less than 0.0001.

Chief Executive Officer Rob Barrow said the company believes the result represents the largest nominal placebo-adjusted change and standardized effect size observed in a pivotal GAD study. Those comparisons were presented as the company’s assessment of the broader treatment landscape.

Definium also reported an early separation from placebo. At week one, DT120 recipients showed an 11.9-point mean improvement from baseline on the HAM-A, translating to a 7.7-point placebo-adjusted change. The company said the treatment effect remained statistically significant at every measured HAM-A time point, with P values below 0.0001.

On the Clinical Global Impression-Severity scale, or CGI-S, the company reported improvement at week 12 and a 0.8-point placebo-adjusted improvement as early as day two. Chief Medical Officer Dan Karlin said the agreement between the centrally rated HAM-A and locally assessed CGI-S supported the clinical relevance of the findings.

• At week 12, 14% of DT120-treated participants reached clinical remission, compared with 4% of placebo participants.
• Fifty-one percent of DT120 recipients achieved mild or better symptom status, compared with 23% receiving placebo.
• Forty-three percent of patients receiving DT120 met the study’s response criterion, versus 16% in the placebo group.

Karlin said subgroup analyses showed generally similar treatment effects across characteristics including sex, time since diagnosis and prior GAD medication exposure. The company highlighted results among participants who had previously received two or more GAD pharmacotherapies.

Patient Population and Safety

Approximately 90% of randomized participants completed the 12-week controlled portion of Voyage. Baseline HAM-A and CGI-S scores were 27.9 and 4.6, respectively, which the company characterized as reflecting severe anxiety. Participants reported GAD symptoms for an average of about 24 years, while the average time since diagnosis was about 12 years.

DT120 was generally well tolerated, according to Definium. Most treatment-emergent adverse events occurred on the dosing day and resolved during the treatment session. The company reported no serious adverse events in the DT120 arm, no deaths, and no suicidal or self-injurious behavior or drug-related suicide signal based on Columbia-Suicide Severity Rating Scale assessments.

One participant in the DT120 group discontinued because of a new-onset depressive episode approximately six weeks after dosing; the participant had comorbid recurrent major depressive disorder. In the placebo group, the company reported three treatment-emergent serious adverse events and one severe adverse event of diverticulitis.

The company said the average time to clear its structured end-of-session checklist was 6.4 hours, with more than half of participants clearing at six hours and 92% clearing by eight hours. Karlin said the eight-item checklist assesses factors including alertness, orientation, resolution of perceptual symptoms and ability to navigate the environment safely.

Extension Data and Regulatory Plans

In the ongoing extension phase, participants become eligible for open-label retreatment if their centrally rated HAM-A score reaches 16 or higher. Definium presented interim data through week 28, when 87 participants initially assigned to DT120 and 90 initially assigned to placebo had entered the extension.

The company said the data showed ongoing durability from the initial DT120 dose and incremental improvement following open-label retreatment. Participants who initially received placebo began to converge with the original DT120 group after receiving open-label doses, according to Karlin.

Barrow said Definium is preparing for a potential new drug application submission for DT120 ODT and continues discussions with the U.S. Food and Drug Administration regarding its filing strategy. He said a positive result from the company’s Panorama study, expected the following month, could support consideration of a filing involving both GAD and major depressive disorder indications. Definium also expects a separate MDD study, Ascend, to report top-line results in 2027 and plans to initiate Haven, a post-traumatic stress disorder study, in 2027.

About Definium Therapeutics (NASDAQ:DFTX)

Definium Therapeutics, Inc, a clinical stage biopharmaceutical company, develops novel products to treat brain health disorders. The company's lead product candidates include MM120, which is in phase 3 for the treatment of generalized anxiety disorder and attention deficit hyperactivity disorder; and DT402, a R-enantiomer of 3,4-methylenedioxymethamphetamine, which is in phase 2a clinical trials for the treatment of core symptoms of autism spectrum disorder. The company was formerly known as Mind Medicine (MindMed) Inc and changed its name to Definium Therapeutics, Inc in January 2026.

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