Definium’s DT120 Generalized Anxiety Disorder Trial Meets Primary Endpoint in Phase 3 Panorama Study

Definium Therapeutics has reported positive topline results from Panorama, the second Phase 3 trial in its DT120 generalized anxiety disorder (GAD) programme. The study met its primary endpoint and all three key secondary efficacy endpoints, giving the company a third positive Phase 3 readout for DT120 ODT, its lysergide-based oral disintegrating tablet.

DT120 generalized anxiety disorder: the Panorama results

Panorama (MM120-301) was a Phase 3, multicenter, randomized, double-blind, placebo-controlled study in adults aged 18 to 74 with a DSM-5-confirmed primary diagnosis of GAD and a minimum HAM-A total score of 20 at screening and baseline. Participants were randomized 2:1:2 to a single dose of DT120 ODT 100 µg, DT120 ODT 50 µg, or matching placebo. The study ran a 12-week double-blind treatment period (Part A) followed by a 40-week open-label extension (Part B), during which participants could receive up to four additional doses, for a total of about 56 weeks. Panorama enrolled 245 participants across approximately 32 study centers.

The primary endpoint measured the change from baseline in the Hamilton Anxiety Rating Scale (HAM-A) total score at Week 12. Participants who received DT120 ODT 100 µg posted a least-squares (LS) mean change of -9.8, against -4.7 for placebo. The placebo-adjusted difference of -5.1 points was statistically significant (p<0.0001), with a standardized effect size of 0.64. Efficacy appeared quickly, with changes seen as early as Day 2 and sustained at every post-baseline timepoint in Part A of the trial.

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Baseline HAM-A scores were well matched across groups, at 28.3 for the DT120 ODT 100 µg arm (n=96) and 28.0 for placebo (n=97). The three multiplicity-controlled key secondary endpoints also reached statistical significance:

Response and remission measures told a similar story. At Week 12, 32% of the DT120 ODT 100 µg group achieved a HAM-A response (a reduction of 50% or more), against 14% for placebo. Remission, defined as a HAM-A score of 7 or lower, was reached by 15% versus 4%, and 35% versus 17% reached a score below 16, classed as mild or better.

A DT120 ODT 50 µg control arm (n=52) was included to help limit functional unblinding and was not powered for statistical comparison. It produced placebo-adjusted changes of -3.5 at Week 4 and -3.6 at Week 12, consistent with the dose-response profile seen in the Phase 2b trial.

A monitored dosing model

DT120 ODT is not a daily pill. Participants were monitored for a minimum of 8 hours on the dosing day and assessed hourly from hour 5 onward against a structured end-of-session checklist (EoSC). The average time to meet the EoSC criteria was 6.2 hours, with a median of 6.0 hours and 94% of participants clearing the checklist by hour 8. Across more than 1,000 treatment sessions in the Phase 3 programme through 10 September 2026, 97% met the criteria by hour 8.

That supervised, episodic delivery model sits at the heart of the treatment’s market access story. If a single dose can hold a response for months, as the company’s data suggest, the therapy would shift the burden away from daily adherence and toward a structured, facility-based service, which payers would need to reimburse differently from a conventional daily prescription.

Scott Aaronson, Chief Science Officer at the Institute for Advanced Diagnostics and Therapeutics at Sheppard Pratt and a Panorama investigator, noted that people with GAD often try two or three medications before finding one they can tolerate, and that daily dosing carries its own burden of sedation, weight change, sexual side effects and, for some drug classes, dependence risk. What sets DT120 ODT apart, he said, is the possibility that a single dose could hold a response for months without the patient managing a pill every day.

The burden of generalized anxiety disorder

GAD is one of the most common psychiatric disorders, affecting roughly 26 million US adults. People with the condition experience persistent, hard-to-control worry, alongside fatigue, muscle tension, trouble concentrating and difficulty sleeping. The disorder is linked to other chronic physical illnesses and to depression and other anxiety disorders, and it drives substantial functional, economic and quality-of-life burdens plus higher healthcare use and costs.

Despite that burden, treatment innovation has been thin. The last new drug approval for GAD came in 2007.

Next steps toward approval

Definium plans a pre-NDA meeting with the FDA in the fourth quarter of 2026, with an NDA filing anticipated in the first half of 2027. Chief Executive Officer Rob Barrow said the results confirmed the efficacy of DT120 in GAD and that the company is advancing toward an NDA submission after the upcoming pre-NDA meeting.

Source: Definium Therapeutics, Inc. press release, 14 September 2026.