Definium Therapeutics, Inc. (NASDAQ:DFTX) ("Definium" or the "Company"), a late-stage clinical biopharmaceutical company developing a new generation of therapeutics intended to address the underlying causes of psychiatric and neurological disorders, today announced that the first patient has been dosed in Ascend, its second Phase 3 study evaluating DT120 ODT (lysergide tartrate) for the treatment of major depressive disorder (MDD). The Ascend study will evaluate the efficacy and safety of DT120 ODT versus placebo and is expected to enroll 175 participants in the United States.

"DT120 ODT represents a potentially transformative treatment for people living with MDD, with our findings from our DT120 Phase 2b study showing strong effects on depression symptoms," said Daniel R. Karlin, M.D. M.A., Chief Medical Officer of Definium. "Too often, existing treatments for MDD fall short, leading many patients to be treated with multiple medications without lasting relief. We expect the Ascend study to continue to build on the clinical evidence that DT120 ODT can deliver a meaningfully differentiated option for one of psychiatry's most significant unmet needs and help alter the course of the growing mental health crisis. As we rapidly approach the anticipated topline readout from our first Phase 3 Study in MDD, Emerge, we believe Definium is entering a pivotal period that could enable meaningful advances in the treatment landscape for patients living with depression and anxiety."

The design of Ascend is aligned with Emerge, as well as the Company's Phase 3 trials of DT120 ODT in generalized anxiety disorder (GAD), and is conducted in two parts: Part A, a 12-week, randomized, double-blind, placebo-controlled, parallel-group period; and Part B, a 40-week extension period during which participants will be eligible for open-label treatment with DT120 ODT based on symptom severity. As with the Company's Panorama study of DT120 ODT in GAD, participants will be randomized 2:1:2 to receive DT120 ODT 100 µg, DT120 ODT 50 µg, or placebo. The 50 µg arm is intended to confound participants' ability to accurately assess the dose condition to which they have been randomized. This approach continues to build on the Company's Phase 2b study of DT120 in GAD, which the Company believes demonstrated that DT120's clinical activity is not attributable to functional unblinding and aligns with FDA guidance on the use of complementary designs across our DT120 clinical development program. The primary endpoint of Ascend is the change from baseline on the Montgomery-Åsberg Depression Rating Scale (MADRS) at Week 6 between DT120 ODT 100 µg and placebo.