Definium Therapeutics to Discuss Topline Results from Phase 3 Emerge Study in Major Depressive Disorder on June 22, 2026

Company to host webcast tomorrow at 8:00 a.m. EDT

NEW YORK--(BUSINESS WIRE)--Definium Therapeutics, Inc. (“Definium” or the “Company”), a late-stage clinical biopharmaceutical company developing a new generation of therapeutics intended to address underlying causes of psychiatric and neurological disorders, today announced that it will host a live webcast tomorrow at 8 a.m. EDT to discuss topline results from Emerge, its first randomized, double-blind, placebo-controlled Phase 3 study evaluating a single dose of DT120 ODT 100 µg in adults with major depressive disorder (MDD).

Webcast Details

Listeners can register for the webcast via this link. Analysts wishing to participate in the question-and-answer session should use this link. A replay of the webcast will be available via the Investor Relations section of the Definium Therapeutics website, ir.definiumtx.com, and archived for at least 30 days after the webcast. Those who plan on participating are advised to join 15 minutes prior to the start time.

About Emerge

Emerge is a Phase 3, multicenter, randomized, double-blind, placebo-controlled study evaluating the efficacy and safety of a single 100 µg dose of DT120 ODT versus placebo in participants with major depressive disorder (MDD). The study consists of a 12-week double-blind phase (Part A) followed by a 40-week open-label extension phase (Part B) during which participants may be eligible to receive DT120 ODT based on symptom severity.

The study enrolled 149 participants aged 18 to 74 years across 20 sites with a DSM-5-confirmed diagnosis of MDD, a Montgomery-Åsberg Depression Rating Scale (MADRS) total score of at least 26, and a Clinical Global Impression–Severity (CGI-S) score of at least 4 at screening and baseline.

The primary endpoint is change from baseline in the MADRS total score at Week 6. Key secondary endpoints are change from baseline in CGI-S score at Week 6, Week 12 and Day 2, and change from baseline in MADRS total score at Week 12 and Week 1.

Emerge is one of two pivotal Phase 3 studies in MDD. Ascend, the second Phase 3 study in MDD, is aligned with Emerge, but includes a low dose arm and is also 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. 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 generalized anxiety disorder (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 the Company’s DT120 clinical development program. The primary endpoint of Ascend is change from baseline in MADRS total score at Week 6 between DT120 ODT 100 µg and placebo.

About Definium Therapeutics

The mission of Definium Therapeutics is to forge a new era of psychiatry by applying scientific rigor to psychedelics, with the goal of developing accessible treatments that unlock healing at scale. Guided by a recognition that patients deserve more than better, Definium is relentlessly advancing a new generation of therapeutics intended to address underlying causes of psychiatric and neurological disorders. By turning evidence into impact, Definium aims to change the trajectory of today’s mental health care crisis and enable a healthier future. Headquartered in New York, Definium Therapeutics trades on Nasdaq under the symbol DFTX.

Forward-Looking Statements

Certain statements in this news release related to the Company constitute "forward-looking information" within the meaning of applicable securities laws and are prospective in nature. Forward-looking information is not based on historical facts, but rather on current expectations and projections about future events and are therefore subject to risks and uncertainties which could cause actual results to differ materially from the future results expressed or implied by the forward-looking statements. These statements generally can be identified by the use of forward-looking words such as "will", "may", "should", "could", "intend", "estimate", "plan", "anticipate", "expect", "believe", "potential" or "continue", or the negative thereof or similar variations. Forward-looking information in this news release includes, but is not limited to, the Company’s plans to host a live webinar to discuss topline results from the Phase 3 Emerge Study; statements regarding the Company’s beliefs regarding potential benefits of DT120 ODT; and statements regarding the design of the Phase 3 Emerge Study and the Phase 3 Ascend Study. There are numerous risks and uncertainties that could cause actual results and the Company's plans and objectives to differ materially from those expressed in the forward-looking information, including history of negative cash flows; limited operating history; incurrence of future losses; availability of additional capital; compliance with laws and regulations; legislative and regulatory developments, including decisions by the Drug Enforcement Administration and states to reschedule any of our product candidates, if approved, containing Schedule I controlled substances, before they may be legally marketed in the U.S.; difficulty associated with research and development; risks associated with clinical studies or studies; heightened regulatory scrutiny; early stage product development; clinical study risks; regulatory approval processes; novelty of the psychedelic inspired medicines industry; ability to maintain effective patent rights and other intellectual property protection; as well as those risk factors discussed or referred to herein and the risks, uncertainties and other factors described in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2025 and its Quarterly Report on Form 10-Q for the fiscal quarter ended March 31, 2026 under headings such as "Special Note Regarding Forward-Looking Statements," and "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" and other filings and furnishings made by the Company with the securities regulatory authorities in all provinces and territories of Canada which are available under the Company's profile on SEDAR+ at www.sedarplus.ca and with the U.S. Securities and Exchange Commission on EDGAR at www.sec.gov. Except as required by law, the Company undertakes no duty or obligation to update any forward-looking statements contained in this release as a result of new information, future events, changes in expectations or otherwise.