Definium Therapeutics Common Shares to Trade under New Nasdaq Ticker Symbol “DFTX” Effective January 15, 2026

NEW YORK--(BUSINESS WIRE)--Definium Therapeutics, Inc. (formerly Mind Medicine (MindMed) Inc.) (the "Company" or “Definium") is updating its previous announcement that the Company’s Common Shares would begin trading on Nasdaq under the ticker symbol “DFTX” effective at market open on January 13, 2026. The Company now expects its Common Shares to begin trading on Nasdaq under the ticker symbol “DFTX” effective at market open on January 15, 2026. There is no action required by the Company’s shareholders with respect to the ticker symbol change.

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 will trade on Nasdaq under the symbol “DFTX” (expected to be effective January 15, 2026).

For more information, visit www.definiumtx.com and follow Definium Therapeutics on Instagram, LinkedIn and X.

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", “aim”, "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, statements regarding the expected timing of the Company’s Common Shares to begin trading under the symbol “DFTX”. 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 but not limited to the risks, uncertainties and other factors described in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2024 and its Quarterly Reports on Form 10-Q for the fiscal quarters ended March 31, 2025, June 30, 2025 and September 30, 2025 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.