Addex Regains Rights to Phase 2 mGlu2 PAM Asset ADX71149

Ad Hoc Announcement Pursuant to Art. 53 LR

Geneva, Switzerland, April 17, 2025 - Addex Therapeutics (SIX/NASDAQ:ADXN), a clinical-stage biopharmaceutical company focused on developing a portfolio of novel small molecule allosteric modulators for neurological disorders, announced today that following the previously announced termination of development of ADX71149 (JNJ-40411813) in epilepsy, its partner Janssen Pharmaceuticals, Inc. (now known as J&J Innovative Medicine) has return all development and commercialization rights to ADX71149 (JNJ-40411813) and the partnership between the two companies has been terminated.

"ADX71149 is a high quality asset which has completed three Phase 2 studies so we are excited to regain control of its development from our partner with its high quality data package and significant material", said Tim Dyer, CEO of Addex. "We are evaluating a number of high value therapeutic indications for the future development of the program as well as pursuing discussions with a number of potential partners for the program."

About Addex:

Addex Therapeutics is a clinical-stage biopharmaceutical company focused on developing a portfolio of novel small molecule allosteric modulators for neurological disorders. Addex's lead drug candidate, dipraglurant (mGlu5 negative allosteric modulator or NAM), is under evaluation for future development in brain injury recovery, including post-stroke and traumatic brain injury recovery. Addex's partner, Indivior, has selected a GABAB PAM drug candidate for development in substance use disorders. Addex is advancing an independent GABAB PAM program for chronic cough. Addex also holds a 20% equity interest in a private company, Neurosterix LLC, which is advancing a portfolio of allosteric modulator programs, including M4 PAM for schizophrenia, mGlu7 NAM for mood disorders and mGlu2 NAM for mild neurocognitive disorders. Addex shares are listed on the SIX Swiss Exchange and American Depositary Shares representing its shares are listed on the NASDAQ Capital Market, and trade under the ticker symbol "ADXN" on each exchange. For more information, visit www.addextherapeutics.com

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Addex Forward Looking Statements:

Addex Forward Looking Statements:

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including statements about the intended use of proceeds of the offering. The words "may," "will," "could," "would," "should," "expect," "plan," "anticipate," "intend," "believe," "estimate," "predict," "project," "potential," "continue," "target" and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Any forward-looking statements in this press release, are based on management's current expectations and beliefs and are subject to a number of risks, uncertainties and important factors that may cause actual events or results to differ materially from those expressed or implied by any forward-looking statements contained in this press release, including, without limitation, uncertainties related to market conditions. These and other risks and uncertainties are described in greater detail in the section entitled "Risk Factors" in Addex Therapeutics' Annual Report on Form 20-F for the year ended December 31, 2023, as filed with the SEC on April 18, 2024, the final prospectus supplement and accompanying prospectus and other filings that Addex Therapeutics may make with the SEC in the future. Any forward-looking statements contained in this press release represent Addex Therapeutics' views only as of the date hereof and should not be relied upon as representing its views as of any subsequent date. Addex Therapeutics explicitly disclaims any obligation to update any forward-looking statements.