Ad Hoc Announcement Pursuant to Art. 53 LR 

Geneva, Switzerland, May 18, 2022 - Addex Therapeutics (SIX: ADXN and Nasdaq: ADXN), a clinical-stage pharmaceutical company pioneering allosteric modulation-based drug discovery and development (the Company), announced today that it had received written notification from Nasdaq indicating that, for the last thirty consecutive business days, the bid price for the Company’s American Depositary Shares (ADSs) had closed below the minimum US$1.00 per ADS requirement for continued listing on Nasdaq under listing rule 5550(a)(2).

In accordance with Nasdaq Listing Rule 5810(c)(3)(A), Addex has been provided an initial period of 180 calendar days to regain compliance and will receive written notification if the Company achieves compliance at any time during this period. Compliance will be achieved if the bid price of the ADSs closes at US$1.00 per ADS or more for a minimum of ten consecutive business days.

Addex will monitor the bid price of its ADSs and evaluate options to regain compliance with Nasdaq’s minimum bid price rule within the compliance period. If compliance with Rule 5550(a)(2) is not regained by November 8, 2023, the Company may be eligible for an additional 180 calendar day compliance period.

Addex’s operations are not affected by the receipt of the notification letter and The Company fully intends to resolve the deficiency and regain compliance with the Nasdaq Listing Rules.

About Addex Therapeutics:
Addex Therapeutics is a clinical-stage pharmaceutical company focused on the development and commercialization of an emerging class of novel orally available, small molecule drugs known as allosteric modulators for neurological disorders. Allosteric modulators offer several potential advantages over conventional, non-allosteric molecules and may offer an improved therapeutic approach to conventional "orthosteric" small molecule or biological drugs. Addex's allosteric modulator drug discovery platform targets receptors and other proteins that are recognized as essential for therapeutic intervention. Addex's lead drug candidate, ADX71149 (mGlu2 positive allosteric modulator or PAM), developed in collaboration with Janssen Pharmaceuticals, Inc., is in a Phase 2 clinical trial for the treatment of epilepsy. Addex's second clinical program, dipraglurant (mGlu5 negative allosteric modulator or NAM), is under evaluation for future development in a range of indications. Indivior PLC has licensed Addex’s GABAB PAM program for the development of drug candidates, with a focus on substance use disorder. Addex is also advancing a broad preclinical pipeline, which includes development of a range of GABAB PAMs for CMT1A, chronic cough and several types of pain, mGlu7 NAM for stress related disorders, mGlu2 NAM for mild neurocognitive disorders and depression, M4 PAM for schizophrenia and other forms of psychosis, as well as mGlu4 PAM and mGlu3 PAM. 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.

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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, 2022, as filed with the SEC on March 30, 2023, 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.