Addex GABAB PAM Candidate Demonstrates Robust Anti-Tussive Activity in Non-Human Primate Chronic Cough Model

Ad Hoc Announcement Pursuant to Art. 53 LR Geneva, Switzerland, April 21, 2026 - Addex Therapeutics (SIX: ADXN and Nasdaq: ADXN), a clinical-stage biopharmaceutical company focused on developing a portfolio of novel small molecule allosteric modulators for neurological disorders, announced today robust anti-tussive activity of its novel gamma-aminobutyric acid sub-type B receptor (GABAB) positive allosteric modulator (PAM) in a non-human primate (NHP) chronic cough model.