Addex Therapeutics Announces Promising Anti‑Tussive Results from GABAB PAM in Non‑Human Primate Model

Addex Therapeutics Ltd. (SIX: ADXN, Nasdaq: ADXN), a clinical‑stage biopharmaceutical company specializing in small‑molecule allosteric modulators for neurological disorders, disclosed on April 21 2026 that its lead GABAB positive allosteric modulator (PAM) has shown robust anti‑tussive activity in a non‑human primate (NHP) chronic cough model. The announcement was issued through an ad hoc release in compliance with Article 53 of the Swiss Code of Obligations.

Key Findings

  • Robust efficacy: The GABAB PAM, which is orally available and highly selective, reduced cough frequency in chronically coughing NHPs, mirroring earlier guinea‑pig data that had already indicated strong anti‑tussive potential.
  • Therapeutic advantage: Chronic cough is notoriously difficult to treat; current off‑label use of baclofen offers efficacy but is limited by dose‑dependent side effects. The new PAM’s profile suggests a once‑daily dosing regimen with fewer adverse events.
  • Strategic positioning: The data reinforce Addex’s commitment to developing next‑generation therapeutics for respiratory and neurological indications, expanding beyond its traditional neurological portfolio.

Executive Commentary

Tim Dyer, CEO of Addex, highlighted the significance of the NHP results:

“These important data in non‑human primates together with previously reported guinea pig data demonstrate the therapeutic potential of our highly selective, orally available GABAB PAM.”

He further emphasized the clinical relevance:

“Chronic cough is a difficult to treat disease in need of novel therapeutics with the efficacy of baclofen, which is used off‑label in these patients, but without the dose‑limiting side effects. Based on the data generated to date, we believe our GABAB PAM drug candidate has this therapeutic profile and the potential to be a once daily treatment.”

Market Context

While the Swiss market remained broadly quiet on the day of the announcement, the broader Swiss Market Index (SPI) recorded a modest gain of 0.215 % at 18,725.00 points, reflecting a steady market trajectory. Addex’s share price, trading at CHF 0.0434 on 19 April 2026, sits within a 52‑week range of CHF 0.0336 to CHF 0.085, underscoring the volatility typical of early‑stage biotech firms. The company’s market capitalization stands at approximately CHF 5.25 million.

Outlook

The NHP anti‑tussive data position Addex’s GABAB PAM as a compelling candidate for clinical development in chronic cough, a niche yet unmet medical need. Continued evaluation in human trials will determine whether the preclinical benefits translate into a safe, effective, and commercially viable therapy. Investors and stakeholders will likely monitor forthcoming Phase I results and potential regulatory interactions closely.

Prepared from the latest financial news releases and company fundamentals.