Addex Therapeutics (ADXN) has reported 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.
The findings build on earlier guinea pig data and highlight the potential of the company's highly selective, orally available drug candidate as a once-daily treatment option.
Study Results
In the primate model, the GABAB PAM significantly reduced citric acid-induced cough frequency, demonstrating efficacy comparable to baclofen, which is limited by side effects such as sedation and tolerance. The Addex candidate showed a wider therapeutic margin and improved tolerability.
Previous studies in guinea pigs also showed reductions in cough frequency, increased cough latency, and no signs of tolerance after repeated dosing. In comparative testing, the candidate's efficacy appeared superior to nalbuphine, baclofen, codeine, or a P2X3 inhibitor, while maintaining a favorable safety profile.
Therapeutic Context
Chronic cough is a difficult-to-treat condition with limited approved therapies. Baclofen has validated the role of GABAB receptor activation in managing cough, but its side effects restrict broader use. By targeting an allosteric site of the receptor, Addex's PAM approach aims to deliver the therapeutic benefits of Baclofen with improved selectivity, tolerability, and durability.
Company Outlook
CEO Tim Dyer emphasized that the new primate data, combined with prior preclinical findings, support the therapeutic potential of the GABAB PAM program. Addex is advancing this candidate independently for chronic cough, while its partner Indivior is developing a separate GABAB PAM program for substance use disorders.
Addex continues to build a portfolio of small-molecule allosteric modulators for neurological and psychiatric disorders, including dipraglurant for brain injury recovery and programs in schizophrenia, mood disorders, and neurodevelopmental conditions.
ADXN has traded between $5.41 and $12.05 over the past year. The stock closed Monday's trading at $7.00, up 1.57%. In pre-market trading the stock is at $6.77, down 3.29%.
Glossary
Anti-tussive: A treatment or drug that suppresses or reduce coughing.
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