ADX71943 is a selective positive allosteric modulator of gamma-aminobutyric acid subtype B (GABA-B) receptors. GABA-B receptors mediate the slow, prolonged physiological effects of the inhibitory neurotransmitter GABA and are implicated in pain processing.
Addex Pharma said that monosodium iodoacetate (MIA) model of osteoarthritis, a model of chronic nociceptive pain, was used to assess the effects of ADX71943 on mechanical hyperalgesia (increased pain sensitivity) and mechanical allodynia (pain produced by a normally innocuous stimulus).
In the study ADX71943 was shown to reduce mechanical hyperalgesia and showed a trend toward reducing mechanical allodynia after both acute and sub-chronic (8 days) dosing. Antihyperalgesic activity was observed on the first day and was maintained on day 8, despite increased pain severity.
Addex reported previously that ADX71943 is orally efficacious in rodent models of inflammatory pain (formalin test and complete Freund’s Adjuvant-induced hypersensitivity) and visceral pain (acetic acid-induced writhing). ADX71943 also displayed an improved tolerability profile.
Vincent Mutel, CEO of Addex Pharma, said: “We believe the allosteric mechanism of ADX71943 is the key factor in the differentiated tolerability and lack of tolerance development observed in these preclinical studies. We look forward to testing this compound in humans.”