DT-0111: a novel drug-candidate for the treatment of COPD and chronic cough.

Background: Extracellular adenosine 5'-triphosphate (ATP) plays important mechanistic roles in pulmonary disorders in general and chronic obstructive pulmonary disease (COPD) and cough in particular. The effects of ATP in the lungs are mediated to a large extent by P2X2/3 receptors (P2X2/3R) localized on vagal sensory nerve terminals (both C and Aδ fibers). The activation of these receptors by ATP triggers a pulmonary-pulmonary central reflex, which results in bronchoconstriction and cough, and is also proinflammatory due to the release of neuropeptides from these nerve terminals the axon reflex. These actions of ATP in the lungs constitute a strong rationale for the development of a new class of drugs targeting P2X2/3R. DT-0111 is a novel, small, water-soluble molecule that acts as an antagonist at P2X2/3R sites.

Methods: Experiments using receptor-binding functional assays, rat nodose ganglionic cells, perfused innervated guinea pig lung preparation , and anesthetized and conscious guinea pigs were performed.

Results: DT-0111 acted as a selective and effective antagonist at P2X2/3R, that is, it did not activate or block P2YR; markedly inhibited the activation by ATP of nodose pulmonary vagal afferents ; and, given as an aerosol, inhibited aerosolized ATP-induced bronchoconstriction and cough .

Conclusions: These results indicate that DT-0111 is an attractive drug-candidate for the treatment of COPD and chronic cough, both of which still constitute major unmet clinical needs.