NS-035

NS-035 is a selective P2X3 receptor antagonist being developed by Nippon Shinyaku for the treatment of refractory chronic cough. P2X3 receptors are ATP-gated ion channels located on sensory nerve fibers, particularly C-fibers in the respiratory tract. In patients with chronic cough, these receptors are thought to be hypersensitized to ATP released during airway irritation or inflammation, leading to an exaggerated cough reflex. By inhibiting these receptors, NS-035 aims to reduce the hypersensitivity of the cough reflex arc and decrease the frequency and severity of coughing episodes. As of 2024, the drug is in Phase 2 clinical development in Japan. Note that the code name NS-035 has also been associated with early-stage research into antisense oligonucleotides for Duchenne muscular dystrophy (exon 35 skipping) and historical GABA-A receptor modulators, but the P2X3 antagonist is the current primary clinical candidate.