potent, selective NaV1.7 ion channel inhibitor
completed Ph. I in HV, discontinued in Ph. II
from optimization of known starting point
J. Med. Chem., May 26, 2020
Daiichi Sankyo, Tokyo, JP
DS-1971a is a potent, isoform-selective selective arylsulfonamide NaV1.7 inhibitor intended for the treatment of neuropathic pain. It has a surprisingly long residence time on NaV1.7, which the authors suggest contributes to better than predicted in vivo activity. 1971a is a good example of a compound which was successfully advanced to clinical trials despite a PK disconnect between rodents and higher species (much lower clearance in higher species than in both mice and rats). There’s also an enormously high bar for safety in pain indications, and in preclinical safety studies, this compound was very well-tolerated in both rodents and cynos (NOAEL = 1000 mg/kg!). It entered clinical development several years ago, and was found to be safe in healthy volunteers in a…