molecules of the month

The Reviral respiratory syncytial virus (RSV) fusion inhibitor (sisunatovir) is an oral Ph. II clinical candidate that demonstrated reduction in viral load and total symptom score in RSV-infected patients and has received the Fast Track designation from the FDA. Crowded areas for development such as for RSV often lead to interesting chemical structures. This molecule is interesting because of some less common structural motifs including a potentially reactive spirocyclic cyclopropyl oxindole and a primary amine. Despite the potential for hERG inhibition, no QT effects were observed in the guinea pig model or dog telemetry studies, and the molecule was taken through human proof of concept. The paper describes the discovery and development thought process in detail and is a great…