Discovery of non-boronic acid Arginase 1 inhibitors through virtual screening and biophysical methods.

Inhibiting Arginase 1 (ARG1), a metalloenzyme that hydrolyzes l-arginine in the urea cycle, has been demonstrated as a promising therapeutic avenue in immuno-oncology through the restoration of suppressed immune response in several types of cancers. Most of the currently reported small molecule inhibitors are boronic acid based. Herein, we report the discovery of non-boronic acid ARG1 inhibitors through virtual screening. Biophysical and biochemical methods were used to experimentally profile the hits while X-ray crystallography confirmed a class of trisubstituted pyrrolidine derivatives as optimizable alternatives for the development of novel classes of immuno-oncology agents targeting this enzyme.

Discovery of IDO1 inhibitors containing a decahydroquinoline, decahydro-1,6-naphthyridine, or octahydro-1H-pyrrolo[3,2-c]pyridine scaffold.

A series of IDO1 inhibitors containing a decahydroquinoline, decahydro-1,6-naphthyridine, or octahydro-1H-pyrrolo[3,2-c]pyridine scaffold were identified with good cellular and human whole blood activity against IDO1. These inhibitors contain multiple chiral centers and all diastereomers were separated. The absolute stereochemistry of each isomers were not determined. Compounds 15 and 27 stood out as leads due to their good cellular as well as human whole blood IDO1 inhibition activity, low unbound clearance, and reasonable mean residence time in rat cassette PK studies.