Discovery and Optimization of Rationally Designed Bicyclic Inhibitors of Human Arginase to Enhance Cancer Immunotherapy

  • ACS Med Chem Lett. 2020 Mar 23;11(4):582-588. doi: 10.1021/acsmedchemlett.0c00058.
Matthew J Mitcheltree  1 ,  Derun Li  1 ,  Abdelghani Achab  1 ,  Adam Beard  1 ,  Kalyan Chakravarthy  1 ,  Mangeng Cheng  1 ,  Hyelim Cho  1 ,  Padmanabhan Eangoor  1 ,  Peter Fan  1 ,  Symon Gathiaka  1 ,  Hai-Young Kim  1 ,  Charles A Lesburg  1 ,  Thomas W Lyons  1 ,  Theodore A Martinot  1 ,  J Richard Miller  1 ,  Spencer McMinn  1 ,  Jennifer O'Neil  1 ,  Anandan Palani  1 ,  Rachel L Palte  1 ,  Josep Saurí  1 ,  David L Sloman  1 ,  Hongjun Zhang  1 ,  Jared N Cumming  1 ,  Christian Fischer  1
Affiliations
  • 1. Discovery Chemistry; Quantitative Biosciences; Pharmacokinetics, Pharmacodynamics, and Drug Metabolism; Computational and Structural Chemistry; Analytical Research and Development; Process Research and Development; Oncology Discovery; and External Discovery Chemistry, Merck & Co., Inc., 33 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States.
PMID: 32292567 DOI: 10.1021/acsmedchemlett.0c00058
Abstract

The action of Arginase, a metalloenzyme responsible for the hydrolysis of arginine to urea and ornithine, is hypothesized to suppress immune-cell activity within the tumor microenvironment, and thus its inhibition may constitute a means by which to potentiate the efficacy of immunotherapeutics such as anti-PD-1 checkpoint inhibitors. Taking inspiration from reported enzyme-inhibitor cocrystal structures, we designed and synthesized novel inhibitors of human Arginase possessing a fused 5,5-bicyclic ring system. The prototypical member of this class, 3, when dosed orally, successfully demonstrated serum Arginase inhibition and concomitant arginine elevation in a syngeneic mouse carcinoma model, despite modest oral bioavailability. Structure-based design strategies to improve the bioavailability of this class, including scaffold modification, fluorination, and installation of active-transport recognition motifs were explored.

Products