Design, synthesis and antitumor study of a series of N-Cyclic sulfamoylaminoethyl substituted 1,2,5-oxadiazol-3-amines as new indoleamine 2, 3-dioxygenase 1 (IDO1) inhibitors

  • Eur J Med Chem. 2019 Oct 1:179:38-55. doi: 10.1016/j.ejmech.2019.06.037.
Shulun Chen  1 ,  Wei Guo  2 ,  Xiaohua Liu  1 ,  Pu Sun  3 ,  Yi Wang  3 ,  Chunyong Ding  1 ,  Linghua Meng  2 ,  Ao Zhang  4
Affiliations
  • 1. CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica (SIMM), Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
  • 2. Division of Anti-tumor Pharmacology, Shanghai Institute of Materia Medica (SIMM), Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
  • 3. Division of Anti-tumor Pharmacology, Shanghai Institute of Materia Medica (SIMM), Chinese Academy of Sciences, Shanghai 201203, China.
  • 4. CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica (SIMM), Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing, 100049, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China. Electronic address: [email protected].
PMID: 31233921 DOI: 10.1016/j.ejmech.2019.06.037
Abstract

Indoleamine 2, 3-dioxygenase 1 (IDO1) plays a key role in tryptophan catabolism which is an important mechanism in immune tolerance. The small molecule epacadostat is the most advanced IDO1 Inhibitor, but its phase III trials as a single agent or in combinations with PD-1 antibody failed to show appreciable objective responses. To gain more insight on the antitumor efficacy of IDO1 inhibitors, we have designed a series of analogues of epacadostat by incorporating a cyclic aminosulfonamide moiety as the sidechain capping functionality. Compound 5a was found to display significant potency against recombinant hIDO1 and hIDO1 expressed HEK293 Cancer cells. This compound has improved physico-chemical properties, acceptable PK parameters as well as optimal cardiac safety. Similar to epacadostat, 5a is ineffective as single agent in the CT-26 syngeneic xenograft model, however, the combination of 5a with PD-1 antibody showed both elevated tumor growth inhibition and prolonged median life span.

Keywords
Immunotherapy; Indoleamine 2,3-dioxygenase; Life span; Oxadiazole; PD-1.