Abstract 3099: Hnd-01: a potent inhibitor of wild type mutant BTK

Abstract

Dasatinib is an oral dual BCR/ABL and Src family tyrosine kinase inhibitor approved for use in patients with chronic myelogenous leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia. Based on the in vitro and in vivo characterization studies of dasatanib, several metabolites were identified. Dasatinib and its metabolite 20 were the major circulating species identified which represented 25.5% and 12.5% of total radioactivity in human plasma respectively. Here, we report the identification of HND-01, a small molecule inhibitor of Bruton’s tyrosine kinase (BTK) which was achieved by modifying metabolite 20 of dasatinib. Bruton’s tyrosine kinase (BTK) is a non-receptor kinase and a key regulator of the B-cell receptor (BCR) signaling pathway. BCR is critical for proliferation and survival of leukemic cells in many B cell malignancies, including chronic lymphocytic leukemia (CLL). BTK is a key target for the development of small molecule inhibitors in B cell malignancies. There are several covalent BTK inhibitors including ibrutinib that have been approved. These covalent inhibitors bind with high affinity to Cys-481 in the active site of BTK. However, some patients develop acquired resistance to ibrutinib due to Cys-481 mutation in the BTK binding site. The acquired resistance to covalent inhibitors can be overcome with the design of new reversible BTK inhibitors. The reversible BTK inhibitors will bind to different sites other than the cysteine residue of BTK and inactivate BTK. These drugs would potentially be active in the presence or absence of the cysteine-to-serine mutation. HND-01, a novel and potent reversible BTK inhibitor inhibits wild type & C481S mutant BTK with IC50 values of 0.157 nM for WTBTK and 0.032 nM for C481SBTK. HND-01 inhibits K562 cell proliferation (IC50 0.183 nM) and it is more stable than dasatinib in human liver microsomes (in vitro clearance; 142 mL/min/kg for HND-01 vs 211 mL/min/kg for dasatinib). In an established human lymphoma efficacy model (TMD-8 model), HND-01 showed stronger tumor inhibition (80.6%) than Ibrutinib (58%). These data demonstrates that HND-01 is a BTK inhibitor that is more potent with potential desirable ADME properties than ibrutinib. HND-01 was filled for international patents, China patent application # 202080030953.6, US patent application #17/636,476, EU application # EP 20853834.8, and Canada application # CA 3148436. Citation Format: Jing Zhang, Ahmed A. Samatar, Yue Tan, Shiqing Pi, Zhigang Zhou, Yan Xu, Daihong Yang. Hnd-01: a potent inhibitor of wild type mutant BTK [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3099.