Discovery of Pyridine-2-Carboxamides Derivatives as Potent and Selective HPK1 Inhibitors for the Treatment of Cancer

Hematopoietic progenitor kinase 1 (HPK1) has emerged as an attractive target for immunotherapy due to its critical role in T cell activation and proliferation. The major challenge in developing HPK1 inhibitors lies in balancing kinase selectivity, pharmacokinetic (PK) properties, and therapeutic efficacy. In this study, we report a series of pyridine-2-carboxamide analogues demonstrating strong HPK1 inhibitory activity in enzymatic and cellular assays, along with good kinase selectivity. Among these analogues, compound 19 showed good in vitro HPK1 inhibitory activity, excellent kinase selectivity (>637-fold vs GCK-like kinase and >1022-fold vs LCK), and robust in vivo efficacy in the CT26 (tumor growth inhibition (TGI) = 94.3%, 2/6 CRs) and MC38 murine colorectal cancer models (TGI = 83.3%, 1/6 complete response) when administered in combination with anti-PD-1. Compound 19 also demonstrated adequate in vitro ADME and in vivo PK properties, displaying good oral bioavailability across multiple species (F % = 35–63). These findings summarize our compound's favorable safety and efficacy profiles, justifying its testing in future translational studies.