Discovery of Imidazo[1,2-]pyrazine Derivatives as Potent ENPP1 Inhibitors.

ENPP1 acts as a negative regulator of the cGAS-STING pathway through the hydrolysis of 2'3'-cGAMP. Inhibitors of ENPP1 are regarded as promising agents for stimulating the immune response in cancer immunotherapy. This study describes the identification and optimization of imidazo[1,2-]pyrazine derivative as a highly potent and selective ENPP1 inhibitor. Compound demonstrated substantial inhibitory activity against ENPP1 with an IC value of 5.70 or 9.68 nM while showing weak inhibition against ENPP2 and ENPP3. Furthermore, compound was shown to enhance the mRNA expression of cGAMP-induced STING pathway downstream target genes, such as , , and 6. pharmacokinetic and antitumor studies showed promising results, with not only exhibiting efficient pharmacokinetic properties but also enhancing the antitumor efficacy of the anti-PD-1 antibody. Treatment with (80 mg/kg) combined with anti-PD-1 antibody achieved a tumor growth inhibition rate of 77.7% and improved survival in a murine model.