ADT-030, a novel PDE10 inhibitor, demonstrates potent antitumor activity in pancreatic ductal adenocarcinoma

Abstract Phosphodiesterase 10 (PDE10) has been noted to be highly expressed in multiple types of cancer and is crucial for the growth and maintenance of cancer cells found in colon, lung, and ovarian cancers. Here, we studied a novel orally bioavailable PDE10 inhibitor, ADT-030, and found that it potently inhibits the proliferation and clonogenicity of KRAS-mutant pancreatic ductal adenocarcinoma (PDAC) cells at levels that block recombinant PDE10. ADT-030 also inhibited PDAC cell motility and triggered G2/M cell cycle halt and programmed cell death. These impacts were facilitated by raised cAMP/cGMP levels, activation of PKA/PKG, reduced β-catenin and RAS signaling. Notably, ADT-030 diminished the proliferation of PDAC cells with KRAS G12D and KRAS G12C mutations that were resistant to both allele-specific and pan-RAS inhibitors. When administered orally, ADT-030 markedly decreased tumor growth, lowered the metastasis to the lungs and liver, and enhanced survival rates without causing systemic toxicity in both syngeneic and patient-derived xenograft (PDX) models of PDAC. ADT-030 also increased chemotherapy response in orthotopic PDAC models. Immune phenotyping and single-cell RNA sequencing revealed remodeling of the tumor microenvironment by ADT-030 with a more favorable anti-tumor immune profile. The findings suggest that ADT-030 holds promise as a potential drug development candidate for treating KRAS-mutant PDAC by simultaneously targeting key oncogenic signaling pathways, resulting in tumor-intrinsic and immunomodulatory effects.