Abstract LB317: Discovery and characterization of a next-generation FGFR inhibitor overcoming FGFR resistant mutations

Introduction: FGFRs play important roles in cancer development and inhibition of FGFR could disrupt tumor cell proliferation and growth. Four selective FGFR inhibitors have been approved (erdafitinib, pemigatinib, infigratinib, and futibatinib) and several others are in clinical development. Unfortunately upon treatment with these first-generation FGFR inhibitors, acquired resistance often develops and is frequently associated with the emergence of secondary FGFR2/3 kinase domain mutations. Therefore, selectively targeting FGFR2/3 as well as their resistant mutations may render a second-generation treatment approach for the refractory/relapsed patients. Using advanced computation-aided structural analysis and medicinal chemistry design, we have discovered a novel, next-generation, and highly selective FGFR inhibitor, ABSK121. This novel inhibitor demonstrated robust anti-tumor activity in FGFR-dependent tumor models with strong activities against not only de novo but also acquired resistant mutations. Method: ABSK121 was evaluated in biochemical and cellular proliferation experiments for its inhibition on wile type FGFR enzymatic activity and FGFR-dependent cancer cell proliferation. Its potency against FGFR mutations was also analyzed in relevant biochemical and cellular experiments. Efficacy studies were conducted in multiple tumor models to confirm its in vivo activities. Preliminary selectivity profile and ADME profiles were also evaluated. Results: ABSK121 inhibited wild type FGFRs with IC50