This agent shows promise in CCNE1-amplified cancers and in CDK4/6 inhibitor-resistant breast cancers. See related article by Dietrich et al., p. 446 (8).
Using cell-based assays, patient-derived xenografts, and transgenic mouse models, we show that INX-315 (i) promotes retinoblastoma protein hypo-phosphorylation and therapy-induced senescence (TIS) in CCNE1-amplified tumors, leading to durable control of tumor growth; (ii) overcomes breast cancer resistance to CDK4/6i, restoring cell cycle control whilst re-instating the chromatin architecture of CDK4/6i-induced TIS; and (iii) delays the onset of CDK4/6i resistance in breast cancer by driving deeper suppression of E2F targets. Our results support the clinical development of selective CDK2 inhibitors.