INX-315 + abemaciclib + fulvestrant

INX-315 + abemaciclib + fulvestrant is an investigational combination therapy under clinical evaluation for advanced or metastatic hormone receptor positive, HER2-negative (HR+/HER2-) breast cancer, particularly in patients with prior progression on CDK4/6 inhibitors and for CCNE1-amplified solid tumors. - **INX-315** is a novel, selective, oral small molecule inhibitor of cyclin-dependent kinase 2 (CDK2), under development by Incyclix Bio. It is intended to overcome resistance to prior CDK4/6 inhibitor therapies and target tumors with dysregulated cell cycling, including CCNE1 amplification[1][2][3][4]. - **Abemaciclib** is a clinically approved oral CDK4/6 inhibitor that blocks CDK4 and CDK6 kinases, thereby preventing cell cycle progression, commonly used in advanced HR+ breast cancer. - **Fulvestrant** is a selective estrogen receptor degrader (SERD), administered intramuscularly, which antagonizes and degrades estrogen receptor alpha (ER), a critical driver in HR+ breast cancer. The combination targets multiple cell cycle and endocrine pathways to maximize antitumor efficacy and overcome acquired resistance mechanisms in advanced breast cancer[2][3][4].