RLY-2608 + fulvestrant + PF-07220060

This is a **combination regimen** of three investigational/marketed drugs: - **RLY-2608**: a novel, oral, mutant- and isoform-selective allosteric inhibitor of PI3Kα (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha), designed to target oncogenic PIK3CA mutations with improved safety and antitumor activity by sparing wild-type PI3Kα. - **Fulvestrant**: an estrogen receptor antagonist used for hormone receptor-positive (HR+), HER2-negative advanced or metastatic breast cancer, administered intramuscularly. - **PF-07220060 (Atirmociclib)**: an oral, highly selective cyclin-dependent kinase 4 (CDK4) inhibitor targeting the cyclin D–CDK4/6–Rb pathway, sparing CDK6, intended to inhibit cell cycle progression in cancer cells. This triple regimen is under clinical investigation for the treatment of advanced or metastatic hormone receptor-positive, HER2-negative breast cancer with PIK3CA mutation after progression on prior standard therapies[1][2][3][4][7].

Other names

Atirmociclib + fulvestrant + RLY-2608