fulvestrant + taselisib

Fulvestrant + taselisib is a combination therapy that pairs fulvestrant, a selective estrogen receptor degrader (SERD), with taselisib, a potent and selective PI3K inhibitor with greater selectivity against mutant PI3Kα isoforms than wild type PI3Kα. This combination was developed to target hormone receptor-positive (HR+), HER2-negative breast cancer, particularly in patients with PIK3CA mutations. The PI3K pathway is activated in approximately 40% of HR+ breast cancers, often via gain-of-function mutations in PIK3CA. Taselisib works by inhibiting this pathway to regulate cell growth and survival, while fulvestrant blocks estrogen receptors and degrades them, preventing hormonal stimulation of breast cancer cells.