fulvestrant + palbociclib + taselisib

The combination of fulvestrant, palbociclib, and taselisib is an investigational triplet therapy for advanced breast cancer. Fulvestrant is a selective estrogen receptor degrader (SERD) that blocks and degrades the estrogen receptor, thereby inhibiting hormone-driven tumor growth. Palbociclib is a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor that prevents cell cycle progression from G1 to S phase, leading to cell cycle arrest in cancer cells. Taselisib is a selective phosphoinositide 3-kinase (PI3K) inhibitor targeting the PI3K pathway—specifically PIK3CA mutations—which are common in hormone receptor-positive breast cancers. This triplet regimen has shown promising efficacy and manageable safety in patients with heavily pretreated PIK3CA-mutant, estrogen receptor-positive (ER+), HER2-negative advanced breast cancer[1][5][7]. The combination aims to overcome resistance mechanisms by simultaneously targeting hormonal signaling, cell cycle regulation, and PI3K pathway activation.