A Randomized, Multicenter, Double-blind Phase 3 Study of SAR439859 Plus Palbociclib Versus Letrozole Plus Palbociclib for the Treatment of Patients With ER (+), HER2 (-) Breast Cancer Who Have Not Received Prior Systemic Anti-cancer Treatment for Advanced Disease
To determine whether SAR439859 in combination with palbociclib improves progression-free survival (PFS) when compared with letrozole in combination with palbociclib in participants with ER+, HER2- advanced breast cancer who have not received any prior systemic anticancer therapies for advanced disease.
- Experimental: SAR439859 with Letrozole-matching placebo Arm
- Active Comparator: Letrozole with SAR439859-matching placebo Arm
- Adult participants with loco-regional recurrent or metastatic disease not amenable to curative treatment
- Confirmed diagnosis of ER+/HER2- breast cancer
- No prior systemic treatment for loco-regional recurrent or metastatic disease
- Measurable or non-measurable disease evaluable per Response Evaluation Criterion in Solid Tumors (RECIST) v.1.1.
- Eastern Cooperative Oncology Group (ECOG) performance status 0-1.
- Participants should be willing to provide tumor tissue
- Capable of giving informed consent