Amcenestrant (SAR439859) Plus Palbociclib as First Line Therapy for Patients With ER (+) HER2(-) Advanced Breast Cancer

Inclusion criteria : - 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 disease evaluable per Response Evaluation Criterion in Solid Tumors (RECIST) v.1.1 or non-measurable bone-only disease - Eastern Cooperative Oncology Group (ECOG) performance status 0-2 - Participants should be willing to provide tumor tissue - Capable of giving informed consent Exclusion criteria: - Known active brain metastases - Prior neo (adjuvant) treatment with any selective estrogen receptor degrader (SERD) - Inadequate organ and marrow function - Disease recurrence while on, or within 12 months of completion of (neo)adjuvant endocrine therapy - Pregnant, breastfeeding, or woman of child bearing potential unwilling to use recommended contraception methods - Male participants who disagree to follow contraception - Participants with advanced, symptomatic visceral spread, that are at risk of life-threatening complications in the short term - Participants with significant concomitant illness The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.