AMEERA-5: This phase III trial is trying to find the best combination of cancer drugs (SAR439859 + palbociclib, compared to letrozole + palbociclib) to improve survival in patients with ER+, HER2- advanced breast cancer who have not received prior treatment for advanced diseaseA 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

Exclusion

• 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 childbearing 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 was not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.