Phase 2 Window Study of SAR439859 (Amcenestrant) Versus Letrozole in Post-menopausal Patients With ER+, HER2- Pre-operative Post-menopausal Primary Breast Cancer

Medical history or ongoing gastrointestinal disorders potentially affecting the absorption of SAR439859 or letrozole.

Participants unable to swallow normally and to take capsules or tablets.

Participants with known active hepatitis A, B, C infection; or hepatic cirrhosis.

Participant with any other cancer; adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer or any other cancer from which the participant had been disease free for \>3 years were allowed.

Evidence of metastatic spread by standard assessment according to local practice.

Treatment with strong Cytochrome P450 3A (CYP3A) inducers or drugs that had the potential to inhibit uridine diphosphate glucuronosyltransferase (UGT) within 2 weeks before first study treatment administration or 5 elimination half-lives whichever was longest.

Treatment with drugs that were sensitive substrates of P-glycoprotein (P-gp) or of breast cancer resistance protein (BCRP) within 2 weeks before first study treatment administration or 5 elimination half-lives whichever was longer.

Use of any investigational agent within 4 weeks prior to randomization.

Recent use of hormone replacement therapy (last dose less than or equal to \[\<=\] 30 days prior to randomization).

Prior anti-cancer treatment was not allowed unless it was then completed at least 1 year prior to inclusion into this trial.

Previous systemic or local treatment for the new primary breast cancer currently under investigation (including surgery, radiotherapy, cytotoxic and endocrine treatments).

Inadequate hematological or renal function.

Prothrombin time/international normalized ratio (INR) \>1.5 \* upper limit of normal (ULN) or outside therapeutic range if received anticoagulation that would have had affected the prothrombin time/INR.

Any of the following abnormal liver function test results: Aspartate aminotransferase \>1.5 \* ULN; Alanine aminotransferase \>1.5 \* ULN; Total bilirubin \>1.5 \* ULN.

Participants were employees of the clinical study site or other individuals directly involved in the conduct of the study, or immediate family members of such individuals.

Sensitivity to any of the study interventions, or components thereof, or drug or other allergy that, in the opinion of the Investigator, contraindicates participation in the study.

The above information was not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.

What this study is about