for people ages 18 years and up (full criteria)
study started
estimated completion



Primary Objective: To determine whether SAR439859 per os improves progression free survival (PFS) when compared with a endocrine monotherapy of the choice of the physician, in participants with metastatic or locally advanced breast cancer. Secondary Objective: - To compare the overall survival in the 2 treatment arms - To assess the objective response rate in the 2 treatment arms. - To evaluate the disease control rate in the 2 treatment arms. - To evaluate the clinical benefit rate in the 2 treatment arms. - To evaluate the duration of response in the 2 treatment arms. - To evaluate the PFS according to the estrogen receptor 1 gene (ESR1) mutation status in the 2 treatment arms. - To evaluate the pharmacokinetics of SAR439859 as single agent. - To evaluate health related quality of life in the 2 treatment arms. - To compare the overall safety profile in the 2 treatment arms.

Official Title

An Open Label Randomized Phase 2 Trial of SAR439859, Versus Endocrine Monotherapy as Per Physician's Choice in Patients With Estrogen Receptor-positive, HER2-Negative Locally Advanced or Metastatic Breast Cancer With Prior Exposure to Hormonal Therapies


The duration of the study for an individual participant will include a period to assess eligibility (screening period) of up to 4 weeks (28 days), a treatment period of at least 1 cycle (28 days of study treatment), and an end of treatment (EOT) visit at least 30 days (or until the participant receive another anticancer therapy, whichever is earlier) following the last administration of study treatment. Study treatment may continue until precluded by unacceptable toxicity, disease progression, death or upon participant's request.


Breast Cancer Metastatic Breast Neoplasms SAR439859 Endocrine monotherapy as per physician choice


You can join if…

Open to people ages 18 years and up


  • 18 years or older
  • Histological or cytological diagnosis of adenocarcinoma of the breast.
  • Locally advanced not amenable to radiation therapy or surgery in a curative intent, and/or metastatic disease.
  • ER positive status
  • HER2 negative status
  • For patients with tumor accessible for paired biopsy at study entry: baseline samples, formalin fixed paraffin embedded (FFPE) archived biopsy samples (within 3 months prior initiation of study treatment) can be used, but preferably fresh biopsies from primary tumor or recurrence or metastasis, will be collected.
  • Participants must have received no more than 1 prior chemotherapeutic or 1 targeted therapy regimen for advanced/metastatic disease.

Participants must have progressed after at least 6 months of a continuous prior endocrine therapy for advanced breast cancer

-Male or Female.

You CAN'T join if...

  • Eastern Cooperative Oncology Group performance status ≥2.
  • Medical history or ongoing gastrointestinal disorders potentially affecting the absorption of SAR439859. Participants unable to swallow normally and to take capsules.
  • 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 has been disease free for >3 years are allowed.
  • Severe uncontrolled systemic disease at screening .
  • Participants with known brain metastases that are untreated, symptomatic or require therapy to control symptoms.
  • Prior treatment with mammalian target of rapamycin inhibitors or any other selective estrogen receptor degrader (SERD) compound, except fulvestrant if stopped for at least3 months before randomization.
  • Treatment with drugs that have the potential to inhibit UGT less than 2 weeks before randomization .
  • Treatment with strong or moderate CYP3A/CYP2C8 inducers within 2 weeks before randomization.
  • Ongoing treatment with drugs that are substrate of P-glycoprotein (P gp) (dabigatran, digoxin, fexofenadine).
  • Treatment with anticancer agents (including investigational drugs) less than 3 weeks before randomization.
  • Inadequate hematological, coagulation, renal and liver functions.

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


  • Investigational Site Number 8400024 accepting new patients
    Santa Monica California 90404 United States
  • Investigational Site Number 8400019 accepting new patients
    Woodland California 95695 United States


accepting new patients
Start Date
Completion Date
Phase 2
Study Type
Last Updated