A Phase I/II Study of SAR439859 Alone and with Palbociclib in Postmenopausal Women with ER-positive Advanced Breast Cancer


Full Title

A Phase 1/2 study for the safety, efficacy, pharmacokinetic and pharmacodynamics evaluation of amcenestrant (SAR439859), administered orally as monotherapy, then in combination with other anti-cancer therapies in postmenopausal women with estrogen receptor-positive advanced breast cancer.


SAR439859 is an investigational drug that belongs to a class of drugs called selective estrogen receptor degraders (SERD). In patients with estrogen receptor (ER)-positive breast cancer, estrogen molecules attach to receptors (proteins) in breast cancer cells and trigger tumor growth. SAR439859 may impair activation of estrogen receptors in breast cancer cells, as well as destroy these receptors.

In this study, researchers are determining the highest dose of SAR439859 that can be given safely in postmenopausal women with ER-positive, HER2-negative advanced breast cancer. SAR439859 is taken orally (by mouth). Researchers will also determine the best dose of SAR439859 to give in combination with palbociclib (another oral breast cancer drug). After determining the best dose for each treatment (SAR439859 alone and in combination of palbociclib), researchers will determine if either treatment can shrink or slow the growth of this type of cancer.


To be eligible for this study, patients must meet several criteria, including but not limited to the following:

  • Patients must have inoperable or metastatic ER-positive, HER2-negative breast cancer.
  • Patients must have received at least 6 months of prior endocrine (hormonal) therapy for metastatic breast cancer.
  • Patients should recover from side effects of previous therapies before entering the study.

For more information and to inquire about eligibility for this study, please contact Dr. Sarat Chandarlapaty at 646-888-5449.