A Phase II Study of Alpelisib plus Fulvestrant or Letrozole for Patients with Metastatic Breast Cancer (the BYLIEVE Study)


Full Title

BYLieve: A phase II, multicenter, open-label, three-cohort, non-comparative study to assess the efficacy and safety of alpelisib plus fulvestrant or letrozole in patients with PIK3CA mutant, hormone receptor (HR) positive, HER2- negative advanced breast cancer (aBC), who have progressed on or after prior treatments


The purpose of this study is to assess the safety and effectiveness of two different treatment combinations for women with metastatic breast cancer that has continued to grow despite previous therapy and whose cancers are driven by the PI3K protein and estrogen/progesterone. Patients will receive the investigational drug alpelisib (BYL719) with either fulvestrant or letrozole. The treatment they receive will depend on their previous therapy.

Alpelisib works by blocking PI3K, which when mutated promotes the growth of several types of cancer, including many breast cancers. Fulvestrant and letrozole are already widely used to treat metastatic breast cancer and work by interfering with the production of estrogen, which can drive breast cancer growth. Alpelisib and letrozole are taken orally (by mouth), and fulvestrant is given by injection.


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

  • Patients must have PI3K-mutated hormone receptor-positive, HER2-negative metastatic breast cancer that has continued to grow despite prior therapy that included a drug that inhibits the CDK4/6 family of proteins (such as palbociclib, ribociclib, or abemaciclib).
  • Patients should recover from the serious side effects of previous treatments before entering the study.
  • Female patients must be postmenopausal.
  • Patients must be able to walk and do routine activities for more than half of their normal waking hours.
  • This study is for patients age 18 and older.

For more information about this study and to inquire about eligibility, please contact Dr. Pamela Drullinsky at 516-256-3955.