A Phase II Study of Fulvestrant Alone or with GDC-0941 or GDC-0980 in Women with Advanced Breast Cancer Resistant to Aromatase Inhibitor Therapy

Full Title
A Phase II, Double-Blind, Placebo-Controlled, Randomized Study of GDC-0941 or GDC-0980 with Fulvestrant Versus Fulvestrant in Advanced or Metastatic Breast Cancer in Patients Resistant to Aromatase Inhibitor Therapy

Some women with breast cancer are treated with aromatase inhibitors. These drugs work by blocking the enzyme needed to make estrogen, a hormone that fuels the growth of many breast cancers. But in some women, the cancer continues to grow despite aromatase inhibitor therapy.

Fulvestrant is another drug used to treat breast cancer. In this study, researchers want to determine if combining fulvestrant with a PI3 kinase inhibitor is more effective than fulvestrant alone in women with advanced or metastatic breast cancer that is resistant to aromatase inhibitor therapy.

PI3 kinase is an enzyme that drives the growth of many cancers, including advanced breast cancer. This study is evaluating two investigational drugs that block the activity of PI3 kinase: GDC-0941 and GDC-0980. Women in this study will be randomly assigned to receive fulvestrant plus placebo, fulvestrant plus GDC-0941, or fulvestrant plus GDC-0980. GDC-0941 and GDC-0980 are taken orally (by mouth); fulvestrant is given via injection.


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

  • Patients must be postmenopausal women with locally advanced or metastatic breast cancer that is negative for HER2 and positive for estrogen receptors.
  • Patients’ disease must have progressed despite at least 4 weeks of aromatase inhibitor therapy. An aromatase inhibitor must have been the most recent treatment for a patient before she can enroll in this study.
  • At least two weeks must have passed since completion of prior chemotherapy or radiation therapy and receipt of the first dose of the study treatment.
  • Patients may not have had prior therapy with a PI3 kinase inhibitor, an mTOR inhibitor, or fulvestrant.
  • Patients must be physically well enough that they are fully ambulatory, capable of all self care, and are capable of all but physically strenuous activities. As an example, patients must be well enough that they would be able to carry out office work or light housework.
  • Patients must be age 18 or older.

For more information about this study and to inquire about eligibility, please contact Dr. Maura Dickler at 646-888-5456.

Breast Cancer
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