A Phase III, Randomized, Double-Blind, Placebo-Controlled Study Evaluating the Efficacy and Safety of GDC-0077 Plus Palbociclib and Fulvestrant Versus Placebo Plus Palbociclib and Fulvestrant in Patients With PIK3CA-Mutant, Hormone Receptor-Positive, Her2-Negative, Locally Advanced or Metastatic Breast Cancer

This study will evaluate the efficacy, safety, and pharmacokinetics of GDC-0077 in combination with palbociclib and fulvestrant compared with placebo plus palbociclib and fulvestrant in patients with PIK3CA-mutant, hormone receptor (HR)-positive, HER2-negative locally advanced or metastatic breast cancer whose disease progressed during treatment or within 12 months of completing adjuvant endocrine therapy and who have not received prior systemic therapy for metastatic disease.

Inclusion Criteria:
• Confirmed diagnosis of HR+/HER2- breast cancer
• Metastatic or locally advanced disease not amenable to curative therapy
• Progression of disease during adjuvant endocrine treatment or within 12 months of completing adjuvant endocrine therapy with an aromatase inhibitor or tamoxifen
• Receiving LHRH agonist therapy for at least 2 weeks prior to Day 1 of Cycle 1 if pre/peri-menopausal
• Confirmation of biomarker eligibility (detection of specified mutation(s) of PIK3CA via specified test)
• Consent to provide fresh or archival tumor tissue specimen
• Life expectancy of > 6 months
• Adequate hematologic and organ function within 14 days prior to initiation of study treatment

Exclusion Criteria:
• Metaplastic breast cancer
• Any history of leptomeningeal disease or carcinomatous meningitis
• Any prior systemic therapy for metastatic breast cancer
• Prior treatment with fulvestrant or any selective estrogen-receptor degrader
• Prior treatment with any PI3K, AKT, or mTOR inhibitor, or any agent whose mechanism of action is to inhibit the PI3K-AKT-mTOR pathway
• Type 2 diabetes requiring ongoing systemic treatment at the time of study entry; or any history of Type 1 diabetes
• Known and untreated, or active CNS metastases. Patients with a history of treated CNS metastases are eligible
• Active inflammatory or infectious conditions in either eye, or any eye conditions expected to require surgery during the study treatment period
• Symptomatic active lung disease, or requiring daily supplemental oxygen
• History of inflammatory bowel disease or active bowel inflammation
• Anti-cancer therapy within 2 weeks before study entry
• Investigational drug(s) within 4 weeks before randomization
• Prior radiotherapy to >= 25% of bone marrow, or hematopoietic stem cell or bone marrow transplantation
• Chronic corticosteroid therapy or immunosuppressants
• Major surgical procedure, or significant traumatic injury, within 28 days prior to Day 1 of Cycle 1
Phase III
Alison Conlin, M.D.
Roche Holding AG (Hoffman-LaRoche)
Nikki Moxon
  • Oncology and Hematology Care Westside
  • Providence Cancer Institute Clackamas Clinic
  • Providence Cancer Institute Franz Clinic
  • Providence Cancer Institute Newberg Clinic