Overview
A study to evaluate the efficacy and safety of triplet combination of inavolisib plus ribociclib and fulvestrant versus placebo plus ribociclib and fulvestrant in the first-line setting in participants with endocrine-therapy-resistant hormone receptor (HR)-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) with chromosome 8p loss (chr8p loss) and without PIK3CA mutation.
Eligibility
Inclusion Criteria:
- Women or men with histologically or cytologically confirmed carcinoma of the breast that is locally advanced or metastatic and is not amenable to surgical or radiation therapy with curative intent
- Documented estrogen receptor (ER)-positive and/or progesterone receptor (PR)-positive tumor according to American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines, defined as \>=1% of tumor cells stained positive based on the most recent tumor biopsy and assessed locally (Allison et al. 2020)
- Participants must not have received any prior systemic therapy for locally advanced unresectable or metastatic breast cancer (mBC) and must have progressed during adjuvant endocrine-based treatment or within 12 months after completing adjuvant endocrine-based therapy with an aromatase inhibitor or tamoxifen
- Confirmed biomarker eligibility as documented through central laboratory testing of a tumor tissue sample documenting both the lack of a phosphatidylinositol-4,5-biphosphate 3-kinase catalytic subunit alpha gene (PIK3CA) mutation and the presence of heterozygous loss of chromosome 8p (i.e., PIK3CAnmd and chr8p loss)
- Measurable disease per Response Evaluation Criteria in Solid Tumors, Version 1.1 (RECIST v1.1)
Exclusion Criteria:
- Metaplastic breast cancer
- Radiotherapy within 2 weeks before randomization
- Appropriate for treatment with cytotoxic chemotherapy at time of entry into the study, as per national or local treatment guidelines (e.g., participants with visceral crisis)
- 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 Central nervous system (CNS) metastases (progressing or requiring anticonvulsants or corticosteroids for symptomatic control). Participants with a history of treated CNS metastases are eligible
- Any history of leptomeningeal disease or carcinomatous meningitis