Phosphatidylinositol 3-kinase (PI3K) Alpha iNhibition In Advanced Breast Cancer

The primary purpose of this study is to determine whether BYL719 is a safe and effective drug treatment for adult patients with advanced breast cancer who have progressed after first line therapy. Who is it for? Patients may be eligible to join this study if over 18 years old, male or female, with advanced metastatic or locally recurring breast cancer which has progressed after first line therapy. Study details All participants enrolled in this study will take the study drug, BYL719, which is a selective phosphatidylinositol 3-kinase (PI3K) alpha inhibitor. This will involve taking tablets daily. Participants will attend regular follow-up visits for up to 2 years in order to evaluate objective response rate, clinical benefit rate, progression free survival, safety and tolerability of treatment. Regular scans and blood tests will be performed There will be two cohorts of participants involved in this study - those with metastatic triple negative breast cancer (TNBC) and those with estrogen receptor positive and HER2 negative (ER+/HER2-) breast cancers with a genetic mutation in the PI3K pathway. Efficacy and safety of BYL719 in these patients and associations with genetic features will be evaluated in order to try to identify biomarkers of response in breast cancer. Study medication will be continued until disease progression, unacceptable toxicity or requirement to start another anti-cancer medication.