Nab-paclitaxel and Alpelisib for the Treatment of Anthracycline Refractory Triple Negative Breast Cancer With PIK3CA or PTEN Alterations

PRIMARY OBJECTIVES: I. To determine if alpelisib in combination with nab-paclitaxel in the neoadjuvant setting will improve rates of pathologic response (pathological complete response \[pCR/RCB-0\] or minimal residual disease \[RCB-I\]) from 5% to 20% in patients with chemotherapy insensitive triple negative breast cancer (TNBC) with PIK3CA alterations (including PTEN loss). (Cohort 1) II. To determine if alpelisib in combination with nab-paclitaxel in the neoadjuvant setting will improve rates of pathologic response (pCR/RCB-0 or RCB-I) from 5% to 20% in patients with chemotherapy insensitive TNBC with PTEN alterations. (Cohort 2) SECONDARY OBJECTIVES: I. Determine the radiographic response rate for alpelisib in combination with nab-paclitaxel as measured by ultrasound and/or magnetic resonance imaging (MRI) (partial response + complete clinical response) in chemotherapy insensitive TNBC with PIK3CA (Cohort-1) or PTEN (Cohort-2) alterations. II. Determine toxicity of alpelisib in combination with nab-paclitaxel given in the neoadjuvant setting following anthracycline based therapy. III. Determine progression free survival (PFS) at 3 years for patients treated with alpelisib in combination with nab-paclitaxel given in the neoadjuvant setting in chemotherapy insensitive TNBC with PIK3CA (Cohort-1) or PTEN (Cohort-2) alterations. EXPLORATORY OBJECTIVES: I. To assess biomarkers of response and resistance to alpelisib and nab-paclitaxel combination. II. To assess the role of circulating tumor deoxyribonucleic acid (ctDNA) allele fraction in predicting response to alpelisib and nab-paclitaxel in early stage TNBC. OUTLINE: Patients receive alpelisib orally (PO) once daily (QD) on days 1-21, and nab-paclitaxel intravenously (IV) over 30 minutes on days 1, 8, and 15. Treatment repeats every 21 days for 4 cycles in the absence of disease progression or unacceptable toxicity. Patients may then undergo surgery to remove the tumor. After completion of study treatment, patients are followed up at 30 days, and then periodically until up to 3 years after surgery.