Alpelisib/iNOS Inhibitor/Nab-paclitaxel in Patients With HER2 Negative Metaplastic Breast Cancer (MpBC)

Patients with HER2 negative metastatic or locally advanced MpBC, will receive a combination of an iNOS inhibitor, nab-paclitaxel and alpelisib . As prophylaxis against deep venous thrombosis and hypertension, patients will receive aspirin (81 mg po daily) and amlodipine (10 mg po Days 0-5 each cycle). Metformin will be initiated at 500 mg once daily starting one week prior to treatment to reduce risk of severe hyperglycemia. Based on tolerability and serial blood sugar assessments, metformin dose will be increased to 500 mg twice daily, followed by 500 mg with breakfast and 1000 mg with dinner, followed by further increase to 1000 mg twice daily if needed. Insulin sensitizers and/or SGLT2i will be used as second anti-diabetic agents, if necessary. For prophylaxis of alpelisib rash, patients will be treated with an anti-histamine (cetirizine 10 mg daily) along with alpelisib.