Metformin in Combination With Standard Induction Therapy for Large B-cell Lymphoma (DLBCL)

Newly diagnosed histologically confirmed CD20 positive previously untreated diffuse large B-cell lymphoma to receive up to 4-6 cycles (21 day cycles) of: R-CHOP: Rituximab 375 mg/m2 IV infusion Day 1 Cyclophosphamide 750 mg/m2 IV Day 1 Doxorubicin 50 mg/m2 IV Day 1 Vincristine 1.4 mg/m2 IV Day 1 (cap @ 2mg) Prednisone 100mg PO daily Days 1-5 Pegfilgrastim 6 mg subcutaneously within 72 if start if cycle Metformin 500 mg PO daily Cycle 1 Days 1-7 Metformin 500 mg PO twice daily Cycle 1 Days 7-21 Metformin 850 mg PO twice daily starting on day 22 and and continuing throughout remainder of cycles plus 22 days post treatment. Restaging will be done after the 4th cycle is complete. Subjects will be monitored with labs and physical exams throughout the study.