Study of 5-azacitidine in Combination With Vorinostat in Patients With Relapsed or Refractory Diffuse Large b Cell Lymphoma (DLBCL)

Eligible subjects will have biopsy proven relapsed or refractory DLBCL, have preserved hematologic and other organ function, and have either progressed following or be inappropriate candidates for autologous stem cell transplantation. Patients will be treated with 5-azacitidine via subcutaneous administration and vorinostat orally at four different dose levels as described below: * Dose level 1: azacitidine 55 mg/m2 on days 1-5 and oral vorinostat at 300 mg BID on Days 1-7. * Dose level 2: azacitidine 75 mg/m2 on days 1-5 and oral vorinostat at 200 mg BID on Days 1-7. * Dose level 3: azacitidine 55 mg/m2 on days 1-5 and oral vorinostat at 300 mg BID on Days 1-14. * Dose level 4: azacitidine 75 mg/m2 on days 1-5 and oral vorinostat at 200 mg BID on Days 1-14. Each cycle will be of 28 days and patients will be treated for up to 6 cycles. Up to 8 patients will be enrolled at each dose level. If at any time 2 patients in a given cohort experience DLT, enrollment to that level will be discontinued. Efficacy will be assessed by standard radiographic and other criteria at baseline and at the end of treatment to determine ORR. Patients will be followed for 2 years or until disease progression. Tumor samples will be obtained for correlative studies at baseline through core needle or surgical biopsy, with an additional biopsy performed on day 15 of cycle 1 as a pharmacodynamic endpoint.