To Evaluate Efficacy of Belinostat or Pralatrexate in Combination Against CHOP Alone in PTCL

Part 1: This is a 5 Arm study primarily to determine the best dose out of the two dose levels of Belinostat and Pralatrexate combined with CHOP/COP in newly diagnosed PTCL patients based on Safety for part 2 study. Part 2 (Efficacy and Safety): This is a 3 Arm study. Patients with previously untreated PTCL will be randomized 1:1:1 into 1 of 3 treatment groups: 2 experimental treatment groups (Bel-CHOP or Fol-COP) or 1 active comparator treatment group (CHOP). Patients will be treated for up to 6 cycles. The primary objective is to compare the Progression Free Survival of patients with newly diagnosed PTCL treated for up to 6 cycles with Beleodaq (belinostat) in combination with CHOP (Bel-CHOP) or Folotyn (pralatrexate injection) in combination with COP (Fol-COP) to CHOP alone.

Study Design and Treatment Plan: Part 1: Dose Finding It is a randomized, open label, multicenter study in patients with PTCL who have not been previously treated and the control arm is CHOP, COP, is the CHOP regimen without Doxorubicin (H). Two investigational agents are separately added to C(H)OP, Belinostat for Bel-CHOP and Pralatrexate for FOL-COP. In this first part, each investigational arm will have two dose levels which will be compared with CHOP as reference. Treatment will be randomized in five arms: 1. Group 1a (Bel-CHOP) Belinostat 600 mg/m2 2. Group 1b (Bel-CHOP) Belinostat 1000 mg/m2 3. Group 2a (Fol-COP) Pralatrexate 20 mg/m2 4. Group 2b (Fol-COP) Pralatrexate 30 mg/m2 5. Group 3 for CHOP alone. Analysis will be done when 75 patients have received their planned treatment cycles to evaluate treatment compliance. Approximately 20 patients will be enrolled into each group and receive at least one cycle of drug thus 15 patients are expected to be evaluated with their planned treatment of 6 cycles completed. The safety data will be evaluated to select the proper dose for Belinostat -CHOP and Pralatrexate-COP for the Part 2 study. Part 2: Efficacy and Safety It is a randomized, open-label, multicenter study in newly diagnosed PTCL patients. This is a three arm study and 143 patients will enroll in each arm. Patients will be randomized in a balance manner (1:1:1) into 1 of 3 treatment groups and treated for up to 6 cycles: Group 1: (Bel-CHOP): Belinostat at the dose determined from Part 1 (600 or 1000 mg/m2) to be administered on Day 1 by 30 min intravenous (IV) infusion once daily for 5 days; CHOP will also be administered starting on Day 1 within 15 min (±5 min) after the end of the belinostat infusion at the doses shown below for Group 3, with cycles repeated every 21 days for up to 6 cycles Group 2: (Fol-COP): Pralatrexate at the dose determined from part 1 (20 or 30 mg/m2) is to be administered on Day 1 and Day 8 as an IV push over 3 to 5 min; CHOP will also be administered starting on Day 1 within 15 min (±5 min) after the end of the pralatrexate administration at the doses shown below for Group 3, with cycles repeated every 21 days for up to 6 cycles. COP combination refers to CHOP without Doxorubicin (H). Group 3: (CHOP): Combination chemotherapy to be administered starting on Day 1 at the doses shown below, with cycles repeated every 21 days for up to 6 cycles * Cyclophosphamide 750 mg/m2 IV, Day 1 * Doxorubicin 50 mg/m2 IV, Day 1 (limit lifetime cumulative dose to \<550 mg/m² to reduce risk of cardiotoxicity) * Vincristine 1.4 mg/m2 (maximum 2 mg) IV, Day 1 * Prednisone 100 mg orally (PO) daily, Day 1 (after the end of the belinostat or pralatrexate administration for Groups 1 and 2) to Day 5 Randomization will be stratified on: * Histology (nodal, extra-nodal) * Prognostic Index for T-Cell Lymphoma (Group 1 or 2 vs 3 or 4) * Region (US, ex-US) The study duration will include up to a 28-day screening period, a 6-cycle treatment period (18 weeks), follow-up until progression, an End-of-Treatment Visit at least 30 days after the last dose of study treatment, and long-term survival follow-up for patients by phone every 6 months thereafter until a 5-year median follow-up of the population is reached. Patients discontinuing the study for other reasons than progression will have the same long-term follow-up for OS analysis. Tumor assessments will be performed every 3 cycles (i.e., 9 weeks) on Cycle 4 Day 1 and End-of-Treatment Visit during treatment, then every 3 months for 3 years for patients with complete response (CR), partial response (PR), or stable disease, and every 6 months thereafter until disease progression or death