CHOP

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.

Background: Diffuse large B-cell lymphoma is the most common type of non-Hodgkin lymphoma. Most people with this cancer can be cured. But those who are not cured have a poor prognosis. Researchers want to add another drug to standard treatment see if it can improve the cure rate. Objective: To see if the drug acalabrutinib given with rituximab and standard combination chemotherapy can improve the cure rate of aggressive B-cell lymphomas such as diffuse large B-cell lymphoma. Eligibility: People ages 18 and older with an aggressive B-cell lymphomas that have not been treated Design: Participants will be screened with: Blood and urine tests Physical exam Medical history Tumor biopsy Bone marrow biopsy: A needle will remove marrow from the participant s hipbone. Lumbar puncture: If necessary, a needle will remove fluid from the participant s spinal canal. Imaging scans Participants will take the study drug for up to 14 days. It is a pill taken 2 times a day. Then they will have more scans. They will get rituximab and chemotherapy. They may get these drugs through a needle in an arm vein. Or they may them through a tube placed in a vein in their chest or in their neck. They might also keep taking the study drug. Each treatment cycle lasts 21 days. They will have up to 6 cycles. Participants may have 4 doses of another drug injected into their spinal fluid. Participants will have repeats of the screening tests throughout the study. Participants will have a follow-up visit 30 days after their last treatment, then every 3 months for 2 years, then every 6 months for 3 years, and then yearly.