I. To evaluate in a Phase II study a preliminary estimate of the complete response (CR) rate of a new chemotherapy regimen involving Cyclophosphamide, Etoposide, Vincristine and Prednisone (CEOP) alternating with Pralatrexate (P) as front line therapy for patients with Stage II, III and IV Peripheral T-Cell NHL not otherwise specified (NOS), Anaplastic large cell lymphoma (ALK negative), Angioimmunoblastic T-cell lymphoma, Enteropathy associated T-cell lymphoma, Hepatosplenic gamma delta T-cell lymphoma followed by an optional stem cell transplant with high dose chemotherapy and Autologous stem cell transplant.