Phase 1 Study of Fusilev to Prevent or Reduce Mucositis in Patients With Non-Hodgkin's Lymphoma Receiving Folotyn

Inclusion Criteria: * At least 18 years of age * Patients with relapsed or refractory NHL who are eligible for Folotyn treatment. Patient has histologically/cytologically confirmed, measurable (lesion or node ≥ 2 cm by computed tomography \[CT\] * Progressive disease or persistent disease after at least 1 prior treatment * ECOG performance status ≤ 2 * Adequate hematological, hepatic, and renal function Exclusion Criteria: * Active concurrent malignancy (except non-melanoma skin cancer or carcinoma in situ of the cervix) * Congestive heart failure * Uncontrolled hypertension * Known human immunodeficiency virus (HIV)-positive diagnosis * Active uncontrolled infection, underlying medical condition, or other serious illness that would impair the ability of the patient to receive protocol treatment * Major surgery within 14 days of enrollment * Pregnant or breast-feeding women * Symptomatic central nervous system (CNS) metastases or lesions for which treatment is required. Patients who received prophylactic CNS treatment are eligible * Previous exposure to pralatrexate