Study of Pralatrexate to Treat Participants With Relapsed or Refractory B-cell Non-Hodgkin's Lymphoma

Inclusion Criteria

• Histologically/cytologically confirmed, measurable (lesion or node =2 cm by CT [at least 1 cm if by spiral CT]) B-cell Non-Hodgkin's Lymphoma, using the Revised European American Lymphoma (REAL) World Health Organization (WHO) disease classification
• Progressive or persistent disease after ≥ 1 prior treatment(s)
• Recovered from toxic effects of prior treatment
• At least 4 weeks since most recent cytotoxic therapy
• Easter Cooperative Oncology Group (ECOG) performance status ≤ 2
• Adequate blood, liver, and kidney functions as defined by laboratory levels
• 1.0 mg/day orally of folic acid for at least 7 days prior & 1 mg intramuscular of vitamin B12 within 10 weeks of the planned start of pralatrexate
• Females of childbearing potential must agree to use medically acceptable birth control from start of pralatrexate until at least 30 days after the last administration of pralatrexate and must have a negative serum pregnancy test within 14 days prior to the first day of study treatment
• Males who are not surgically sterile must agree to use medically acceptable birth control from start of pralatrexate until at least 90 days after the last administration of pralatrexate
• Available for repeat dosing and follow-up
• Able to give written informed consent

Exclusion Criteria

• Relapsed participants with diffuse large B-cell lymphoma (DLBCL) who are candidates for high-dose therapy and autologous stem cell transplantation (SCT) and for whom high-dose therapy and autologous SCT is a standard curative option
• Active concurrent malignancy (except non-melanoma skin cancer or carcinoma in situ of the cervix). If there is a history of prior malignancies other than those exceptions listed above, the participant must be disease-free for ≥ 5 years. Participants with other prior malignancies 10%] amount of bone marrow) within 4 weeks (6 weeks for nitrosoureas or mitomycin C) prior to study treatment or planned use during the course of the study
• Receipt of systemic corticosteroids within 1 week of study treatment, unless participant has been taking a continuous dose of no more than 10 mg/day of prednisone or its equivalent for at least 1 month
• Use of any investigational drugs, biologics, or devices within 4 weeks prior to study treatment or planned use during the course of the study
• Previous exposure to pralatrexate
• Females who are pregnant or breastfeeding