Ofatumumab and Bendamustine Followed by Maintenance Ofatumumab for Rituximab Relapsed Indolent B-cell Non-Hodgkin's Lymphoma (B-NHL)

Inclusion Criteria

• Signed written informed consent
• Small lymphocytic, lymphoplasmacytic, marginal zone lymphoma, and follicular lymphoma; Grades 1, 2 and 3a, defined according to World Health organization (WHO) guidelines. [Tefferi, 2008]
• Tumor was verified to be CD20+ (based on local evaluation), from a current or previous tissue biopsy. Tissue biopsy should be repeated if no report or specimen is available, CD20 staining was not previously performed, or there is clinical suspicion that the indolent lymphoma has transformed to aggressive lymphoma/higher malignancy grade.
• Rituximab-sensitive disease, defined as a Partial Remission (PR) or Complete Remission (CR) to the last rituximab-containing therapy lasting at least 6 months following completion of therapy. Last rituximab-containing therapy is defined as the last therapy regimen containing at least one full dose of rituximab.
• Relapse or disease progression following response to prior rituximab-based therapy, that requiried treatment by 2007 Revised Response Criteria for Malignant Lymphoma (RRCML) guidelines.
• CT imaging in screening (based on local evaluation) showing 2 or more clearly demarcated lesions with a largest diameter > 1.5 cm, or 1 clearly demarcated lesion with a largest diameter > 2.0 cm.
• ECOG Performance Status of 0, 1, or 2.
• Age ≥ 18 years.
• Life expectancy of at least 6 months in the opinion of the investigator.
• Women of childbearing potential must have had a negative serum pregnancy test within 14 days of first dose of study treatment and agree to use effective contraception during the study and for one year following the last dose of study drug.
• Men with a female partner of childbearing potential must have had either had a prior vasectomy or agree to use effective contraception from 2 weeks prior to administration of the first dose of study treatment until one year after the last dose of study treatment.
• Must not have been on any prohibited medications.
• Subjects who had received prior bendamustine were eligible if they had achieved a response (CR/PR) which lasted > 6 months after the end of bendamustine containing treatment.

Exclusion Criteria

• Lactating women
• CLL, Grade 3b follicular lymphoma or evidence that the indolent lymphoma had transformed to aggressive lymphoma. Subjects suspicious for transformation should have undergone a biopsy to exclude the possibility of transformation. Subjects with a previous diagnosis of small lymphocytic leukemia (SLL) and a screening monoclonal B-lymphocyte count of ≥ 5000/µl are defined by 2008 International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria to have CLL; such patients were NOT eligible for this study.
• Rituximab-refractory disease, defined as failure to have responded to or progression within 6 months of completing rituximab or rituximab-containing combination therapy.
• Previous treatment with ofatumumab.
• Previous radioimmunotherapy (RIT) within 6 months of study entry. Subjects who have received RIT must have attained a PR or CR lasting at least 6 months, and must have recovered from any hematologic or other toxicity.
• Previous allogeneic stem cell transplantation at any time OR autologous stem cell transplantation within 6 months of study entry.
• Prior use of monoclonal antibody (other than anti CD20) within 3 months prior to randomization. Chemotherapy or other systemic lymphoma therapy within 4 weeks of study entry.
• Received treatment with an investigational agent within 4 weeks of study entry, or was actively participating in another interventional clinical study.
• Known Central Nervous System (CNS) involvement by lymphoma.
• Current or previous other malignancy within 2 years of study entry. Exception: Subjects who have been disease-free for 2 years or more, or subjects with a history of completely resected non-melanoma skin cancer or successfully treated in situ carcinoma are eligible.
• Chronic or currently active infectious disease requiring syst