Study to Evaluate the Efficacy and Safety of Treatment With Bendamustine in Combination With Ofatumumab in Previously Untreated Patients With Indolent B-Cell Non-Hodgkin's Lymphoma (NHL)

Key Inclusion Criteria: * The patient has histopathologic confirmation of one of the protocol-specific CD20+ B-cell non-Hodgkin's lymphomas. Tissue diagnostic procedures must be performed within 6 months of study entry and with biopsy material available for review. * The patient meets 1 of the following need-for-treatment criteria: 1. Presence of at least 1 of the following B-symptoms: * fever (\>38ºC) of unclear etiology * night sweats * weight loss of greater than 10% within the prior 6 months 2. large tumor mass (bulky disease) characterized by lymphomas with a diameter of more than 3 cm in 3 or more regions or by a lymphoma with a diameter of more than 7 cm in 1 region 3. presence of lymphoma-related complications 4. hyperviscosity syndrome due to monoclonal gammopathy * The patient's tumor is verified to be CD20+ positive from current or previous excisional or incisional tissue diagnostic procedures performed within 6 months of study entry. * The screening phase CT scan (based on local evaluation) shows: * 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 * The patient was not previously treated for indolent lymphoma (with the exception of a single course of local radiation therapy not exceeding 2 adjacent lymph node regions). * The patient has adequate hematologic and hepatic function. * The patient has Eastern Cooperative Oncology Group (ECOG) performance status 0, 1, or 2. * The patient has serum creatinine of 2.0 mg/dL or less or creatinine clearance of 30 mL/min or more, based on the Cockcroft-Gault method, or from a 24-hour urine collection. * The patient is willing to comply with contraception requirements. Key Exclusion Criteria: The patient: * Has small lymphocytic lymphoma or mantle cell lymphoma. * Has documented history of central nervous system (CNS) lymphomatous involvement. * Has or has had an active malignancy, other than NHL, within the past 3 years except for localized prostate cancer without evidence of bone metastases, bladder, cervical, or breast carcinoma in-situ, or non-melanoma skin cancer . * Has New York Heart Association (NYHC) Class III or IV heart failure, uncontrolled arrythmias or unstable angina, electrocardiographic evidence of active ischemia or active conduction system abnormalities, or myocardial infarction within the last 6 months. * Has known human immunodeficiency virus (HIV) infection. * Has acute or chronic hepatitis B or hepatitis C infection. * Is a pregnant or lactating woman. (Any women becoming pregnant during the study will be withdrawn from the study.) * Has any serious uncontrolled, medical or psychological disorder that would impair the ability of the subject to receive study drugs. * Has received another investigational agent within 30 days of study entry. * Has known hypersensitivity to mannitol. * Has Ann Arbor stage I disease.