Study to Assess Safety, Tolerability and Efficacy of MB-106 in Patients With Relapsed or Refractory B-Cell NHL or CLL

This is a multicenter, Phase 1/2, open-label, non-randomized study of MB-106 in patients ≥18 years of age with selected CD20-expressing malignancies. In both the Phase 1 and Phase 2 portions of the study, all patients must have evidence of CD20 expression. In Phase 1, patients will be enrolled in 1 of 3 arms, based on their primary diagnosis, as follows: * Arm 1: Patients with aggressive B-cell non-Hodgkin lymphoma (NHL) including, but not limited to, diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL). * Arm 2: Patients with indolent NHL including, but not limited to, follicular lymphoma (FL). * Arm 3: Patients with chronic lymphocytic lymphoma (CLL)/small lymphocytic lymphoma (SLL). In Phase 1, escalating MB-106 dose levels will be tested independently in each arm using a 3+3 design. A total of up to 18 patients are anticipated to be treated in each independent arm in Phase 1, including 6 patients at the maximum tolerated dose (MTD; highest dose level at which ≤1 of 6 patients experiences a dose-limiting toxicity \[DLT\]), prior to proceeding to the Phase 2 portion of the study for each respective arm, where a total of up to 71 patients will participate in each independent arm. An assessment of the safety and tolerability of the dose will be made by the Safety Review Committee (SRC) based on the data from the 28-day DLT observation period. An SRC composed of Principal Investigators and Sponsor representatives will review the safety of each dose level for each arm prior to enrollment at the next dose level in the Phase 1 dose escalation part of study. This process will be repeated for each dose level within each arm until the MTD has been reached, and the recommended Phase 2 dose (RP2D) has been established for that arm. In Phase 2, the following specific arms of relapsed or refractory CD20-positive B-cell NHL or CLL patients will be treated with MB-106 at the respective RP2D for each arm. Each arm will initially include up to 20 patients: * Arm 1 Expansion (E): Relapsed or refractory DLBCL, including high-grade B-cell lymphoma with MYC and B-cell lymphoma 2 (BCL2) and/or B-cell lymphoma 6 (BCL6) rearrangements, primary mediastinal large B-cell lymphoma and transformed FL. * Arm 2E: Relapsed or refractory FL. * Arm 2E-Basket: Relapsed or refractory B-cell NHL subtypes that have progressed after available therapies. This "basket" arm will include but will not be limited to MCL, marginal zone lymphoma (MZL), Waldenstrom's macroglobulinemia (WMG), Burkitt and Burkitt-like lymphoma, and hairy cell leukemia (HCL). * Arm 3E: Relapsed or refractory CLL/SLL Arms 1E, 2E and 3E of Phase 2 will have an interim efficacy analysis for futility prior to completion of recruitment to the arm. Arm 2E-Basket will be summarized descriptively only. Safety data from all arms will also be provided at this interim timepoint to the Data Safety Monitoring Board (DSMB) for review. Based on the results of the interim analysis, an additional 51 patients may be added to each of these arms.