Inclusion Criteria:

• Must have a histologically confirmed B-cell malignancy (defined as FL [any grade], DLBCL, MCL or SLL/CLL);
• Male or non-pregnant, non-lactating females age ≥18 years;
• Ability to swallow and retain oral medication.;
• Have failed at least one prior therapy and have documentation of either, relapsed disease, or refractory disease (i.e., no response or stable disease on their last regimen of therapy);
• ECOG performance status 0 or 1;
• All clinically significant toxicities from prior therapy must have fully resolved;
• Must have discontinued treatment with monoclonal antibodies for a minimum of 90 days prior to first dose of AT-101, or have objective documentation of disease progression if within 90 days of monoclonal antibody administration;
• Patients with FL, DLBCL, MCL, and SLL with normal lymphocyte counts must have at least one bi-dimensional lesion that is radiographically measurable (skin lesions, palpable lymph nodes, and bone marrow as the only site of disease are not considered measurable disease);
• Patients with SLL whose lymphocytes are elevated at baseline or CLL must have palpable lymph nodes and/or disease localized to the bone marrow per the NCI-Sponsored Working Group Guidelines for CLL.

Exclusion Criteria:

• Requirement of systemic corticosteroids within 7 days prior to and during AT-101 administration;
• Must not have received anti-cancer therapy within 28 days of first dose of AT-101. Cannot have received hormonal agents or biologic dose modifiers (with the exception of HRT) or any investigational treatments within 28 days of treatment with AT-101;
• Patients with CNS lymphoma, HIV-related lymphoma, symptoms suggesting HIV infection or active auto-immune hemolytic anemia are excluded;
• Previous treatment with gossypol, or are hypersensitive to its excipient are excluded;
• Patients who have an uncontrolled, concurrent illness are also excluded.