Inclusion Criteria:

• >= 18 years of age.

• Documented diagnoses:

  • 1a/1b - lymphoid malignancy/WHO;
  • 2a, Arm A - follicular lymphoma;
  • 2a, Arm B - mantle cell, peripheral or cutaneous T-cell, or B-cell lymphomas;
  • 2a, Arm C - diffuse large B-cell lymphoma. Received at least 1 prior chemotherapy treatment regimen (P1a/1b) & have relapsed or refractory disease.
• ECOG score of <= 1.
• Age of >= 70 documented MRI or CT negative for subdural or epidural hematoma w/i 28 days prior to 1st dose.
• Receiving a stable dose of SSRI antidepressants for at least 21 days prior to 1st dose.

• Adequate bone marrow (BM) function, renal & hepatic function as follows:

  • ANC >= 1000/µL;
  • Platelets >= 100,000/mm3;
  • Hemoglobin >= 9.0/dL;
  • Serum creatinine <= 2.0 mg/dL or calculated creatinine clearance >= 50;
  • AST and ALT <= 3.0 x ULN;
  • Bilirubin <= 1.5 x ULN.
  • Gilbert's Syndrome may have a bilirubin > 1.5 x ULN; aPTT, PT not to exceed 1.2 x ULN.
• Females must be surgically sterile, postmenopausal (at least 1 year), or negative results for a pregnancy test performed at Screening on a serum sample obtained w/i 14 days prior to initial dose, & prior to dosing on a urine sample obtained on C1 D-3 (P1a) or Lead-in D1 (P1b), or C1D1 (P2a) if > 7 days since serum results.
• Females not surgically sterile or postmenopausal (at least 1 year) & non-vasectomized males must practice birth control.

• P2a only: History of autologous BM transplant must be > 6 months post transplant with adequate BM function, renal and hepatic function as follows:

  • ANC >= 1500/µL;
  • Platelets >= 125,000/mm3;
  • Hemoglobin >= 10.0g/dL;
  • Serum creatinine <= 2.0 mg/dL or calculated creatinine clearance >= 50;
  • AST and ALT <= 3.0 x ULN;
  • Bilirubin <= 1.5 x ULN.
  • Gilbert's Syndrome may have bilirubin > 1.5 x ULN; aPTT, PT not to exceed 1.2 x ULN.
• Measurable disease by IWG criteria for tumor response.

• Archived diagnostic tissue for assessment of Bcl-2 family protein expression. One of following for PD:

  • core needle biopsy of malignant lymph node,
  • bone marrow aspirate or core positive for lymphoma, or
  • archived tumor tissue with no intervening treatment since biopsy.

Exclusion Criteria:

• History of, or is, clinically suspicious for cancer-related CNS disease, lymphoid or non-lymphoid.
• Undergone an allogeneic or autologous stem cell transplant.
• Underlying, predisposing condition of bleeding or currently exhibits signs of bleeding.
• Recent history of non-chemotherapy induced thrombocytopenic associated bleeding w/i 1 year prior to 1st dose.
• Active peptic ulcer disease or other hemorrhagic esophagitis/gastritis.
• Active immune thrombocytopenic purpura or history of being refractory to platelet transfusions w/i 1 year prior to 1st dose.
• Significant history of cardiovascular disease, renal, neurologic, psychiatric, endocrinologic, metabolic, immunologic, or hepatic disease.
• Females pregnant or breast-feeding.
• Positive for HIV.
• Previous or current malignancies at other sites, except adequately treated in situ carcinoma of the cervix uteri; basal or squamous cell carcinoma; previous malignancy confined and surgically resected with no evidence of disease w/i 3 years.
• Evidence of other clinically significant uncontrolled condition(s), including, but not limited to active systemic fungal infection; diagnosis of fever and neutropenia w/i 1 week prior to study drug.
• Received steroid therapy w/i 7 days prior to 1st dose of study drug for anti-neoplastic intent.
• Received any anti-cancer therapy, including chemotherapy, immunotherapy, radiotherapy, hormonal or any investigational therapy, w/i 14 days prior to 1st dose of study drug, or has not recovered to <Gr2 clinically significant AE(s) /toxicity(s) of the previous therapy.
• Received a biologic w/i 30 days prior to 1st dose.
• Currently receiving or requires anticoagulation therapy or any drugs or herbal supplements that affect platelet function, with the exception of low-dose anticoagulation medications that are used to maintain the patency of a central venous catheter.
• Received aspirin w/i 7 days prior to 1st dose and during ABT-263 administration.
• Consumed grapefruit or grapefruit products w/i 3 days prior to 1st dose.
• P1a/1b only: Diagnosed with PTLD; Burkitt's, Burkitt-like, or HIV-associate lymphoma; lymphoblastic lymphoma/leukemia; or multiple myeloma.