This is a Phase 1, randomized, open-label, single center, three period crossover study to determine the oral bioavailability of a new ABT-263 formulation relative to that of the current ABT-263 formulation being administered in ongoing Phase 1/2a studies. Approximately 12 healthy female subjects will be enrolled in this study.

This is a Phase 1, randomized, open-label, single center, three period crossover study to determine the oral bioavailability of a new ABT-263 formulation relative to that of the current ABT-263 formulation being administered in ongoing Phase 1/2a studies. Approximately 12 healthy female subjects will be enrolled in this study.

Inclusion Criteria:

• Female and age is between 18 and 55 years, inclusive.
• Must be surgically sterile (bilateral tubal ligation, bilateral oophorectomy or hysterectomy), postmenopausal (for at least 2 years), or practicing at least one acceptable method of birth control.
• Must have negative results for pregnancy tests performed at Screening on a urine sample obtained within 28 days prior to initial study drug administration, and on Period 1 Day -1 on a serum specimen.
• Body Mass Index (BMI) is 18 to 29, inclusive. BMI is calculated as weight in kg divided by the square of height measured in meters.
• Must have adequate bone marrow function per local laboratory reference range (Platelets >/= lower limit of normal range, ANC >/= lower limit of normal range)
• A condition of general good health, based upon the results of a medical history, physical examination, vital signs, laboratory profile and a 12-lead electrocardiogram (ECG).
• Must voluntarily sign and date each informed consent, approved by an Independent Ethics Committee (IEC)/Institutional Review Board (IRB), prior to the initiation of any study-specific procedures.

Exclusion Criteria:

• History of significant sensitivity to any drug
• History of drug or alcohol abuse w/i 6 months or currently receiving Disulfiram
• Known/suspected history of HIV
• History of or active medical condition(s) or surgical procedure(s) that might affect GI motility, pH, absorption
• History of thrombocytopenic associated bleeding w/i 1 year prior to ABT-263
• Significant history of cardiovascular disease (e.g., MI, thrombotic or thromboembolic event in last 6 months), renal, neurologic, psychiatric, endocrinologic, metabolic, immunologic, respiratory (except mild asthma), gastrointestinal, hematologic, or hepatic disease or diabetes, cancer, epilepsy, or seizures that in the opinion of the PI would adversely affect her participating in the study.
• Underlying condition predisposing to bleeding or currently exhibits signs of clinically significant bleeding or active peptic ulcer disease or other hemorrhagic esophagitis/gastritis.
• Positive result for drugs of abuse, alcohol, cotinine, hepatitis A virus immunoglobulin M (HAV-IgM), hepatitis B surface antigen (HBsAg) or hepatitis C virus antibody (HCV Ab).
• Consumed alcohol, grapefruit or starfruit product, or Seville oranges w/i 3 days prior to ABT-263
• Received aspirin, anticoagulation therapy, or any drugs or herbal supplements that affect platelet function w/i 7 days prior to/during ABT-263
• Used any medications, vitamins, or herbal supplements (except contraceptives) w/i 14 days prior to ABT-263
• Received any drug by injection or biologic agent w/i 30 days prior to ABT-263 (except parenteral hormonal contraceptives)
• Used known inhibitors or inducers CYP3A w/i 1 month prior to ABT-263; Received any investigational product w/i 6 weeks prior to ABT-263
• Used tobacco or nicotine-products w/i 6 months prior to ABT-263
• Pregnant or breastfeeding
• Donation or loss of >/=550 mL blood or received transfusion of blood product w/i 8 weeks prior ABT-263
• Currently enrolled in another study.
• The PI decides the subject is unsuitable to receive ABT-263.