The purpose of this study is to evaluate the safety, tolerability, and pharmacokinetics (behavior in the body) of bevirimat administered for 15 days to HIV-positive individuals.

Inclusion Criteria:

• Have documentation of HIV-1 infection in their medical records (documentation of any prior plasma viremia is acceptable).
• Have a CD4+ lymphocyte count >/= 100 cells/mm3.
• Have a screening plasma HIV-1 RNA value, measured by the Roche Amplicor assay, of <400 copies/mL.
• Be receiving an ARV therapy regimen containing at least 3 drugs which has been unchanged for at least 8 weeks prior to screening, and which is to be continued through Day 15 of the study.
• Be informed of the nature of the study and provide written informed consent.
• Be legally competent and able to communicate effectively with study personnel.
• Be able and willing to comply with outpatient visits.

Exclusion Criteria:

• Presence of any acute illness within 14 days prior to study entry.
• Presence of any AIDS-related opportunistic infection (Category C according to the CDC Classification System for HIV-1 Infection, 1993 Revised Version) that is unstable in the Investigator's opinion or diagnosed in the 30 days prior to study entry.
• Patients who are, in the opinion of the Investigator, unable to comply with the dosing schedule and protocol evaluations.
• Patients with malabsorption syndromes affecting drug absorptions (e.g. Crohn's disease, chronic pancreatitis).
• Patients with systolic blood pressure < 90 mmHg or > 160 mmHg or diastolic blood pressure < 50 mmHg or > 110 mmHg.
• A history of seizures (excluding pediatric febrile seizures) or current administration of prophylactic anti-seizure medication for the indication of seizures or seizure-related conditions.
• A history of cerebrovascular accident (CVA) or transient ischemic attacks (TIA).
• Patients who have received radiation therapy or cytotoxic chemotherapeutic agents within 4 weeks prior to first dose of study drug.
• Patients who have received treatment with immunomodulating agents such as IL-2, alpha-interferon, beta-interferon, or gamma-interferon within 4 weeks prior to first dose of study drug.
• Receipt of an investigational drug or product, or participation in a drug study within a period of 30 days prior to receiving study medication.
• Bupropion-containing products require at least a 14-day washout period and will not be approved for co-administration.
• Rifampin or other rifamycin products require at least a 28-day washout period and will not be approved for coadministration.