Comparison of Abacavir Following Once-Daily And Twice-Daily Administration In HIV Infected Subjects

An Open-Label, Two-Period, Crossover, Pharmacokinetic Study of Abacavir and Its Intracellular Anabolite Carbovir Triphosphate Following Once-Daily and Twice-Daily Administration of Abacavir in HIV-Infected Subjects.

The purpose of the study is to look at the levels of the drug abacavir (ABC) in blood. Also, the study will look at the levels of carbovir triphosphate (CBV-TP), which is the active substance produced from ABC in the bodyâ s cells which helps prevent HIV from multiplying. CBV-TP will be measured in specific blood cells. The amount of ABC and CBV-TP will be looked at when subjects receive ABC as a 300mg dose twice a day and compared with the levels when they receive ABC as a 600mg dose once a day.

Inclusion criteria:

• Healthy adults , inclusively.
• Documented HIV-1 infection (documented by historical data or current validated assay).
• Undetectable viral load.
• Currently on an ABC-tablet containing regimen for at least 8 weeks.
• Willingness to temporarily switch ABC schedule from BID to QD, or vice versa, for 11 days.
• Weigh between 40-100kg, inclusive.

Exclusion criteria:

• Subjects who are receiving tenofovir.
• Previous study participation in other experimental drug trial(s) within 30 days before the screening phase of the study.
• Subjects who currently regularly take drugs-of-abuse, with the exception of cannabinoids.
• Subjects who cannot refrain from taking herbal remedies during the course of the study.
• Subjects who regularly consume more than an average amount of alcohol per day.
• Poor general health preventing fasting or blood sampling.
• Subjects who are not able to discontinue use of hydroxyurea, mycophenolate or ribavirin for 14 days prior to entering the study until discharge from the study.
• An unwillingness of a male subject to abstain from sexual intercourse with women of childbearing potential or an unwillingness to use a condom in addition to having their female partner use another form of contraception.
• The subject is pregnant or nursing an infant.
• History of symptoms consistent with a hypersensitivity reaction to ABC.
• Positive HCV Antibody or HepBsAg (Hepatitis B surface antigen).