The reported rate of suspected hypersensitivity to abacavir was 9 percent in the ABC QD group and 7 percent in the ABC BID group and no new safety concerns emerged as a result of ABC being administered QD.
CNA10905 Evaluates QD ABC PK
Pharmacokinetic (PK) data evaluating the use of abacavir in QD regimens also were presented at ICAAC this week. The PK of the active form of ABC, carbovir triphosphate (CBV-TP), demonstrated a long elimination half-life (geometric mean 20.6 hours) in the blood cells of patients studied, according to CNA10905 study results.
"Abacavir is a carbocyclic synthetic nucleoside analogue which, intracellularly, is converted to the active metabolite carbovir triphosphate," said Dr. Manion. "Carbovir triphosphate inhibits the activity of HIV-1 reverse transcriptase, and its half-life in the blood cells of patients is a measure of the length of time in which ABC remains active," he said. ABC is a member of the nucleoside reverse transcriptase inhibitor (NRTI) class of anti-HIV drugs.
In the study, 20 HIV-positive patients, aged 18 to 55, who were already on a stable treatment regimen that included 300mg of ABC twice daily, underwent PK sampling over a 24-hour period to characterize the PK profiles of ABC in plasma and CBV-TP in peripheral blood mononuclear cells (PBMCs). On the PK sampling day, patients took their usual regimen in the morning, but withheld their evening dose of ABC in order to better characterize the elimination of CBV-TP. All other medications in their regimens remained unchanged. Blood samples were drawn before the patients took their morning doses and at hours 2, 4, 8, 12, 16 and 24 following dose administration.
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16-Sep-2003