Maraviroc

Absorption

The absolute oral bioavailability of a 100 mg dose is 23% and is predicted to be 33% at 300 mg. Coadministration of a 300mg tablet with a high fat breakfast reduced maraviroc Cmax and AUC by 33% in healthy volunteers.

Description

Maraviroc is the first CCR5 receptor antagonist that has been developed and launched for the treatment of HIV-1. Maraviroc binds in a slowly reversible, allosteric manner to CCR5, which is one of two principle chemokine co-receptors for viral entry into the host cell, the other being CXCR4. Binding of maraviroc to CCR5 induces conformational changes within the chemokine receptor, thereby preventing CCR5 binding to the viral gp120 protein and the ultimate CCR5- mediated virus-cell fusion that is a prerequisite for HIV invasion. Maraviroc, with its unique mechanism of action as a fusion inhibitor, joins the greater than 20 marketed antiretrovirals, including nucleotide reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), and PIs. It is approved for use in combination with these other antiretroviral drugs in adult patients with R5-tropic HIV-1 infection (but not X4 or dual/mixed tropic HIV-1).

The Uses of Maraviroc

Maraviroc is a CCR5 antagonist for MIP-1α, MIP-1β and RANTES with IC50 of 3.3 nM, 7.2 nM and 5.2 nM, respectively

Indications

Maraviroc is indicated in combination with other antiretroviral agents for the treatment of CCR5-tropic HIV-1 infection in adults and pediatric patients weighing at least 2kg. It is not recommended in patients with dual/mixed- or CXCR4-tropic HIV-1.

Background

Maraviroc (brand-named Selzentry, or Celsentri outside the U.S.) is a chemokine receptor antagonist drug developed by the drug company Pfizer that is designed to act against HIV by interfering with the interaction between HIV and CCR5. It was originally labelled as UK-427857 during development but was assigned the Maraviroc name as it entered trials. It was approved for use by the FDA in August, 2007.

Pharmacokinetics

Maraviroc is a chemokine receptor antagonist drug developed by the drug company Pfizer that is designed to act against HIV by interfering with the interaction between HIV and CCR5.

Metabolism

In vitro studies indicate that CYP3A is the major enzyme responsible for maraviroc metabolism.