Results of the two phase three multicenter studies find that the drug, taken with an optimised standard HIV drug regimen, resulted in significantly greater suppression of the virus at 48 weeks, with concurrent increases in immune system T-cell counts, when compared with placebo, the researchers state. Rates of side effects were not different between the maraviroc and placebo groups. Preliminary results of these studies led to FDA approval of maraviroc in August 2007.
Because it is from a new class of HIV medications known as HIV entry inhibitors, people living with HIV generally will not have resistance to maraviroc because they have not been exposed to any drugs from the class previously. Unlike earlier HIV drugs that target the virus, maraviroc acts on the human T-cell, binding to it in such a way that prevents HIV from binding and subsequently infecting the T-cell.
"It is now possible to expect that a majority of treatment-experienced patients who experience failure on their current HIV drugs will regain control of their HIV infection with maraviroc combined with other newer antiretroviral drugs. This is an important step forward," says study principal investigator Dr. Roy Gulick. "Suppressing virus levels and increasing immune system T-cells with HIV treatment regimens helps HIV-infected people live longer, healthier lives."
The double-blind study followed 1,049 of patients with advanced HIV and resistance to three antiretroviral drug classes. Patients were randomised to receive maraviroc once-daily, twice-daily or placebo. Safety and efficacy were assessed at 48 weeks. The studies were conducted in Canada, Australia, Europe and the U.S.
42 respectively 47 of the patients receiving maraviroc once- or twice daily had no detectable virus load after 48 weeks. Of the placebo group, this was only the case for 16 to 18 percent. Frequencies of side effects and toxicities were similar across groups.
MEDICA.de; Source: Weill Cornell Medical College