April 27 2007 12:00 AM ET
When combined with an optimized background regimen for patients who have limited treatment options because of resistance, CCR5 entry inhibitor maraviroc doubles the number of people with undetectable levels of HIV when taken twice a day, compared to the current salvage treatments, according to Phase IIb/III trials reported by drugmaker Pfizer. Experts had been cautious about maraviroc, since two other CCR5 inhibitors did not work out in development.
Data from two Phase III trials of raltegravir (MK-0518), each of which enrolled patients with multidrug-resistant HIV and advanced infection, indicate that the Merck experimental integrase inhibitor has 'potent and superior' antiretroviral activity for people with limited treatment options. At 16 weeks 79% of patients in the two groups given raltegravir had viral loads below 400. Merck has given the brand name Isentress to the medication.
Data from a Phase II trial of elvitegravir (GS-9137), an integrase inhibitor being developed by Gilead Sciences, have shown beneficial activity against multidrug-resistant HIV for patients with limited treatment options. Less than a third of patients in the control group had viral loads below 50 after 16 weeks, compared to 38% of patients in the 50-milligram elvitegravir group and 40% of patients in the 125-milligram group. CD4 counts increased by 28 among patients in the control group after 16 weeks, compared to increases of 52 in the 50-milligram group and 61 in the 125-milligram group.
Results from a Phase II trial of rilpivirine (TMC-278), an experimental nonnuke from Tibotec, indicate that the drug shows beneficial effects, when combined with Truvada or Combivir similar to Sustiva.
Researchers have halted two studies of a vaginal microbicide in Africa and India after early results suggested it might raise the risk of HIV infection instead of lowering it. It was 'a disappointing and unexpected setback' to efforts to find a simple tool to reduce women's risk of contracting HIV through sexual transmission, according to the World Health Organization.