ISENTRESS® (raltegravir), from MSD, was as Effective as Efavirenz at

ISENTRESS® (raltegravir), from MSD, was as Effective as Efavirenz at Suppressing HIV Viral Load and Increasing CD4 Cell Counts in Treatment-Naïve Patients up to 144 Weeks When Used in Combination Therapy
CAPE TOWN, South Africa--(BUSINESS WIRE)-- Not For Distribution To South African Journalists
ISENTRESS ® (raltegravir), an integrase inhibitor from Merck Sharpe & Dohme (MSD) was as effective as efavirenz at maintaining viral load suppression to undetectable levels (less than 50 copies/mL) and at improving CD4 counts in previously untreated (treatment-naïve) patients through 144 weeks in a Phase II study still underway. Both medicines were administered in combination with two other anti-HIV medicines, tenofovir and lamivudine. These results were presented today at the 5th International AIDS Society’s (IAS) Conference on HIV Pathogenesis, Treatment & Prevention in Cape Town, South Africa.
“We are encouraged that these data demonstrate the efficacy and tolerability profile of raltegravir, with less effect on lipid levels, for up to 144 weeks,” said Martin Markowitz, M.D., study investigator and clinical director of the Aaron Diamond AIDS Research Center in New York. "It is important for patients at any stage of HIV to have treatment options like raltegravir that are effective and have a demonstrated tolerability profile in order to help them manage their disease."
On July 8, raltegravir was approved by the U.S. Food and Drug Administration (FDA) for use in treatment-naïve adult patients in combination with other antiretroviral (ARV) medicines for the treatment of HIV-1 infection. In markets outside the United States, where raltegravir is approved for treatment-experienced patients, the use of raltegravir in treatment-naïve patients is investigational and not currently licensed in this patient group. The expanded indication in the United States for raltegravir was based on analyses of plasma HIV-1 RNA levels through 48 weeks in three double-blind controlled studies. Two of these studies were conducted in clinically advanced, three-class antiretroviral (NNRT, NRTI, PI) treatment-experienced adults and one was conducted in treatment-naïve adults. The use of other active agents with raltegravir is associated with a greater likelihood of treatment response. The safety and efficacy of raltegravir have not been established in pediatric patients.
In addition, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMEA) is expected to issue an opinion soon regarding an expanded marketing authorisation of raltegravir in the European Union for patients starting HIV therapy for the first time, as well as all treatment-experienced patients, when used in combination with other antiretroviral medicines for the treatment of HIV-1 infection in adult patients.
Raltegravir studied for 144 weeks in nearly 200 previously untreated adult patients
These 144-week findings are from an ongoing multi-center, dose-ranging, double-blind, randomised trial of previously untreated HIV-infected adult patients. In this study, 198 treatment-naïve, HIV-infected patients received either raltegravir administered orally twice daily in combination with tenofovir and lamivudine or 600 mg efavirenz dosed orally once daily in combination with the same agents. During the first 48 weeks of the study, patients were randomised to one of four dose regimens (100, 200, 400 and 600 mg twice daily). After 48 weeks, all groups receiving raltegravir received 400 mg dosed twice daily. The primary endpoints were reductions in HIV RNA to below 400 copies/mL and the evaluation of safety at 144 weeks. The evaluation of total cholesterol, LDL cholesterol and triglycerides were exploratory endpoints.
Viral load reductions and increase in CD4 cell counts maintained through 144 weeks
After 144 weeks of therapy, 78 percent of the 160 patients on the regimen containing raltegravir maintained HIV viral load suppression to below 50 copies/mL. Results were comparable for patients taking the efavirenz-based regimen, with 76 percent of the 38 patients maintaining suppression to below 50 copies/mL (95 percent CI). Eighty percent of patients receiving the regimen containing raltegravir maintained suppression in viral load to less than 400 copies/mL compared to 76 percent of patients taking the regimen containing efavirenz (95 percent CI). Patients on both treatment regimens experienced increases in CD4 cell counts. At 144 weeks of treatment, the mean increase in CD4 cell counts from baseline was 252 cells/mm3 for patients receiving the regimen containing raltegravir and 233 cells/mm3 for patients receiving the regimen containing efavirenz.