Positive Ph III findings for Merck & Co's HIV/AIDS drug Isentress

The online edition of The Lancet has published results from a 48-week Phase III study of treatment-naive HIV-infected patients which showed that US drug major Merck & Co's Isentress (raltegravir), a first-in-class integrase inhibitor, was found to be as effective as efavirenz at suppressing viral load to undetectable levels (less than 50 copies/mL) when used in combination therapy.

Additionally, at week 48, patients taking raltegravir had significantly fewer side effects compared to the efavirenz group and there were greater increases in mean CD4 cell count recorded for the latter arm, although this was not statistically significant. Both raltegravir and efavirenz were administered in combination with two other anti-HIV medicines, tenofovir and emtricitabine. The use of raltegravir in treatment-naive patients is investigational and the product is not currently licensed in this patient group in Europe.

'These findings show that a raltegravir-based regimen was as effective as an efavirenz based regimen, a standard first-line medication, in reducing viral load to undetectable levels and increasing CD4 cell counts in treatment-naïve patients,' said Mark Nelson, Consultant in HIV Medicine at the Chelsea and Westminster Hospital, London, UK. 'This study suggests that raltegravir in combination therapy with other antiretroviral treatments may become an important new treatment option for a broader spectrum of patients, including those who have not been previously treated with HIV therapy,' he added.