MSD drug ‘reduces HIV viral load and increases CD4 cell counts’

Merck, Sharp, Dohme (MSD) has announced the results of an ongoing phase II study of its first-in-class integrase inhibitor Isentress (raltegravir) at the International Aids Conference in Mexico City.

The company reported that the compound reduced HIV viral load to less than 50 copies/ML – an undetectable level – in 83 per cent of previously-untreated patients infected with HIV.

These results were similar to those seen in patients treated with Sustiva/Stocrin (efavirenz), which was found to reduce viral load to undetectable levels in 84 per cent of patients.

Patients were administered with these compounds in conjunction with the same anti-HIV medicines through 96 weeks of treatment.

Furthermore, patients taking Isentress experienced a mean increase in CD4 cell counts of 221 cells per cubic mm.

Martin Markowitz, study investigator and clinical director of the Aaron Diamond AIDS Research Centre in New York, said: “These findings are consistent with the efficacy and safety data seen with Isentress in treatment-experienced patients.”

He added viral loads were sustained throughout the 96 weeks of treatment in the study, which was the longest conducted with Isentress to date.

In July 2008, MSD announced the publication of positive study data for Isentress in the New England Journal of Medicine.