Merck’s HIV Drug Acts Fast Against Virus

Merck’s investigative AIDS drug raltegravir — sold as Isentress — did as well as the standard of care treatment for new patients, say U.S. doctors.

About 90 percent of all the patients treated with either raltegravir of efavirenz — marketed as Sustiva — were able to suppress HIV to undetectable levels.

In a report at the 4th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention in Sydney, Martin Markowitz, clinical director of the Aaron Diamond AIDS Research Center in New York, said that treatment with raltegravir — awaiting approval by the U.S. Food and Drug Administration — caused fewer adverse side effects in the patients during the 48-week trial.

Markowitz also told United Press International that treatment with raltegravir resulted in a faster reduction of virus than with efavirenz.

Raltegravir, if approved by the Food and Drug Administration, would be the first in a new class of drugs known as integrase inhibitors. Integrase is one of the three key enzymes required by the virus to replicate. Efavirenz attack the reverse transcriptase enzyme; other HIV drugs attack the protease enzyme.

Isentress will be reviewed by the FDA in an advisory committee hearing Sept. 5, Lynn Kenny, a Merck executive, told UPI.

The FDA application for raltegravir is for its use in patients who have had previous antiretroviral treatments but have not been able to suppress viral levels to undetectable, Markowitz said. The studies we presented here in Sydney are exploring the possibility of using the drug early in treatment.

Regardless of the study dose, it took only about four weeks for patients to reach an undetectable viral load. In contrast, patients on efavirenz took between eight and 12 weeks to reach the same level.

— Ed Susman, UPI Correspondent