Studies show HIV
integrase inhibitors are promising

Studies presented in Denver this week at the 13th Conference on Retroviruses and Opportunistic Infections show that experimental HIV integrase inhibitors developed by Merck and Gilead Sciences show promise in fighting HIV. The drugs aim to interfere with integrase, a key enzyme HIV uses to infect immune system cells and make copies of itself. Currently, there are no integrase inhibitors on the market, so an eventual product in this drug class would be a major step forward in treating HIV infection. Integrase inhibitors also would be particularly useful for HIV patients who've developed resistance to existing treatments.

Merck's experimental drug, MK-0518, was shown in a trial of 167 HIV patients with multiple-drug resistance to help reduce HIV viral loads to undetectable levels in 56% of those with the weakest response to the drug and up to 72% of those responding well to the medication.

The Gilead study, testing its experimental drug GS 9137 in 30 HIV patients, showed that the integrase inhibitor, when combined with other anti-HIV drugs, lowered HIV viral levels by as much as 99%. The 10-day study also found GS 9137 was safe and well tolerated by the study subjects.

Larger clinical trials of both experimental drugs are scheduled to begin later this year.

"The search for integrase inhibitors has been a long one," Warner Greene, director of the Gladstone Institute of Virology and Immunology in San Francisco, told the San Francisco Chronicle. "We've said all along that you need to attack this virus in multiple parts of its life cycle. The third viral enzyme has been elusive, but the barrier seems to be cleared." (Advocate.com)