Raltegravir Beneficial in Drug-Resistant HIV
Integrase inhibitor more effectively suppresses virus than optimized background therapy alone
WEDNESDAY, July 23 (HealthDay News) -- In patients with drug-resistant HIV, treatment with raltegravir -- an integrase inhibitor -- in combination with optimized background therapy leads to significantly improved viral suppression, according to two studies published in the July 24 issue of the New England Journal of Medicine.
In one study, Roy T. Steigbigel, M.D., of the State University of New York at Stony Brook, N.Y., and colleagues randomly assigned 699 patients to receive either raltegravir or placebo. After 48 weeks, they found that 62.1 percent of raltegravir patients achieved suppression of HIV-1 RNA to a level below 50 copies per milliliter compared to 32.9 percent of placebo patients.
In a second study, David A. Cooper, M.D., of the University of New South Wales in Sydney, Australia, and colleagues assessed the same group of patients. In patients who were using both enfuvirtide and darunavir for the first time, they found that 89 percent of raltegravir patients achieved HIV-1 RNA levels of less than 50 copies per milliliter compared to 68 percent of placebo patients. In 64 raltegravir patients who experienced virologic failure, however, they identified integrase mutations associated with resistance to raltegravir.
"Raltegravir is a powerful weapon for patients combating drug-resistant HIV," states the author of an accompanying editorial. "However, the low genetic barrier to drug resistance against raltegravir represents a major point of vulnerability. With attention to adherence and with the use of accompanying active antiretroviral agents, the risk can be minimized. Nonetheless, we must acknowledge that even though regimens are sufficiently potent to treat drug-resistant HIV, they may require a substantial pill burden and use of the injectable drug enfuvirtide. These regimens can be overwhelming even for the most motivated patient."
Both studies were supported by Merck.