Long-Acting HIV Drug
In monkey studies, shots guarded against disease for human equivalent of up to three months
By Dennis Thompson
TUESDAY, March 4, 2014 (HealthDay News) -- A long-acting, injectable HIV drug could potentially protect people from infection with the AIDS virus for up to three months, new animal studies suggest.
The experimental drug, called GSK744, protected macaque monkeys from repeated attempts to infect the animals with a hybrid simian/human AIDS virus called SHIV, scientists said.
GSK744 is a reformulated, long-acting version of an HIV drug known as dolutegravir (Tivicay), which has been approved by the U.S. Food and Drug Administration for treatment in people who have already been infected with HIV.
While GSK744 hasn't been tested on humans, doctors hope that it will lead to a medication that could effectively protect people against HIV infection, mostly because it would only need to be administered on a quarterly basis. However, findings from animal studies often don't hold up in human trials.
Such a long-lasting drug would help overcome one of the major problems with current medications that attempt to protect against HIV infection -- the ability of people to take their medication on a daily basis.
"Some of the really good pre-exposure prophylaxis treatments have not been effective, mainly because people don't take the drug," said Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases. "The major stumbling block the field has experienced has been the lack of adherence. It's not because the drugs don't work. It's because people don't take them as directed."
Researchers expect to launch human trials for GSK744 within a matter of months, said study author Chasity Andrews, a scientist with the Aaron Diamond AIDS Research Center at Rockefeller University in New York City.
GSK744 is in a class of antiretroviral drugs called integrase inhibitors. These medications block HIV from inserting its genetic material into the body's immune cells.
GSK744 is different in that it crystallizes in the bloodstream, allowing a slow, steady release of the medicine over time, the Rockefeller researchers explained.
Their findings are published online March 6 in the journal Science. The Rockefeller study, and similar results from a study conducted by researchers at the U.S. Centers for Disease Control and Prevention, were presented Tuesday at the annual Conference on Retroviruses and Opportunistic Infections in Boston, according to published reports.
The medication levels that protected the monkeys translate to doses that could sustain human protection for 12 weeks to 16 weeks, Andrews said.
Effective protection against HIV is necessary to fight the spread of AIDS. There were 2.3 million new HIV infections globally in 2012, the researchers noted in background material, with more than 35.3 million people already infected.