Clinical Trial Registration and News
A new drug in development to prevent HIV infection showed promising results in a recent animal study. Researchers at the Aaron Diamond AIDS Research Center say the data provides them with enough rationale to move forward with initial safety testing in humans.
The drug at the center of the research is an integrase inhibitor known as GSK744 long-acting (LA), which blocks replication of the virus by inhibiting a viral enzyme from inserting DNA into chromosomes. The animal study investigated the drug’s protective effect in monkeys using a virus resembling HIV. Transmission by way of anal intercourse was simulated via intrarectal injection of the virus. After an initial dose of GSK744 LA, eight rhesus macaques were then challenged with low doses of the HIV-related virus once a week for eight weeks. A second dose of the drug was administered about halfway through the process.
Researchers found that while untreated monkeys generally became infected after two challenges, not one of the drug-treated monkeys contracted the virus.
“We treated the rhesus macaques with the drug then challenged the animals repeatedly with the virus to see if they’d get infected,” said Dr. Martin Markowitz, co-investigator and clinical director at the Aaron Diamond AIDS Research Center. “The treated monkeys did not get infected, while the untreated ones did.”
The results echoed another study put out by the U.S. Centers for Disease Control and Prevention that tested GSK744 in female monkeys. For the CDC study, the monkeys were exposed to the virus via vaginal injection that simulated intercourse. When compared to non-treated monkeys, the ones that received the drug did not become infected.
The antiretroviral drug represents a potentially huge step forward in HIV prevention. Pre-exposure prophylaxis (PrEP) is an approach that involves taking HIV treatment drugs as a way of preventing infection. Up to this point, it has rendered the most encouraging results in decreasing the rate of infection among high-risk individuals. An FDA-approved drug called Truvada is currently available for non-infected people who are at higher risk of contracting the virus (men who have sex with men and heterosexual couples where one partner has HIV and the other doesn’t). But while Truvada is taken as a once-daily pill, GSK744 LA may potentially be administered as a shot given every three months.
“The important thing about this result is that the level of drug that was protective in the animal model is achievable with 800 mg of GSK744 long-acting given every 12 weeks,” said Markowitz.
Developed by GlaxoSmithKline, the drug will soon be tested in sexually active men who are at low risk for HIV infection. Researchers hope to test the drug among high-risk individuals thereafter.
By Marianne Hayes