Sci-fi ways to treat HIV: Implants, monoclonal antibodies & more
There are more drugs than ever before on the market to treat HIV. At this point in time, there are a total of 29 approved HIV drugs in the U.S. Potent, powerful antiretrovirals are able to keep HIV in check and suppress viral loads to undetectable levels for most people who take them daily. So researchers are now focused on developing ways to make it even easier for people living with HIV to treat HIV. What’s on the horizon, and what might we see next to treat HIV?
Here are a few of the strategies being tested now, all shared by Roy Gulick, MD, MPH in a recent webinar by IAS-USA.
Long-acting subdermal (under the skin) implants
Researchers are now testing HIV prevention and treatment implanted rods that are modeled after contraceptive implants that deliver birth control medications (e.g., Norplant and Jadelle). Implants are inserted under the skin—and could offer a discrete HIV treatment or prevention option that doesn’t rely on having to take a medication every day.
One implant, containing the medication tenofovir alafenamide (TAF), was tested in animal models to see if it could deliver the medication to the blood stream over an extended period of time.
Gunawardana and colleagues, in a study published in Antimicrobial Agents and Chemotherapy, implanted TAF-containing rods into four beagle dogs and measured drug levels over 40 days. They found that the implant was able to keep sustained levels of drug in the blood over the course of the study. After removing the implants, they found only trace amounts of the drug on the implants. On average, 98% of the drug was delivered over the 40-day study.
“Our report of the first sustained-release nucleoside reverse transcriptase inhibitor (NRTI) for systemic delivery demonstrates a successful proof of principle and holds significant promise as a candidate for HIV-1 prophylaxis,” the authors said, while adding, “it is conceivable that a similar device could be used in the treatment of HIV/AIDS.”
Currently, the research team is in the process of testing a next-generation device that would be implanted for one year, and are close to evaluating the device in human participants.
Injectable HIV medications
Researchers are also currently testing injectable HIV medications—as a different long-acting method of antiretroviral therapy.
Cabotegravir, an integrase inhibitor similar to dolutegravir (Tivicay), is now being studied as a long-acting injectable HIV therapy. The drug has a long half-life—between 21 and 50 days—so the hope is that people might only need to receive drug injections once a month or once every two months.
The LATTE-2 study, which enrolled 309 people new to HIV treatment, showed that an injectable form of cabotegravir along with an injected version of rilpivirine helped 92% of people maintain an undetectable viral load (of people assigned to injections every 8 weeks). People in the study reported that the injections were painful—with 7% reporting swelling after receiving the injections.
People with multi-drug resistant forms of HIV—or strains of HIV that aren’t controlled by currently available HIV medications—may soon have a new type of antibody therapy available to them. The first “biologic” therapy for HIV, a monoclonal antibody called ibalizumab, is now being studied as an intravenous (IV) therapy for people living with HIV.
In a study presented at IDWeek in 2016, participants living with HIV received an IV of the therapy every two weeks, with 60% achieving significant viral load decreases after seven days of treatment.
“This is the first drug in a long time for patients with multidrug resistance,” said Jacob Lalezari, MD, lead author of the study and medical director for Quest Research in a press release. “This therapy showed good activity in patients who were resistant to everything else, which is very exciting for these vulnerable patients and those who care for them.”
New drugs & new research at CROI
The HIV community will get an update on new HIV drug research at the upcoming Conference on Retroviruses and Opportunistic Infections (CROI) in February 2017. Come back to BETA during the conference (February 13 – 16) for coverage of research on new drugs, new delivery methods and new treatment options.
Gunawardana, M. and colleagues. Pharmacokinetics of long-acting tenofovir alafenamide (GS-7340) subdermal implant for HIV prophylaxis. AAC. July, 2015.
Infectious Diseases Society of America. New Drug Benefits Patients with Multi-Drug Resistant HIV. First Monoclonal Antibody for HIV, Given Once Every Two Weeks. Press release. October 28, 2016.
Margolis, D. Cabotegravir + rilpivirine as long-acting maintenance therapy: LATTE 2 week 48 results. AIDS 2016.