Long-Acting HIV Injectable Starts Phase 3 Clinical Testing

Long-acting pre-exposure prophylaxis may improve adherence to HIV treatment.

The National Institutes of Health (NIH) recently started a large clinical trial (HPTN 084) of a long-acting injectable HIV drug in sexually-active women living in southern and eastern Africa, according to a press release.

The authors of the new study are investigating whether a long-acting form of investigational cabotegravir injected every 8 weeks can protect against HIV. Currently, emtricitabine/tenofovir (Truvada) is the only drug approved as pre-exposure prophylaxis (PrEP).

“This new study, driven by African women scientists and volunteers, is testing the efficacy of a new HIV prevention tool for women who need more options for protection,” said Anthony S. Fauci, MD, director of the National Institute of Allergy and Infectious Diseases (NIAID), part of the NIH. “Taking a daily pill can be challenging for some people. For some women, a long-acting injectable form of protection may be an easier, more desirable and discreet alternative.”

In southern and eastern Asia, women accounted for nearly 60% of new cases of HIV in 2016, making the development of a long-acting preventive therapy crucial for this population, according to the release.

The authors said that current research projects that women using PrEP may fail to take it daily, which can increase the risk of transmission and adverse events.

“Injectable cabotegravir has the potential to give sexually active women a choice of biomedical HIV prevention tools for the first time—somewhat similar to the choices available to women for contraception,” said study protocol chair Sinead Delany-Moretlwe, MBBCh, PhD. “Current HIV prevention tools can be especially difficult for women to control or negotiate with a partner. An effective, long-acting injectable drug would allow a woman to discreetly protect herself from HIV during sex.”

The phase 3 clinical trial is sponsored by the NIAID and a partnership between ViiV Healthcare and the Bill & Melinda Gates Foundation. Both ViiV Healthcare and Gilead are providing the therapies, according to the release.

The NIH plans to enroll 3200 sexually active women aged 18 to 45 years who will be randomized to receive cabotegravir or PrEP.

During the first 5 weeks, patients will receive either drug as an oral tablet plus a placebo. At week 6, patients will either receive an injection of cabotegravir and placebo or PrEP tablet and a placebo injection, according to the release.

The first 2 injections will be administered 4 weeks apart, followed by every 8 weeks for an average of 2.6 years.

After the injections are completed, patients will receive 18 weeks of daily PrEP and transitioned to local HIV prevention services, according to the NIH.

All patients will receive HIV prevention services, condoms, and counseling for medication adherence during the trial. Patients will also be tested for sexually transmitted infections and HIV frequently and will be referred to proper treatment when necessary, according to the release.

The NIH said that the new trial complements a previous study of the drug for HIV prevention in men who have sex with men and transgender women who have sex with men.

“HPTN 084 also will examine how women experience long-acting injectable cabotegravir—whether they find it desirable and usable,” said study protocol co-chair Mina Hosseinipour, MD, MPH. “Understanding what types of HIV prevention fit best in women’s lives will help further refine HIV prevention research, delivering tools that are ultimately safe, effective and desired.”

The results of HPTN 084 will not be available until 2022, according to the NIH.