AIDS 2016: Undetectable with long-acting, user-friendly injectable HIV medications

August 2, 2016, by Liz Highleyman

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Two long-acting injectable antiretrovirals administered once every 4 or 8 weeks maintained undetectable viral load in people who switched from a daily oral regimen, researchers reported at the 21st International AIDS Conference (AIDS 2016) in Durban, South Africa. People who used the injectables said getting shots was worthwhile and they liked not having to think about HIV treatment every day.

 Long-acting injectables could offer an attractive option for people with HIV facing a lifetime of antiretroviral therapy (ART). Some people may find it easier and more convenient to get a shot once a month than to remember to take their pills each day. But the potential drawback of this kind of treatment is that long-acting drugs cannot be removed from the body if problems occur.

David Margolis, MD

David Margolis, MD, from ViiV Healthcare (abstract THAB0206LB) presented findings from the LATTE-2 trial, which tested a maintenance regimen using injectable formulations of ViiV’s experimental integrase inhibitor cabotegravir and the approved NNRTI rilpivirine (an injected formulation of the Edurant pill).

To make sure these drugs were safe and effective before testing the injected version in humans, the initial LATTE-1 trial gave people oral versions of cabotegravir and rilpivirine first. After taking a simplified two-drug therapy for 96 weeks, 76% of people who switched to oral cabotegravir plus rilpivirine still had undetectable HIV compared to 63% of those who stayed on a three-drug regimen containing efavirenz (Sustiva), and the combination was safe and well tolerated.

These promising results laid the groundwork for testing the long-acting injectable formulations in the Phase 2b LATTE-2 trial. This open-label study enrolled 309 participants new to HIV treatment. They first started on a three-drug “induction” regimen of 30 mg oral cabotegravir plus abacavir/lamivudine (the drugs in Epzicom). Most were white men and the median age was 35.

Those who achieved viral suppression (<50 copies/mL) at 20 weeks were randomly assigned to either stay on the same oral regimen or switch to long-acting cabotegravir and rilpivirine administered as intramuscular injections in the buttocks. One group received 400 mg cabotegravir plus 600 mg rilpivirine given every 4 weeks (Q4W) and another received 600 mg cabotegravir plus 900 mg rilpivirine given every 8 weeks (Q8W).

All these treatment regimens were found to work well. At 48 weeks after randomization, 92% of patients who switched to the injectables given every 8 weeks and 91% of those who got the shots every 4 weeks maintained undetectable viral load, as did 89% of those who stayed on the pills.

Injectable cabotegravir and rilpivirine were generally safe and well tolerated, with no drug-related serious adverse events. Most people receiving the injectable drugs reported injection site reactions, but these were usually mild or moderate, and 90% resolved within a week. Fewer than 1% of participants withdrew from the study for this reason.

Most people in the said they were satisfied with the injectables and would like to continue on this regimen, rating their satisfaction as 5 or 6 on a 6-point scale.

Deanna Kerrigan, PhD

At the same conference session Deanna Kerrigan, PhD, from Johns Hopkins Bloomberg School of Public Health (abstract THAB0204) reported findings from a qualitative analysis providing more details about patients’ experiences using long-acting injectables.

The researchers conducted in-depth interviews with 27 people with HIV and 12 clinical providers who participated in LATTE-2. The patient analysis included 10 men and one woman in the U.S. and 15 men and one woman in Spain. Most participants in both countries were gay men. The providers included 12 physician investigators, nurses, and study coordinators.

The patients generally agreed that the injection side effects were worthwhile when compared to taking daily pills. They said the long-acting injectables were simpler, more convenient, and allowed greater confidentiality. Some said long-acting ART reduced their feelings of stigma and gave them relief from the daily reminder of living with HIV, as expressed by this man from Spain:

“It seems to me that it’s much better because you simply don’t have to worry about anything…If you go on a trip, you don’t have to bring your pills or take anything at all along. You follow your ‘normal life’. You come once a month. You get the shot and it’s over. You don’t have to be thinking everyday…oh, I forgot to take the pill. Or…when did I take it last…You just don’t worry about anything. In reality, taking the pill everyday keeps it [HIV] present…and the shot is just once a month…you remember it when you come in and the rest of the time you can basically forget it.” 

While participants said they felt comfortable coming to the clinics to receive their shots, some expressed concern about the number of visits, which could prove to be a bigger issue with monthly injections compared to every 8 weeks.

Since monthly dosing resulted in a modestly lower rate of virological non-response it was selected for Phase 3 studies planned for later this year. But Margolis said evaluation of both dose schedules will continue through 96 weeks in LATTE-2, and every-other-month dosing may still be a possibility. 

Providers who responded to the survey recognized the benefits of long-acting injectable ART and said they would consider it on a case-by-case basis. But they were not as supportive as the patients. They expressed concerns about drug resistance and clinical management, patients not returning for follow-up care, and not being able to remove the medication in case of side effects or intolerance.

The injectable formulations of cabotegravir and rilpivirine are also being studied for pre-exposure prophylaxis or PrEP, as descried in this report from the conference. The qualitative survey findings about convenience and simplicity will likely also apply to long-acting options for HIV prevention. 

Liz Highleyman is a freelance medical writer and editor-in-chief of HIVandHepatitis.com.

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