Long-Acting Injectable HIV Regimen on Par With Daily Drugs

— Trial shows noninferiority to daily antiretroviral pills for controlling HIV


SEATTLE -- People living with HIV who have maintained undetectable virus levels with daily oral treatment could safely ditch the pills and transition to a more convenient every 2-month injectable alternative -- without sacrificing efficacy, researchers found.

In the 12-month results of the SOLAR trial, switching to the injectable long-acting cabotegravir plus rilpivirine (Cabenuva) from oral bictegravir/emtricitabine/tenofovir alafenamide (Biktarvy) proved noninferior in maintaining undetectable viral loads, reported Moti Ramgopal, MD, director of the Midway Immunology and Research Center in Fort Pierce, Florida.

In the trial, five of the 447 patients (1.1%) who switched to the injectable agent experienced a virologic increase above the 50 c/mL assay limit of detection compared with one of the 223 (0.04%) who continued to take oral HIV suppressive medication. That adjusted difference was within the pre-specified boundary for non-inferiority (95% CI -0.7 to 2.0), Ramgopal said at a press conference during the annual Conference on Retroviruses and Opportunistic Infections.

"This is the first head-to-head study of an injectable HIV medication compared with an oral medication," Ramgopal told app. "Switching to a long-acting regimen offers patients a lot of benefits aside from its safety."

He pointed to people living with HIV having less worry about missing or taking pills on time, not having to carry around pills during brief periods of travels, not having to hide pills from friends or coworkers, and not being constantly reminded that they have HIV.

For study eligibility, patients had to have suppressed the virus to undetectable levels for at least 6 months on oral therapy, but Ramgopal said that some of the patients had successfully suppressed their HIV for as long as 7 years.

SOLAR was designed as a phase IIIb, randomized, open-label, multicenter study. The primary analysis was based on the prespecified modified intention-to-treat, drug-exposed population. A group of 11 patients were excluded from the study due to site-specific protocol deviation. The primary endpoint was the proportion of participants with plasma HIV-1 RNA greater than 50 c/mL with a 4% non-inferiority margin at month 11 or 12, depending on whether participants had an oral treatment lead-in.

The researchers started with 670 patients, and eventually assigned them in a 2:1 ratio to the injectable combination where they received injections 1 month apart to begin and then every other month, or to remain on their three-drug oral treatment.

At the end of the trial, Ramgopal and colleagues administered the HIV Treatment Satisfaction Questionnaire status version to determine satisfaction levels with their treatment. Before the trial, the group had a 60-70% satisfaction level with their regimens; after the trial, those on the injectable drug had a 90% satisfaction level.

Ramgopal noted that the intramuscular injections have to be administered in a doctor's office, but in cases in which patients have to be away for extended periods of time, oral medication can be used to bridge the gap and avoid a lapse in coverage.

In commenting on the study, press conference moderator Diane Havlir, MD, of the University of California San Francisco, told app, "I see the switch to an injectable every 2-month treatment as a standard option for people on HIV therapy. It really is all about choice. It appears that it really works well for those people who want this kind of therapy and are willing to commit to every-2-month injections."

"We can, with this therapy, accommodate people who have to travel and cannot be available for the injection with oral medication," she said. "We are comfortable doing that, and we do maintain suppression."

Havlir said the injections administered in doctors' offices would guarantee adherence to the medication, "provided you can get the patient to come to the office," she said. "For people who are used to coming every 6 months to see their doctor and who are on pills, the every-2-month visit is a change. And that's why we need options for people: Do you prefer coming to the office every 2 months, or if you are on pills, do you want to come every 6 months?"

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    Ed Susman is a freelance medical writer based in Fort Pierce, Florida, USA.


The study was sponsored by ViiV.

Havlir disclosed relationships with ViiV.

Ramgopal disclosed relationships with AbbVie, Gilead Sciences, Janssen, Merck, and ViiV.

Primary Source

Conference on Retroviruses and Opportunistic Infections

Ramgopal M, et al "SOLAR (Switch Onto Long-Acting Regimen) 12-month results – randomized switch trial of CAB + RPV LA vs. oral BIC/FTC/TAF" CROI 2023.