Offering a long-acting antiretroviral treatment (LA-ART) every 4 to 8 weeks to patients who have been historically underserved, including those experiencing housing insecurity, mental illnesses, and substance use disorders, improved HIV suppression rates, according to research presented at the Conference on Retroviruses and Opportunistic Infections (CROI), held February 19-23, 2023 in Seattle, WA.1 The research was supported in part by the National Institute of Allergy and Infectious Diseases and the National Institute of Mental Health.

Antiviral therapy (ART) “has been a medical game-changer for saving lives as treatment and as a potent prevention tool with Undetectable=Untransmittable, or U=U. Yet, we have substantial gaps that remain for people who face co-occurring health, housing, and other socio-economic challenges,” said Carl W. Dieffenbach, PhD, director of the National Institute of Allergy and Infectious Diseases (NIAID) Division of AIDS. “Making progress against the HIV pandemic necessitates that societies prioritize reaching those who have historically been left behind, yet stand to benefit the most from making newer, easier formulations of ART available,” he said.

Long-acting injectable medications could help break some of these treatment barriers, however, the regimen approved by the Food and Drug Administration (FDA), an injectable intramuscular combination of cabotegravir and rilpivirine, is approved for patients who have achieved viral suppression and are currently on oral ART. As such, people who face challenges adhering to daily oral ART also face barriers to accessing LA-ART, according to the National Institutes of Health.

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To address this gap, Monica Gandhi, MD, MPH, medical director of the Ward 86 HIV clinic at San Francisco General Hospital, and her team enrolled 133 patients with HIV started on LA-ART including 57 people (43%) with untreated or unsuppressed HIV and 76 people (57%) who were virologically suppressed on oral ART patients between June 2021 and November 2022.2 The researchers performed biweekly review of each participant’s health status, and pharmacy staff conducted regular outreach to remind patients of their injection appointments.

Among participants who began the study with virologic suppression, all (100%) remained suppressed over the follow-up period, noted Dr Gandhi, who is also professor of medicine and associate division chief at the University of California, San Francisco. Among participants who did not have virologic suppression at baseline, 55 out of 57 (96.5%) had achieved virologic suppression at a median of 33 days. Only 2 of the 133 study participants did not achieve or maintain viral suppression, a rate of 1.5%, which is in line with findings from previous clinical trials that studied LA-ART in people with HIV who had achieved viral suppression on daily oral ART, Dr Gandhi noted.

Participants had a median age of 45 years, 88% identified as cisgender men, 68% identified as non-White, 58% reported having unstable housing, 8% reported experiencing homelessness, 38% reported having a mental illness, and 33% reported substance use.

“Our patient population does not look like the patient population that got enrolled in the clinical trials to determine the approval criteria for long-acting ART,” said Dr. Gandhi. “It is the role of researchers to help address disparities through intentionally and proactively including diverse groups in our studies, and for this population to have the same successful outcomes as those in the other clinical trials was very important and exciting. We want to have the ability to offer these drugs to patients who stand to benefit the most, including those who face challenges adhering to daily treatment.”

More Long-Acting Antiretroviral Therapy Research From the NIH

The results from 3 NIAID-funded clinical trials ― START, SMART, and HPTN 052 ― ”conclusively demonstrated that starting antiretroviral treatment promptly after HIV diagnosis, and continuing it without interruption, protects the health of the person living with HIV while preventing transmission of the virus to sexual partners,” noted the NIH. “Despite these positive results, persistent barriers, including stigma, often delay the start of ART and reduce adherence among people who face significant health and social challenges.”

An ongoing NIAID-supported clinical trial (The LATITUDE Study) conducted in the AIDS Clinical Trials Group network is using a randomized design to directly compare the efficacy of LA-ART and oral ART regimens among people experiencing adherence challenges. The study authors noted that reaching patients and following up with them requires intensive resources, a limitation that should be addressed to make LA-ART more widely available.

“The most effective treatments are those that fit into the lives of people who need them. These findings show that with the right support, long-acting ART can make it easier for people with HIV who face barriers in adhering to daily oral treatment to keep the virus under control,” said NIMH Director Joshua A. Gordon, MD, PhD.

“Dr. Gandhi and her team have made state-of-the-art HIV treatment finally available to people with unique challenges, like those who use drugs, and have found success,” said Nora Volkow, MD, director of the National Institute on Drug Abuse. “This is the sweet spot for addressing HIV ― thinking outside the box to deliver care in a way that meets people’s needs, even when that means it happens outside the clinic walls, by phone, or on neighborhood streets. This can be done ― but it requires creativity and resolve.”


1. Long-acting antiretroviral therapy suppresses HIV among people with unstable housing, mental illnesses, substance use disorder. News release. National Institute of Health. February 21, 2023. Accessed April 11, 2023.

2. Gandhi M, Salaza J, Hickey MD, et al. High virologic suppression rates on long-acting art in a safety-net clinic population (abstract 518) . Presented at: CROI February 19-21, 2023; Seattle., WA.