based on a meta-analysis including data from more than 5,000 patients.
Although triple therapy remains the standard of care, the availability of more potent drugs has revived interest in dual and mono therapies, wrote Pisaturo Mariantonietta, MD, of the University of Campania Luigi Vanvitelli, Naples, Italy, and colleagues.
In a study published in Clinical Microbiology and Infection, the researchers identified 14 articles including 5,205 treatment-naive HIV adults. The studies were published between 2008 and 2020; 13 were randomized, controlled trials.
The dual therapies used in the studies included atazanavir/r plus maraviroc; lopinavir/r plus lamivudine; raltegravir plus darunavir/r; lopinavir/r plus tenofovir, raltegravir, efavirenz, or maraviroc; atazanavir/r plus raltegravir and darunavir/r plus maraviroc; and dolutegravir plus lamivudine.
Overall, no significant differences occurred in the primary endpoint of treatment failure across 10 studies between dual therapy and triple therapy patients based on data at 48 weeks (relative risk 1.20). “The rate of treatment failure did not differ among the two groups when stratifying the patients according to the drug used in the dual regimen,” the researchers said.
Low viral load’s link to treatment failure
Among 2,398 patients with a low HIV viral load (less than 100,000 copies/mL), dual therapy patients were significantly more likely to experience treatment failure than were triple therapy patients (RR, 1.47, P = .007). No differences were noted between dual and triple therapy failure among patients with high HIV viral loads at baseline. Patterns were similar at 96 weeks, but only three studies included 96-week data, the researchers said.
The rate of discontinuation because of adverse events was not significantly different between the groups at 48 weeks.
The study findings were limited by several factors, including the use of different regimens in the dual strategies, some of which are no longer in use, as well as there being insufficient data to fully compare outcomes at 96 weeks, and lack of information on cerebrospinal fluid viral load, the researchers noted.
However, the results suggest that dual therapy might be considered for HIV-naive patients with a low viral load, they said.
“Further RCTs that will evaluate the efficacy of antiretroviral regimens in use today among difficult-to-treat populations, such as patients with high viral load, including both intention-to-treat and per-protocol analysis, are needed to address this topic,” they concluded.
Consider range of patient factors when choosing therapies
Conducting the study at this time was important because of the expanding options for treating HIV patients, Donna E. Sweet, MD, an HIV specialist and professor of medicine at the University of Kansas, Wichita, said in an interview.
“We now have two single tablet formulations that are dual rather than triple therapy, and as treaters we are all trying to know when to use them,” she explained.
Dr. Sweet said she was not surprised by the study findings, given that well-conducted, randomized, controlled trials allowed the combination therapies to be approved.
Some of the key challenges to identifying the optimal treatment for HIV patients include factoring in the use of concomitant medications that could lead to drug-drug interactions, noted Dr. Sweet, who serves an editorial advisory board member of Internal Medicine News.
The take-home message for clinicians, in her opinion, is that “less drugs may mean less toxicity, but we don’t want to sacrifice efficacy,” she said. “There may be patients who are better suited than others for two vs. three drugs,” Dr. Sweet emphasized.
The next steps for research on the value of dual vs. triple therapy should include longer term efficacy studies, especially in those with lower CD4 counts and higher viral loads, said Dr. Sweet. In addition to factors such as CD4 counts and viral load, the food requirements of certain ART regimens could affect adherence and therefore a clinician decision to use two drugs rather than three, she noted.
Dr. Sweet disclosed past relationships with ViiV, Gilead, Merck, and Janssen on their speakers bureaus, and current advisory roles with Gilead and ViiV.
The study received no outside funding. Lead author Dr. Mariantonietta and several coauthors disclosed relationships with companies including ViiV Healthcare, AbbVie, Janssen-Cilag and Gilead Science, and Merck Sharp & Dohme, but no conflicts in connection with this study.
SOURCE: Mariantonietta P et al. Clin Microbiol Infect. 2020 Oct 5. doi: 10.1016/j.cmi.2020.09.048.