Two-Drug Regimen Increases Risk for Virologic Failure in Individuals With HIV Infection

The following article is a part of conference coverage from the IDWeek 2021, being held virtually from September 29 to October 3, 2021. The team at Infectious Disease Advisor will be reporting on the latest news and research conducted by leading experts in the field. Check back for more from the IDWeek 2021.

In individuals with HIV Infection who previously achieved virologic suppression, the risk for virologic failure was increased among those who switched to a single-tablet 2-drug (2DR) regimen compared with those who switched to a single-tablet 3-drug (3DR) regimen. These findings were presented at IDWeek, held virtually from September 29 to October 3, 2021.

This study was a retrospective observational analysis of the Trio Health HIV Research Network cohort, which comprised a total of 60,000 participants with HIV infection. Participants who had previously achieved virologic suppression were switched to either dolutegravir/rilpivirine (2DR), dolutegravir/lamivudine (2DR), or a 3DR regimen. Efficacy for treatment was assessed, and virologic failure was defined as 2 consecutive viral loads with a CD4 count greater than200 cells/mL.

Of participants (n=1668) who had achieved virologic suppression, 8% (n=132) received the 2DR regimen. At baseline, comparisons between the 2DR group vs the 3DR group showed that the 2DR group included a greater number of participants who were White (52% vs 39%; P <.05) and fewer who were Black (27% vs 43%; P <.05). Additional comparisons between the 2DR vs 3DR groups showed that the 2DR group included a greater number of participants with an estimated glomerular filtration rate (eGFR) of less than 60/mL/min/1.73 m² (17% vs 6%; P <.05) and fewer with an eGFR of greater than or equal to 90 mL/min/1.73 m² (36% vs 55%; P <.05).

Virologic failure occurred among 7% of participants in the 2DR group vs 4% of those in the 3DR group (P =.166), with a mean time to failure of 963.7 and 982.8 days (P =.089), respectively.

The risk for virologic failure among participants who received the 2DR regimen was not significantly different compared with those who received the 3DR regimen (hazard ratio [HR], 1.8; 95% CI, 0.9-3.7; P =.094). After adjustment for gender, ethnicity, age, and eGFR, the researchers noted a statistically significantly increased risk for virologic failure among participants who received the 2DR regimen (adjusted HR, 2.2; 95% CI, 1.1-4.5; P =.032).

This study was likely limited by its small sample of individuals who were switched to the 2DR regimen. In addition, it remains unclear whether 1 of the 2DR combinations was more strongly associated with virologic failure.

These data indicated that among individuals with HIV infection who previously achieved virologic suppression, a single-tablet 2DR regimen was associated with an increased risk for virologic failure compared with a single-tablet 3DR regimen. “Future analysis is warranted using a larger sample of [participants treated with the] 2DR [regimen], with additional adjustment for prior regimen failure,” the researchers concluded.

Disclosure: Some author(s) declared affiliations with industry. Please refer to the original article for a full list of disclosures.

Reference

Sax P, Eron JJ, Radtchenko J, et al. Risk of virologic failure among treatment-experienced suppressed people with HIV (PWH) treated with single-tablet 2-drug (2DR) vs 3-drug (3DR) regimens. Presented at: IDWeek; September 29 to October 3, 2021.Poster 77.

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