Results of a phase 3, noninferiority trial found that switching to dolutegravir/lamivudine (DTG/3TC) was noninferior compared with continuing various 3- or 4-drug current antiretroviral regimens (CAR) for maintaining virologic suppression among adults with HIV-1 infection. These findings were published in Clinical Infectious Diseases.

This trial was conducted at 119 centers across 17 countries between 2019 and 2021. Eligible patients included adults with virologically suppressed HIV-1 infection (HIV-1 RNA, <50 copies/mL) with no history of virologic failure. Enrolled patients (N=493) were randomly assigned in a 1:1 fashion to either switch to DTG/3TC (50 mg/300 mg) once daily (n=246) or continue treatment with CAR (n=247). Viral load was assessed on weeks 4, 12, 24, 36, 48, and 52. The primary endpoint was the number of adults who achieved virologic suppression at week 48.

Among patients in the DTG/3TC and CAR groups, the median age was 45 (range, 22-74) and 45 (range, 23-83) years, 44% and 34% were women, 61% and 58% were White, median CD4+ cell count was 675 (range, 154-2089) and 668 (range, 94-1954) cells/mm3, and the median duration of ART was 63 (range, 4-240) and 71 (range, 12-253) months, respectively.


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At week 48, 94% of patients in the DTG/3TC group and 93% of those in the CAR group maintained virologic suppression (adjusted difference, 1.6%; 95% CI, -2.8 to 5.9). The researchers noted that the median CD4+ cell count was increased among patients who received DTG/3TC (30.0 mm/3; IQR, -83.0 to 115.5) compared with those who received CAR (2.0 mm/3; IQR, -105.0 to 94.0) at 48 weeks, with a CD4+ to CD8+ cell count ratio of 0.04 and 0.05 mm/3, respectively.

Between baseline and week 48, the adjusted mean difference in BMI was increased among patients in the DTG/3TC group vs those in the CAR group (0.5 kg/m2; 95% CI, 0.2-0.8; P <.001). In addition, 3 patients in the DTG/3TC group and 1 patient in the CAR group were diagnosed with diabetes within the follow-up period.

Although the rate of self-reported adverse events (AE) was similar among the DTG/3TC and CAR groups (73% vs 70%, respectively), drug-related AEs were increased among patients who received DTG/3TC vs those who received CAR (20% vs 6%). The most commonly reported AEs were weight gain (8%), headache (7%), onset of COVID-19 infection (6%), back pain (6%), insomnia (6%), and dizziness (5%) among patients who received DTG/3TC. For the CAR group, the most common AEs were headache (7%) and upper respiratory tract infection (6%). A total of 5 and 3 patients in the DTG/3TC and CAR groups were lost to follow-up, respectively.

This study may have been limited by heterogeneity due to the variety of CART regimens included in the study.

These data support the effectiveness of DTG/3TC as a treatment option for a diverse population of individuals with HIV-1 infection.

Disclosure: Multiple authors declared affiliations with industry. Please see the original reference for a full list of disclosures.

Reference

Llibre JM, Brites C, Cheng C-Y, et al. Efficacy and safety of switching to the 2-drug regimen dolutegravir/lamivudine versus continuing a 3- or 4-drug regimen for maintaining virologic suppression in adults living with HIV-1: week 48 results from the phase 3, non-inferiority SALSA randomized Trial. Clin Infect Dis. 2022;ciac130. doi:10.1093/cid/ciac130