Noninferiority of the once-daily 2-drug versus the once-daily 3-drug ARV regimen was demonstrated in both the GEMINI-1 and GEMINI-2 trials for the intent-to-treat-exposed population. In GEMINI-1, 90% (n = 320) in the 2-drug ARV group achieved virologic suppression at week 48 compared to 93% (n = 332) in the 3-drug ARV group (no statistically significant difference). In GEMINI-2, 93% (n =335 ) in the 2-drug ARV group achieved virologic suppression at week 48 compared to 94% (n = 337) in the 3-drug ARV group (no statistically significant difference).
A subgroup analysis found no significant impact of baseline HIV RNA (> 100,000 compared to ≤ 100,000 copies/mL) on achieving virologic suppression at week 48. However, a subgroup analysis did find that participants with CD4 counts < 200 copies/mL had a reduced response in the once-daily 2-drug versus 3-drug ARV regimen for achieving virologic response at week 48 (79% versus 93%, respectively).
Overall, 10 participants met virological withdrawal criteria during the study period, and 4 of these were on the 2-drug ARV regimen. For these 10 participants, genotypic testing did not find emergence of resistance to either nucleoside reverse transcriptase or integrase strand transfer inhibitors.
Regarding renal biomarkers, increases of both serum creatinine and urinary excretion of protein creatinine were significantly greater in the 3-drug ARV group. Also, biomarkers indicating increased bone turnover were elevated in both groups, but the degree of elevation was significantly lower in the 2-drug ARV regimen cohort. It is unclear whether these findings reflect an increased or decreased risk of developing osteopenia or osteoporosis in the 2 study groups.
Conclusion. The once-daily 2-drug ARV regimen dolutegravir and lamivudine is noninferior to the guideline-recommended once-daily 3-drug ARV regimen dolutegravir, TDF, and emtricitabine at achieving viral suppression in ART-naive HIV-1 infected individuals with HIV RNA counts < 500,000 copies/mL. However, the efficacy of this ARV regimen may be compromised in individuals with CD4 counts < 200 cells/mL.