HIV-1 viral decay in blood and semen in antiretroviral-naïve adults initiating dolutegravir/lamivudine vs. bictegravir/emtricitabine/tenofovir alafenamide.

Background: Co-formulated dolutegravir and lamivudine (DTG/3TC) is recommended as the first-line antiretroviral therapy (ART); however, the data on the viral decay in seminal plasma (SP) and blood plasma (BP), as well as changes in inflammatory biomarkers in BP, remain limited among antiretroviral-naïve people with HIV (PWH) receiving DTG/3TC. A prospective observational cohort study was conducted to compare the impact of DTG/3TC vs. bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) on viral decay kinetics and changes in inflammatory biomarkers in antiretroviral-naïve PWH.

Methods: Newly diagnosed PWH who initiated BIC/FTC/TAF (n=57) or DTG/3TC (n=43) were enrolled. BP and SP were collected at 0, 4, 12, 24, and 48 weeks after ART initiation. The primary endpoint was viral suppression of HIV-1 in BP and SP at week 48. Secondary endpoints included changes in HIV-1 DNA levels and inflammatory biomarkers over the 48-week follow-up.

Results: Overall, 96 (96.0%) PWH completed the 48-week follow-up (DTG/3TC, n=40; BIC/FTC/TAF, n=56). Viral suppression rates in BP and SP were comparable in the BIC/FTC/TAF and DTG/3TC groups in the per-protocol analyses at week 48 (BP, 96.4% vs. 100%, P=0.519; SP, 100% vs. 100%, P>0.999). Both regimens demonstrated similar effectiveness in reducing HIV-1 RNA levels in BP (3.0 vs. 3.1 log copies/mL) and SP (0.9 vs. 1.2 log copies/mL). There were no statistically significant differences in the reductions in HIV-1 DNA levels and changes in inflammatory biomarkers over the 48-week follow-up.

Conclusion: These findings indicated comparable effectiveness of DTG/3TC vs. BIC/FTC/TAF in achieving viral suppression in BP and SP, and similar changes in inflammatory biomarkers in BP.