GSK announced "positive" results from a study comparing the efficacy of the 2-drug regimen dolutegravir/lamivudine (DTG/3TC) to the 3-drug regimen bictegravir/emtricitabine/tenofovir alafenamide fumarate (BIC/FTC/TAF) in managing virologically-suppressed adults living with HIV after 48 weeks of therapy. Both regimens are administered as a single tablet per day.

According to GSK and ViiV Healthcare, Dovato (DTG/3TC) exhibited non-inferior antiviral efficacy compared to Biktarvy (BIC/FTC/TAF) while resulting in significantly less weight gain. The results of the study will be presented this month at the 25th International AIDS Conference in Germany.

Using the FDA snapshot and a 4% non-inferiority margin (risk difference between the two regimens) in the exposed intention-to-treat group, the study's primary goal was achieved when dolutegravir/lamivudine showed non-inferior efficacy over bictegravir/emtricitabine/tenofovir alafenamide fumarate. This conclusion was based on the percentage of patients with viral RNA equal to or above 50 copies/mL at 48 weeks.

The clinical trial, named PASO DOBLE, demonstrated a non-inferiority margin of 1.4%, with 2.2% of participants on Dovato and 0.7% of participants on Biktarvy having viral RNA at or above 50 copies/mL in their blood samples. PASO DOBLE, conducted by the SEIMC-GeSIDA Foundation (FSG) across 30 sites in Spain, included virologically suppressed individuals on regimens containing one or more pills per day, boosters, or drugs with cumulative toxicity such as efavirenz or tenofovir (TDF). Participants were then randomized (1:1) to either DTG/3TC or BIC/FTC/TAF.

In a secondary endpoint, the study found a significantly higher increase in weight among participants who transitioned to BIC/FTC/TAF (adjusted mean change of 1.81 kg) compared to those who switched to DTG/3TC (adjusted mean change of 0.89 kg). Additionally, the proportion of individuals who experienced weight gain of more than 5% was significantly higher for BIC/FTC/TAF at 29.9% compared to 20% for DTG/3TC.

"This is a meaningful outcome, as treatment-related weight gain is an important topic for many people living with HIV," stated Harmony P. Garges, Chief Medical Officer of ViiV Healthcare.