Viking-3 study is a single-arm, open-label, multi-center study which evaluated dolutegravir 50 mg BID in ART-experienced patients. Inclusion criteria where HIV-1 RNA ≥ 500 copies/mL at screening and documented evidence (at screening or historic) of resistance to raltegravir and/or elvitegravir and to ≥ 2 other ARV classes. Patients received a 7-day functional monotherapy of DTG 50 mg BID (replacement of raltegravir or elvitegravir by dolutegravir in the previously failing antiretroviral therapy regimen) followed by a second phase with continuation of dolutegravir 50 mg BID and optimization of the background ART according to baseline resistance data, with the need to have in this new regimen ≥ 1 fully active drug. Primary efficacy endpoints: mean change in HIV-1 RNA at day 8 was -1.43 log10 c/mL; 69% of patients achieved HIV-1 RNA < 50 c/mL at week 24. In multivariate analysis, there was a strong association between baseline DTG susceptibility and response. Response was the lowest in subjects with integrase mutation Q148 plus ≥ 2 resistance-associated mutations. Tolerance of DTG BID was good with only 3% of discontinuation due to adverse events.
In conclusion, dolutegravir 50 mg BID is effective in highly treatment-experienced HIV infected patients with integrase resistant virus, when combined with at least one fully active drug.