Results from the DUALIS study demonstrated that dual therapy with dolutegravir (DTG) and boosted darunavir (bDRV) tended to be an effective treatment option with no treatment-emergent resistance for people with HIV receiving suppressive first or further-line antiretroviral therapy (ART) regardless of pre-existing resistance to nucleoside reverse-transcriptase inhibitors (NRTIs), non-NRTIs (nNRTI) or resistance-associated mutations (RAMs). These results were presented at the virtual Conference on Retroviruses and Opportunistic Infections, held from March 8 to 11, 2020.
Advances in potency and resistance barrier of ART for HIV infection support the use of dual therapy in specific patient populations. DUALIS is a phase 3b, open-label randomized clinical trial designed to investigate the effectiveness of switching to DTG+bDRV (2-drug regimen) vs continuous 2NRTI+bDRV (3-drug regimen) in patients with HIV who demonstrate virologic suppression.
The study included patients who demonstrated viral suppression for ≥24 weeks (HIV-RNA level <50 copies/mL), with no history/evidence of drug resistance to integrase strand transfer inhibitors or bDRV. Virologic outcomes in the subgroups included the primary end point of percentage of patients with HIV-RNA <50 copies/mL at week 48 and virologic nonresponse. The study cohort included 263 patients (2-drug regimen, n=131; 3-drug regimen, n=132), a majority of whom were men (90.1%), with a median age of 48 years; 47.0% showed a CD4 nadir <200/µL.
Results of the DUALIS study demonstrated that maintenance 2-drug therapy with DTG+bDRV was noninferior to continuous triple ART with 2NRTI+bDRV, with week-48 virologic response rates of 86% and 88%, respectively. In addition, neither the presence of protease inhibitor resistance-associated mutations that were unassociated with bDRV nor NRTI or NNRTI resistance-associated mutations affected virologic response in patients who received the 2-drug regimen after 48 weeks. There was also no development of treatment-emergent resistance.
A limitation of the study was that prior resistance testing was only available in roughly two-thirds of patients, with a limited number of patients with major protease or NRTI RAMs.
Researchers concluded that switching to a 2-drug regimen was noninferior to continuing a 3-drug regimen with high rates of maintained viral suppression.
Wolf E, Boesecke C, Balogh A, Bidner H, Cordes C, Heiken H, et al. Virologic outcomes by resistance category and pre-treatment in the DUALIS study. Poster presented at: CROI 2020; March 8-11, 2020.http://www.croiconference.org/sites/default/files/uploads/croi2020-boston-abstract-ebook.pdf. Accessed March 19, 2020.