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.


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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.

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Researchers concluded that switching to a 2-drug regimen was noninferior to continuing a 3-drug regimen with high rates of maintained viral suppression.

Reference

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.