Switching to doravirine-based antiretroviral therapy without genotypic resistance tests in virologically suppressed...

Doravirine is a non-nucleoside reverse transcriptase inhibitor (NNRTI) recommended for first-line antiretroviral therapy (ART), and for suppressed switching, in combination with a two nucleos(t)ide reverse transcriptase inhibitor (NRTI) backbone. Doravirine does not have a high barrier to resistance, and genotypic resistance testing (GRT) preswitch is recommended. Data on its use without preswitching GRT is limited. This retrospective cohort study presents data on doravirine use in virologically suppressed people with and without prior GRT.

A retrospective single-center review of health records was conducted among prescribed doravirine-based ART at a London HIV service.

Of the 582 adults included, 75% were men, 56% were of White ethnicity. The median age at baseline was 51 years (IQR: 44-58). Median time on doravirine was 127 weeks (IQR: 93-175). GRT showing no doravirine resistance was available for 78% ( n   =  454) of individuals before switching to doravirine, of whom 2% experienced virological failure ( n   =  9), including two people with NNRTI and NRTI resistance. Among those without preswitching GRT ( n  = 97), 1% experienced virological failure ( n   =  1), with NNRTI and NRTI resistance. There was no statistical significant difference in virologic suppression (viral load <50 copies/ml) rates (GRT 95% versus no-GRT 95%; P  = 0.823). A similar proportion of people with (24%) and without (27%) preswitching GRT switched away from doravirine, most commonly due to adverse effects.

We did not find differences in efficacy and tolerability in people switched to doravirine-based ART with or without GRT. As expected, emergent NNRTI and NRTI resistance was common amongst those with virological failure on doravirine.