In the context of a rilpivirine/emtricitabine/tenofovir disoproxil fumarate switch in HIV-1-infected patients with at least 1 year of virological success, we determined whether proviral DNA is an alternative to plasma HIV RNA for resistance genotyping.
Resistance-associated mutations (RAMs) in DNA after at least 1 year of virological success [viral load (VL) <50 copies/mL] were compared with those identified in the last plasma RNA genotype available. Rilpivirine/emtricitabine/tenofovir disoproxil fumarate RAMs studied were K65R, L100I, K101E/P, E138A/G/K/R/Q, V179L, Y181C/I/V, M184V/I, Y188L, H221Y, F227C and M230I/L in the RT. We studied patients without virological failure (VF) and with at least 1 VF (two consecutive VLs >50 copies/mL). Kappa’s coefficient was used to measure agreement between the DNA and RNA genotypes.
In patients without VF (n = 130) and with VF (n = 114), RNA and DNA showed resistance to at least one drug of the rilpivirine/emtricitabine/tenofovir disoproxil fumarate combination in 8% and 9% and in 60% and 45%, respectively. For rilpivirine RAMs, correlation between RNA and DNA was higher in patients without VF than in patients with VF (kappa = 0.60 versus 0.19, P = 0.026). Overall, the prevalence of RAMs was lower in DNA than in RNA.
Incomplete information provided by the DNA genotypic test is more notable in patients with VF, suggesting that all resistance mutations associated with prior VF have not been archived in the proviral DNA or decreased to a level below the threshold of detection. In the case where no historical plasma genotypic test is available, DNA testing might be useful to rule out switching to rilpivirine/emtricitabine/tenofovir disoproxil fumarate.