Early assessment of antiretroviral efficacy is critical to prevent the emergence of resistance mutations in HIV-tuberculosis coinfected patients: a substudy of the CARINEMO-ANRS12146 trial [version 1; peer review: 1 approved, 1 approved with reservations]

Background: In the CARINEMO ANRS 12146 clinical trial, HIV-tuberculosis co-infected patients in Mozambique were randomized to nevirapine (NVP) or to efavirenz (EFV)-based antiretroviral therapy to compare these two non-nucleoside reverse transcriptase inhibitors (NNRTIs) in treatment naïve patients. Methods: In this sub study, we explored the relationship of NNRTI concentrations with virological escape and the possible emergence of resistance mutations at week 48. The virological escape was defined as an HIV-RNA above 400 copies/m at week 48. Results: Among the 570 randomized patients, 470 (82%) had an HIV-RNA result at week 48; 54 (12.1%) patients had a viral escape and 35 patients had at least one major resistance mutation detected. Low drug concentration at weeks 12 and 24 (below the 10 th percentile) were independently associated with virologic escape at week 48 (adjusted odds ratio [aOR]=2.9; 95% CI: 1.1 -7.2; p=0.0312 and aOR=4.2; 95% CI: 1.8-9.8; p=0.0019, respectively), and independently associated with an increased risk of emergence of resistance mutation (aOR=4.5; 95% CI: 1.8-14.6; p=0.009 at week 12; aOR=5.1; 95% CI: 1.8-14.6 at week 24). Receiver operating characteristic curves analyses indicated a better predictability of the mid-dose concentration and of the HIV-1 RNA values on resistance mutations in contrast to virological escape. Conclusions: Very low drug plasma concentrations early after treatment initiation (week 12) were predictive factors of virological escape and the emergence of resistance mutations at week 48, and early monitoring of drug intake may prevent the occurrence of late virological escape and the selection of vial resistance mutations.