Baseline antiretroviral resistance mutations and treatment-emergent resistance in HIV-1 RNA-suppressed patients switching to EVG/COBI/FTC/TDF or continuing on their PI-, NNRTI-, or RAL-based regimen

Safety and efficacy of switching to elvitegravir, cobicistat, emtricitabine, tenofovir disoproxil fumarate in treatment-experienced people with HIV: a multicenter cohort study

OBJECTIVES

We assessed the virologic efficacy of switching to co-formulated elvitegravir, cobicistat, emtricitabine, tenofovir disoproxil fumarate (E/C/F/TDF) in patients with controlled HIV infection.

METHODS

We conducted a retrospective multicenter observational cohort study including adult patients with controlled HIV-1 infection on any stable antiretroviral (ART) regimen, who switched to E/C/F/TDF. Success was measured by the proportion of patients with plasma viral load < 50 copies/ml at W48 using the FDA snapshot algorithm. We also assessed risk factors associated with virological failure (VF).

RESULTS

382 patients with HIV RNA < 50 copies/mL who switched to E/C/F/TDF were included in the study. Most patients (69.9%) were male, with median age 44 years (IQR 38-51), who had been on ART for a median of 7 years (IQR 4-13). Median CD4 count was 614/mm³ and 24.6% of the patients had a history of previous virological failure. The reasons for switching were simplification (67.0%) and tolerance issues (22.0%). At week 48, 314 (82.0% [95% CI 78.4-86.0]) patients had HIV RNA < 50 copies/mL, 13 (3.5% [95% CI 3.64-8.41]) experienced virological failure. Genotype at failure was available in 6/13 patients with detection of resistance-associated mutations to integrase inhibitors and NRTIs in 5/6 (83.3%) patients. We found no predictive factor associated with virological failure except for a borderline significance with the duration of viral suppression before the switch. Tolerability of E/C/F/TDF was good with 23/382 (6.0%) patients experiencing mild adverse reactions.

CONCLUSION

In our cohort, switching well-suppressed patients to E/C/F/TDF resulted in few virologic failures and was well tolerated. However, resistance to integrase inhibitors emerged in patients with virological failure.

Prevalence of Antiretroviral Drug Resistance Mutations in HIV Seropositive Patients from an Outpatient Clinic of a Large University Hospital from São Paulo, Brazil

Drug resistance mutations (DRMs) can affect the success of the therapy and compromise new prevention strategies. Increasing rates of resistance to antiretroviral (ARV) drugs have been reported in some areas. This study evaluated the DRMs prevalence among patients at Hospital das Clínicas (São Paulo). Among treatment-naive patients, the prevalence of transmitted DRMs (Stanford Calibrated Population Resistance) was 8.4% (21/249), with 69% (75/109) of acquired resistance among treatment-experienced patients. Rates of transmitted DRM showed an increase (6.6% in 2002-2009 vs. 15.1% in 2010-2015, p = .05), from the first to the second decade, mainly due to mutations to the NNRTI (non-nucleoside reverse transcriptase inhibitor) class. Among treatment-experienced cases, a nonsignificant decrease overall, significant for the protease inhibitors (PIs) class, was documented. Subtype B predominated in both groups (78%), followed by subtype F, BF recombinants, and subtype C. Our results add to the growing evidence of an increase in transmitted DRM, document extensive DRM among experienced patients, and a decrease in resistance to PIs class that may reflect the increased use of boosted PIs and newer ARV classes in more recent years.

Accumulated pre-switch resistance to more recently introduced one-pill-once-a-day antiretroviral regimens impacts HIV-1 virologic outcome

BACKGROUND

One-pill-once-a-day regimens (OPODs) appeal to providers and patients. The impact of resistance to OPODs in routine clinical care is important yet unclear, particularly in treatment-experienced patients.

OBJECTIVES

We hypothesized that resistance to any OPOD component impacts treatment success and that historical, vs. most recent, resistance better predicts it.

STUDY DESIGN

In the largest RI HIV Center, we identified all patients starting/switching to Complera/Stribild, evaluated their 12-month viral load (VL) suppression, and examined the impact of demographic, clinical and laboratory data on it, focusing on recent-only vs. accumulated significant resistance, defined as low-, intermediate- or high-level predicted resistance to any OPOD component. Associations with outcomes were evaluated using Fisher exact and Wilcoxon rank sum tests. Hypotheses were tested using logistic regression.

RESULTS

Of 1624 patients, 224 started/switched to Complera or Stribild, mean age 44 years, 8 years post-diagnosis, CD4 468 cells/μL; 183 treatment-experienced (140 with genotypes; 61% suppressed at switch). Significant OPOD-associated resistance was in 30% by recent-only genotypes, and 38% by all genotypes. 12-month VL suppression was in 83% of treatment-experienced participants: 96% of suppressed at switch, associated with older age, higher CD4, fewer prior genotypes, less accumulated resistance, and better adherence; and 61% of unsuppressed at switch, associated with better adherence. Accumulated resistance independently predicted 12-month failure, better than most-recent resistance only.

CONCLUSION

12-month VL suppression with Complera/Stribild was high, suggesting that OPODs remain options even for experienced patients. Clinicians should consider resistance history before switching to OPODs and continue to focus on improving adherence.