Late treatment failures in cerebrospinal fluid in patients on long-term maintenance ART with ritonavir-boosted protease PI monotherapy

Evaluation of cerebrospinal fluid virological escape in patients on long-term protease inhibitor monotherapy

BACKGROUND

A strategy of protease inhibitor (PI) monotherapy with re-introduction of triple therapy in those who rebound has been shown to be a safe and effective treatment simplification approach for long-term management. We sought evidence for cerebrospinal fluid (CSF) virological escape in patients on long-term PI monotherapy.

METHODS

We performed lumbar puncture in asymptomatic participants with suppressed plasma HIV RNA after 96 weeks on the PI monotherapy arm (PI-mono) of the PIVOT trial. We also report CSF HIV RNA concentration in trial participants who were investigated for neurological/neurocognitive symptoms during the trial regardless of study arm allocation.

RESULTS

All 11 asymptomatic participants on PI-mono who were tested had undetectable CSF HIV RNA at week 96. One of the three symptomatic participants on PI-mono had CSF HIV RNA of 1,895 copies/ml (undetectable in plasma) and neither of two symptomatic participants on triple therapy had CSF HIV RNA detected.

CONCLUSIONS

CSF virological escape appears rare in asymptomatic patients on PI monotherapy and may not warrant routine CSF monitoring, but patients with symptoms merit more concern.

Refining criteria for selecting candidates for a safe lopinavir/ritonavir or darunavir/ritonavir monotherapy in HIV-infected virologically suppressed patients

Objective

The primary objective of this study was to estimate the incidence of treatment failure (TF) to protease inhibitor monotherapies (PI/r-MT) with lopinavir/ritonavir (LPV/r) or darunavir/ritonavir (DRV/r).

Design

A multicenter cohort of HIV-infected patients with viral load (VL) ≤50 copies/mL, who underwent a switch from any triple combination therapy to PI/r-MT with either LPV/r or DRV/r.

Methods

VL was assessed in each center according to local procedures. Residual viremia was defined by any HIV-RNA value detectable below 50 copies/mL by a Real-Time PCR method. Standard survival analysis was used to estimate the rate of TF (defined by virological failure or interruption of monotherapy or reintroduction of combination therapy). A multivariable Cox regression analysis with automatic stepwise procedures was used to identify factors independently associated with TF among nadir and baseline CD4+ counts, residual viremia, time spent with <50 HIV-RNA copies/mL before switch, history of virological failure, HCV co-infection, being on a PI/r and hemoglobin concentrations at baseline.

Results

Six hundred ninety patients fulfilled the inclusion criteria and were included in this analysis. Their median follow-up was 20 (10–37) months. By month 36, TF occurred in 176 (30.2%; 95% CI:25.9–34.5) patients. Only CD4+ nadir counts (adjusted hazard ratio [aHR] = 2.03 [95% CI: 1.35, 3.07] for counts ≤100 vs. >100 cells/μL) and residual viremia (aHR = 1.48 [95% CI: 1.01–2.17] vs. undetectable VL) were independently associated to TF.

Conclusions

Residual viremia and nadir CD4+ counts <100 cells/μL should be regarded as the main factors to be taken into account before considering switching to a PI/r-MT.