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.