Ineffective central nervous system HIV suppression of once-a-day maraviroc and ritonavir-boosted darunavir dual therapy: four case reports.

Novel two-drug combinations including a protease inhibitor are an attractive nucleoside reverse transcriptase inhibitor sparing option for some patients, particularly as a switch strategy. We have used the two-drug combination of maraviroc and darunavir/ritonavir once a day as a switch strategy in patients with stable low or undetectable plasma HIV viral loads, but identified four patients who failed on this combination, indicating it may be insufficient to prevent replication of neurotropic HIV in treatment-experienced patients. Further investigation of our cases highlighted the need for a better understanding of the plasma and cerebro-spinal fluid (CSF) pharmacodynamics of these drugs.