What happens if a CCR5 antagonist is administered to a patient with D/M or X4 virus?
CCR5 antagonists show potent in vitro and in vivo antiviral activity against a broad range of viruses that use CCR5 to enter CD4+ cells, but do not show antiviral activity in CXCR4-using strains. A clinical trial exploring the use of maraviroc in patients who had D/M virus showed that the addition of maraviroc to optimized background therapy (OBT) did not reduce viral load further than OBT alone. However, there were no deleterious effects on viral load and, contrary to what was seen when X4 virus emerged during the natural course of disease, patients treated with maraviroc experienced a greater increase in CD4+ cell count at time of virologic failure than patients receiving OBT alone.
