Thanks for sharing the pharmacogenomic paper, but

Thanks for sharing the pharmacogenomic paper, but I don't understand how a drug being broken down in the body automatically leads to toxicity for that drug. All drugs are broken down / metabolized eventually. Are you saying maraviroc has toxic metabolites when broken down in the liver by CYP450 system? If so, what are they? Or are you saying that simply taxing the CYP3A4 and CYP3A5 pathways in itself is somehow harmful? Or are there off-target effects (perhaps on other CCRs) of maraviroc?