Coadministration has not been studied but based on metabolism and clearance a clinically significant interaction is unlikely. Alemtuzumab is a monoclonal IgG antibody. Elimination is similar to endogenous IgG and occurs primarily via proteolytic catabolism throughout the body. Raltegravir is mainly metabolized by UGT1A1. CYP-mediated drug interactions are not expected with alemtuzumab. Note, use of alemtuzumab (marketed as Lemtrada) for the treatment of relapsing remitting multiple sclerosis is contraindicated in patients with HIV infection as it causes prolonged reductions of CD4+ lymphocyte counts.