CYP1A1 and 1B1-mediated metabolic pathways of dolutegravir, an HIV integrase inhibitor.

Dolutegravir (DTG), a potent integrase inhibitor, is part of a recommended initial regimen for the treatment of human immunodeficiency virus (HIV). Prior reports demonstrated that the clearance of DTG was higher in current smokers than non-smokers, but the mechanism remains unclear. Using a metabolomic approach, M4 (an aldehyde) was identified as a novel metabolite of DTG. In addition, the formation of M4 was found to be mediated by cytochrome P450 (CYP) 1A1 and 1B1, the enzymes that can be highly induced by cigarette smoking. CYP1A1 and 1B1 were also identified as the major enzymes contributing to the formation of M1 (an N-dealkylated metabolite of DTG) and M5 (an aldehyde). Furthermore, the production of M1 and M4 was significantly increased in the lung of mice treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin, an inducer of CYP1A1 and 1B1. In summary, the current study uncovered the CYP1A1 and 1B1-mediated metabolic pathways of DTG. These data suggest that persons with HIV infection receiving DTG should be cautious to cigarettes, and drugs, or exposure to environmental chemicals that induce CYP1A1 and 1B1.