The primary aim of this study is to validate the integrated population PK-VD model that quantitatively describes the relationship between dolutegravir (DTG) exposure and HIV viral decay in blood plasma. The second aim of this study is to develop an integrated population pharmacokinetic-viral dynamic (PK-VD) model to describe the relationship between DTG exposure and HIV viral decay in peripheral blood mononuclear cells and rectal tissue reservoir sites. The third aim is exploratory and will investigate sex differences in DTG penetration into blood plasma, peripheral blood mononuclear cells and rectal tissue reservoirs reservoirs as well as its impact on the rectal microbiome.