MK-2048 is a second generation integrase inhibitor, intended to be used against HIV infection. MK-2048 inhibits subtype B and subtype C integrase activities. MK-2048 inhibits R263K mutants slightly more effectively than G118R mutants. MK-2048 inhibits S217H intasome and, by contrast, MK-2048 remains fully active against the N224H intasome. MK-2048 displays substantially lower dissociation rates compared with raltegravir, another integrase inhibitor. MK-2048 is active against viruses resistant to RAL and EVG. MK-2048 exposure leads to the selection of G118R as a possible novel resistance mutation after 19 weeks. MK-2048, with continued pressure, subsequently leads to an additional substitution, at position E138K, after 29 weeks, within the IN gene. Although the G118R mutation alone confers only slight resistance to MK-2048 but not to RAL or EVG, its presence arouses a dramatic reduction in viral replication capacity compared to wild-type NL4-3. E138K both partially restores viral replication capacity and also contributes to increased levels of resistance against MK-2048.