Omarigliptin (MK-3102) is a competitive, reversible inhibitor of DPP-4 (IC50 = 1.6 nM, Ki = 0.8 nM). It is highly selective over all proteases tested (IC50 > 67 μM), including QPP, FAP, PEP, DPP8, and DPP9 and has weak ion channel activity (IC50 > 30 μM at IKr, Caγ1.2, and Naγ1.5).