Carbamic acid, N-[(1S,2R)-2-[(1S)-2-(1-azetidinyl)-1-(3-fluorophenyl)-1-[1-[[1-[4-[[1-[(2E)-1-oxo-4-(1-piperidinyl)-2-buten-1-yl]-3-azetidinyl]sulfonyl]phenyl]-3-azetidinyl]methyl]-4-piperidinyl]ethyl]cyclopentyl]-, methyl ester

M-808 (16) is well tolerated in severe combined immunodeficiency (SCID) mice with intravenous administration of 10 mg/kg (or 25 mg/kg) every other day dosing (three times a week) for one week. M-808 (25 mg/kg) achieves a maximum tumor growth inhibition (TGI) of 97% during treatment (day 35) and reduces the average tumor volume from 92 mm³ at the beginning of the treatment to 59 mm³ at day 35, with no significant toxicity^[1].