(3R)-4-[[(2R)-1-[[(2R)-1-[[(1S)-2-[[1-[3-[[(12aS)-8-methoxy-6-oxo-11,12,12a,13-tetrahydroindolo[2,1-c][1,4]benzodiazepin-9-yl]oxymethyl]-5-[[(12aS)-8-methoxy-6-oxo-12-sulfo-11,12,12a,13-tetrahydroindolo[2,1-c][1,4]benzodiazepin-9-yl]oxymethyl]-N-[2-[2-(2-methoxyethoxy)ethoxy]ethyl]anilino]-2-methylpropan-2-yl]disulfanyl]-1-carboxyethyl]amino]-3-carboxy-1-oxopropan-2-yl]amino]-5-(diaminomethylideneamino)-1-oxopentan-2-yl]amino]-3-methyl-4-oxobutanoic acid