1-{[(4R,7S,10S,16S)-7-(2-amino-2-oxoethyl)-10-(3-amino-3-oxopropyl)-13-[(2S)-butan-2-yl]-16-(3,5-dibromo-4-hydroxybenzyl)-20,20-diethyl-6,9,12,15,18-pentaoxo-1,2-dithia-5,8,11,14,17-pentaazacycloicosan-4-yl]carbonyl}prolyl-L-leucylglycinamide