Abstract: Vinblastine derivatives of the formula ##STR1## wherein R.sub.1 is an ester of a .alpha.-aminoacid selected from the group consisting of glycine, alanine, valine, leucine, isoleucine, serine, threonine, aspartic acid, glutamic acid, aspargine, glutamine, arginine, lysine, cysteine, cystine, methionine, phenylalanine, tyrosine, tryptophan, proline, histidine, hydroxy-lysine, hydroxyproline, or of a peptide consisting of 1-6 identical or different such amino-acids, and the ester group, which may be straight or branched, being a carboalkoxy group having 2-9 carbon atoms, and R.sub.2 is hydrogen or a C.sub.2 -C.sub.9 alkanoyl group, R.sub.5 is H or OH, R.sub.6 is CH.sub.3, CHO or H and X=H or Br and their pharmaceutically acceptable mineral or organic acid addition salts. The compounds are useful as antitumor drugs.

Abstract: Amino acid derivatives of vinblastine, including peptide derivatives, methods of their preparation and pharmaceutical compositions containing such vinblastine derivatives for use as antitumor agents are described.