A synthetic process for manufacture of a tumor-vascular targeting antitumor agent wherein the antitumor agent comprises an annexin-1 binding peptide conjugated to an anticancer drug through a linker. An efficient, practical, reproducible and scalable process for the manufacturing of a tumor-vascular targeting antitumor agent wherein the antitumor agent comprises an annexin-1 binding peptide conjugated to an anticancer drug through a linker with high purity and yield.
