A cyclic depsipeptide extracted from the Caribbean tunicate Trididemnum cyanophorum. Didemnin B activates caspase, thereby inducing apoptosis, and prevents eukaryotic elongation factor 2 (eEF-2)-dependent translocation, thereby inhibiting protein synthesis. This agent also has immunosuppressive and antiviral properties. Check for active clinical trials using this agent. (NCI Thesaurus)