NEW ANTITUMORAL CYCLOPEPTIDES

Chlamydocin is a powerful in vitro antitumoral agent, quickly inactiva ted in vivo. A series of cyclic tetrapeptides related to chlamydocin o r HC toxin and bearing a bioactive alkylating group on an epsilon-amin o-lysyl function have been examined for their antitumoral activity on L1210 and P388 murine leukemia cell lines. One analog was found to be potent at inhibiting L1210 cell proliferation and had a higher therape utic index than the reference compound bis-beta-chloroethylnitrosourea on the in vivo P388-induced leukemia model.