Therapeutic activity of pretazettine on Ehrlich ascites carcinoma: adjuvant effect on standard drugs in ABC regimen.

A narcissus alkaloid, pretazettine hydrochloride (PTZ), has been shown to be active against Ehrlich ascites carcinoma. The Ehrlich cells are more sensitive to PTZ in DBA/2 mice than in Swiss mice. The therapeutic activity of the individual standard drugs in ABC (adriamycin, BCNU, and cyclophosphamide) regimen against Ehrlich ascites carcinoma has been increased remarkably by the adjuvant therapy of PTZ following the preliminary use of standard drugs. The independent inhibitory action of PTZ on cellular protein synthesis in the presence of the DNA-binding agent has been demonstrated in KB-cell cultures. Adriamycin-pretreated KB cells are found to be more sensitive to PTZ than nontreated cells.