Antitumor activity of Virulizin, a novel biological response modifier (BRM) in a panel of human pancreatic cancer and melanoma xenografts.

Abstract

To define the anticancer efficacy of Virulizin in vivo as a single agent or in combination with conventional drugs in human pancreatic tumor and melanoma xenografts. The therapeutic effect of Virulizin was evaluated in a series of human tumor xenografts in athymic nude mice. Virulizin had a high level of antitumor activity against all the pancreatic tumors (BxPC-3, SU 86.86. and Mia-PaCa-2) and melanomas (C8161 and A2058), as indicated by suppression of tumor growth with an optimal T/C value of <or=40% when administered as a single agent. No significant changes in Virulizin antitumor activity were observed when different schedules (3 days/week vs 7 days/week) or routes of administration (i.p. vs i.m.) were used. In combination therapy, Virulizin significantly enhanced the antitumor activity of gemcitabine and 5-fluorouracil against pancreatic tumors and of dacarbazine against metastatic melanomas, as reflected by a further decrease in tumor growth as compared to tumors in animals treated with the conventional drugs alone. These studies suggest that Virulizin effectively inhibits the growth of solid human pancreatic tumors and melanomas in the xenograft model.