Cytotoxic activity of 9-beta-D-arabinofuranosyl-2-fluoroadenine 5-monophosphate (fludarabine, NSC 312887) in a human tumor cloning system.

A human tumor cloning system was utilized to screen for in vitro antitumor effects of the new purine antimetabolite 9-beta-D-arabinofuranosyl-2-fluoroadenine 5-monophosphate. Two hundred and thirty-one specimens were evaluable for drug sensitivity information (i.e. greater than or equal to 20 colonies on control plates). The overall in vitro response rates (defined as a less than or equal to 50% survival of tumor colony forming units) at two different concentrations of the new drug (0.1; 1.0 micrograms/ml) were between 21 and 24%. The new drug had significant antitumor activity (i.e. in more than 35% of specimens of those with at least five tested specimens) only against non-Hodgkin's lymphoma and breast cancer.