The combinational treatment between the selective antimetastatic agent, sodium-trans-rutheniumtetrachloridedimethylsulfoxideimidazole,
Na[trans-RuCl4(DMSO)Im], and the cytotoxic drug
5-fluorouracil (5-FU) on primary tumor growth and on the survival time of experimental tumors results
in an effect significantly greater than that of each single agent used alone either with the solid
metastasizing MCa mammary carcinoma of the CBA mouse or with the lymphocytic leukemia P388
and its platinum resistant P388/DDP subline. Thus the inorganic compound Na[trans-RuCl4(DMSO)Im], known for its potent and selective antimetastatic effects, positively interacts with
the antitumor action of an organic anticancer agent such as 5-FU on both a solid metastasizing
tumor and a tumor of lymphoproliferative type. In particular, the effects of the combinational
treatment on the survival time of tumor bearing mice seem to be related to the selective
antimetastatic activity of the ruthenium complex that joins the potent cytotoxicity of 5-FU for the
tumor. Moreover, these data show that Na[trans-RuCl4(DMSO)Im] is almost as effective on the
subline of P388 made resistant to cisplatin as it was on the parental line.