Antineoplastic activity and toxicity of an organometallic complex of ruthenium(II) in comparison with cis-PDD in mice bearing solid malignant neoplasms.

The antineoplastic activity of an organometallic complex of ruthenium(II), [cis-RuCl2(DMSO)4]o, has been examined in comparison with that of cis-PDD, using three metastasizing tumors of the mouse: Lewis lung carcinoma, B16 melanoma and MCa mammary carcinoma. [cis-RuCl2(DMSO)4]o significantly reduces primary tumor growth in all the tumors tested, and its activity is similarly pronounced at three different dosages in mice bearing Lewis lung carcinoma. On the contrary, the survival time of animals having i.v. or i.m. tumor implants are only moderately increased, and also in the case of combined treatments with surgery. The antineoplastic activity of cis-PDD appears to be less pronounced than that of [cis-RuCl2(DMSO)4]o, and is limited to mice bearing B16 melanoma, which, among the three tumors used, appears to be naturally more responsive to cis-PDD and [cis-RuCl2(DMSO)4]o. The use of [cis-RuCl2(DMSO)4]o appears advantageous over that of cis-PDD since, unlike cis-PDD, its antineoplastic effects have been obtained at dosages with reduced host toxicity, indicated by the absence of significant hematological toxicity and toxicity for normal proliferating tissues.