Cicaprost does not affect tumor inhibitory potential of cytostatic drugs.

Cicaprost, a stable prostacyclin analogue with antimetastatic potential, was investigated as regards its effect on the tumor inhibitory potential of cytostatic drugs exhibiting different modes of action in the MXT-OVEX mouse mammary carcinoma. Cicaprost itself in doses of 0.5 mg/Kg and 1.0 mg/Kg po. daily had no effect on the growth of the sc.-implanted tumor. cis-Platinum at a dose of 1.5 mg/Kg sc. strongly inhibited tumor growth, while at a dose of 0.75 mg/Kg only a weak effect was seen. The efficacy of both treatments was not altered by cicaprost (0.5 mg/Kg; po.) administered in two different schedules. Whereas cyclophosphamide (400 mg/Kg; sc) completely inhibited the growth of the MXT-OVEX tumor, doxorubicin (2.5 mg/kg; sc.) and 5-FU (10 mg/Kg; sc.) had only a weak effect. The combination of cicaprost with either cyclophosphamide, doxorubicin or 5-FU did not alter the inhibition of tumor growth. On the basis of these data, we anticipate that the antimetastatic agent cicaprost can be used in combination with cytostatic regimens without interfering with their clinical effectiveness.