Since an involvement of platelet aggregation in the metastatic process has been found, platelet activation inhibitors were investigated for their potential to reduce
tumor metastases. Recent in-vitro and in-vivo investigations showed an antimetastatic effect of
prostacyclin (PGI2) and stable
prostacyclin analogues. This study concentrates on the effect of the stable
prostacyclin analogue
Cicaprost (Schering AG) on
tumor metastases in two metastasizing
tumors of rodents. C57BL/6 mice bearing s.c.-implanted M5076 reticulum
sarcoma were treated with
Cicaprost in doses of 0.1-1.0 mg/kg throughout the experiment.
Cicaprost in all doses tested reduced the number of liver
metastases in a statistically significant manner. The 1.0 mg/kg dose, which decreases the median number of liver
metastases to more than 93% compared to the control, was most effective.
Cicaprost in the 0.5 mg/kg dose reduced the number of liver
metastases in mice bearing i.v.-implanted M5076 reticulum
sarcoma. In Cop-Fisher rats bearing s.c.-implanted spontaneously metastasizing R3327 MAT Lu prostate
carcinoma,
Cicaprost in a dose of 1.0 mg/kg p.o. daily strongly reduced the number of lung
metastases. These results indicate that
Cicaprost is a potent inhibitor of
tumor metastases in different
tumor models in rodents.