Antitumour effect of interferons, cytostatic drugs and their combinations in subrenal capsule assay (SRCA).

Combinations of interferons (IFNs) and cytostatic drugs were studied in subrenal capsule assay (SRCA) using fresh human ovarian cancer samples. Slight tumour growth inhibition was observed with IFN-alpha and IFN-gamma. The effect was more pronounced if combination IFN-alpha + IFN-gamma was used. Cytostatic drug combination cyclophosphamide + cisplatin + doxorubicin (combination I) was more effective than interferons, and combination methotrexate + tegafur (combination II) was about equal to IFN-alpha. When IFN-alpha was given together with cytostatic drugs, the antitumour effect was diverse: both synergistic and antagonistic effects were found, as well as no evidence of interaction. IFNs did not increase the toxicity of cytostatic drugs. If there is a good correlation between SRCA and clinical results, the combination of IFNs and cytotoxic drugs should be used clinically in connection with a predictive test.