Augmentation of activity of cis-diamminedichloroplatinum(II) and mitomycin C by interferon in human malignant mesothelioma xenografts in nude mice.

Abstract

Two human mesothelioma xenograft lines, BG and ES, serially passaged in athymic mice, were studied to determine the efficacy of alpha-interferon in this type of tumor. Treatment began after progressive tumor growth was established. Recombinant human alpha-interferon-2a (Roferon- A) was given by s.c. injection, at a site distant from the tumor, at a dose of 2 x 10(5) IU 5 days per wk for 5 wk. Mild inhibitory activity was noted in both lines with interferon alone. cis-Diamminedichloroplatinum(II) (CDDP) (4 mg/kg) weekly x 5 was effective in line BG, while mitomycin C (1.5 mg/kg) weekly x 3 was effective in line ES. CDDP was not as effective in line ES. The moderate activity of CDDP in line BG and of mitomycin C in line ES was markedly increased by the addition of alpha-interferon. The combination of mitomycin C and alpha-interferon was as effective as mitomycin C and CDDP. No additional toxicity was noted by the addition of alpha-interferon. The combination of recombinant human alpha-interferon-2a and active chemotherapeutic agents is effective in mesothelioma xenografts.