Responsiveness of the Madison 109 lung carcinoma to maleic vinyl ether copolymer.

This study establishes the responsiveness of mice bearing the Madison 109 lung carcinoma (M109), a tumor relatively resistant to chemotherapy, to the immunomodulator maleic vinyl ether (MVE-2; molecular weight 15,500). BALB/c mice inoculated with 5 X 10(5) M109 cells into the hind footpad developed a primary tumor which metastasized to the lung within 7 days and resulted in death of the host between 36 and 42 days. Early in the disease, weekly intratumor (i.t.) or intravenous administration of MVE-2 (25 mg/kg) inhibited the growth of the primary tumor and significantly prolonged the life span of the host. During the pulmonary metastatic process, systemic administration of MVE-2 alone or MVE-2 coupled with surgical excision or radiotherapy of the primary tumor became decreasingly efficacious. Late in the disease only MVE-2 introduced directly into the metastatic tumor bed by intrapleural injection proved to be effective in prolonging life span. These studies indicate that both the primary and metastatic M109 tumors are sensitive to MVE-2 and suggest that the efficacy of MVE-2 treatment is largely dependent upon its distribution in the tumor-bearing mice.