Background: Experiments in animal tumor models suggest that the antitumor effects of interleukin-2 (IL-2) or IL-2 in combination with lymphokine-activated killer (LAK) cells can be enhanced by chemotherapy agents such as cyclophosphamide or doxorubicin or by the biologic agent interferon alpha.
Purpose: We determined the toxicity and clinical response rate of an IL-2-LAK cell regimen modified by the addition of moderate, immunomodulatory doses of chemotherapy and sequenced with interferon alfa-2a (IFN alpha-2a) in patients with metastatic melanoma and renal cell carcinoma.
Methods: IL-2 (3-6 million units/m2 per day) was administered by continuous infusion on days 0-5 and days 11-16. LAK cells were infused on days 11 and 12 or on days 11, 12, and 14. Low doses of cyclophosphamide (300 mg/m2) and doxorubicin (25 mg/m2) were given on day 9 before the LAK cell infusions. Following the IL-2-LAK cell infusion, IFN alpha-2a (12 million units/m2) was administered for a total of nine doses to complete a cycle of treatment. A total of 89 patients were enrolled in the study.
Results: For each histology, there were eight partial responses in 40 assessable patients, for an overall response rate of 20% (90% confidence interval = 10%-33%). The median response duration was 5 months, although two patients with renal cell carcinoma and one patient with metastatic melanoma had almost complete disappearance of tumor and are still responding after 26+, 22+, and 26+ months, respectively. Toxic effects were severe in patients receiving the highest dose of IL-2 administered in this study and similar to those reported with other high-dose IL-2-LAK cell regimens. Although toxic effects were completely reversible in most patients, there were four treatment-related deaths.
Conclusions: This regimen is active in patients with metastatic melanoma and renal cell carcinoma and produces meaningful responses in a small percentage of these patients; however, it is not clear whether cyclophosphamide, doxorubicin, and IFN alpha-2a as used in this protocol appreciably augmented the antitumor activity of the IL-2-LAK cell regimen.