A phase II study of combined intravenous and subcutaneous interleukin-2 in malignant pleural mesothelioma.

A total of 29 previously untreated patients with histologically proven malignant pleural mesothelioma, with an ECOG score of < or = 2 and UICC stage I-II disease, were enrolled between May 1994 and October 1996. On days 1 and 2, 18 x 10(6) IU/day of rIL-2 was administered by continuous intravenous infusion, and 6 x 10(6) IU/day of rIL-2 by subcutaneous injection on days 5--20 inclusive of a 42-day cycle. Further treatment was administered if no radiological disease progression was demonstrated. A total of 29 patients were assessable for toxicity and 25 for response, and 49 cycles of IL-2 were administered with a median of one per patient (range, < 1-4). Toxicity included mild fever, nausea and vomiting, and skin rashes, < grade II. Three patients failed to complete one cycle of treatment because of toxicity and one died of disease before response evaluation. Two patients achieved a partial response (8%, 95% CI 1-26%) surviving 18.1 and 18.7 months from diagnosis. A total of 11 patients (44%, 95% CI 24-65%) with stable disease had a median survival of 13.6 months (range 6.5-33.8). The median survival was 8.6 months (range 3.7-34.5) for the 12 patients with progressive disease (48%, 95% CI 28-69%). This regimen of rIL-2 is well tolerated and shows limited activity in mesothelioma.