Purpose: The Cancer and Leukemia Group B (CALGB) conducted a multi-center phase II trial to evaluate the activity of irinotecan in malignant mesothelioma (CALGB protocol 9733).
Patients and methods: Twenty-eight patients accrued between January 1998 and January 1999 received irinotecan 125 mg/m2 by intravenous infusion over 90 min weekly for 4 weeks, every 6 weeks. Eligibility included a performance status of 0-2 by CALGB criteria, and no prior chemotherapy. Twenty-five patients had pleural mesothelioma; two patients had peritoneal mesothelioma, and one patient had pericardial mesothelioma. Sixty-one percent of patients had epithelial histology.
Results: There were no complete or partial responders. Thirty-three percent of patients had stable disease and 52% were shown to have progressive disease at the first reassessment. One patient was not evaluable for response. Median survival from study entry was 9.3 months (95% CI 4.5-13.2 months); 1-year survival was estimated at 46% (95% CI 28-65%). Toxicity was moderately severe. Grade 3 or 4 toxicities included neutropenia in 28% of patients, lymphopenia in 43%, and diarrhea in 18%. Three patients died of treatment-related toxicities. All three experienced grade 4 diarrhea, two also had neutropenic sepsis.
Conclusion: Single-agent irinotecan in this dose and schedule has considerable toxicity in patients with malignant mesothelioma and has no anti-tumor activity. The relatively long median survival seen in this study principally reflects the prognostic features of the accrued patients.