Treating refractory advanced or metastatic urothelial carcinoma with interleukin-2: A phase II study

Patients with refractory advanced or metastatic urothelial carcinoma derive only minor benefit from chemotherapy. Based on evidence that urothelial carcinoma may be associated with impaired immunological reactivity, we conducted a phase II trial of interleukin-2 (IL-2), a biologic response modifier, to assess its efficacy and toxicity in treating refractory advanced or metastatic urothelial carcinoma. Seventeen patients with urothelial carcinoma who had undergone no more than 1 cisplatin-containing chemotherapy regimen were treated with IL-2 at a dose of 3 × 10⁶ IU/m²/day by continuous intravenous infusion for 4 consecutive days each week for 4 weeks. Cycles were to be repeated every 6 weeks until disease progression. Toxic effects could be assessed in all 17 patients and response in 13. The most common grade III and IV toxic effects included hypotension (13/17); anemia (6/17); thrombocytopenia (4/17); granulocytopenia (3/17); and, in 1 patient each, cardiac ischemia, bowel perforation, and an increase in creatinine level. One sudden death was assumed to be treatment related. Although we found no objective antitumor activity for IL-2, median patient survival was 10.5 months (95% confidence interval, 5.8 to 17.1 months), with a 15.9-month median survival for 3 patients with poor performance status and visceral metastases. Further clinical investigation of the biological effect of IL-2 in urothelial carcinoma may be warranted.