Intrapleural immunotherapy with escalating doses of interleukin‐2 in metastatic pleural effusions

Background. The authors assessed the tolerance and efficacy of intrapleural interleukin‐2 (IL‐2) in patients with malignant effusion. Methods. Twenty‐three patients had a total of 25 metastatic pleural effusions; the patients were treated with recombinant IL‐2 by means of a continuous intrapleural infusion for 5 days. The daily dosage used in this Phase I/II trial initially was 3 × 106 IU/m2/day; the dosage was increased with every third patient, culminating in a dosage of 24 × 106 IU/m2/day. Results. One patient who had received the highest dosage died of renal failure on day 8. Ninety‐six percent of patients had Grade 2–3 fever, which was easily controlled with paracetamol administration. Two (8%) patients had pleural empyema. All other side effects were mild and resolved spontaneously by the end of treatment. The objective response rate was 21.7%. The five patients who responded to IL‐2 therapy were alive 7–24 months after treatment, and the survival rate of the whole group was 59% after 13 months. Conclusion. A daily dose of 10–24 × 106 IU/m2/day of IL‐2 administered intrapleurally gave response rates similar to those reported in the literature using the intravenous route, but a much lower morbidity rate was recorded.