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Targeting pulmonary metastases of renal cell carcinoma by inhalation of Interleukin-2 (IL-2).

4662 Background: Pulmonary metastases of renal cell carcinoma (RCC) are associated with poor prognosis especially when the disease is rapidly progressing. The lung is a common site for metastases and respiratory failure is a common cause of death in patients with RCC. Inhalation therapy with IL-2 is thus an appealing method for palliation. This multi-center study summarizes the national experience with IL-2 inhalation in patients with lung metastases of RCC.


METHODS
All the patients had to have radiologically documented lung metastases, had to be able to comply with inhalation technique, and were not candidates for other treatment options. Treatment included 3 daily inhalations of 18 MU IL-2 by using a Salvia Lifetec Jetair inhalator. Treatment had to be continued until progression or complete response or life threatening toxicity or patient's refusal. Response was evaluated according to RECIST.


RESULTS
Forty patients (median 66.5 years), with histological or cytological diagnosis of RCC were enrolled. Nephrectomy was performed in a total of 32 patients. Previous treatments for metastatic disease included various combinations of systemic chemo-immunotherapy in 12 patients. Twenty-eight patients were systemic-treatment-naïve.The observed true response rate was 2.5% and disease stabilization rate was 55%. The disease-control rate (partial response plus disease stabilization rate) reached 57.5%. Time to progression ranged from 0.3 (in case of rapidly progressing disease) to more than 43 months, with a median of 8.7 months. The side effects included cough in 8 patients, weakness in 9, dyspnea in 3, fever in 2, sleepiness in 1, asthenia in 1, decreased appetite in 1, and abdominal pain in 1.


CONCLUSIONS
Inhalation of IL-2 for treating pulmonary metastases of RCC is feasible, tolerable, and efficacious in controlling a progressive disease for considerable periods of time. Definition of response of biological therapy by RECIST system should be re-assessed and modified: stable disease should be regarded as a favorable and an important response. No significant financial relationships to disclose.