4603 Background: Patients with metastatic renal cell carcinoma have a poor prognosis, including those with pulmonary metastases (PMRCC). The objective of this study was to obtain efficacy and safety data on inhaled rIL-2 used in clinical practice in PMRCC patients. Methods: Data provided from 107 PMRCC patients from 48 centres in Spain and 6 in Portugal, treated with inhaled rIL-2 between 2000 and 2005 were evaluated. Data were analyzed by ITT, considering a valuable patient when receiving the first dose of inhaled rIL-2. The treatment schedule was: 3 cycles of 36 MIU rIL-2 per day for 5 days/week for 12 weeks (with one week treatment free between cycles) in Spain and for 3 weeks (out of each 4 weeks) for 12 weeks in Portugal. Efficacy was assessed by best response following each treatment cycle and overall (WHO criteria). The Kaplan-Meier method was used to estimate progression free survival (PFS) and overall survival (OS) that were measured from the time of administration of the first dose of inhaled rIL-2 until progression or death. Safety data were analysed using descriptive statistics, with toxicities expressed as number of weeks in which each toxicity was reported by cycle and by grade. Results: After 1902 treatment weeks administered (median 17.8), the overall objective response rate (complete and partial response,) was 12.2% (95% CI: 6.0–18.4) and a stable disease rate of 22.45% (95% CI: 14.5–30.3). Median PFS and OS were 3.72 (95% CI: 2.86–4.57) and 18.5 (12.69– 23.61) months, respectively. Non-haematological toxicities were the most notable adverse events observed, especially in terms of cough (20.4% of weeks) and fatigue (4.4%) being grade 1 or 2 in severity and reversible by removing the treatment in all cases. Conclusions: This study provides data of efficacy and mild toxicity of inhaled rIL-2. On the basis of these findings inhaled rIL-2 might be considered as an alternative to its systemic administration to treat patients with PMRCC. No significant financial relationships to disclose.
Targeting pulmonary metastases of renal cell carcinoma by inhalation of interleukin-2