Background: We report 6 years of experience in 116 patients who used inhaled interleukin-2 (IL-2) and were treated in different protocols with natural, recombinant glycosylated and recombinant nonglycosylated IL-2.
Materials and methods: All protocols had in common high-dose inhalation of IL-2, either exclusively (11%), with low-dose systemic IL-2 (33%), or with low-dose systemic IL-2 and interferon-alpha (56%). Maximal toxicity per total treatment time (median treatment time, 7.2 months) was mild and at a low incidence (16%) of WHO grade 3 toxicity. Treatment was allowed in patients for whom systemic IL-2 was not suitable.
Results: Progressive pulmonary metastases responded in 15% of patients for a median of 15.5 months (range 4.1-33) and were stabilized in 55% for a median of 6.6 months (range, 3-51.7). Overall response rate was 16%, 49%, and 35%, respectively. Median overall response duration was 9.6 mo. Median achieved survival was 11.8 months (range 1.7-68.8).
Conclusions: Inhaled IL-2 prevents progress of pulmonary metastases effectively in 70% of patients. Local use of IL-2 allows the use of the full potential of cytokines with little or no toxicity.