Abstract
The authors performed a Phase I study to assess the toxicity and hematologic effect of recombinant human interleukin‐2 (rIL‐2) in seven children with advanced malignancies. The rIL‐2 was given as a bolus injection of 1 or 3 × 106 U/m2/dose three times a week (Monday, Wednesday, and Friday) for 3 weeks. No life‐threatening toxicity occurred with the dose of 1 × 106 U/m2 of rIL‐2. At a dose of 3 × 106 U/m2, therapy had to be terminated due to cardiovascular toxicity in two patients. Toxic effects at low‐dose rIL‐2 included fever, nausea, vomiting, and mild hypotension. High‐dose rIL‐2 toxicity included fluid retention, increased creatinine, oliguria, elevated liver enzymes, and significant hypotension. Immunologic studies showed that rIL‐2 caused a drop in the number of circulating peripheral blood mononuclear cells, T‐cells, and natural killer cells which returned to pretherapy levels or above by 24 to 48 hours. The rIL‐2 exerted no growth or stimulatory activity on the leukemic cell population. To the authors' knowledge, this is the first report of a Phase I study of IL‐2 therapy in children.