PURPOSEA phase I dose-escalation trial of recombinant human interleukin-4 (IL-4) was performed to determine its toxicity, biologic activity, and potential antineoplastic effects.PATIENTS AND METHODSTen patients with refractory malignancies received IL-4 by bolus intravenous injection every 8 hours on days 1 to 5 and 15 to 19 (maximum, 28 doses) of a 31-day study period. Three patients received 10 micrograms/kg per dose and seven received 15 micrograms/kg per dose of IL-4.RESULTSToxic symptoms noted at the second dose level included nasal congestion, diarrhea, nausea and vomiting, fatigue, anorexia, headache, dyspnea, and capillary leak syndrome (median weight gain, 6.1%; range, 3.4% to 11.7%). Fever or sustained hypotension sufficient to require pressors did not occur. Decreases in lymphocyte count and serum bicarbonate, sodium, albumin, fibrinogen and immunoglobulin (Ig) levels, and increases in hematocrit, prothrombin time/partial thromboplastin time (PT/PTT), soluble CD23, and, occasionally, serum crea...