Phase I study of recombinant human interferon gamma in children with relapsed acute leukemia

Fourteen children (ages 2-15 years) with acute leukemia in relapse were treated with daily recombinant interferon gamma for 14 days by subcutaneous injections at fixed dose levels of 0.1, 0.25, 0.5, or 0.75 mg/m2 (1.0, 2.5, 5.0, or 7.5 x 10(6) units/m2) without intrapatient escalation. Patients received a second 14-day course of therapy followed by thrice weekly administration unless there were signs of progressive disease or grade 3 or 4 toxicity. Side effects in the 13 evaluable patients included fever (n = 10), fatigue (9), decreased Karnofsky performance score (8), hypertriglyceridemia (8), myalgia (5), weight loss > 5% (4), elevated liver transaminases (4), and abdominal pain (3). There was only one grade 4 toxicity: one of the six patients at the 0.5 mg/m2 dose level developed reversible acute renal failure. One patient died of gastrointestinal hemorrhage due to disease-related refractory thrombocytopenia. One child had an oncolytic response and two others stable disease for 138 and 148 days. An appropriate dose level for phase II studies in children is 0.5 mg/m2 per day.