Results of a Phase II Trial Testing Interferon Alpha 2b and Cytarabine in Children with Chronic Myelogenous Leukemia.

Before the Imatinib era, a prospective phase II trial was conducted in 2000 to assess the efficacy and the tolerance a combination of interferon alpha 2b (IFN) and cytarabine in children and adolescents with chronic myelogenous leukemia in first chronic phase without a suitable HLA-identical donor. Children received daily IFN (5 million units/m²) and subcutaneous cytarabine (20 mg/m²) for monthly course of 10 days. Between September 2000 and March 2003, 14 children (10 males, 4 females) median age 12 years (range 2–16.5) were recruited from 12 french centres. Patients (pts) were evaluated for time to, rate of hematologic and cytogenetic responses, toxicity and progression free survival. The median duration of follow-up is 13 months (range 2–32 mo). Eight pts achieved a complete hematologic response after a median time of treatment of 3 months (range 0–4 mo) including a pt enrolled in complete hematologic response after 1 month of therapy with hydroxyurea. Three pts were not evaluable for the cytogenetic response (early discontinuation for toxicity, no achievement of complete hematologic response within 3 months of treatment, progression). The best cytogenetic response by 12 months was: major response in 7 pts including complete cytogenetic response in 2 pts, minor response in 3 pts and failure in 1 pt. The median time to major cytogenetic response was 7 months (range 3–12 mo). Thirteen pts discontinued treatment protocol with a median time of 11 months for the following reasons: absence of complete hematologic response at 3 months (2 pts), loss of hematologic response (2 pts), absence of major cytogenetic response at 12 months (1 pt ), loss of major cytogenetic response (2pts), progression (3 pts), adverse event (1pt), other (2 pts). Probability of progression free survival at 18 months was 66% (95% CI, 34–98%). No treatment-related death occurred. The most frequently reported drug-related events were fever, mucositis, neutropenia and thrombocytopenia. Grade 3 and 4 non hematologic toxicity (fever and mucositis) was observed in 4 pts and grade 3 and 4 hematologic toxicity (anemia, neutropenia and thrombocytopenia) in 7 pts. The median total dose of IFN and cytarabine administered was 3.7 million units/m² /day (range 2.3–5.1) and 20 mg/m² /day (range 11–23). The median duration of IFN therapy was 11 months (range1–117 mo). The median number of courses of cytarabine was 7 (range 1–37). The combination of IFN and cytarabine is a well tolerated therapy providing hematologic and cytogenetic responses in children and adolescents with CML. Rates of hematologic and cytogenetic responses compare favourably with results observed in adults. Results should be compared to these of imatinib in children and adolescents.