Cytogenetic Remissions in Chronic Myelogenous Leukemia Using Interferon Alpha-2a and Hydroxyurea with or without Low-Dose Cytosine Arabinoside.

Twenty-four patients with Philadelphia positive (Ph +) chronic myelogenous leukemia including 12 who were previously untreated, received recombinant interferon alpha-2a (IFN) (5 × 10(6) U/m(2)/d) and hydroxyurea (HU) (50 mg/kg/d) at the induction phase. Low dose cytosine arabinoside (Ara-C) (10-20 mg/m(2)/d, 10 to 15 d/month) was added during IFN maintenance therapy at month 3 to 11 in cases with no cytogenetic response and/or hematological resistance. A complete hematological remission was achieved rapidly (med 5 weeks), with the induction regimen in 9/12 previously untreated patients, and obtained or maintained in 9/12 patients who had already received conventional chemotherapy. Thirteen patients (8 untreated, 5 previously treated) showed a cytogenetic improvement and 9 of them had complete suppression of the Ph + clone after 3 to 24 months of treatment. Six patients had durable complete cytogenetic remissions lasting 6 + to 15 + (med 9 +) months. Two of the patients with minor or no cytogenetic response progressed to blastic crisis and died shortly thereafter. The low-dose Ara-C-IFN regimen was well tolerated and no intercurrent infections or bleeding was recorded. This preliminary data suggests a high incidence of hematologic remissions and cytogenetic response with the combination of IFN alpha, HU and low dose Ara-C.