[Treatment of chronic myeloid leukemia using alpha-interferon and hydroxyurea. Study of 30 cases]

To evaluate the efficacy of the combination, alpha-interferon (IFN)-hydroxyurea (HU) in the treatment of patients with Philadelphia positive chronic myelogenous leukaemia (Ph'-CML).

A prospective study was started in 1988 in which 30 patients with chronic phase, low-risk Ph'-CML, according to Kantarjian's staging system, were included. They were treated with IFN at a dose of 5 MU/m2 subcutaneously twice a week plus HU in doses between 0.5 and 3 g/m2/day. The clinic and biologic controls performed twice a month included granulocyte alkaline phosphatase, and cytogenetic studies of bone-marrow and peripheral blood were carry out every third month. The quality and duration of haematologic and cytogenetic remissions were evaluated, along with the untoward effect of the treatment. Survival was estimated in accordance to the Kaplan Meier method.

The mean age was 49 years (range: 17-70) and the M/F ratio was 18/12. The median follow-up was 51 months (range: 8-89). Twenty patients were in early- and four late-chronic phase. Complete haematological remission (CHR) was achieved in 26 patients (87%) with a median of 52 months and an estimated global median survival of 81 months. Cytogenetic response was seen in 11 patients (52%) of the 21 who were evaluable after 11 months of treatment. Disappearance of Ph' (complete cytogenetic response) was seen in 6 cases (28%). The incidence of early blast crisis in the first three years was, respectively, 0%, 3% and 6%. The treatment toxicity was negligible in most cases, having to suppress the treatment only in one patient due to persistent fever.

The association of IFN and HU is effective and well tolerated in patients with low-risk CML, and it improves survival in CHR and overall survival.