Purpose: To evaluate the cytologic and cytogenetic response attained with interferon alpha-2a (IFN, Roferon*A) in patients with Ph '-positive chronic myelogenous leukaemia (CML) in the chronic phase.
Material and methods: A prospective study was carried out on 22 CML patients diagnosed in the Haematology Service at the Princesa Hospital in Madrid. The therapeutic regime consisted of two phases: A) Hydroxyurea was given until the white-cell count was reduced to 15-20 x 10(9)/L. B) Roferon*A was then given subcutaneously at a doses of 5 MU/m2 per day. The follow-up was performed weekly, and monthly once the leucocyte count had stabilized. The cytologic and cytogenetic response was assessed by bone marrow aspiration performed after 6, 9, 12 and 18 months. The toxicity was evaluated in accordance with the WHO recommendations.
Results: The median follow-up is 263 days (21-930). Thirteen patients (65%) had initial complete haematological response and 3 (15%) had partial response. The mean time to achieve response was 42 days (0-321). In the last evaluation, 69% of the patients were in sustained haematological remission (53% complete and 16% partial) with median follow-up of 232 days (21-930). The cytogenetic response was evaluable in 13 patients (follow up > or = 6 months): three attained complete response (23%) and three others partial response (23%). The commonest untoward effects were hypertriglyceridaemia (100%) and myelosuppression (86%). Grade-III thrombocytopenia was seen in 19% of the patients and grade-III anaemia or leucopenia in 5%. No infectious or haemorrhagic complications have appeared. Therapy was discontinued in 3 patients (14%), two due to severe flu-like syndrome and one for parkinsonism after 809 days of treatment. At the moment of evaluation two patients had died, one in lymphoid blastic crisis on day 217 and the other in the immediate post-BMT period.
Conclusion: Treatment with interferon-alpha 2A is useful in the chronic phase of CML. An important number of responses can be attained, even in patients in the late chronic phase, and the toxicity seems acceptable.