Low-dose recombinant alfa-2a-interferon: a feasible maintenance therapy in acute myeloid leukaemia in the older patient.

Eleven patients with acute myeloid leukaemia (AML) in first complete remission (CR) were treated with alfa-2a-interferon (for short 'interferon') maintenance therapy, at a dose of 3 MU twice to thrice weekly subcutaneously. Adjustments were made to maintain neutrophil counts > 1 x 10(9)/l and platelet counts > 100 x 10(9)/l. A transient fall in haemoglobin, neutrophil and platelet counts was noted in all 9 evaluable patients. Median time to nadir was 7 weeks. Initial dosage reductions were necessary in 5 patients, 3 of whom were later able to tolerate the starting dose. No episodes of infection or bleeding were documented during therapy and no red cell or platelet transfusions were necessary. At the time of writing (median follow-up of 31 weeks), 7 patients continue in CR, 6 of whom remain on interferon. One patient discontinued interferon on developing sicca syndrome. Other than in this patient, side effects were minor. Mean dose administered was 6.7 MU/patient/week. We conclude that low-dose IFN maintenance therapy is well tolerated in older patients with AML in first CR.