Cytoreductive effect of recombinant alpha interferon in patients with myelofibrosis with myeloid metaplasia.

In an attempt to reduce myeloproliferation, we administered recombinant alpha-2b interferon (r-alpha INF) to ten patients with myelofibrosis with myeloid metaplasia (MMM) in a hypercellular phase, as part of a phase II trial. Two patients experienced severe side effects and stopped treatment before completion of the first week. In the eight evaluable patients, r-alpha INF was given for 16 weeks at an initial dosage of 3 X 10(6) U/day, with monthly increments in the case of response failure, i.