Interferon treatment in polycythaemia vera.

Recent studies have shown rIFN alpha to be an effective agent in the management of polycythemia vera. Red cell mass can be controlled within 6 to 12 months, eliminating the need for phlebotomy in up to 70% of cases. In addition, significant improvement in the platelet counts, iron status, pruritus scores and the degree of splenomegaly have been reported. Most patients require between 9 and 25 x 10(6)U/week, although once the disease is under control it may be possible to reduce both the dose and frequency of administration. Side-effects remain a significant problem, occurring in over 30% of patients, and may be related to the high mean age of the patients. Long-term studies are now indicated to determine if the natural history of the disease is altered and whether, in particular, the incidence of myelofibrosis and/or leukaemic transformation is reduced.