Recombinant alpha 2a interferon-an effective maintenance agent in essential thrombocythaemia

Recombinant alpha 2a, 2b and 2c interferons have been shown to be effective short-term agents in essential thrombocythaemia and thrombocythaemia associated with the other myeloproliferative disorders, including chronic granulocytic leukaemia, polycythaemia rubra vera and myelofibrosis. Few data exist on the use of the recombinant interferons as maintenance agents in patients with thrombocythaemia. We report on a cohort of 22 previously untreated patients, with essential thrombocythaemia, treated with recombinant alpha 2a interferon maintenance therapy for a minimum period of 6 months. Effective long-term control of platelet counts, without evidence of haematological toxicity, was achieved in 19 of 22 patients. No objective haemorrhagic or thrombotic event occurred in 298 patient months of interferon therapy. Three patients discontinued alpha interferon therapy due to adverse side-effects. Alpha 2a interferon is an effective maintenance agent in essential thrombocythaemia.