Vincristine therapy in refractory chronic idiopathic thrombocytopenic purpura.

12 patients with refractory, chronic idiopathic thrombocytopenic purpura, (ITP) received weekly (1 mg) vincristine injections to a cumulative dose not greater than 3 mg. No complications were encountered. 8 patients (67%) showed a rise in the platelet count following the first injection. 5 out of the 8 patients achieved a normal platelet count (greater than 150 X 10(9)/1) after the second dose of vincristine, while 3 obtained variable platelet rises of 20 to 110 X 10(9)/1 above the pre-treatment levels. The duration of platelet response to vincristine without concomitant azathioprine therapy was less than 10 weeks. The simultaneous administration of vincristine and azathioprine resulted in a sustained response in 5 patients.