Resistance to therapy of acute leukemia developing in the course of polycythemia vera

Thirteen patients in whom acute leukemia developed in the course of polycythemia vera were initially treated with vincristine and prednisone in an attempt at remission induction. None responded, and four died during this initial course of therapy. Induction was then attempted in the nine survivors, using cytosine arabinoside and adriamycin. Only one complete remission of 38 weeks and one partial remission were achieved, while median survival was 32 days. Poor results may reflect both the intrinsic biologic properties of the acute leukemia occurring in this setting and the advanced age of the patients.