ALLOGENEIC MARROW TRANSPLANTATION FOR PRIMARY MYELOFIBROSIS AND MYELOFIBROSIS SECONDARY TO POLYCYTHEMIA-VERA OR ESSENTIAL THROMBOCYTOSIS

Primary myelofibrosis is a clonal haemopoietic disorder, incurable wit h conventional therapy and associated with a median survival of 4-5 ye ars. Patients with polycythaemia vera and essential thrombocytosis who progress into a myelofibrotic picture also have a poor prognosis. Bet ween 1980 and 1996, 13 patients with myelofibrosis due to one of these three myeloproliferative disorders (primary myelofibrosis [n=8], esse ntial thrombocytosis [n=3], polycythaemia vera [n=2]) underwent alloge neic marrow transplantation in Seattle, The median age was 40 years (r ange 18-49). The median time from myeloproliferative diagnosis to tran splantation was 39 months (range 5-192). Three patients received prepa rative regimens containing total body irradiation and 10 received busu lphan-cyclophosphamide regimens. Nine patients received marrow from HL A-matched related donors, one from a one antigen mismatched related do nor, and three from HLA-matched unrelated donors. The median time to b oth granulocyte and platelet engraftment was 21 d. Nine patients survi ve between 1.2 and 7.1 years post-transplant. Two patients relapsed at 1 year post-transplant, both of whom survive in a chronic myeloprolif erative state. Four patients died of transplant-related complications between 43 d and 2.2 years post-transplant. At 1 year post-transplant the majority of the disease-free survivors have normal peripheral bloo d counts and none-to-minimal marrow fibrosis. These preliminary result s are encouraging, and suggest that stem cell transplantation can be c urative therapy for selected patients with myelofibrosis.