Myeloablation and autologous peripheral blood stem cell rescue results in hematologic and clinical responses in patients with myeloid metaplasia withmyelofibrosis

Current therapeutic options for myeloid metaplasia with myelofibrosis (MMM) are limited. A pilot study was conducted of autologous peripheral blood st em cell (PBSC) collection in 27, followed by transplantation in 21 patients with MMM. The median age was 59 (range 45-75) years. PBSCs were mobilized at steady state (n = 2), after granulocyte colony-stimulating factor (G-CSF ) alone (n = 17), or after anthracycline-cytarabine induction plus G-CSF (n = 8). A median of 11.6 X 10(6) (range 0 to 410 x 10(6)) CD34(+) cells per kilogram were collected. Twenty-one patients then underwent myeloablation w ith oral busulfan (16 mg/kg) and PBSC transplantation. The median times to neutrophil and platelet recovery after transplantation were 21 (range 10-96 ) and 21 (range, 13 to greater than or equal to 246) days, respectively. Fi ve patients received back-up PBSC infusion because of delayed neutrophil or platelet recovery. The median follow-up is 390 (range 70-1623) days after transplantation, and the 2-year actuarial survival Is 61%. After transplant ion, 6 patients died: 3 of nonrelapse causes (1 within 100 days of PBSC inf usion) and 3 of disease progression. Erythroid response (hemoglobin greater than or equal to 100 g/L [10 gm/dL] without transfusion for greater than o r equal to 8 weeks) occurred in 10 of 17 anemic patients. Four of 8 patient s with a platelet count less than 100 x 10(9)/L (100 000/muL) responded wit h a durable platelet count more than 100 x 10(9)/L (100 000/muL). Symptomat ic splenomegaly improved In 7 of 10 patients. It is concluded that (1) PBSC collection was feasible and stable engraftment occurred after transplantat ion In most patients with MMM, (2) myeloablation with busulfan was associat ed with acceptable toxicity, (3) a significant proportion of patients deriv ed clinical benefit after treatment, and (4) further investigation of this novel approach is warranted.