BACKGROUND/METHODS: Long-term survivors with Philadelphia chromosome-negative myeloproliferative neoplasms (Ph-neg MPNs) can eventually develop acute myeloid leukemia (AML, i.e. blast transformation). Allogeneic hematopoietic stem cell transplantation (allo-HSCT) can be the only curative treatment for such patients. To clarify its outcome, we retrospectively studied the cases with AML transformed from Ph-neg MPNs using the national registry data of JSHCT. The cases transplanted after 2000 were collected.

RESULTS: Thirty-nine cases were extracted (male, n=21; female, n=18). Median age was 57 years (range, 22-71). Underlying Ph-neg MPNs included essential thrombocythemia (ET, n=21), primary myelofibrosis (PMF, n=11) and polycythemia vera (PV, n=7). FAB classification was M0 (n=4), M1 (n=4), M2 (n=10), M3 (n=0), M4 (n=1), M5 (n=3), M6 (n=0), M7 (n=1) and unknown (n=16). Median value of WBC at diagnosis of AML was 8300/uL (250-338000). Karyotype at diagnosis of AML was normal (n=6), complex (n=12), others (n=17) and unknown (n=4). Thirty-two cases (82%) were not in remission at the time of allo-HSCT (1st relapse, n=7; primary induction failure, n=18; untreated, n=12). Median duration between diagnosis of AML and allo-HSCT was 134 days (range, 24-369). The donors were related bone marrow or related mobilized peripheral blood stem cell (rBM/rPBSC, n=8), unrelated bone marrow (uBM, n=15) and unrelated umbilical cord blood (uCB, n=16). Myeloablative conditioning regimens (MAC) were used in 15 cases, and the remaining 24 cases were conditioned by reduced-intensity regimens (RIC), according to CIBMTR definition (Giralt S, et al, 2009). Cumulative incidence of neutrophil engraftment was 74.4% at day 60 (patients engrafted, n=29; death before day 60, n=6; relapse before day 60, n=4). At 2 years after transplant, overall survival (OS) was 29.2%. The median duration of follow up of survivors was 1989.5 days (range, 285-3270). In univariate analysis, age (>57 vs. <57, p=0.87), underlying MPNs (PMF vs. ET vs. PV, p=0.16), disease status at allo-HSCT (CR vs. non-CR, p=0.09), conditioning regimen (MAC vs. RIC, p=0.95) and donor selection (rBM/PBSC vs. uBM vs. uCB, p=0.10) had no impact on OS. The only variable that influenced on OS was chromosome at diagnosis of AML (normal vs. others vs. complex, p=0.02). The cumulative incidence of relapse and non-relapse mortality at 3 years was 34.4% and 38.1%, respectively.

CONCLUSION: Although the prognosis of AML transformed from Ph-neg MPNs is dismal in general, the study suggested a promising result that there were curable patients with allo-HSCT.

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Figure 1.
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Figure 2.
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Disclosures

No relevant conflicts of interest to declare.

Topics:
allogeneic hematopoietic stem cell transplant, hematopoietic stem cell transplantation, leukemia, myelocytic, acute, myeloproliferative disease, allopurinol, complement membrane attack complex, mac protocol, mdc protocol, mitral valve annular calcification, monitored anesthesia care

Author notes

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Asterisk with author names denotes non-ASH members.

© 2014 by The American Society of Hematology
2014
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