International Working Group (IWG) consensus criteria for treatment response in myelofibrosis with myeloid metaplasia, for the IWG for Myelofibrosis Research and Treatment (IWG-MRT).
Myelofibrosis with myeloid metaplasia (MMM) is a clinicopathologic entity characterized by stem cell-derived clonal myeloproliferation, ineffective erythropoiesis, extramedullary hematopoiesis, and bone marrow fibrosis and osteosclerosis. Patients with MMM have shortened survival and their quality of life is compromised by progressive anemia, marked hepatosplenomegaly, and severe constitutional symptoms including cachexia. After decades of frustration with ineffective therapy, patients are now being served by promising treatment approaches that include allogeneic hematopoietic stem cell transplantation and immunomodulatory drugs. Recent information regarding disease pathogenesis, including a contribution to the myeloproliferative disorder phenotype by a gain-of-function JAK2 mutation (JAK2(V617F)), has revived the prospect of targeted therapeutics as well as molecular monitoring of treatment response. Such progress calls for standardization of response criteria to accurately assess the value of new treatment modalities, to allow accurate comparison between studies, and to ensure that the definition of response reflects meaningful health outcome. Accordingly, an international panel of experts recently convened and delineated 3 response categories: complete remission (CR), partial remission (PR), and clinical improvement (CI). Bone marrow histologic and hematologic remissions characterize CR and CR/PR, respectively. The panel agreed that the CI response category is applicable only to patients with moderate to severe cytopenia or splenomegaly.
Tefferi
Ayalew
A
Mayo Clinic, 200 First Street SW, Rochester MN 55905, USA. tefferi.ayalew@mayo.edu
Barosi
Giovanni
G
Mesa
Ruben A
RA
Cervantes
Francisco
F
Deeg
H Joachim
HJ
Reilly
John T
JT
Verstovsek
Srdan
S
Dupriez
Brigitte
B
Silver
Richard T
RT
Odenike
Olatoyosi
O
Cortes
Jorge
J
Wadleigh
Martha
M
Solberg
Lawrence A
LA
Camoriano
John K
JK
Gisslinger
Heinz
H
Noel
Pierre
P
Thiele
Juergen
J
Vardiman
James W
JW
Hoffman
Ronald
R
Cross
Nicholas C P
NC
Gilliland
D Gary
DG
Kantarjian
Hagop
H