A unified definition of clinical resistance/intolerance to hydroxyurea in essential thrombocythemia: results of a consensus process by an international working group.
A widely accepted definition of resistance or intolerance to hydroxyurea (HU) in patients with essential thrombocythemia (ET) is lacking. An international working group (WG) was convened to develop a consensus formulation of clinically significant criteria for defining resistance/intolerance to HU in ET. To this aim, an analytic hierarchy process (AHP), a multiple-attribute decision-making technique, was used. The steps consisted of selecting the candidate criteria for defining resistance/intolerance; identifying the motivations that could influence the preference of the WG for any individual criterion; comparing the candidate criteria in a pair-wise manner; and grading them according their ability to fulfill the motivations. Every step in the model was derived by questionnaires or group discussion. The WG proposed that the definition of resistance/intolerance should require the fulfillment of at least one of the following criteria: platelet count greater than 600,000/micro l after 3 months of at least 2 g/day of HU (2.5 g/day in patients with a body weight over 80 kg); platelet count greater than 400,000/micro l and WBC less than 2500/micro l or Hb less than 10 g/dl at any dose of HU; presence of leg ulcers or other unacceptable muco-cutaneous manifestations at any dose of HU; HU-related fever.
Barosi
G
G
Unit of Clinical Epidemiology and Center for the Study of Myelofibrosis, IRCCS Policlinico S Matteo, Pavia, Italy. barosig@smatteo.pv.it
Besses
C
C
Birgegard
G
G
Briere
J
J
Cervantes
F
F
Finazzi
G
G
Gisslinger
H
H
Griesshammer
M
M
Gugliotta
L
L
Harrison
C
C
Hasselbalch
H
H
Lengfelder
E
E
Reilly
J T
JT
Michiels
J J
JJ
Barbui
T
T
D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use; D003245:Consensus Statements as Topic; D004351:Drug Resistance; D006801:Humans; D006918:Hydroxyurea / Q000009:adverse effects / Q000627:therapeutic use*; D018579:Patient Selection; D015203:Reproducibility of Results; D013920:Thrombocythemia, Essential / Q000188:drug therapy*
D000970:Antineoplastic Agents; D006918:Hydroxyurea