title: Response criteria for essential thrombocythemia and polycythemia vera: result of a European LeukemiaNet consensus conference.
abstract: European experts were convened to develop a definition of response to treatment in polycythemia vera (PV) and essential thrombocythemia (ET). Clinicohematologic (CH), molecular, and histologic response categories were selected. In ET, CH complete response (CR) was: platelet count less than or equal to 400 x 10(9)/L, no disease-related symptoms, normal spleen size, and white blood cell count less than or equal to 10 x 10(9)/L. Platelet count less than or equal to 600 x 10(9)/L or a decrease greater than 50% was partial response (PR). In PV, CH-CR was: hematocrit less than 45% without phlebotomy, platelet count less than or equal to 400 x 10(9)/L, white blood cell count less than or equal to 10 x 10(9)/L, and no disease-related symptoms. A hematocrit less than 45% without phlebotomy or response in 3 or more of the other criteria was defined as PR. In both ET and in PV, molecular CR was a reduction of any molecular abnormality to undetectable levels. Molecular PR was defined as a reduction more than or equal to 50% in patients with less than 50% mutant allele burden, or a reduction more than or equal to 25% in patients with more than 50% mutant allele burden. Bone marrow histologic response in ET was judged on megakaryocyte hyperplasia while on cellularity and reticulin fibrosis in PV. The combined use of these response definitions should help standardize the design and reporting of clinical studies.
authors.affiliation: Unit of Clinical Epidemiology and Center for the Study of Myelofibrosis, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Policlinico S. Matteo, Pavia, Italy. barosig@smatteo.pv.it
authors.forename: Giovanni
authors.initials: G
authors.lastname: Barosi
authors.forename: Gunnar
authors.initials: G
authors.lastname: Birgegard
authors.forename: Guido
authors.initials: G
authors.lastname: Finazzi
authors.forename: Martin
authors.initials: M
authors.lastname: Griesshammer
authors.forename: Claire
authors.initials: C
authors.lastname: Harrison
authors.forename: Hans Carl
authors.initials: HC
authors.lastname: Hasselbalch
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Kiladjian
authors.forename: Eva
authors.initials: E
authors.lastname: Lengfelder
authors.forename: Mary Frances
authors.initials: MF
authors.lastname: McMullin
authors.forename: Francesco
authors.initials: F
authors.lastname: Passamonti
authors.forename: John T
authors.initials: JT
authors.lastname: Reilly
authors.forename: Alessandro M
authors.initials: AM
authors.lastname: Vannucchi
authors.forename: Tiziano
authors.initials: T
authors.lastname: Barbui
mesh_terms: D032921:Consensus; D005060:Europe; D006801:Humans; D011087:Polycythemia Vera / Q000175:diagnosis* / Q000628:therapy*; D017410:Practice Guidelines as Topic; D011379:Prognosis; D012074:Remission Induction; D012955:Societies, Medical / Q000458:organization & administration; D013920:Thrombocythemia, Essential / Q000175:diagnosis* / Q000628:therapy*