Annals of Hematology

, Volume 92, Issue 7, pp 907–915

Effects of imatinib mesylate in patients with polycythemia vera: results of a phase II study

  • Kirsten Merx
  • Alice Fabarius
  • Philipp Erben
  • Martin Griesshammer
  • Andreas Reiter
  • Wolf-Karsten Hofmann
  • Rüdiger Hehlmann
  • Andreas Hochhaus
  • Eva Lengfelder
Original Article

DOI: 10.1007/s00277-013-1725-1

Cite this article as:
Merx, K., Fabarius, A., Erben, P. et al. Ann Hematol (2013) 92: 907. doi:10.1007/s00277-013-1725-1

Abstract

The antiproliferative effects of the tyrosine kinase inhibitor imatinib mesylate were reported in single cases with polycythemia vera (PV). We, therefore, conducted a clinical phase II study to assess the rate and quality of response in patients with PV. Thirty-one patients, with a median age of 64 years (range, 45–84 years), were included. All but one patient were on phlebotomy; 14 (45 %) had previously received cytoreductive therapy. Imatinib was started with 400 mg/day. In 26 % of patients, dose escalation up to 800 mg was performed. After a median treatment duration of 8.3 months (range, 0.1–62.1 months), the overall response rate was 55 %. No complete remission (normalization of all parameters: hematocrit, white blood cell (WBC) count, platelet count, and spleen size determined by ultrasound examination) was reached because the spleen remained enlarged in all patients. Thirteen patients (42 %) achieved partial remission (≥25 % reduction of at least one of the previously mentioned parameters); in 10 of these, the respective reduction was ≥50 %. In four patients (13 %) with minor response, the reduction was <25 %. No change or progressive disease was seen in 14 patients (45 %). The nonresponders had a longer previous disease duration and had received more antecedent cytoreductive therapy (p = 0.009). Compared to baseline characteristics, imatinib induced the reduction of phlebotomies (p = 0.003), of WBC count (p = 0.002), and of platelet count (p = 0.04). Three patients became free from phlebotomies. In six investigated patients, no significant reduction of the JAK2V617F burden was observed despite clinical improvement. The results show that imatinib has moderate cytoreductive effects in PV.

Keywords

Polycythemia veraImatinib mesylateTreatment effects

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Kirsten Merx
    • 1
  • Alice Fabarius
    • 1
  • Philipp Erben
    • 1
  • Martin Griesshammer
    • 2
  • Andreas Reiter
    • 1
  • Wolf-Karsten Hofmann
    • 1
  • Rüdiger Hehlmann
    • 1
  • Andreas Hochhaus
    • 3
  • Eva Lengfelder
    • 1
  1. 1.III. Medizinische Klinik, Hämatologie und OnkologieUniversitätsmedizin MannheimMannheimGermany
  2. 2.Johannes Wesling KlinikumMindenGermany
  3. 3.Abteilung Hämatologie und internistische Onkologie, Klinik für Innere Medizin IIUniversitätsklinikum JenaJenaGermany