Impact of JAK2(V617F) mutation status on treatment response to anagrelide in essential thrombocythemia: An observational, hypothesis-generating study

Nicola Cascavilla, Valerio De Stefano, Fabrizio Pane, Alessandro Pancrazzi, Alessandra Iurlo, Marco Gobbi, Francesca Palandri, Giorgina Specchia, A. Marina Liberati, Mariella D’Adda, Gianluca Gaidano, Rajmonda Fjerza, Heinrich Achenbach, Jonathan Smith, Paul Wilde, Alessandro M. Vannucchi

Research output: Contribution to journalArticle

Abstract

A JAK2(V617F) mutation is found in approximately 55% of patients with essential thrombocythemia (ET), and represents a key World Health Organization diagnostic criterion. This hypothesis-generating study (NCT01352585) explored the impact of JAK2(V617F) mutation status on treatment response to anagrelide in patients with ET who were intolerant/refractory to their current cytoreductive therapy. The primary objective was to compare the proportion of JAK2-positive versus JAK2-negative patients who achieved at least a partial platelet response (≤600×109/L) after anagrelide therapy. Of the 47 patients enrolled, 46 were included in the full analysis set (JAK2-positive, n=22; JAK2-negative, n=24). At 12 months, 35 patients (n=14 and n=21, respectively) had a suitable platelet sample; of these, 74.3% (n=26) achieved at least a partial response. The response rate was higher in JAK2-positive (85.7%, n=12) versus JAK2-negative patients (66.7%, n=14) (odds ratio [OR] 3.00; 95% confidence interval [CI] 0.44, 33.97). By using the last observation carried forward approach in the sensitivity analysis, which considered the imbalance in patients with suitable samples between groups, the overall response rate was 71.7% (n=33/46), with 77.3% (n=17/22) of JAK2-positive and 66.7% (n=16/24) of JAK2-negative patients achieving at least a partial response (OR 1.70; 95% CI 0.39, 8.02). There was no significant change in median allele burden over 12 months in the 12 patients who achieved a response. In conclusion, the overall platelet response rate was high in both JAK2-positive and JAK2-negative patients; however, a larger study would be required to confirm the differences observed according to JAK2(V617F) mutation status.

Original languageEnglish
Pages (from-to)2687-2694
Number of pages8
JournalDrug Design, Development and Therapy
Volume9
DOIs
Publication statusPublished - May 18 2015

Keywords

  • Allele burden
  • Anagrelide
  • Essential thrombocythemia
  • JAK2
  • Mutation
  • Treatment response

ASJC Scopus subject areas

  • Pharmaceutical Science
  • Pharmacology
  • Drug Discovery

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    Cascavilla, N., De Stefano, V., Pane, F., Pancrazzi, A., Iurlo, A., Gobbi, M., Palandri, F., Specchia, G., Marina Liberati, A., D’Adda, M., Gaidano, G., Fjerza, R., Achenbach, H., Smith, J., Wilde, P., & Vannucchi, A. M. (2015). Impact of JAK2(V617F) mutation status on treatment response to anagrelide in essential thrombocythemia: An observational, hypothesis-generating study. Drug Design, Development and Therapy, 9, 2687-2694. https://doi.org/10.2147/DDDT.S79576