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Ruxolitinib’s Impact on JAK2 Allele Burden in PV

Ann Hematol; ePub 2017 Apr 30; Vannucchi, et al

Ruxolitinib treatment appears to reduce JAK2 p.V617F allele burden in patients with polycythemia vera (PV) who do not tolerate hydroxyurea, according to a multicenter, open-label, phase 3 randomized study involving more than 200 individuals.

Participants received either ruxolitinib (n=107) or best available therapy with crossover to ruxolitinib at week 32 (n=97). Among the results:

  • Average changes from baseline over time in JAK2 p.V617F allele burden ranged from -12.2 to -40.0% in those receiving ruxolitinib; this range was -6.3 to -17.8% in the crossover group.
  • Complete molecular response was observed in 2 ruxolitinib patients and 1 crossover patient.
  • Partial response occurred in 33 and 20 patients, respectively.
  • 1 patient receiving best available therapy achieved partial response before crossover.
  • Among patients treated with interferon, average maximal reduction in allele burden from baseline was ~26% after crossover, vs ~7% before.


Vannucchi A, Verstovsek S, Guglielmelli P, et al. Ruxolitinib reduces JAK2 p.V617F allele burden in patients with polycythemia vera enrolled in the RESPONSE study. [Published online ahead of print April 30, 2017]. Ann Hematol. doi:10.1007/s00277-017-2994-x.