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The RESPONSE trial evaluated JAKAVI in patients with inadequately controlled PV1,2

The RESPONSE trial was a randomised, open-label, active-controlled Phase III trial1,2

  • RESPONSE evaluated the efficacy and safety of JAKAVI in PV patients who had inadequate response to or unacceptable side effects from HU1
  • Eligibility criteria included all of the following: resistance to or intolerance of HU (based on modified ELN criteria), phlebotomy dependence, splenomegaly, and haematocrit control (40%-45%) within 14 days prior to randomisation1

RESPONSE study design1,2

JAK2 Inhibitor for Polycythemia Vera RESPONSE study design - JAKAVI

Patients were stratified by HU intolerance/resistance and randomised to JAKAVI (starting dose of 10 mg BID individually titrated up to a maximum of 25 mg BID) or investigator-selected BAT as monotherapy (HU, interferon/pegylated interferon, anagrelide, pipobroman, immunomodulatory drugs [IMIDs], or observation). Patients were to receive low-dose aspirin unless medically contraindicated.1,2 The data cutoff for the primary analysis occurred when all patients reached Week 48 or discontinued therapy.1

86% of patients in the BAT arm had crossed over to the JAKAVI arm by Week 483

Endpoints in the RESPONSE trial assessed haematologic, symptomatic, and safety parameters1,2

Primary endpoint

Definition of the primary endpoint in RESPONSE1,2

JAKAVI for PV RESPONSE trial primary endpoint -  reduction in spleen volume & haematocrit control without phlebotomy

Haematocrit control was defined as the absence of phlebotomy eligibility from Week 8 to Week 32, with no more than one post-randomisation phlebotomy allowed prior to Week 8. Phlebotomy eligibility was defined as haematocrit >45% and ≥3% higher than baseline or >48%, whichever was lower.1,2 Spleen volume was assessed by MRI or CT.1

Key secondary endpoints

  • Durability of primary response at Week 481,2
  • Complete haematologic remission at Week 321,2

Other endpoints

  • Duration of response1
  • Symptom reduction1
  • Safety1

Next: JAK dysregulation in PV

BAT=best available therapy; BID=twice daily; CT=computed tomography; ELN=European LeukemiaNet; HCT=haematocrit; HU=hydroxyurea; MRI=magnetic resonance imaging; RESPONSE=Randomized Study of Efficacy and Safety in Polycythemia Vera with JAK Inhibitor INCB018424 versus Best Supportive Care.


  1. Vannucchi AM, Kiladjian JJ, Griesshammer M, et al. Ruxolitinib versus standard therapy for the treatment of polycythemia vera. N Engl J Med. 2015;372(5):426-435.
  2. JAKAVI® (ruxolitinib) tablets: EU Summary of Product Characteristics. Novartis; May 2019.
  3. Data on file. Novartis Pharma AG. Basel, Switzerland.