Novartis has announced results from the first-ever pivotal Phase III study evaluating a JAK 1/2 inhibitor for the treatment of polycythemia vera (PV).
Jakavi® (ruxolitinib) significantly improved haematocrit control without the need for phlebotomy (a procedure to remove blood from the body to reduce the concentration of red blood cells(2) and reduced spleen size in patients with PV who are resistant to or intolerant of hydroxyurea.(1) Findings are being presented at the 19th Congress of the European Hematology Association in Milan, Italy.
PV is a chronic, incurable blood cancer associated with an overproduction of blood cells that can cause serious cardiovascular complications, such as stroke and heart attack.(2) Currently, there are limited treatments for polycythemia vera and a high unmet need exists for new therapies that provide effective disease control.(3)
“Uncontrolled polycythemia vera in patients who are refractory or resistant to standard therapy can lead to cardiovascular complications and other systemic manifestations, and currently patients and their physicians have few options to treat them,” said Dr. Alessandro M. Vannucchi, Department of Hematology, University of Florence, Italy, and study author. “The RESPONSE trial showed that patients treated with ruxolitinib had marked improvement in disease control, including controlled haematocrit levels without the need for phlebotomy and reduced spleen size, and also improvement in symptom management compared to best available therapy.”
At week 32 of the study, 77% of patients randomised to ruxolitinib achieved one or both components of the composite endpoint of haematocrit control (volume percentage of red blood cells in whole blood(2)) or spleen size reduction in comparison with 20% of patients randomised to best available therapy.(1) A significantly greater proportion of patients achieved the composite primary endpoint when treated with ruxolitinib compared to best available therapy (21% compared to 1%, respectively; p<0.0001), and 91% of these patients treated with ruxolitinib maintained their response at week 481.
“New treatments for polycythemia vera are greatly needed, as this is a disease that causes debilitating daily symptoms, which are as severe as symptoms associated with myelofibrosis, and also puts patients at risk for serious cardiovascular complications, such as stroke and heart attack,” said Alessandro Riva, MD, Global Head, Novartis Oncology Development and Medical Affairs. “These findings reinforce ruxolitinib’s significant clinical benefit and potential to become an important new treatment option for polycythemia vera patients who are no longer responding to or are intolerant of prior therapy.”
In the study, a 50% or more improvement in PV-related symptoms was seen in 49% of ruxolitinib-treated patients compared to 5% of patients treated with best available therapy.(1) Patients treated with ruxolitinib also experienced a reduction in night sweats and itchiness (approximately 99% and 95%, respectively).(4) In addition, a greater proportion of patients on the ruxolitinib treatment arm achieved complete haematologic response as defined by the modified 2009 European LeukemiaNet (ELN) criteria, a key secondary endpoint, when compared to the best available therapy arm (24% compared to 9%, respectively; p=0.003).(1)
Ruxolitinib was well tolerated and adverse events (AEs) were consistent with those previously seen in ruxolitinib studies in PV and myelofibrosis.(1,5,6) Within the first 32 weeks of treatment, Grade 3 or 4 haematologic AEs in the ruxolitinib treatment arm were anaemia (1.8%) and thrombocytopenia (5.5%), and fewer patients treated with ruxolitinib experienced thromboembolic events when compared to those who received best available therapy (1 patient compared to 6 patients, respectively).(1) The most common non-haematologic AEs were headache, diarrhoea and fatigue, which were mainly Grade 1 or 2.(1) Additionally, 3.6% of patients randomised to the ruxolitinib treatment arm discontinued treatment due to AEs compared to 1.8% on the best available therapy arm.(4)
Data from the RESPONSE trial will support worldwide regulatory submissions planned this year.
Ruxolitinib is currently approved in more than 60 countries for patients with myelofibrosis, a debilitating and life-threatening blood cancer.
Study Design
RESPONSE is a global, randomised, open-label study conducted at 109 sites. 222 patients with PV resistant to or intolerant of hydroxyurea were randomised 1:1 to receive either ruxolitinib (starting dose of 10mg twice-daily) or best available therapy, which was defined as investigator selected monotherapy or observation only. Ruxolitinib dose was adjusted as needed throughout the study.(1)
The primary endpoint of the study was the proportion of patients whose haematocrit was controlled without phlebotomy from week 8 through 32 and whose spleen volume was reduced by 35% or more from baseline as assessed by imaging at 32 weeks. In addition, efficacy was further assessed using two key secondary endpoints: durable primary response and complete haematological remission. Other endpoints include safety, symptom improvement (as measured by the MPN-SAF 14-item total symptom score) and quality of life.(1)
About polycythemia vera
PV is a chronic, incurable blood cancer associated with an overproduction of blood cells in the bone marrow(2) that affects roughly one to three people per 100,000 globally.(7) It is typically characterised by an elevated haematocrit, the volume percentage of red blood cells in whole blood, which can lead to a thickening of the blood and an increased risk of blood clots.(2) This can cause serious cardiovascular complications, such as stroke and heart attack,(2) resulting in increased morbidity and mortality.(8) Phlebotomy, a procedure to remove blood from the body to reduce the concentration of red blood cells, is commonly used to maintain a normal haematocrit level.(2)
Additionally, patients with PV often have enlarged spleen and numerous debilitating symptoms that significantly affect their daily life.(2) A proportion of patients become intolerant or resistant to currently available therapies. In fact, approximately 25% of PV patients become resistant to or intolerant of hydroxyurea treatment, which results in inadequate disease control and an increased risk of progression.(9,10)
About Jakavi
Jakavi (ruxolitinib) is an oral inhibitor of the JAK 1 and JAK 2 tyrosine kinases and was approved by the European Commission in August 2012 for the treatment of disease-related splenomegaly or symptoms in adult patients with primary myelofibrosis (also known as chronic idiopathic myelofibrosis), post-polycythemia vera myelofibrosis or post-essential thrombocythemia myelofibrosis. Jakavi is approved in more than 60 countries, including the European Union, Canada and some countries in Asia, Latin and South America. Additional worldwide regulatory filings are underway.
Novartis licensed ruxolitinib from Incyte Corporation for development and commercialisation outside the United States. Both the European Commission and the US Food and Drug Administration (FDA) granted ruxolitinib orphan drug status for myelofibrosis. Jakavi is marketed in the US by Incyte Corporation under the name Jakafi® for the treatment of patients with intermediate or high-risk myelofibrosis.
The recommended starting dose for Jakavi in patients with myelofibrosis is 15mg twice daily for patients with a platelet count between 100,000 cubic millimetres (mm3) and 200,000 mm3, and 20mg twice daily for patients with a platelet count of >200,000 mm3. Doses may be titrated based on safety and efficacy. There is limited information to recommend a starting dose for patients with platelet counts between 50,000/mm3 and<100,000/mm3. The maximum recommended starting dose in these patients is 5mg twice daily, and patients should be titrated cautiously.(11)
Jakavi is a registered trademark of Novartis AG in countries outside the US. Jakafi is a registered trademark of Incyte Corporation. The safety and efficacy profile of Jakavi has not yet been established outside the approved indication.
References
- Verstovsek S, et al. Results of a prospective, randomized, open-label Phase III study of ruxolitinib in polycythemia vera patients resistant to or intolerant of hydroxyurea: The RESPONSE Trial. Abstract #7026. 50th American Society of Clinical Oncology (ASCO) Chicago, IL.
- Leukemia & Lymphoma Society. “Polycythemia Vera Facts.” Available at: http://www.lls.org/content/nationalcontent/resourcecenter/freeeducationmaterials/mpd/pdf/polycythemiavera.pdf. Accessed on April 28, 2014.
- Barbui T, Finazzi G. Treatment of polycythemia vera. Haematologica.1998:83:143-149.
- Novartis Data on File.
- Vannucchi, A, et al. Long-Term Outcomes From A Phase 3 Study Comparing Ruxolitinib With Best Available Therapy (BAT) For The Treatment of Myelofibrosis (MF): A 3 Year Update of Comfort II. Abstract #S1111.18th Congress of European Hematology Association (EHA), 2013. Stockholm, Sweden.
- Verstovsek S, Ruben M, Gotlib J, et al. Long-Term Outcome of Ruxolitinib Therapy in Patients with Myelofibrosis: 3-Year Update From COMFORT-I. Abstract #396. 55th American Society of Hematology (ASH) Annual Meeting and Exposition, 2013. New Orleans, LA.
- Titmarsh G, Duncombe A, McMullin M, et al. How common are myeloproliferative neoplasms? A systematic review and meta-analysis.American Journal of Hematology.2014:1-7.
- Finazzi G and Barbui T. How I treat patients with polycythemia vera. Blood. 2007;109(12):5104-5111.
- Alvarez-Larran A, et al. Assessment and prognostic value of the European LeukemiaNet criteria for clinicohematologic response, resistance, and intolerance to hydroxyurea in polycythemia vera Blood. 2012;119(6):1363-1369.
- Najean Y, Dresch C, Rain JD. The very-long-term course of polycythaemia: a complement to the previously published data of the Polycythaemia Vera Study Group. Br J Haematol. 1994;86(1):233-235.
- JAKAVI [Summary of Product Characteristics]. Basel, Switzerland: Novartis Pharma AG; 2012.
