The European Commission has approved Novartis' Jakavi (ruxolitinib) for the treatment of adult patients with polycythemia vera (PV) who are resistant to or intolerant of hydroxyurea. Jakavi is the first targeted treatment approved by the European Commission for these patients.

PV is a rare and incurable blood cancer associated with an overproduction of blood cells that can cause serious cardiovascular complications, such as blood clots, stroke and heart attack. Approximately 25% of patients with PV develop resistance to or intolerance of hydroxyurea and are considered to have uncontrolled disease. This is typically defined as hematocrit levels greater than 45%, elevated white blood cell count and/or platelet count, and may be accompanied by debilitating symptoms and/or an enlarged spleen.

"The European Commission's approval of Jakavi is encouraging news for patients," said Dr. Claire Harrison, study investigator and Consultant Hematologist, Guy's and St. Thomas' NHS Foundation Trust, London. "Jakavi will fill an unmet need as the first treatment shown to significantly improve hematocrit, as well as symptom control and reduce spleen size in patients with polycythemia vera resistant to or intolerant of hydroxyurea."

The approval is based on data from the pivotal phase III RESPONSE clinical trial demonstrating that a significantly greater proportion of patients achieved the composite primary endpoint of hematocrit control without use of phlebotomy and spleen size reduction, key measures of disease control, when treated with Jakavi compared to best available therapy (21% compared to 1%, respectively; p<0.0001). In the study, a 50% or more improvement in PV-related symptoms was seen in 49% of Jakavi-treated patients compared to 5% of patients treated with best available therapy.

"The approval of Jakavi in polycythemia vera underscores what's possible in today's era of precision oncology research," said Bruno Strigini, president, Novartis Oncology.  "Jakavi specifically targets the JAK-STAT pathway, which regulates blood cell production and is known to play a key role in the underlying mechanism of this disease, bringing patients and physicians a new way to treat polycythemia vera."

Overall, non-hematologic adverse events (AEs) were consistent with those previously seen in other Jakavi studies in PV and myelofibrosis. Within the first 32 weeks of treatment, the most common Grade 3 or 4 hematologic AEs in the Jakavi-treatment arm were anemia (1.8%) and thrombocytopenia (5.5%). The most common non-hematologic AEs were dizziness (15.5%), constipation (8.2%) and herpes zoster (6.4%). The three most frequent non-hematological laboratory abnormalities (any Grade) were hypercholesterolemia (30.0%), raised alanine aminotransferase (22.7%) and raised aspartate aminotransferase (20.9%), which were mainly Grade 1 and 2.

The European Commission approval applies to all 28 EU member states, plus Iceland, Norway and Liechtenstein. Additional regulatory applications for ruxolitinib in PV are currently ongoing in countries worldwide, and further regulatory filings are under review by health authorities. Ruxolitinib, which is marketed in the US by Incyte Corporation as Jakafi, received approval in December 2014 from the US Food and Drug Administration (FDA) for the treatment of patients with PV who have had an inadequate response to or are intolerant of hydroxyurea.

RESPONSE is a global, randomized, open-label trial conducted at more than 90 trial sites. 222 patients with PV resistant to or intolerant of hydroxyurea were randomized 1:1 to receive either Jakavi (starting dose of 10 mg twice daily) or best available therapy, which was defined as investigator-selected monotherapy or observation only. The Jakavi dose was adjusted as needed throughout the trial. In the Jakavi arm, patients had a PV diagnosis for a median of 8.2 years and had previously received hydroxyurea for a median of approximately three years. Most patients (>80%) had received at least two phlebotomies in the last 24 weeks prior to screening. Patients were classified as intolerant or resistant to hydroxyurea based on the modified European LeukemiaNet (ELN) defined criteria.

The primary endpoint of the trial was the proportion of patients whose hematocrit was controlled without phlebotomy eligibility from week 8 through 32 (with no more than one phlebotomy eligibility between randomization and week 8) and whose spleen volume was reduced by 35% or more from baseline as assessed by imaging at week 32. Patients in the trial who were deemed to be eligible for phlebotomy had hematocrit that was greater than 45% and had increased three or more percentage points from the time they entered the trial (e.g., at baseline), or hematocrit greater than 48%. In addition, efficacy was further assessed using two key secondary endpoints: durable primary response and complete hematological remission. Other endpoints include safety and symptom improvement (as measured by the MPN-SAF 14-item total symptom score).

PV is a rare and incurable blood cancer associated with an overproduction of blood cells in the bone marrow that affects roughly one to three people per 100,000 globally. The disease is driven by the dysregulation of the JAK-STAT pathway. It is typically characterized by elevated hematocrit, 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, as well as an elevated white blood cell and platelet count. This can cause serious cardiovascular complications, such as stroke and heart attack, resulting in increased morbidity and mortality. Additionally, patients with PV may have an enlarged spleen and symptoms that are frequent and burdensome, with an overall impact on quality of life similar to that seen with myelofibrosis.

Jakavi (ruxolitinib) is an oral inhibitor of the JAK 1 and JAK 2 tyrosine kinases. Jakavi is  approved by the European Commission for the treatment of adult patients with polycythemia vera (PV) who are resistant to or intolerant of hydroxyurea and 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 80 countries for patients with myelofibrosis, including countries in the European Union, Canada, Japan and some countries in Asia, Latin and South America. Additional worldwide regulatory filings are underway in myelofibrosis and PV.

Novartis licensed ruxolitinib from Incyte Corporation for development and commercialization outside the United States. Jakavi is marketed in the United States by Incyte Corporation as Jakafi for the treatment of patients with PV who have had an inadequate response to or are intolerant of hydroxyurea and for the treatment of patients with intermediate or high-risk myelofibrosis.