The US Food and Drug Administration (FDA) has approved Incyte Corporation's Jakafi (ruxolitinib) for the treatment of patients with polycythemia vera (PV) who have had an inadequate response to or are intolerant of hydroxyurea. Jakafi, an oral medication, is the first and only product approved by the FDA for PV, a rare and progressive blood cancer.

“The approval of Jakafi represents an important advance for patients with uncontrolled PV. For the first time we are able to provide these patients a treatment that has been shown to provide effective and consistent control of their blood counts and reduce spleen volume,” said Srdan Verstovsek, MD, Professor, Department of Leukaemia, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center.

PV is a myeloproliferative neoplasm (MPN) and is typically characterised 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. PV may occur at any age but often presents later in life, with a median age at diagnosis of 60 years.

Approximately 100,000 patients in the US are living with PV3. Current standard treatment for PV is phlebotomy (the removal of blood from the body) plus aspirin. When phlebotomy can no longer control PV, chemotherapy such as hydroxyurea, or interferon, is utilised. Approximately one in four (~25,000) patients with PV are considered uncontrolled because they have an inadequate response to or are intolerant of hydroxyurea, the most commonly used chemotherapeutic agent for the treatment of PV.

Patients with PV who fail to consistently maintain appropriate blood count levels, including appropriate hematocrit levels, have an approximately four times higher risk of major thrombosis (blood clots) or cardiovascular death. Patients with PV can also suffer from an enlarged spleen, and a significant symptom burden which may be attributed to thickening of the blood and a lack of oxygen to parts of the body. These symptoms commonly include fatigue, itching, night sweats, bone pain, fever, and weight loss.

“Being diagnosed with a serious disease affects a person in a way that cannot be predicted,” said Robert Rosen, a patient living with PV and founder and chairman of the MPN Research Foundation. “The FDA approval of this drug is good news for our community and provides a new treatment option for those patients who do not respond to other therapies. This news confirms the ongoing importance of continued research, and the critical role that the MPN Research Foundation plays in improving the lives of patients.”

Jakafi is also the first and only FDA-approved product for the treatment of intermediate or high-risk myelofibrosis, a closely related blood cancer. Jakafi is a JAK1 and JAK2 inhibitor that targets overactive JAK pathway signaling, which plays a critical role in the development of both myelofibrosis and polycythemia vera.

“The team at Incyte is proud that a second indication has been approved for Jakafi, further confirming the strength of our science and our commitment to discovering and developing innovative treatments for patients with cancer,” said Hervé Hoppenot, Incyte’s president and chief executive officer.

The approval of Jakafi for the treatment of patients with polycythemia vera who have had an inadequate response to or are intolerant of hydroxyurea was based on data from the pivotal phase III RESPONSE trial, which was conducted under a Special Protocol Assessment from the FDA. In this trial, patients treated with Jakafi demonstrated superior hematocrit control and reductions in spleen volume compared to best available therapy. In addition, a greater proportion of patients on the ruxolitinib treatment arm achieved complete hematologic remission which was defined as achieving hematocrit control, and lowering platelet and white blood cell counts. In the RESPONSE trial, the most common hematologic adverse reactions (incidence > 20 per cent) were thrombocytopenia and anaemia. The most common non-hematologic adverse events (incidence >10 per cent) were headache, abdominal pain, diarrhoea, dizziness, fatigue, pruritus, dyspnea and muscle spasms.

Jakafi is a first-in-class JAK1/JAK2 inhibitor approved by the US Food and Drug Administration for treatment of people with polycythemia vera (PV) who have had an inadequate response to or are intolerant of hydroxyurea.

Jakafi is also indicated for treatment of people with intermediate or high-risk myelofibrosis (MF), including primary MF, post–polycythemia vera MF, and post–essential thrombocythemia MF.Jakafi is marketed by Incyte in the United States and by Novartis as Jakavi (ruxolitinib) outside the United States.