The European Commission has approved Novartis' Jakavi (INC424, ruxolitinib), a JAK 1 and JAK 2 inhibitor 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.

The European Commission's decision was based on positive findings from the COMFORT (COntrolled MyeloFibrosis Study with ORal JAK Inhibitor Therapy) clinical trial programme.

"The approval of Jakavi by the European Commission brings an urgently needed new treatment option with the potential to make a real difference in patients' lives," said Dr. Claire Harrison, MD, Guy's and St. Thomas' NHS Foundation Trust, Guy's Hospital, London. "By targeting the dysregulated JAK pathway, Jakavi delivers a rapid and durable benefit that has the potential to become a new standard of care."

Myelofibrosis is an uncommon, life-threatening blood cancer characterized by bone marrow failure, enlarged spleen (splenomegaly), debilitating symptoms, such as extreme fatigue, night sweats and intractable pruritus (itching), poor quality of life and weight loss, as well as shortened survival. In the EU, the disease affects about 0.75 out of every 100,000 people annually. Myelofibrosis develops when uncontrolled signaling in the JAK pathway - which regulates blood cell production - causes bone marrow scarring and faulty blood cell production, resulting in an enlarged spleen and other severe complications. Jakavi directly targets the underlying mechanism of disease, significantly reducing splenomegaly and improving symptoms regardless of JAK mutational status, disease subtype or any prior treatment, including hydroxyurea.

"This approval marks a significant milestone in addressing unmet treatment needs for patients in the European Union," said Hervé Hoppenot, president, Novartis Oncology. "We are committed to the development of innovative treatments for orphan diseases, and are furthering research to assess the potential of targeted Jakavi therapy for other malignancies associated with a dysregulated JAK pathway."

The efficacy and safety of Jakavi in the treatment of patients with myelofibrosis was established in clinical studies, including the two pivotal phase III trials - COMFORT-I and COMFORT-II. Chronic inflammation through elevated cytokine levels is one of the primary consequences of dysregulated JAK 1 and JAK 2 signaling, and may be a major contributor to morbidity and mortality of patients with myeloproliferative neoplasms such as myelofibrosis. In one pivotal phase III study, Jakavi was shown to alter the clinical course of myelofibrosis by reversing symptom progression and splenomegaly, thus improving quality of life and potentially impacting overall survival.

COMFORT-I demonstrated that 41.9% of Jakavi-treated patients achieved at least a 35% reduction (roughly equivalent to a reduction in palpable spleen size by 50%) in spleen volume at 24 weeks from baseline compared to 0.7% of patients in the placebo group (p<0.001). An early analysis of COMFORT-I data at 51 weeks of treatment showed Jakavi treatment resulted in an overall survival benefit as compared to placebo (hazard ratio=0.50 [95% confidence interval: 0.25, 0.98])[5].

The most frequently reported grade 3 or higher adverse events were hematologic. One patient in each group discontinued treatment for thrombocytopenia or for anaemia, respectively. The most common non-haematologic adverse events of any grade reported for patients receiving Jakavi or placebo, respectively, were fatigue (25% vs 34%), diarrhoea (23% vs 21%), peripheral edema (19% vs 22%) and ecchymosis (19% vs 9%). One week after discontinuing Jakavi, these patients experienced a return of myelofibrosis symptoms that were present before initiating therapy; however, any symptoms they experienced as a result of treatment discontinuation subsided. COMFORT-I was conducted in the US by Incyte under the worldwide collaboration and license agreement for INC424 (ruxolitinib).

In COMFORT-II, Jakavi produced a volumetric spleen size reduction of 35% or greater in 28% of patients compared to 0% of patients in the best available therapy (BAT) group at 48 weeks (p<0.001). The BAT is any commercially available agent (such as monotherapy or in combination) or no therapy at all. At week 24, 32% of patients treated with Jakavi demonstrated a 35% or greater volumetric spleen size reduction compared to 0% of patients treated with the BAT (p<0.001) for the key secondary endpoint. Additionally, Jakavi was associated with improvements in myelofibrosis symptoms at each evaluation as compared with the BAT group. Jakavi showed modest toxicity as compared with the BAT, with increased frequency of anaemia and thrombocytopenia. The most frequently reported serious adverse event (SAE) was anemia for both groups (INC424, 5%; BAT, 4%). Pneumonia was the only SAE reported in &ge;5% of patients in either group (INC424, 1%; BAT, 5%). These findings are consistent with previous investigation of INC424.   

Continuous Jakavi therapy also provided a marked and durable improvement in overall quality of life measures, functioning and symptoms, including loss of appetite, dyspnea (shortness of breath), fatigue, insomnia and pain, at week 48, compared to a worsening of symptoms in BAT-treated patients. Jakavi showed modest toxicity as compared with the BAT, with increased frequency of anaemia and thrombocytopenia. The most frequently reported SAE for Jakavi was anaemia for both groups (5%). Pneumonia was reported in 1% of patients taking Jakavi.

Myelofibrosis is a life-threatening blood cancer with a poor prognosis and limited treatment options. Studies show that patients with myelofibrosis have a decreased life expectancy, with a median survival of 5.7 years. Although allogeneic stem cell transplantation may cure myelofibrosis, the procedure is associated with significant morbidity and transplant-related mortalityand is available to less than 5% of patients who are young and fit enough to undergo the procedure.

Jakavi (INC424, ruxolitinib) is an oral inhibitor of the JAK 1 and JAK 2 tyrosine kinases. The recommended starting dose for Jakavi is 15 mg twice daily for patients with a platelet count between 100,000cubic millimeters (mm3) and 200,000 mm3,and 20 mg twice daily for patients with a platelet count of >200,000 mm3. Doses may be titrated based on safety and efficacy.

Novartis licensed INC424 (ruxolitinib) from Incyte for development and potential commercialization outside the US. Incyte has retained rights for the development and commercialization of INC424 (ruxolitinib) in the US. Both the European Commission and the US Food and Drug Administration (FDA) granted INC424 (ruxolitinib) orphan drug status for myelofibrosis. Incyte received FDA approval for INC424 (ruxolitinib) in November 2011 under the name Jakafi for the treatment of patients with intermediate or high-risk myelofibrosis.