Myelofibrosis is a rare blood cancer that causes scar tissue to build up in the bone marrow, where blood cells are made. This often leads to low levels of blood cells in the body.
When the bone marrow is unable to produce enough red blood cells, the spleen takes over production and grows bigger than normal as a result. This enlarged spleen causes discomfort and can destroy the blood cells it produces or refuse to release them into the bloodstream.
This causes a condition called anaemia (a low red blood cell count in the bloodstream), and other associated symptoms such as night sweats, fever, bone pain and weight loss.
Julian Beach, MHRA Interim Executive Director, Healthcare Quality and Access, said:
Myelofibrosis patients often rely on blood transfusions to counter their anaemia, but studies have shown that these transfusions are often linked to reduced quality of life and survival.
Keeping patients safe and enabling their access to high quality, safe and effective medical products are key priorities for us.
We’re assured that the appropriate regulatory standards for the approval of this medicine have been met.
As with all products, we will keep the safety of this medicine under close review.
Research has shown that around 40% of all myelofibrosis patients have moderate to severe anaemia at diagnosis and nearly all patients develop anaemia through the course of their disease. Patients with anaemia require more care, such as blood transfusions. However, more than 30% of transfusion-dependent patients stop treatment, leading to worse health outcomes including shorter survival.
The treatment is taken in tablet form, once daily, at the same time each day.
The active ingredient in Omjjara, momelotinib, inhibits the action of enzymes called Janus Associated Kinases (JAK1, JAK2) that control the activity of cytokines.
Cytokines are proteins that are involved in inflammation in the body, the production of different blood components and regulating the immune system.
It also inhibits activin A receptor, type 1 (ACVR1) which increases production of hepcidin, a protein that traps iron in the liver and reduces absorption from food, resulting in anaemia.
Myelofibrosis causes these proteins to act abnormally. By inhibiting them, the medicine blocks the over-production of cytokines and hepcidin, reducing inflammation and increasing iron and haemoglobin levels in the blood.
This approval is supported by evidence from a randomised, double-blind phase 3 clinical trial involving 195 patients with myelofibrosis and anaemia, who had previously been treated with a JAK inhibitor.
The patients were given either 200mg momelotinib once daily, or 300mg of danazol (another medication that has been used to treat myelofibrosis) twice daily, for 24 weeks.
This study showed that momelotinib was more effective than danazol at reducing symptoms and spleen size over those taking danazol.
25% of patients on momelotinib saw their symptoms reduce by at least half (against 9% on danazol), 22% on momelotinib saw their enlarged spleen volume decrease by at least 35% (against 2% on danazol).
The most common side effects of the medicine (which may affect more than 1 in 10 people) include infections, a low blood platelet count which can result in bruising or bleeding for longer than usual when hurt, dizziness, headache, cough, diarrhoea, feeling sick, stomach-ache, feeling weak and tiredness.
As with any medicine, the MHRA will keep the safety and effectiveness of Omjjara under close review. Anyone who suspects they are having a side effect from this medicine are encouraged to talk to their doctor, pharmacist or nurse and report it directly to the Yellow Card scheme, either through the website (https://yellowcard.mhra.gov.uk/) or by searching the Google Play or Apple App stores for MHRA Yellow Card.
Notes to editors
- The new marketing authorisation was granted on 30 January 2024 to Glaxo Smith Kline UK Ltd.
- More information can be found in the Summary of Product Characteristics and Patient Information leaflets which will be published on the MHRA Products website within 7 days of approval.
- More information on the effect of anaemia on treatment options for myelofibrosis patients can be found here: Myelofibrosis-Related Anemia: Current and Emerging Therapeutic Strategies – PubMed (nih.gov)
- This was a randomised, double-blind clinical trial, where neither the participants nor the staff on the trial were aware of what each participant was taking. For more information about the studies, see the Summary of Product Characteristics.
- For more information on myelofibrosis see: Myelofibrosis (MF) Macmillan Cancer Support.
- The Medicines and Healthcare products Regulatory Agency (MHRA) is responsible for regulating all medicines and medical devices in the UK by ensuring they work and are acceptably safe. All our work is underpinned by robust and fact-based judgements to ensure that the benefits justify any risks.
- The MHRA is an executive agency of the Department of Health and Social Care.
- For media enquiries, please contact the [email protected], or call on 020 3080 7651.