Muramyl tripeptide phosphatidyl ethanolamine or mifamurtide (Mepact?, Takeda UK), is not recommended for NHS use in combination with post-operative chemotherapy drugs for the treatment of high-grade non-metastatic, surgically treatable osteosarcoma. This according to a recommendation published today by NICE, the UK’s National Institute for Health and Clinical Excellence.
While rare, osteosarcoma is the most common form of bone cancer. Around 150 new cases are diagnosed each year in the UK. Tumours can grow anywhere in the skeleton, but the most common places are in the legs or upper arm. Common symptoms include pain, redness and swelling in the affected area. Approximately 55% of all patients treated in the UK will live for at least five years after treatment.
The exact causes of osteosarcoma are unknown. It is thought genetic factors, previous exposure to radiotherapy, past bone damage and certain bone diseases like Paget’s disease may increase the risk of developing osteosarcoma. However, the reasons for this are unclear.
Although the evidence presented to the NICE showed that mifamurtide plus multi-agent chemotherapy may be more effective than multi-agent chemotherapy alone, there was substantial uncertainty around how much extra benefit it could offer over and above currently available treatments, especially considering the exceptionally high cost the NHS is being asked to pay. The recommendation can be reviewed at the NICE’s webpage.
Current treatment for osteosarcoma involves chemotherapy before and after surgery, first to shrink the tumour and then to destroy any remaining cancer cells, and surgery to remove the part of the bone or limb affected. In most cases limb-saving surgery can be performed although some patients will need an amputation. Despite no major new treatment advance over the last 20 years, clinical specialists believe that overall survival rates for osteosarcoma have improved by 10-20% over the past decade, because of the introduction of high dose methotrexate as a chemotherapy option and better implementation of treatment regimens.
Mifamurtide, a powder, which is mixed with saline and administered via an intravenous drip and given after surgery with the recommended dose being 2 mg/m? body surface area and is used in combination with postoperative multi-agent chemotherapy, works by stimulating macrophages, a type of white blood cell that helps the body fight infections by absorbing the disease-causing organism. These cells can normally be found in the bloodstream and connective tissue. Patients receive mifamurtide twice a week at least 3 days apart for 12 weeks, followed by once-weekly treatments for another 24 weeks.
According to Takeda’s submission, mifamurtide costs ?2,375 for one dose and ?114,000 for a full treatment course of 48 doses. A patient access scheme has been proposed by the manufacturer to reduce the cost of the drug to the NHS. Under the scheme, mifamurtide would be available at no charge to the NHS for the first 7 doses.
The independent Appraisal Committee agreed the best-case incremental cost-effectiveness ratios (ICER) based on the evidence available would be at least ?70,100 per QALY gained (based on the deterministic analysis) and ?67,000 per QALY gained (based on the probabilistic analysis), including the patient access scheme.
The research presented to the committee for consideration was a clinical trial where the primary focus was to compare mifamurtide in combination with postoperative multi-agent adjuvant chemotherapy (three or four agent using high-dose methotrexate, doxorubicin and cisplatin with or without ifosfamide) with postoperative multi-agent adjuvant chemotherapy (three or four agent) alone. Patients recruited to the trial all had non-metastatic, surgically treatable, malignant osteosarcoma.
The analyses highlighted that although there was a statistically significant increase in overall survival, there was substantial uncertainty around the size of the treatment effect relative to standard UK clinical practice. Furthermore, the study failed to show a statistically significant improvement in disease-free survival (the amount of time a patient can remain free of the disease) for mifamurtide compared with the currently available treatments.
Sir Andrew Dillon, NICE Chief Executive, said: ?The NHS has finite resources, which means NICE can only recommend treatments that are shown to work better than currently available treatments, taking into account any possible side-effects, and represents good value for money for the NHS for the amount of benefit it offers patients. Although the independent advisory committee thought mifamurtide could become a valuable new treatment for osteosarcoma, when used in combination with post-operative chemotherapy, the evidence presented by the manufacturer highlighted substantial uncertainty around the size of the treatment effect relative to standard UK clinical practice. This uncertainty, together with the drug’s exceptionally high cost, meant the Committee considered mifamurtide not to be an appropriate use of NHS resources.?
This draft guidance is now with consultees who have until Friday 22 October to appeal against the recommendations via the NICE website. NICE has not yet issued final guidance for mifamurtide for the treatment of osteosarcoma to the NHS – this is expected to be published later this year. Until then, NHS bodies will make decisions locally on the funding of specific treatments.
Mifamurtide is approved for use in the European Union. The drug has an ‘orphan designation’ which means that it is used to treat life-threatening or chronically debilitating conditions that affect no more than five in 10,000 people in the European Union. The ‘orphan designation’ (EU/3/04/206) was granted by the European Commission On 21 June 2004, for the treatment of osteosarcoma and since 6 March 2009 the drug has been authorised in the European Union in children, adolescents and young adults for the treatment of high-grade resectable non-metastatic osteosarcoma after macroscopically complete surgical resection. It is used in combination with post-operative multi-agent chemotherapy.