Anti TNF therapy is changing the way AS is managed
In people with AS, along with some other forms of inflammatory arthritis, a protein called tumour necrosis factor (TNF) is over-produced in the body. This causes inflammation and damage to bones, cartilage and tissue. Anti TNF therapy blocks the action of TNF and can reduce inflammation.
There five anti TNF drugs licensed by the European Medicines Agency for the treatment of AS. Cimzia, Enbrel and Humira are also licensed for the treatment of non radiographic axial spondyloarthritis.
Biosimilar medicines are developed to be highly similar to a biological medicine which has already been approved and made available for patients. They can be developed by manufacturers once the original patent for the product has expired.
They are called "biosimilar" because the molecular structures are so complex that it is not possible to produce an absolutely identical drug to the original - referred to as the "originator". With smaller drugs, such as non-steroidal anti-inflammatory drugs, it is common for different manufacturers to produce identical "copies" of the originator drug, known as "generic" drugs.
Why make biosimilars?
Biosimilar medicines are developed in order to provide alternative products, usually at a lower cost than the original biological medicine. This can provide more treatment options for patients and increase accessibility. Some biosimilar drugs are already in use in other areas of medicine.
Hospira has begun launching its Remicade biosimilar Inflectra (infliximab) in major European markets for patients suffering from a range of inflammatory conditions, including RA, AS, Crohn's disease and psoriasiatic arthritis.
Meanwhile, Napp Pharmaceuticals has launched Celltrion's Remicade biosimilar Remsima (infliximab) in the UK. Remsima is also licensed to treat a range of inflammatory conditions.
Regulations for biosimilar medications
Once approved, a biosimilar medicine is recognised to be a highly similar version of a biological medicine and has comparable quality, safety and efficacy.
Biosimilars introduced into the UK market first have to be approved by the European Medicines Agency (EMA). They undergo a comprehensive regulatory process which demands comparability studies, both clinical and non-clinical, that demonstrate equivalence to the originator product in terms of quality, efficacy and safety. That is to say, a biosimilar will have a similar treatment effect and side-effect profile to the originator drug. This has particularly important implications for which conditions a biosimilar drug can be used to treat. In this regard the EMA states:
‘In certain cases it may be possible to extrapolate therapeutic similarity shown in one indication to other indications of the reference medicinal product'
This means that once licensed a biosimilar anti TNF may be used to treat all the conditions for which the originator has been shown to be effective. It may only be necessary to test the biosimilar in one condition. So, for example, a biosimilar anti-TNF drug may only have undergone clinical trials in rheumatoid arthritis but will get a license that includes AS. One advantage of this is that the drug will be available without so many years of clinical testing through which the originator had to pass. So it should be available to treat sufferers more quickly.
Position Statements on biosimilar medications
The British Society for Rheumatology (BSR) have issued a position statement on biosimilar medications which contains 9 recommendations. The European League Against Rheumatism has also published a position statement.
Last reviewed: June 2015
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