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Biological drugs (also known as biotherapeutics or biopharmaceuticals) are made from proteins and other substances which occur in nature. They are produced by a biological rather than chemical process – for example they can be created inside living cells. Biological drugs are a lot larger in size and more complicated than normal chemical drugs used in IBD, such as steroids, 5-ASAs and azathioprine.
There are several different biological drugs used in IBD. These are:
Infliximab and Adalimumab are referred to as ‘anti-TNF drugs’ because they work by targeting a protein in the body called TNF-alpha. This protein is found in everyone’s blood as part of the body’s response to infection. However, in people with IBD, too much TNF-alpha is produced, and this causes excessive inflammation. Biological drugs such as infliximab and adalimumab block the action of TNF-alpha, and reduce inflammation. Golimumab is a newer anti-TNF drug which is currently less widely used.
Vedolizumab, another biological drug, works in a different way to the anti-TNF drugs, because it is a ‘gut-selective integrin blocker’. White blood cells are made by the immune system to fight against infection. However, in CD and UC, overproduction of white blood cells leads to inflammation – Vedolizumab works by stopping the white blood cells from entering the lining of the gut. This means that the drug only targets the gut, rather than the whole of the body like the anti-TNF drugs do, and may cause fewer side effects.
Another biological drug Ustekinumab has different mechanism of action and is directed against interleukin 12 and interleukin 23. Interleukin 12 & 23 are proteins that circulate in your body naturally. They are used by the body to fight infection by causing an inflammation response. In IBD the body appears to produce too much interleukin 12 & 23 and this can damage the intestine leading to your CD and UC.
Current biological drugs cannot be given as tablets by mouth because the digestive system would break down and destroy the drug. Infliximab, Ustekinumab and Vedolizumab are given by an infusion through a drip in the arm. Both Adalimumab and Golimumab are given via a subcutaneous injection (injection under the skin), either into the thigh or stomach.
Biological drugs are made using living organisms, such as modified plant and animal cells. The cells receive a gene (a piece of DNA) which instructs them to make a specific protein – in the case of infliximab the protein is the antibody which targets TNF alpha. The cell with the gene in it then multiplies, and produces the biological protein which can be ‘harvested’. The cells that are the best at producing the protein are identified and grown on an industrial scale - these special cells are called a ‘cell line’ and are unique to each manufacturer. The cell line is then grown in huge tanks, and the final product harvested. This is an extremely complex process, and very small changes to it can lead to very large changes in the final product.
If you have been prescribed infliximab, you may come across the term ‘biosimilar’. All drugs when they are first discovered are subject to a patent. A patent is an exclusive set of rights given to the inventor of a new product or drug, which allows them to be the only person or company making and selling that particular drug. This allows them to offset the huge costs involved in the research and development of a new drug. Patents can last for twenty years before they expire – after which other pharmaceutical companies can manufacture the drug.
Infliximab (REMICADE®) was the first biological drug to be used in IBD, and the patent expired in February 2015, meaning that other companies can now produce their own versions of the same drug. However, biologic drugs are not like other ‘chemical’ drugs, and are made by living cells, which means that the process by which they are manufactured is much more complicated. Each manufacturer has its own unique cell line and manufacturing process– so the final products can never be exactly identical because they are made using different cells. Hence we have biosimilars, which are similar to, but not identical to the original biological drug.
However, in order for a biosimilar to gain approval to be used, it has to meet strict standards to show it is as safe and effective as the original biologic drug, and to have the same quality, although it may have small structural differences.
So far, there is one biosimilar drugs approved by Health Canada and available for use in Canada for IBD. This is Inflectra, the biosimilar versions of Infliximab. It came onto the Canadian market in June 2016 when the patent for Remicade expired. Inflectra is given as an infusion, and at the same dose and frequency as Remicade. It is currently less expensive than Remicade, meaning that more IBD patients may eventually have access to this drug. The patent for Adalimumab is due to run out in Europe in 2018, so biosimilar versions of the drug may be available then.
As yet, there have been no formal clinical trials on the use of biosimilars in IBD patients. However, there has been research into the use of infliximab biosimilars in two other autoimmune diseases: Rheumatoid Arthritis and Ankylosing Spondylitis (a form of arthritis which affects the spine). These trials did not show any differences in safety or effectiveness between the original biological drug and the biosimilar. This is called ‘extrapolation’, and has to be viewed with some caution because people with IBD may react differently from people with Ankylosing Spondylitis and Rheumatoid Arthritis.
There are currently several ongoing clinical trials studying the effect of biosimilars on IBD, that should provide more answers. Meanwhile, it is worth noting that infliximab biosimilars are already being used for IBD patients in countries such as Norway and Hungary, and the current results from these countries suggest that they are as effective and safe as Remicade. In summary, while the evidence suggests that biosimilars may be a good option for people with IBD, they should still be used cautiously until the results of the clinical trials for IBD have become available.
People on Inflectra will be monitored carefully to make sure that all side effects are quickly identified and recorded correctly. New medicines and vaccines that are under additional monitoring have an inverted black triangle symbol (▼) displayed in their package leaflet. You can help with this monitoring by reporting any side effects you may have – this could either be telling your doctor or IBD nurse. Biosimilars of Infliximab must always be prescribed by brand name – so Remicade or Inflectra. This is so there is no uncertainty about which type of Infliximab is being used, and so that any side effects can be assigned to the correct drug.
Patients with IBD should be fully informed about the drugs they are being prescribed, and have their views taken into account in any discussions about switching. However, if your doctor does recommend switching you from Remicade to Inflectra, the evidence so far suggests there should be no difference in the effectiveness and safety of the drug. It is also important that pharmacists do not substitute Inflectra for Remicade – so prescriptions should always be written by the brand name to prevent any such substitutions occurring. If you are concerned about anything to do with your treatment, you should discuss this with our IBD team.
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