Joint Canadian Association of Gastroenterology and Crohn’s Colitis Canada Position Statement on Biosimilars for the Treatment of Inflammatory Bowel Disease

摘要

The development of anti-tumour necrosis factor (TNF) therapies has transformed the care of patients with immune-mediated diseases such as inflammatory bowel disease (IBD), including ulcerative colitis and Crohn’s disease, psoriasis and inflammatory arthropathies, including rheumatoid arthritis and ankylosing spondylitis. For IBD patients, these biologic therapies are effective at inducing and maintaining remission (), reducing the need for surgery () and improving quality of life (). Although anti-TNF therapies are effective in several different immune-mediated disorders, individual biologics are not, necessarily, equally effective in all disorders suggesting that their actions may differ between disorders. For example, the paradox that anti-TNF drugs used to treat rheumatoid arthritis (RA) and psoriasis may yet cause joint pains and skin reactions in IBD patients, emphasizes our imperfect understanding of the mechanism of action of these biologic therapies and the need to evaluate treatment outcomes separately for different disorders. The main factors that limit the use of anti-TNF drugs are adverse events and cost. Anti-TNF therapy is associated with joint pains, dermatological disorders and transfusion reactions (). Transfusion reactions are associated with the development of antibodies to anti-TNF agents and this may also be associated with reduced treatment efficacy (). Anti-TNF agents are also associated with an increased risk of infection () and risk of lymphoma although these risks may be exacerbated, to a greater or lesser extent, by the concomitant use of azathioprine or other immunosuppressive agents (). Anti-TNF therapies are also expensive costing up to $20,000 per year for each patient in Canada. Canada spent more on biologic therapies for all indications than on any other class of drug in 2018 accounting for 8.2% of the $33.7 billion spent on prescription medications (). While the cost of these therapies is significant, the cost of having IBD is also expensive to society. It is estimated that the indirect cost of IBD was $1.29 billion in Canada in 2018 (,). Anti-TNF therapies can improve quality of life and productivity and, accounting for these societal costs, biologics may offer value for money (). In the Canadian setting, health care is mainly funded centrally by the tax payer and the government, understandably, focuses on how biologic therapy may reduce health care costs. This is less clear cut with research using health administrative data failing to demonstrate any significant decrease in hospitalizations or surgical resections in the anti-TNF era compared to what would be expected if these drugs had not been introduced (). Given this perspective, it is understandable that approaches to reducing the cost of these drugs are being explored. The emergence of biosimilars, also known as subsequent entry biologics have provided an opportunity for third party payers to reduce anti-TNF therapy drug costs. A biosimilar is a biological medical product that is similar to the original but manufactured by a different company once the patent for that product has expired. They are typically less expensive than the original product and therefore an obvious target in attempts to reduce biologic drug costs. Biosimilars are distinct from usual generic drugs, which are simple small molecules that are relatively straightforward to reproduce and manufacture on a large scale, and identical to the original drug. Biologic therapies are more complex proteins and require replication in living cells. The product is dependent on the type of genetically modified cell being used, the production process and purification techniques (). The manufacturing process is considerably more expensive than standard small molecules and therefore costs of biosimilars are higher than generically produced drugs. Furthermore, the variation from the originator is greater than would normally be seen with generics. However, it is important to emphasize that even with the original manufacturer there is potential for variability between each manufacturing run due to the complexity of living organisms. The Federal Drug Agency has released documents regarding the approval process for biosimilars () that other regulatory authorities have largely adopted (). Essentially biosimilars must show a high degree of similarity to the original product and have no clinically meaningful differences in safety, purity and potency (). This is a reasonable definition in principle but the definitions of ‘high degree of similarity’ as well as ‘clinically meaningful differences in safety and potency’ need further clarification in clinical practice. The Canadian Association of Gastroenterology has previously published a position statement on biosimilars () but this was 6 years ago, and more data are now available. Crohn’s and Colitis Canada has published a position statement more recently () but the two organizations felt it was of value to release a joint pos