If you’ve been managing IBD with a biologic therapy and your doctor or pharmacist mentions switching to a biosimilar, it’s natural to feel uncertain. Understanding what biosimilars are, how they relate to the original biologic, and what the evidence shows can help you feel more confident about the decision.
What Are Biologic Medicines?
Biologic medicines are complex treatments made from living cells. They work by targeting specific parts of the immune system that drive inflammation in IBD. Unlike conventional drugs, which are chemically synthesised, biologics are produced using biological processes involving cell cultures. Common examples used in IBD include infliximab, adalimumab, vedolizumab, and ustekinumab. These therapies have transformed management of Crohn’s disease and ulcerative colitis, particularly for people who do not respond to standard treatments.
Because biologics are large, complex molecules, they cannot be copied in the same way as traditional medicines. This is where biosimilars come in.
What Are Biosimilars?
A biosimilar is a biologic medicine that is highly similar to an already approved biologic, known as the reference product or originator. Biosimilars are not identical copies, which is impossible given the complexity of biologic manufacturing, but they are designed to have no clinically meaningful differences in terms of safety, quality, or effectiveness.
To gain approval, a biosimilar must undergo rigorous testing to demonstrate that it matches the reference biologic in structure, function, purity, and clinical effect. Regulatory agencies such as the European Medicines Agency (EMA) and the Medicines and Healthcare products Regulatory Agency (MHRA) require extensive comparative data before a biosimilar can be used.
Why Biosimilars Are Introduced
The main reason biosimilars exist is to increase access to biologic treatment and reduce costs. When the patent on an originator biologic expires, other manufacturers can develop biosimilars. Because they do not require the full clinical development programme of the original product, biosimilars are less expensive to bring to market, leading to significant cost savings for healthcare systems. This may allow more patients to access biologic therapy or free up resources for other treatments.
In the UK, biosimilar adoption is encouraged by the NHS as part of efforts to improve sustainability and value. For patients, this does not mean the treatment is inferior, but rather that the healthcare system is using a version meeting the same standards at lower cost.
How Biosimilars Are Tested
Biosimilars undergo stepwise comparison with the reference biologic. This includes laboratory analysis of molecular structure, studies in cell cultures, and clinical trials in patients. The goal is to show that the biosimilar behaves in the same way as the originator in terms of absorption, distribution, clearance, and clinical effects.
Importantly, biosimilars are not required to repeat every trial conducted for the original biologic. Instead, they rely on the principle of biosimilarity, demonstrating equivalence in key areas rather than starting from scratch. Regulatory approval is only granted when the evidence confirms no meaningful difference.
Switching from an Originator to a Biosimilar
Switching refers to moving from one biologic to another that targets the same pathway, usually from an originator to a biosimilar. Real-world data and clinical studies have shown that switching to an approved biosimilar is safe and effective for most patients with IBD. Evidence from large registries, observational cohorts, and randomised trials supports this practice.
Some patients worry that switching will lead to loss of response or increased side effects. The evidence does not support this concern when the switch is to a properly approved biosimilar. Outcomes such as remission rates, inflammatory markers, and adverse events remain stable in the majority of patients.
That said, individual responses can vary. If you notice new symptoms or changes after switching, communicate with your IBD team. Sometimes, changes in formulation, device, or administration schedule can affect how the treatment is experienced, even if the clinical effect remains the same.
Multiple Switches and Interchangeability
Some patients may be asked to switch more than once, for example from an originator to one biosimilar, and later to another biosimilar of the same reference product. This practice, called multiple switching, is less studied but emerging data suggest it is also safe when done under medical supervision.
In some countries, pharmacists are allowed to substitute a biosimilar without consulting the prescribing doctor. In the UK, this is not standard practice for biologics. Switches are typically discussed and agreed upon by the prescribing clinician, often in consultation with the patient.
What to Expect During a Switch
Your healthcare team should inform you in advance if a switch is planned. You may be offered information about the biosimilar, including its name, manufacturer, and how it differs from your current treatment. In many cases, the main difference is the brand name and packaging. The dose, frequency, and method of administration are usually the same.
Monitoring after a switch is important. Your IBD team may arrange blood tests, symptom reviews, or other follow-up to check the biosimilar is working as expected. This is standard practice to ensure continuity of care, not an indication of risk.
If you have concerns, discuss them with your doctor or IBD nurse. You are entitled to understand why the change is being recommended and what the evidence shows. Patient preferences should be considered as part of shared decision-making.
Practical Takeaways
- A biosimilar is not a generic. It is a highly similar biologic that meets the same regulatory standards as the originator.
- Switching from an originator to a biosimilar is supported by clinical evidence and is considered safe for most patients with IBD.
- Cost savings from biosimilars can improve access to biologic therapy and support healthcare sustainability.
- If you are asked to switch, your IBD team should explain the reasons, provide information, and arrange appropriate monitoring.
- Report any new symptoms or concerns after switching. Individual responses can vary, and adjustments can be made if needed.
- You have the right to be involved in decisions about your treatment. Ask questions and share your preferences.
Conclusion
Biosimilars represent an important development in IBD care. They offer the same clinical benefits as originator biologics but at lower cost, which can improve access and sustainability. The evidence supports switching from originators to biosimilars, and most patients continue to do well after the change. If you are asked to switch, understanding the reasons and evidence behind the decision can help you feel more confident. Open communication with your IBD team is key to ensuring your treatment remains effective and aligned with your needs.
References
- Jørgensen KK, Olsen IC, Goll GL, et al. Switching from originator infliximab to biosimilar CT-P13 compared with maintained treatment with originator infliximab (NOR-SWITCH): a 52-week, randomised, double-blind, non-inferiority trial. Lancet. 2017;389(10086):2304-2316. doi:10.1016/S0140-6736(17)30068-5
- Allocca M, Fiorino G, Zallot C, et al. Incidence and patterns of COVID-19 among inflammatory bowel disease patients from the Nancy and Milan cohorts. Clin Gastroenterol Hepatol. 2020;18(9):2134-2135. doi:10.1016/j.cgh.2020.04.071
- Komaki Y, Yamada A, Komaki F, et al. Systematic review with meta-analysis: the efficacy and safety of CT-P13, a biosimilar of anti-tumour necrosis factor-α agent (infliximab), in inflammatory bowel disease. Aliment Pharmacol Ther. 2017;45(8):1043-1057. doi:10.1111/apt.13990
- Gisbert JP, Chaparro M. Switching from an originator anti-TNF to a biosimilar in patients with inflammatory bowel disease: can it be recommended? A systematic review. Gastroenterol Hepatol. 2018;41(6):389-405. doi:10.1016/j.gastrohep.2018.04.005
- Danese S, Fiorino G, Raine T, et al. ECCO position statement on the use of biosimilars for inflammatory bowel disease: an update. J Crohns Colitis. 2017;11(1):26-34. doi:10.1093/ecco-jcc/jjw198
- Gecse KB, Lovász BD, Farkas K, et al. Efficacy and safety of the biosimilar infliximab CT-P13 treatment in inflammatory bowel diseases: a prospective, multicentre, nationwide cohort. J Crohns Colitis. 2016;10(2):133-140. doi:10.1093/ecco-jcc/jjv220
- Feagan BG, Marabani M, Wu JJ, et al. The challenges of switching therapies in an evolving multiple biosimilars landscape: a narrative review of current evidence. Adv Ther. 2020;37(11):4491-4518. doi:10.1007/s12325-020-01472-1
- Armuzzi A, Fiorino G, Danese S, et al. The PROSIT cohort of infliximab biosimilar in IBD: a prolonged follow-up on the effectiveness and safety across Italian inflammatory bowel disease centers. Inflamm Bowel Dis. 2019;25(3):568-574. doi:10.1093/ibd/izy264
This article is intended for informational and educational purposes only. It does not constitute medical advice and should not be used as a substitute for professional medical guidance, diagnosis, or treatment.