Inflammatory Bowel Disease (IBD) encompasses chronic conditions such as Crohn’s disease and ulcerative colitis, characterized by persistent inflammation within the gastrointestinal tract. This inflammation can lead to a range of challenging symptoms, including abdominal pain, diarrhea, and weight loss, significantly affecting a person’s quality of life. For individuals experiencing more severe forms of IBD, or those who have not responded adequately to conventional treatments, a class of advanced medications known as biologics has emerged. These therapies play an important role in managing the underlying inflammation and promoting healing in the gut, helping many patients achieve remission and sustained relief from their symptoms.
What Biologics Are
Biologics are a distinctive category of medications derived from living organisms, such as cells or proteins, setting them apart from traditional drugs created through chemical synthesis. Unlike small-molecule drugs that have simpler chemical structures and are often manufactured in standard facilities, biologics are large, intricate molecules. This complexity stems from their biological origin, as they are produced within living cells through specialized processes like biomanufacturing involving recombinant DNA technology.
These medications are specifically engineered to interact with the body’s immune system in a precise manner. They are designed to target and bind to particular components of the immune response that contribute to the inflammation seen in IBD. This targeted approach allows biologics to address the disease at its source, rather than broadly suppressing the immune system, which distinguishes their mechanism from older, less specific therapies.
How Biologics Work
Biologics reduce inflammation in IBD by precisely interacting with specific proteins or pathways involved in the inflammatory cascade. Instead of broadly dampening the immune system, these medications are designed to block particular chemical messages that drive the inflammatory response in the gastrointestinal tract. This targeted action helps to “turn down” the immune system’s inappropriate attack on the body’s own tissues.
For example, certain biologics work by blocking tumor necrosis factor-alpha (TNF-alpha), a protein that plays a central role in promoting inflammation. By binding to TNF-alpha, these biologics prevent it from interacting with receptors on cell surfaces, thus disrupting the inflammatory signals.
Other biologics target integrins, which are adhesion molecules that facilitate the migration of inflammatory white blood cells into the gut. Blocking these integrins reduces the influx of these cells, preventing them from reaching and damaging the gastrointestinal lining. Additionally, some biologics inhibit interleukins, such as IL-12 and IL-23, which are messenger chemicals that recruit white blood cells and contribute to inflammation.
Main Types of IBD Biologics
Several classes of biologics are used to treat IBD, each targeting distinct inflammatory pathways.
The first class approved for IBD were the anti-TNF agents, which block tumor necrosis factor-alpha (TNF-alpha). Examples include infliximab, adalimumab, certolizumab pegol, and golimumab.
Another group consists of anti-integrin agents, which prevent inflammatory white blood cells from entering the gastrointestinal tract. Vedolizumab and natalizumab are examples.
A third class includes IL-12/23 inhibitors, which target specific interleukins involved in the inflammatory cascade. Ustekinumab, for instance, targets both IL-12 and IL-23. Risankizumab is another example that specifically targets IL-23.
Starting and Continuing Biologic Treatment
When initiating biologic therapy, patients can expect the medication to be administered in one of two main ways: intravenous (IV) infusions or subcutaneous (SC) injections. IV infusions, such as with infliximab, are typically given in a clinic setting, where the drug is delivered directly into a vein over a period, often ranging from 30 minutes to 2 hours. Subcutaneous injections, like adalimumab or some forms of infliximab, can often be self-administered at home using a pre-filled pen or syringe after proper training, offering greater flexibility.
The frequency of doses varies depending on the specific biologic, often ranging from weekly to every eight weeks for maintenance therapy. During the initial phase of treatment, known as induction, doses may be given more frequently to achieve symptom control and reduce inflammation quickly. Ongoing monitoring is a standard part of biologic therapy, which typically involves regular blood tests to assess drug levels, check for antibodies against the medication, and monitor for any potential changes in blood counts or liver function. This long-term commitment to treatment and monitoring is important for maintaining remission and managing the disease effectively.
Considering Biologic Therapy
Healthcare providers typically consider biologic therapy for IBD patients who have moderate to severe disease, especially if they have not responded sufficiently to conventional treatments. The decision to start a biologic is a collaborative one, made in consultation between the patient and their healthcare team, considering individual disease characteristics and lifestyle.
Before beginning treatment, patients will undergo pre-screening tests to ensure the therapy is appropriate and to identify any underlying conditions. This often includes screening for active or latent infections, such as tuberculosis and hepatitis B and C, as biologics can affect the immune system’s ability to fight off infections. Vaccination status is also reviewed and updated as needed. Patients should discuss potential considerations, including the long-term commitment required for therapy and the importance of adherence to the treatment schedule.