IL-23 biologics are biologic therapies, which are derived from living organisms. These therapies are designed to precisely target certain components of the immune system to treat chronic inflammatory diseases. They work by interfering with specific proteins involved in inflammation, offering a focused approach to managing conditions driven by an overactive immune response.
The Role of IL-23 in Disease
Interleukin-23 (IL-23) is a cytokine, a protein that regulates the body’s immune response. Normally, IL-23 helps activate the immune system to defend against threats like bacteria and fungi. It is involved in the differentiation and proliferation of T helper type 17 (Th17) cells, which are immune cells that produce other inflammatory substances such as IL-17, IL-21, IL-22, and GM-CSF.
When the immune system becomes dysregulated, excessive IL-23 can be produced, even without an infection. This overproduction leads to chronic inflammation and contributes to various autoimmune or inflammatory conditions. In these diseases, the overactive IL-23 causes Th17 cells to generate too many inflammatory substances, perpetuating the inflammatory cycle. IL-23 is present in the skin of individuals with psoriasis, the bowel wall of those with inflammatory bowel disease, and the synovial membrane in rheumatoid arthritis.
How IL-23 Biologics Work
IL-23 biologics operate by targeting and blocking the activity of the IL-23 protein. These medications bind to the p19 subunit of the IL-23 cytokine, which is unique to IL-23. By binding to this subunit, the biologics prevent IL-23 from attaching to its receptor on immune cells.
This blockade interrupts the signaling pathway that activates and multiplies Th17 cells. Consequently, the production of inflammatory cytokines is reduced, decreasing overall inflammation. This targeted approach helps alleviate symptoms and slows the progression of inflammatory diseases by addressing a key upstream regulator of the inflammatory cascade.
Conditions Treated by IL-23 Biologics
IL-23 biologics are used for treating several chronic inflammatory and autoimmune conditions. These include plaque psoriasis, psoriatic arthritis, and inflammatory bowel diseases such as Crohn’s disease and ulcerative colitis. In plaque psoriasis, IL-23 contributes to red, scaly patches by stimulating keratinocyte proliferation and perpetuating T cell-mediated inflammation. IL-23 biologics work to reduce this inflammation, leading to significant improvements in skin clearance and relief from symptoms like itching and pain.
For psoriatic arthritis, IL-23 also plays a role in the inflammatory process. By reducing the inflammatory response, these medications help alleviate joint pain, swelling, and stiffness, which improves physical function. In inflammatory bowel diseases, an overactive IL-23 pathway can lead to chronic inflammation of the gastrointestinal tract, causing symptoms such as abdominal pain and diarrhea. Targeting IL-23 helps suppress this inflammation, promoting tissue healing in the gut and reducing disease activity.
Important Considerations for Treatment
IL-23 biologic treatments are typically administered through subcutaneous injection. The frequency of these injections can vary, with some medications requiring doses at the start of treatment, then at four weeks, and subsequently every 8 to 12 weeks. This less frequent dosing schedule can be a benefit for patients.
While generally well-tolerated, IL-23 biologics can have common side effects. An increased risk of infections, such as upper respiratory infections, fungal infections, or herpes simplex, is a consideration because these medications modulate the immune system. Injection site reactions, like redness or discomfort, can also occur. It is important to discuss the potential benefits and risks of any treatment with a healthcare provider to determine the most appropriate plan.