Infliximab is a biologic medication used to manage various autoimmune diseases. It is a type of monoclonal antibody that specifically targets a protein in the body known as tumor necrosis factor-alpha (TNF-alpha). This protein plays a role in triggering inflammation, and by inhibiting its action, infliximab helps to reduce inflammatory responses and control disease symptoms. While traditionally administered intravenously, a subcutaneous form of infliximab has recently become available, offering a new treatment option.
Understanding Infliximab and Its Uses
Infliximab is classified as a chimeric monoclonal antibody, meaning it is engineered from both mouse and human antibody components. This design allows it to bind to and neutralize TNF-alpha, a cytokine that contributes to systemic inflammation and tissue damage in autoimmune conditions. By blocking TNF-alpha, infliximab reduces inflammation and helps manage symptoms of various inflammatory diseases.
The medication is approved for treating a range of autoimmune disorders in adults and some pediatric populations. These include:
Crohn’s disease, a chronic inflammatory bowel disease that can affect any part of the digestive tract
Ulcerative colitis, which primarily affects the large intestine
Rheumatoid arthritis, a condition causing joint inflammation and damage
Ankylosing spondylitis, which affects the spine
Psoriatic arthritis
Chronic severe plaque psoriasis
The Shift to Subcutaneous Administration
Historically, infliximab has been administered through intravenous (IV) infusions, typically in a hospital or clinic setting. These infusions usually take about two hours, with initial treatments given at weeks 0, 2, and 6, followed by maintenance infusions every six to eight weeks. This method requires patients to visit a healthcare facility regularly, which can be time-consuming.
The development of a subcutaneous (SC) form of infliximab, approved by the FDA as Zymfentra in October 2023, allows for self-administration through an injection under the skin. The SC form is often given as maintenance therapy after an initial induction period with IV infliximab.
A primary advantage of subcutaneous infliximab is enhanced convenience for patients, as it reduces the need for frequent hospital or clinic visits. This allows for greater flexibility in managing treatment at home. Studies also suggest that subcutaneous administration may lead to more stable drug levels in the body compared to the fluctuating peak and trough concentrations seen with IV infusions. This consistent drug exposure can contribute to sustained therapeutic effects and improved outcomes.
Important Considerations for Treatment
Patients considering subcutaneous infliximab should be aware of safety considerations. Common side effects include:
Injection site reactions (redness, pain, itching, or swelling)
Headaches
Stomach pain
Indigestion
Upper respiratory infections
Infliximab suppresses the immune system, increasing infection risk. Before starting treatment, patients are screened for latent infections, including tuberculosis (TB) and hepatitis B, as infliximab can reactivate these conditions. Monitoring for infection symptoms, such as fever or persistent cough, is important throughout treatment.
Healthcare providers assess a patient’s medical history and current health status to determine suitability for subcutaneous infliximab. Patients with certain conditions, such as moderate to severe congestive heart failure, may not be suitable candidates. Adherence to the prescribed regimen and ongoing communication with a physician are important for safe and effective use, ensuring proper monitoring for side effects and disease response.