Juvenile spondyloarthritis Trials in Disease

Study on the Safety and Body Processing of Bimekizumab in Children with Juvenile Idiopathic Arthritis

This clinical trial is examining bimekizumab, a medication given as an injection under the skin, in children and teenagers with specific types of juvenile idiopathic arthritis. The study focuses on enthesitis-related arthritis, which includes juvenile-onset ankylosing spondylitis, and juvenile psoriatic arthritis. These conditions cause joint inflammation, pain, and stiffness in young patients.

Main focus and goals: The primary purpose of this study is to learn whether bimekizumab is safe for children with these types of arthritis and to understand how the medication moves through the body. Researchers will monitor participants over time to observe how the medication affects them, measure drug levels in the blood, and track any changes in health, including growth and vital signs like blood pressure and heart rate. The study will also assess any reactions at the injection site and monitor for serious side effects such as infections.

Investigational drug: Bimekizumab, also known as UCB4940, is a monoclonal antibody that works by targeting specific proteins in the body involved in causing inflammation. By blocking these proteins, the medication aims to reduce symptoms such as pain and swelling, and improve overall quality of life for young patients with arthritis.

Who can participate - inclusion criteria:

• Children and teenagers between 2 and 17 years old at the start of the study
• Confirmed diagnosis of enthesitis-related arthritis (including juvenile-onset ankylosing spondylitis) or juvenile psoriatic arthritis for at least 6 months
• Active disease with at least 3 active joints and, for enthesitis-related arthritis, at least 1 site of enthesitis (inflammation where tendons or ligaments attach to bone)
• Previous inadequate response or intolerance to at least one nonsteroidal anti-inflammatory drug (NSAID) for at least 1 month
• Weight of at least 10 kg (about 22 pounds)
• Participants may continue taking methotrexate or sulfasalazine if on a stable dose for the past 4 weeks, though these medications are not required to join the study
• Female participants of childbearing potential must agree to use contraception during the study and for at least 20 weeks after the last dose

Who cannot participate - exclusion criteria:

• Patients with any other active autoimmune disease
• Recent serious infection in the past 3 months
• Receipt of any live vaccine within 4 weeks before the study starts
• History of cancer, except for certain treated types of skin cancer
• Pregnant or breastfeeding patients
• History of drug or alcohol abuse in the past year
• Participation in another clinical trial within the last 30 days
• Known allergies to the study medication or its ingredients
• Any condition that study doctors believe would make participation unsafe

Throughout the study, participants will undergo regular assessments including monitoring of vital signs, laboratory tests to check blood chemistry, and measurements of growth including height and weight. The response to treatment will be evaluated using specific criteria such as the American College of Rheumatology pediatric response and the Juvenile Arthritis Disease Activity Score. These assessments help determine how well the medication is working. Researchers will also test for antibodies the body may produce in response to bimekizumab, as this can influence the medication's effectiveness.