NCT06668181 - An Open-label Study to Evaluate the Pharmacokinetics and Safety of Bimekizumab in Pediatric Study Participants With Active Juvenile Idiopathic Arthritis Subtypes Enthesitis-related Arthritis (Including Juvenile-onset Ankylosing Spondylitis) and Juvenile Psoriatic Arthritis | Crick

Eligibility

Sex: ALLMin age: 2 YearsMax age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Study participant must be 2 to \<18 years of age inclusive, at the Baseline Visit. * Study participants who have confirmed diagnosis of enthesitis-related arthritis (ERA; including juvenile-onset ankylosing spondylitis (JAS)) and/or juvenile psoriatic arthritis (JPsA) according to the juvenile-International League of Associations for Rheumatology (JIA-ILAR) classification criteria of at least 3 months duration prior to the Screening Visit. * Study participants who have active disease (ERA \[including JAS\] and/or JPsA) defined as having at least 3 active joints, each of which needs to be included in the joints assessed in the JADAS27, and for ERA at least 1 site of enthesitis at Baseline or documented by history. * Study participants with inadequate response (at least 1 month) or intolerance to at least 1 nonsteroidal anti-inflammatory drug (NSAID). * Study participants taking concomitant methotrexate or sulfasalazine are allowed to continue the medication if it has been used for the past 12 weeks with a stable dose for the 4 weeks prior to Baseline, with no change in dose for the first 16 weeks of treatment foreseen. (Note: prior or concomitant use of methotrexate or sulfasalazine is NOT required for study participation.) * Study participants with no concomitant use of second line agents such as disease-modifying and/or immunosuppressive drugs with the exception of methotrexate or sulfasalazine. * Body weight of ≥10kg. * Male and female. * A female study participant will be eligible to participate if she is not pregnant, not breastfeeding, and at least 1 of the following conditions applies: 1. Not a woman of childbearing potential (WOCBP) OR 2. A WOCBP who agrees to follow the contraceptive guidance during the Initial Treatment Period, the Open-label Extension (OLE) Period, and for at least 20 weeks after the final dose of investigational medicinal product (IMP; ie, the Safety Follow-up (SFU) Period) * Capable of giving/having parent(s) or legal representative provide signed informed consent/assent (where appropriate), which includes compliance with the requirements and restrictions listed in the Informed Consent Form (ICF) and assent and in this protocol. Exclusion Criteria: * Study participants fulfilling any International League of Associations for Rheumatology (ILAR) diagnostic juvenile idiopathic arthritis (JIA) category other than enthesitis-related arthritis (ERA; including juvenile-onset ankylosing spondylitis (JAS)) and/or juvenile psoriatic arthritis (JPsA). * Study participant has history of inflammatory bowel disease (IBD) or signs/symptoms suggestive of IBD. * Study participant has active uncontrolled uveitis. * Study participant has history of active tuberculosis (TB) unless successfully treated, latent TB unless prophylactically treated. * Study participant has had major surgery (including joint surgery) within the 3 months prior to the Baseline Visit or has planned major surgery within 6 months after entering the study. * Study participant has laboratory abnormalities at Screening defined in the Protocol. * Study participant has an active infection or history of infections (such as serious infection, chronic infections, opportunistic infections, unusually severe infections). * Study participant has received drugs listed in the protocol outside the specified timeframes relative to the Baseline Visit or receives prohibited concomitant treatments. * Study participant had previous therapy with bimekizumab or prior treatment with other IL-17 biologic response modifier. * Study participant had prior treatment with more than one biologic response modifier (other than an IL-17). * Presence of active suicidal ideation, or positive suicide behavior. * Study participant has been diagnosed with severe depression in the past 6 months.

Outcomes

Primary Outcomes

Plasma bimekizumab concentrations over the Initial Treatment Period

Plasma samples will be collected at pre-specified timepoints for measurement of plasma bimekizumab concentrations over the Initial Treatment Period.

Time frame: Up to Week 16

Secondary Outcomes

Incidence of Treatment-emergent adverse events (TEAEs)

An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of IMP, whether or not considered related to the IMP.

Time frame: From Baseline (Week 0) to End of Safety Follow-up (up to 141 weeks)

Incidence of Serious TEAEs

A SAE is defined as any untoward medical occurrence that, at any dose: * Results in death * Is life-threatening * Requires inpatient hospitalization or prolongation of existing hospitalization * Results in persistent disability/incapacity * Is a congenital anomaly/birth defect * Important medical events

Time frame: From Baseline (Week 0) to End of Safety Follow-up (up to 141 weeks)

Incidence of TEAEs leading to discontinuation of investigational medicinal product (IMP)

An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of IMP, whether or not considered related to the IMP.

Time frame: From Baseline (Week 0) to End of Safety Follow-up (up to 141 weeks)

Incidence of TEAEs leading to withdrawal from the study

An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of IMP, whether or not considered related to the IMP.

Time frame: From Baseline (Week 0) to End of Safety Follow-up (up to 141 weeks)

Incidence of selected safety events of interest (including infection [serious, opportunistic, fungal, and tuberculosis (TB)], inflammatory bowel disease [IBD], and injection site reactions)

Safety topics of interest are infections (serious, opportunistic, fungal, and tuberculosis), inflammatory bowel disease, and injection site reactions.

Time frame: From Baseline (Week 0) to End of Safety Follow-up (up to 141 weeks)

Change from Baseline in vital signs (systolic and diastolic blood pressure) at Week 16

Blood pressure will be measured in millimeters of mercury (mmHg).

Time frame: Baseline and Week 16

Change from Baseline in vital signs (heart rate) at Week 16

Heart rate will be measured in beats per minute (beats/min).

Time frame: Baseline and Week 16

Change from Baseline in biochemistry parameters (alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase) at Week 16

Alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase and gamma-glutamyltransferase will be measured in units per liter (U/L).

Time frame: Baseline and Week 16

Change from Baseline in biochemistry parameters (glucose, potassium, sodium, calcium) at Week 16

Glucose, potassium, sodium and calcium will be measured in millimoles per liter (mmol/L).

Time frame: Baseline and Week 16

Change from Baseline in biochemistry parameters (total bilirubin and direct bilirubin, total protein, blood urea nitrogen, and creatinine) at Week 16

Biochemistry parameters will be measured in micromols per liter (μmol/L).

Time frame: Baseline and Week 16

Change from Baseline in hematology parameters (hemoglobin) at Week 16

Hemoglobin will be measured in grams per liter (g/L).

Time frame: Baseline and Week 16

Change from Baseline in hematology parameters (hematocrit) at Week 16

Hematocrit will be measured in volume percentage (%) of red blood cells in blood.

Time frame: Baseline and Week 16

Change from Baseline in hematology parameters (erythrocytes) at Week 16

Erythrocytes will be measured in number of red blood cells per liter (10\^12/L).

Time frame: Baseline and Week 16

Change from Baseline in hematology parameters (platelets, leukocytes neutrophils, lymphocytes, eosinophils, basophils, and monocytes) at Week 16

Platelets, leukocytes, neutrophils, lymphocytes, eosinophils, basophils, and monocytes will be measured in number of white blood cells per liter (10\^9/L).

Time frame: Baseline and Week 16

Change from Baseline in growth assessments (height) at Week 16

Growth assessment, as assessed by the change from Baseline in height will be measured in centimeters (cm).

Time frame: Baseline and Week 16

Change from Baseline in growth assessments (weight) at Week 16

Growth assessment, as assessed by the change from Baseline in weight will be measured in kilograms (kg).

Time frame: Baseline and Week 16

Acceptability assessments by injection site pain adverse events (AEs) during the Initial Treatment Period (Week 0 to Week 16)

Incidence rate of injection site pain AEs during the ITP will be reported.

Time frame: Week 0 to Week 16

American College of Rheumatology pediatric (ACR Pedi) 30/50/70/90/100 response at Week 16

ACR assessments are based on a 30%, 50%, 70%, 90%, 100% or greater improvement (for ACR Pedi 30/50/70/90/100 respectively) in at least 3 of the 6 core set measures with no more than 1 of the remaining worsened by \>30%. The 6 core set measures are: * Number of joints with active arthritis (joints with swelling not due to deformity or inactive synovitis, or joints with limitation of motion with pain, tenderness, or both) * Number of joints with limitation of range of motion * Physician's Global Assessment of Disease Activity * CHAQ total score (Disability Index) completed by parent or caregiver * Parent/caregiver global assessment of overall well being of study participant * Acute phase reactant (hs-CRP)

Time frame: Week 16

Change from Baseline in Juvenile Arthritis Disease Activity Score (JADAS27) -high sensitivity C-reactive protein (hs-CRP) at Week 16

The JADAS27-hs-CRP is a composite disease activity score based on 4 core measures: * Number of joints with active arthritis * Physician's Global Assessment of Disease Activity * Parent/caregiver global assessment of overall well being of study participant * Acute phase reactant (hs-CRP); inflammation biomarker. The JADAS27-hs-CRP is calculated as the sum of the scores of the 4 components with a total score range of 0 to 57.

Time frame: Baseline and Week 16

Anti-bimekizumab antibody and neutralizing antibody detection prior to and following IMP administration during the Initial Treatment Period

Anti-bimekizumab antibody and neutralizing antibody detection prior to and following IMP administration during the Initial Treatment Period.

Time frame: Up to Week 16

An Open-label Study to Evaluate the Pharmacokinetics and Safety of Bimekizumab in Pediatric Study Participants With Active Juvenile Idiopathic Arthritis Subtypes Enthesitis-related Arthritis (Including Juvenile-onset Ankylosing Spondylitis) and Juvenile Psoriatic Arthritis

Overview

Conditions

Interventions

Eligibility

Locations (23)

Outcomes

Primary Outcomes

Secondary Outcomes

Central Contacts