Abatacept, marketed as Orencia by Bristol-Myers Squibb, was seen to improve the symptoms of polyarticular-course juvenile idiopathic arthritis (pJIA) in a Phase 3 clinical trial. Additionally, subcutaneous administration of Orencia was well-tolerated across different age and weight groups for a period of 24 months, researchers found.
The study, “Subcutaneous Abatacept in Patients With Polyarticular-Course Juvenile Idiopathic Arthritis: Results From a Phase III Open-Label Study,” was published in the journal Arthritis & Rheumatology.
Methotrexate (MTX) is usually the recommended first-line treatment for pJIA, which refers to JIA that affects five or more joints. When disease symptoms persist after three months of MTX treatment, a biological agent is frequently initiated. Tumor necrosis factor inhibitor (TNFi) is the most commonly used treatment at that point, followed by an anti-interleukin 6 agent, or Orencia. This normally occurs when patients are intolerant or do not respond to MTX or TNFi.
Intravenous administration of Orencia in pJIA patients proved effective and well-tolerated, with benefits persisting for up to seven years of treatment in patients ages 6 to 17. The therapy also is sold in a subcutaneous formulation that allows for administration at home. This offers patients and caregivers greater flexibility.
In the Phase 3 study (NCT01844518), researchers investigated the pharmacokinetics, efficacy, and safety of subcutaneous Orencia over 24 months in patients with pJIA, including patients as young as 2.
The study, initiated in 2013, included 48 centers worldwide that are members of the Paediatric Rheumatology International Trials Organisation and the Pediatric Rheumatology Collaborative Study Group.
JIA-American College of Rheumatology criteria (JIA-ACR) was used to evaluate disease status in pJIA patients and consists of six core criteria: 1) physician’s global assessment of disease activity, 2) parent/patient assessment of overall well-being, 3) the number of joints with active arthritis, 4) the number of joints with limited range of motion, 5) functional ability, 6) erythrocyte sedimentation rate (ESR).
Other parameters measured included the concentration of Orencia in the blood, safety and immune tolerance, and median Juvenile Arthritis Disease Activity Score (JADAS)71-C-reactive protein (CRP) over time. The JADAS71-CRP test also includes physician and parent/patient assessments, as well as the number of joints with active disease. But ESR is replaced by CRP measurement, a marker for inflammation.
Results showed that the concentration of Orencia in the blood in both groups did not drop below the minimal level required for it to have therapeutic action.
Also, the JIA-ACR30/50/70/90/100/inactive parameter, which corresponds to 30, 50, 70, 90, 100, and zero percent of disease improvement, were 83.2%, 72.8%, 52.6%, 28.3%, 14.5%, and 30.1% in group 1, respectively, and 89.1%, 84.8%, 73.9%, 58.7%, 41.3%, and 50% in group 2, after four months. This trend was maintained after 24 months.
Additionally, median JADAS71-CRP improved from the start of the study to the 24th month (21 to 4.6 in group 1, and 18.1 to 2.1 in group 2; a lower score corresponds to less disease activity), and were maintained until the 24th month, when 27 patients from group 1 and 11 patients from group 2 achieved JADAS71-CRP remission.
Researchers reported no unexpected adverse events.
Based on the results, the team concluded that “weight-stratified SC [subcutaneous] abatacept yielded target therapeutic exposures across age and weight groups, was well tolerated, and improved pJIA symptoms over 24 months.”