Longterm safety, efficacy, and inhibition of structural damage progression over 5 years of treatment with abatacept in patients with rheumatoid arthritis in the abatacept in inadequate responders to methotrexate trial.

OBJECTIVE: Evaluate the safety and efficacy of longterm abatacept (ABA) treatment over 5 years in methotrexate (MTX)-refractory patients with rheumatoid arthritis (RA).

METHODS: Patients from the 1-year, double-blind Abatacept in Inadequate Responders to Methotrexate (AIM) study (NCT00048568) received open-label ABA (∼10 mg/kg) in the longterm extension (LTE). Safety was assessed for patients who received ≥ 1 ABA dose, and efficacy for patients randomized to ABA and treated in the LTE. Radiographs were evaluated for changes in Genant-modified Sharp scores.

RESULTS: Out of 652 patients, 539 entered the LTE (ABA, n = 378; placebo, n = 161). At Year 5, 72.4% were ongoing; discontinuation rates declined over time. Incidence rates of serious adverse events, serious infections, malignancies, and autoimmune events were 13.87, 2.84, 1.45, and 0.99 events/100 patient-years exposure, respectively. American College of Rheumatology 20 response was 82.3% (n = 373) and 83.6% (n = 268) at years 1 and 5, respectively. Disease Activity Score 28 C-reactive protein (DAS28-CRP) < 2.6 and ≤ 3.2 were achieved by 25.4% and 44.1% of patients at Year 1 (n = 370), and 33.7% and 54.7% at Year 5 (n = 267), respectively. Mean changes in DAS28-CRP and Health Assessment Questionnaire-Disability Index at Year 1 [-2.83 (n = 365) and -0.68 (n = 369)] were maintained at Year 5 [-3.14 (n = 264) and -0.77 (n = 271)] for patients continuing treatment. Of them, 59.5% (n = 291) and 45.1% (n = 235) remained free from radiographic progression at years 1 and 5, respectively.

CONCLUSION: In MTX-refractory patients with RA, longterm ABA treatment was well tolerated and provided consistent safety and sustained efficacy, with high patient retention. Radiographic progression continued to be inhibited with ongoing treatment.