FAILURE OF THE FIRST BIOLOGIC TREATMENT IN PATIENTS WITH SPONDYLOARTHRITIS: DATA FROM THE MOROCCAN REGISTRY OF BIOLOGICAL THERAPIES IN RHEUMATIC DISEASES (RBSMR)

Introduction:Spondyloarthritis is a group of chronic inflammatory rheumatic diseases that commonly affect young adults. The advent of biological background treatments has revolutionized the management of these conditions, although some patients may not respond adequately to these interventions.

Objectives: To assess the prevalence of first biological treatment failure in spondyloarthritis and identify the factors associated with this outcome.

Methods: Our study included patients with spondyloarthritis retained according to the ASAS criteria, aged over 18 years, treated with biological treatment, and providing written informed consent. The participants were sourced from the ten rheumatology departments in Morocco, utilizing data from the RBSMR registry, a multicenter historical-prospective registry. Primary failure was characterized by treatment inefficacy within the initial six months, while secondary failure concerns cases of ineffectivenessbeyond six months of treatment. Patients were assessed every six months with a scheduled follow-up period of three years. Inclusion began in June 2017 and ended in January 2019, when the database was first frozen.

Results: A total of 194 patients were included in the study. The mean age was 40.23 years with a standard deviation of 13.68. The gender ratio was 1.73 (M/F). The average disease duration was 615.9 weeks with a standard deviation of 349.12. HLA-B27 antigen was positive in 66% of patients. Peripheral involvement was observed in 70% of patients, axial involvement in 96.4%, and enthesic involvement in 61.5%. Radiographic sacroiliitis was identified in 87.6% of patients, radiographic coxitis in 40.7%, and sonographic coxitis in 19.8%. Regarding extra-articular manifestations, 14.5% of patients experienced anterior uveitis, 6.9% had cutaneous psoriasis, and 10.7% had concomitant chronic inflammatory bowel disease. The ASDAS CRP indicated high activity in 50.9% of patients, and the BASDAI (spondyloarthritis activity index) exceeded 4 in 79.2% of patients. During the initial visit, 22.5% of patients were undergoing corticosteroid therapy, and 53.8% were receiving csDMARDs. Etanercept was the most commonly prescribed biological, accounting for 33%. Over the three-year follow-up, five primary failures and 17 secondary failures to the first biological treatment were observed (eight failures at the 12th month, six at the 18th month, and three at the 24th month), resulting in a prevalence of 11,85% for the failure of the first biological. In bivariate analysis, no statistically significant factors were found to be associated with the failure of the first biological at the 6th, 12th, or 24th month visits. However, at the 18th-month visit, both the average BASDAI and C-reactive protein (CRP) levels were statistically higher in patients who experienced failure with the first biological.

Conclusion: The failure of the first biologicaltreatment is a rather rare situation in our study. Specific factors were notably linked to this failure and should be considered in patient management, particularly elevated BASDAI and CRP values. These factors have also been reported in the literature to be associated with first biological treatment failure, along with additional factors.