Effectiveness of bDMARDs in ankylosing spondylitis patients by biologic use: experience from the CorEvitas PsA/SpA Registry

Objective: To describe bDMARD initiators by biologic experience among ankylosing spondylitis (AS) patients and change in disease activity and patient-reported outcomes (PROs) in real-world US patients.Methods: We included patients >= 18 years with AS based on physician diagnosis enrolled between 3/2013 and 11/2019 in the CorEvitas Psoriatic Arthritis (PSA)/Spondyloarthritis Registry (NCT02530268). Patients concurrently diagnosed with PSA were excluded. Baseline (bDMARD initiation) demographics, comorbidities, disease characteristics, treatment, and PROs were collected. Response rates and changes in disease activity and PROs between baseline and 6- and 12- month follow-up visits were calculated.Results: Of the 489 AS patients in the PsA/SpA Registry, 254 AS (52.0%) patients initiated a bDMARD at enrollment or during follow-up (total initiations: AS = 313). Of the 313 AS initiations, 179 (57.2%) had a 6-month follow-up, 122 (39.0%) had a 12-month follow-up, and 94 (30.0%) had a 6- and 12-month follow-up visit. For those AS initiators with a 6-month follow-up, the mean age was 49.1 years, 44.4% were female, and 70.4%, 47.5%, 96.1%, and 46.9% had never used cDMARDs, TNFis, non-TNFis, and bDMARDs, respectively. Of these 179 AS initiators, 20.1% and 14.0% achieved ASAS20/40, respectively. Further, only 34% achieved low disease activity (ASDAS <2.1). When stratified by biologic-naivete and biologic-experience, the ASAS 20/40 achievement rates were 26.2% and 14.7%, and 21.4% and 7.4%, respectively, for this cohort.Conclusion: Although AS patients initiate bDMARDs, many do not achieve optimal treatment responses. Future research is needed to investigate the aspects associated with inadequate improvement and treatment response to bDMARDs.