Treatment of severe ankylosing spondylitis with high-dose secukinumab: A retrospective study

Abstract Background: Secukinumab is an effective biological agent for the treatment of ankylosing spondylitis(AS); however, some patients do not respond well to the administration of 150 mg every 4 weeks and require more effective management measures. This retrospective study evaluates the efficacy and safety of the administration of secukinumab (300 mg every 4 weeks) in patients with severe AS. Methods: We reported 12 patients with severe ASand retrospectively reviewed their clinical records and follow-up data. These 12 patients were predominantly men (83.33%)with a mean age of 39.33 ± 13.01 years at the start of secukinumab treatment. Their mean body mass index was 27.48 ± 1.21kg/m2. The patients showed severe disease activity at baseline [Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score > 4]. The protocol of administration of subcutaneous loading doses of secukinumab every 5 weeks was instituted, followed by subcutaneous administration of secukinumab, 300 mg every 4 weeks or 150 mg every 3 weeks; the patients were advised against off-label use. The assessment of the patients’ conditions, including the Ankylosing Spondylitis Disease Activity Score (ASDAS), BASDAI, and Bath Ankylosing Spondylitis Functional Index (BASFI) was performed at weeks 12 and 24. Results: All 12 patients had a reduction of more than 1.1 in the ASDAS at week 12, and the effect persisted through to week 22. The 50% BASDAIresponse rate was 58.3% at week 12 and 83.3% at week 24. No new safety findings were observed. Conclusion: Subcutaneous administration of secukinumab, 300 mg every 4 weeks or 150 mg every 3 weeks, showed sustained efficacy of AS and a consistent safety profile after 24 weeks of treatment. This study is a retrospective study with a limited number of cases and a short observation period, which were the major limitations of the study. This retrospective study provides powerful evidence for the novel treatment strategy of refractory active AS switching to 300 mg secukinumab.