Long-term safety and clinical outcomes of certolizumab pegol treatment in patients with active non-radiographic axial spondyloarthritis: 3-year results from the phase 3 C-axSpAnd study

Background 52-week results from C-axSpAnd demonstrated the safety and efficacy of certolizumab pegol (CZP) in patients with active non-radiographic axial spondyloarthritis (nr-axSpA) and objective signs of inflammation (sacroiliitis on MRI and/or elevated C-reactive protein levels). Long-term safety and clinical outcomes, including MRI assessments, are evaluated up to 3 years for CZP-treated patients with nr-axSpA. Methods C-axSpAnd was a phase 3 study comprising a 1-year double-blind, placebo-controlled period and 2-year open-label safety follow-up extension (SFE). At baseline, 317 patients were randomised 1:1 to placebo or CZP 200 mg every 2 weeks. Patients completing the double-blind phase who enrolled into the SFE received open-label CZP for an additional 104 weeks. Long-term safety and clinical outcomes are reported to Week 156. Continuous outcomes are presented as observed case (OC) and dichotomous outcomes as OC and with non-responder imputation. Results 243/317 (76.7%) patients entered the SFE, during which 149 (61.3%) experienced ≥1 treatment-emergent adverse event (TEAE); 15 (3.3/100 patient-years) experienced serious TEAEs. Continuous outcome scores (including Ankylosing Spondylitis Disease Activity Score [ASDAS]: 1.8; Bath Ankylosing Spondylitis Disease Activity Index [BASDAI]: 2.7) at Week 52 were maintained at Week 156 (ASDAS: 1.8; BASDAI: 2.6) for the initial CZP-randomised group. Mean SPARCC MRI sacroiliac joint inflammation scores for these patients decreased at Week 52 (baseline: 7.6; Week 52: 1.7), remaining low at Week 156 (2.4). Conclusions CZP treatment was well tolerated up to 3 years, with no new safety signals versus previous reports. Clinical outcomes achieved after 1 year were sustained to 3 years. Trial registration number NCT02552212.