Recapture and retreatment rates with ixekizumab after withdrawal of therapy in patients with axial spondyloarthritis: results at week 104 from a randomised placebo-controlled withdrawal study.

OBJECTIVES

To evaluate the recapture of response with open-label (OL) ixekizumab (IXE) retreatment at week 104 in patients with axial spondyloarthritis who flared after withdrawal of IXE therapy.

METHODS

COAST-Y (NCT03129100) is a phase III extension study that included a double-blind, placebo-controlled, randomised withdrawal-retreatment period (RWRP). Patients who achieved remission (Ankylosing Spondylitis Disease Activity Score (ASDAS) <1.3 (inactive disease, ID) at least once at week 16 or 20 and <2.1 (low disease activity, LDA) at both visits) were randomised 2:1 at week 24 to continue IXE or withdraw to placebo. Patients who subsequently flared were switched to OL IXE every 2 or 4 weeks (Q2W or Q4W) at the next visit. The proportions of patients who recaptured ASDAS LDA and ID were summarised for those who experienced flare.

RESULTS

Of the 155 patients who entered the RWRP (placebo, n=53; IXE Q4W, n=48; IXE Q2W, n=54), 138 (89%) completed week 104. Of the placebo-treated patients (n=53), 28 (53%) experienced a flare during weeks 24-104; of these, 4 (14%) recaptured ASDAS LDA before retreatment with OL IXE, and 23 (82%) recaptured ASDAS LDA and 19 (68%) met ASDAS ID after retreatment. Of the continuously treated IXE patients (n=102), 13 experienced flare; 7 of 13 (54%) recaptured ASDAS LDA before switching to OL IXE retreatment, while 5 of 13 (38%) recaptured ASDAS LDA and 4 of 13 (31%) met ID after switching.

CONCLUSIONS

Ninety-six per cent of patients withdrawn to placebo recaptured at least ASDAS LDA and 71% recaptured ASDAS ID with IXE retreatment at week 104. This may provide support to patients who may require a brief interruption in therapy.