The cost-effectiveness of a bimekizumab versus IL-17A inhibitors treatment-pathway in patients with active axial spondyloarthritis in Scotland

ObjectiveTo estimate the cost-effectiveness of a treatment-pathway initiated with bimekizumab, a monoclonal IgG1 antibody that selectively inhibits interleukin (IL)-17F and IL-17A, in patients with axial spondyloarthritis (axSpA) compared with IL-17Ai's, ixekizumab, and secukinumab, from the NHS Scotland perspective.MethodsThe axSpA treatment-pathway was modeled using a decision tree followed by a lifetime Markov model. The pathway included first- and second-line biologic disease-modifying antirheumatic drugs (bDMARD), followed by best supportive care (bDMARD, nonbiologic). Bimekizumab followed by any bDMARD ("BKZ") was compared with IL-17Ai's: secukinumab 150 mg followed by a blend ("SEC") of dose up-titration to secukinumab 300 mg and any bDMARD, or ixekizumab followed by any bDMARD ("IXE"). Transition to the next therapy was triggered by Bath Ankylosing Spondylitis Disease Activity Index-50% (BASDAI50) non-response or any-cause discontinuation. A published network meta-analysis provided efficacy data. EuroQoL-5-dimensions utilities were derived by mapping from Ankylosing Spondylitis Disease Activity Score. Costs included disease management (linked to functional limitations), biologics acquisition (list prices), administration and monitoring (NHS 2021/22). Discounting was 3.5%/year. Probabilistic results from patients with non-radiographic axSpA and ankylosing spondylitis were averaged to reflect the axSpA disease spectrum. Scenario and sensitivity analyses were performed.ResultsThe incremental cost-effectiveness ratio (ICER) of BKZ was 24,801 pound/quality-adjusted life-year (QALY) vs. SEC (95% credible interval 24,163- pound 25,895) pound. BKZ had similar costs (Delta -385 pound [-15,239- pound 14,468]) pound and QALYs (Delta 0.039 [-0.748-0.825]) to IXE, with 1,523 pound (862- pound 2,222) pound net monetary benefit. Conclusions remained unchanged in most scenarios. Results' drivers included BASDAI50 response rate and disease management cost.LimitationsResults were based on list prices. Data concerning up-titration to secukinumab 300 mg was scarce.ConclusionsThe bimekizumab treatment-pathway represents a cost-effective option across the axSpA disease spectrum in Scotland. Bimekizumab is cost-effective compared to a secukinumab-pathway that includes dose up-titration, and has similar costs and QALYs to an ixekizumab-pathway.