To determine the cost-effectiveness of secukinumab, a fully human IL-17A inhibitor, for adult patients in the UK with active ankylosing spondylitis (AS) who have not responded adequately to previous treatment with conventional care (CC) or previous biologic therapy.

A de novo combined decision tree/Markov state-transition model was developed to evaluate two populations: 1) biologic-naïve patients with an inadequate response to CC; 2) biologic-experienced patients with an inadequate response to prior biologic treatment. Comparators were licensed anti-TNF therapies and CC in the two populations, respectively. Clinical parameters captured treatment response rates, short-term treatment effects on disease activity and patient functioning, and long-term impact of structural disease progression. Utility values were derived from secukinumab trial data via regression methods. List prices were used for all drugs; where available, other costs were sourced from NHS reference costs. Outcomes included total discounted costs and quality-adjusted life years (QALYs), and the incremental cost-effectiveness ratio (ICER). The analysis perspective was the UK NHS in 2017.

In the biologic-naïve population, secukinumab dominated adalimumab and infliximab and was associated with ICERs of <£20,000 per QALY gained compared to certolizumab pegol and etanercept. Secukinumab was less costly and associated with a minor decrement in QALYs versus golimumab, saving £19,782 per QALY foregone. In biologic-experienced patients, the ICER for secukinumab versus CC was £4,817 per QALY gained. At a £20,000 per QALY gained threshold, the probability of secukinumab being the most cost-effective intervention was estimated to be 45.5% in the biologic-naïve population (the highest probability of any intervention) and 98.2% in the biologic-experienced population.

Secukinumab provides a cost-effective use of NHS resources for patients with active AS who have responded inadequately to either CC or biologic treatment. The availability of a confidential patient access scheme discount for secukinumab in the UK further strengthens the case for cost-effectiveness in these populations.