OBJECTIVES: Biologic disease-modifying antirheumatic drugs (bDMARDs) are a major driver of total costs in psoriatic arthritis (PsA), a chronic inflammatory rheumatic condition associated with psoriasis. To date, there are no cost-effectiveness analyses (CEAs) comparing the interleukin-17A antagonists ixekizumab and secukinumab in PsA in the UK. We conducted a CEA from the UK National Health Service perspective to compare the cost-effectiveness of ixekizumab versus secukinumab in bDMARD-naïve patients with PsA and concomitant moderate-to-severe psoriasis.

METHODS: A Markov model derived from the widely accepted York model was developed. The model used a lifetime horizon with monthly cycles. Treatment sequences evaluated were ixekizumab→ustekinumab→best supportive care (BSC) versus secukinumab→ustekinumab→BSC. The model included the health states trial bDMARD period, continuous bDMARD treatment, BSC and death. At the end of the bDMARD trial period, Psoriatic Arthritis Response Criteria (PsARC) responders transitioned to continuous treatment with trial bDMARD. PsARC non-responders and patients who discontinued continuous treatment transitioned to trial period of next bDMARD or BSC, as appropriate. Clinical efficacy was measured in terms of proportion of patients achieving a PsARC response and change from baseline Health Assessment Questionnaire – Disability Index (HAQ-DI) and Psoriasis Area Severity Index (PASI) scores, which were derived from network meta-analyses. Health utilities were estimated by applying regression analysis to HAQ-DI and PASI scores collected in the SPIRIT trials with ixekizumab in PsA. Only direct medical costs were included.

RESULTS: Ixekizumab was associated with lower total costs (£155,455 vs £155,530 [year of costing 2017]) and higher total QALYs (8.127 vs 7.989) than secukinumab, although differences were modest. Robustness of results was assessed through deterministic and probabilistic sensitivity analyses.

CONCLUSIONS: In bDMARD-naïve patients with PsA and concomitant moderate-to-severe psoriasis in the UK, first-line ixekizumab in this biologic treatment sequence provided slight advantages in cost savings and QALYs gained over first-line secukinumab in a similar sequence.