Cost-effectiveness analysis of ixekizumab versus secukinumab in patients with psoriatic arthritis and concomitant moderate-to-severe psoriasis in Spain

Abstract

Objective: To conduct a cost-effectiveness analysis from the perspective of the Spanish National Health System (NHS) comparing ixekizumab versus secukinumab.

Design: A Markov model with a lifetime horizon and monthly cycles was developed based on the York model. Four health states were included: a biological disease-modifying antirheumatic drug (bDMARD) induction period of 12 or 16 weeks, maintenance therapy, best supportive care (BSC) and death. Treatment response was assessed based on both Psoriatic Arthritis Response Criteria (PsARC) and ≥90% improvement in the Psoriasis Area Severity Index score (PASI90). At the end of the induction period, responders transitioned to maintenance therapy. Non-responders and patients who discontinued maintenance therapy transitioned to BSC. Clinical efficacy data were derived from a network meta-analysis. Health utilities were generated by applying a regression analysis to Psoriasis Area Severity Index and Health Assessment Questionnaire‒Disability Index scores collected in the ixekizumab SPIRIT studies. Results were subject to extensive sensitivity and scenario analysis.

Setting: Spanish NHS.

Participants: A hypothetical cohort of bDMARD-naïve patients with psoriatic arthritis and concomitant moderate-to-severe psoriasis was modelled.

Interventions: Ixekizumab and secukinumab.

Results: Ixekizumab performed favourably over secukinumab in the base-case analysis, although cost savings and quality-adjusted life-year (QALY) gains were modest. Total costs were €153 901 compared with €156 559 for secukinumab (difference -€2658). Total QALYs were 9.175 vs 9.082 (difference 0.093). Base-case results were most sensitive to the annual bDMARD discontinuation rate and the modification of PsARC and PASI90 response to ixekizumab or secukinumab.

Conclusion: Ixekizumab provided more QALYs at a lower cost than secukinumab, with differences being on a relatively small scale. Sensitivity analysis showed that base-case results were generally robust to changes in most input parameters.

Trial registration number: SPIRIT-P1: NCT01695239; Post-results, SPIRIT-P2: NCT02349295; Post-results.

Keywords: Spanish population; biologics; cost-effectiveness analysis; ixekizumab; psoriatic arthritis; secukinumab.

Conflict of interest statement

Competing interests: BS and CM are full-time employees of ICON who were commissioned by Eli Lilly and Company to conduct the analysis for this work. MN, TD, CS and SH are full-time employees of Eli Lilly and Company; they receive a salary and own company stock.

© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Figures

Figure 1

Schematic representation of the model structure in biological disease-modifying antirheumatic drug-naïve patients with active psoriatic arthritis and concomitant moderate-to-severe psoriasis. Dosage regimens were aligned with the European market authorisation. Although not shown in the figure, patients could transition to death from any state. BSC, best supportive care; Q4W, every 4 weeks.

Figure 2

Combination of PsARC response and PASI90 was used to capture both joint and skin responses at the end of the induction period. PASI, Psoriasis Area Severity Index; PASI90, ≥90% improvement in the Psoriasis Area Severity Index score; PsARC, Psoriatic Arthritis Response Criteria.

Figure 3

Scenarios for Health Assessment Questionnaire–Disability Index rebound after the discontinuation of treatment. HAQ, Health Assessment Questionnaire.

Figure 4

Results of the one-way sensitivity analysis in biological disease-modifying antirheumatic drug-naïve patients with psoriatic arthritis and concomitant moderate-to-severe psoriasis. FBC, full blood count; HAQ-DI, Health Assessment Questionnaire–Disability Index; ICER, incremental cost effectiveness ratio; Ixe, ixekizumab; p.a., per annum; PASI, Psoriasis Area Severity Index; PASI90, ≥90% improvement in the Psoriasis Area Severity Index score; PsARC, Psoriatic Arthritis Response Criteria; QALY, quality-adjusted life-year; Q4W, every 4 weeks.

Figure 5

Results of the probabilistic sensitivity analysis in biological disease-modifying antirheumatic drug-naïve patients with psoriatic arthritis and concomitant moderate-to-severe psoriasis. Approximately 49.5% of observations were in the southeast quadrant; 28.6% were in the southwest quadrant; and 21.9% were in the northeast quadrant of the cost effectiveness plane. Ixe, ixekizumab; QALY, quality-adjusted life-year; Q4W, every 4 weeks; Sec, secukinumab; WTP, willingness to pay.

Figure 6

Results of scenario analyses in biological disease-modifying antirheumatic drug-naïve patients with psoriatic arthritis and concomitant moderate-to-severe psoriasis. PASI100, 100% reduction in Psoriasis Area Severity Index score; PASI75, ≥75% reduction in Psoriasis Area Severity Index score; PsARC, Psoriatic Arthritis Response Criteria; QALY, quality-adjusted life-year; Resp., response.