Secukinumab vs. Adalimumab for treatment of ankylosing spondylitis: A cost per responder analysis at 52 weeks from an Argentinian perspective

Objectives: To estimate and compare the long-term cost per responder (CPR) based on the Assessment of Spondyloarthritis International Society (ASAS) outcomes following 52 weeks of treatment of ankylosing spondylitis (AS) with secukinumab, the first and only fully human anti-IL-17A antibody, relative to the anti-TNF, adalimumab, in Argentina. Methods: The target population for the model was biologicnaïve patients. The CPR for each treatment was calculated by dividing the drug acquisition cost for the course of treatment with its response rate. Drug costs were estimated by multiplying the retail price with the number of doses required for 52 weeks. The 52-week response rates were estimated using a matching-adjusted indirect comparison (MAIC) based on data from MEASURE 2 and ATLAS clinical trials of secukinumab and adalimumab, respectively. Sensitivity analysis was conducted by varying baseline characteristics used in the MAIC analysis. Results: The MAIC analysis showed that ASAS (20, 40 and 5/6) response rates were significantly higher for secukinumab compared to adalimumab at 52 weeks. ASAS 20, ASAS 40 and ASAS 5/6 response rates were 81% and 65%, 62% and 47%, 74% and 55% for secukinumab and adalimumab, respectively. The cost per ASAS 20 responder was ARS 415,901 and ARS 773,817, the cost per ASAS 40 responder was ARS 540,671 and ARS 1,075,879, and the cost per ASAS 5/6 responder was ARS 465,578 and ARS 920,561 for secukinumab and adalimumab, respectively. The costs per ASAS (20, 40 and 5/6) responders were approximately 54%, 50%, and 51% lower for secukinumab compared to adalimumab. The sensitivity analysis confirmed the robustness of the main analysis. Conclusions: The long term CPR for all ASAS response rates were consistently lower for secukinumab versus adalimumab. Furthermore, with better outcomes at lower costs, these findings suggest dominance of secukinumab over adalimumab. More AS patients could be treated more effectively with secukinumab versus adalimumab in Argentina.