OBJECTIVES: To estimate the cost per responder of ankylosing spondylitis (AS) treatment with secukinumab 150 mg versus adalimumab 40 mg from the Portuguese National Health System (NHS).

METHODS: The cost per responder for each treatment was estimated by dividing the drug acquisition cost of a 52-week course of treatment with its response rate based on the Assessment of Spondyloarthritis International Society outcomes (ASAS20, ASAS40 and ASAS5/6). Drug acquisition costs were estimated using 2018 official prices from the perspective of the NHS; number of doses required for the course of treatment were defined according to the approved EU label. Long-term response rates were estimated using a matching-adjusted indirect comparison (MAIC) based on the data from MEASURE 2 and ATLAS clinical trials of secukinumab and adalimumab, respectively. MAIC analysis matched baseline characteristics such as age, gender, Bath Ankylosing Spondylitis Functional Index (BASFI), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), C-reactive protein and TNF-naive proportion at baseline.

RESULTS: The predicted ASAS20, ASAS40 and ASAS5/6 response rates for secukinumab were 80%, 61% and 72% versus 65%, 47% and 55% for adalimumab, respectively. The 52-week cost of secukinumab was €6,739 versus €9,362 for adalimumab. For a given budget to treat 100 patients with adalimumab, 139 patients could be treated with secukinumab instead. Cost per ASAS20 responder for secukinumab and adalimumab was €8,423 and €14,402, cost per ASAS40 responder was €11,047 and €19,918, and cost per ASAS5/6 responder was €9,359 and €17,021, respectively.

CONCLUSIONS: Response rates were higher for secukinumab compared to adalimumab at 52 weeks for all considered ASAS outcomes and cost estimates per responder were consistently lower for secukinumab. These findings indicate that it is more efficient to treat AS patients with secukinumab than with adalimumab in the Portuguese NHS.