Background: Rheumatoid Arthritis (RA) is a chronic condition causing fatigue, swelling and deformation of the joints. Together with its associated co-morbidities and high indirect costs represents a high humanistic and economic burden ¹ . In Spain, RA has a prevalence around 1% ² , representing about 473.942 people. Since biological treatments were introduced, such as adalimumab (ADA), the clinical outcomes of RA’s have improved ³ . Nevertheless, due to its high cost, biologics introduction was hurdled until biosimilars appeared ⁴ . At the moment, the available network meta-analyses ^5,6 do not show a statistically significant difference in effectiveness between the different available treatment. Therefore, cost-minimization analysis can be a useful tool in this pathology.

Objectives: Our objective was to conduct a cost-minimization analysis for RA in Spain.

Methods: All the cost information for the therapeutic alternatives (certolizumab, etanercept, golimumab, infliximab, tocilizumab, tofacitinib, and upadacitinib) was gathered from drug cost datasets ⁷ , and a range of discounts were applied according to experts opinion obtained through a survey. Finally, non-pharmacological costs were obtained from literature review ⁸ . With all this information, a cost-minimization analysis between the suitable therapeutic alternatives was performed for a 1-year time horizone. Robustness of results was validated by a deterministic and probabilistic sensitivity analysis (PSA).

Results: ADA was the less expensive option with an annual cost of 4,529€ vs 4,650€ - 10,001€ for the alternative treatments. Infliximab had only a slightly higher cost than ADA (2,7% higher). Certolizumab, etanercept, and tofacitinib showed a higher cost profile, with an annual cost between 54% and 71% higher than ADA. Finally, golimumab, tocilizumab and upadacitinib had the highest cost, between 103% and 137% higher than ADA.

Sensitivity analysis showed similar results. The deterministic sensitivity analysis showed ADA to be the best option with average and maximum discounts. In the PSA, only ADA and infliximab performed as the best alternative. ADA was the best option 63% of times.

Conclusion: According to our model, ADA was the most cost-effective biologic option for treating RA in Spain, and the sensitivity analysis validated the results.

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Disclosure of Interests: José Manuel Martínez-Sesmero Speakers bureau: Abbvie, Pfizer, Fresenius, Galapagos, Lilly, and Novartis, Consultant of: Abbvie, Pfizer, Fresenius, Galapagos, Lilly, and Novartis, Joan Antoni Schoenenberger-Arnaiz Speakers bureau: Biogen, Astra-zeneca, and LEO Pharma, Paid instructor for: Biogen, Astra-zeneca, and LEO Pharma, Carlos Crespo-Diz Speakers bureau: Abbvie, Amgen, AstraZeneca, Fresenius-Kabi, Grifols, Janssen-Cilag, Kern Pharma, GSK, Novartis, and Pfizer., Paid instructor for: Abbvie, Almirall, Amgen, Bayer, Biogen, BMS, Fresenius-Kabi, Gilead, GSK, Janssen-Cilag, Novo Nordisk, Novartis, Pfizer, Roche, Shire, SOBI, Takeda, and UCB., Mónica Cerezales Consultant of: I work for Axentiva Solutions, a consultancy firm working for several pharmaceutical companies