A Budget Impact and Cost Per Additional Responder Analysis for Baricitinib for the Treatment of Moderate-to-Severe Rheumatoid Arthritis in Patients with an Inadequate Response to Tumor Necrosis Factor Inhibitors in the USA

Background/objective: Baricitinib is a selective and reversible Janus kinase (JAK) inhibitor indicated for the treatment of adult patients with moderately to severely active rheumatoid arthritis (RA) who have had an inadequate response to one or more tumor necrosis factor inhibitors (TNFis) and has been shown to improve multiple clinical and patient-reported outcomes. However, it is unclear what the budgetary impact would be for US commercial payers to add baricitinib to their formulary and how the efficacy of baricitinib compares to other disease-modifying antirheumatic drugs (DMARDs) with a similar indication.

Methods: A budget impact model (BIM) was developed for a hypothetical population of 1 million plan members that compared a world without and with baricitinib. A retrospective observational study was carried out to estimate market utilization of advanced therapies. Number needed to treat (NNT) and cost per additional responder were calculated for American College of Rheumatology (ACR) 20%/50%/70% improvement criteria (ACR20/50/70) response outcomes combining cost estimates from the BIM and efficacy values from a network meta-analysis (NMA). The model included costs related to drug acquisition and monitoring costs.

Results: Adding baricitinib would save a commercial payer $US169,742 for second-line therapy and $US135,471 for third-line therapy over a 2-year time horizon (all costs correspond to 2019 US dollars). Cost savings were driven by baricitinib drawing market share away from more expensive comparators. The NMA, based on nine studies, found no statistically significant differences in the median treatment difference between baricitinib and comparators except for versus a conventional synthetic DMARD (csDMARD), and thus NNT versus a csDMARD was similar. The cost per additional responder for baricitinib in patients with inadequate response to a TNFi was substantially lower than all other treatments for all three ACR response criteria at 12 weeks (ACR20: $US129,672; ACR50: $US237,732; ACR70: $US475,464), and among the lowest at 24 weeks (ACR20: $US167,811; ACR50: $US259,344; ACR70: $US570,557).

Conclusions: Baricitinib, compared to other DMARDs, was a less expensive option (- $US0.01 incremental cost per member per month in second- and third-line therapy over a 2-year time horizon) with comparable efficacy in patients with inadequate response to TNFi. Adding baricitinib to formulary would likely be cost saving for US payers and expands treatment options for these patients.