OBJECTIVES: Ixekizumab is an interleukin-17A inhibitor approved in the United States (US) for the treatment of adult patients with psoriatic arthritis (PsA). This analysis assessed the budget impact of introducing ixekizumab into the US market for the treatment of PsA in biologic disease-modifying anti-rheumatic drug (bDMARD)-naïve patients and in tumor necrosis factor inhibitor (TNFi)-experienced patients.

METHODS: A budget impact model was developed to demonstrate the economic impact of adding ixekizumab to a reference formulary for treatment of PsA from both third-party US payer and US Medicare Part D perspectives over a 3-year time horizon. Model input parameter values for epidemiology, clinical response, resource use, and direct costs were obtained from published literature and other publicly available sources. Future market share projections were derived from Eli Lilly internal market research data. Response to treatment (ACR 20) was obtained from clinical trials and patients not achieving response were assumed to switch to another biologic treatment, using corresponding market shares for subsequent treatment lines. The robustness of the results was tested via deterministic sensitivity analyses (DSA).

RESULTS: Model analyses showed that introducing ixekizumab as a treatment option for PsA to a commercial plan results in an average increase of $0.02 per member per month (PMPM) (or $0.23 per member per year, PMPY) over 3 years. From a US Medicare Part D perspective, analyses showed an average increase of $0.03 PMPM (equivalent to $0.36 PMPY) over 3 years. DSA results indicated that the parameter value for the ixekizumab market share uptake was the primary driver of model outcomes. Results were relatively insensitive to most other parameter values.

CONCLUSIONS: These budget impact analyses show that for the combined bDMARD-naïve and TNFi-experienced PsA population, adding ixekizumab to the US formulary would result in a modest net budget impact over a time horizon of 3 years.