BUDGET IMPACT OF MIRIKIZUMAB-MRKZ IN THE TREATMENT OF ADULT PATIENTS WITH MODERATELY-TO-SEVERELY ACTIVE ULCERATIVE COLITIS IN THE UNITED STATES
Authors: Stargardter Matthew , Upadhyay Navneet , Raj Sayooj , Fisher Deborah , Creveling Thomas , Bires Nicholas , Johnson Nate , Milev Sandra 
Published: January 2024

Abstract

BACKGROUND
Mirikizumab (miri), an IL-23p19 antagonist, is undergoing US FDA review for treatment of moderately-to-severely active ulcerative colitis (UC) in adults. However, the budget impact of its addition to payer formularies is unknown.

METHODS
A de novo budget impact model was developed to estimate the cost of introducing miri to the formulary of a hypothetical one-million-member health insurance plan. Epidemiological inputs drew primarily from published sources, while market research informed the current and future market share of advanced therapies. The model accounted for drug acquisition, drug administration, treatment monitoring, and adverse event management, derived from US prescribing information, trial results, and published sources. Discontinuation and dose escalation rates were based on the literature, applying assumptions where data gaps existed. In the base case, the model assumed that half of miri’s market share would be accrued from ustekinumab (an IL-12/IL-23 antagonist). The base-case analysis adopted a US commercial payer perspective over a 3-year period. Deterministic sensitivity analyses (DSA) assessed the implications of uncertainty in model inputs, while scenario analyses estimated budget impact under alternative assumptions about the origin of miri’s market share, and about the patient population under consideration.

RESULTS
In the base-case, 445, 480, and 515 patients were predicted eligible for advanced therapies for UC in Year1, Year2, and Year3, respectively with total UC drug management expenditures of $137.4 million over three years. Introducing miri to formulary for moderately-to-severely active UC yielded cumulative incremental costs of $1.3 million (relative impact=0.93%), equivalent to $0.04 per member per month (PMPM) or $0.43 per member per year (PMPY). Among patients who had already failed an advanced therapy, miri yielded lower cumulative incremental costs of $0.8 million (relative impact=1.1%), equivalent to $0.02 PMPM/$0.28 PMPY, consistent with the more narrowly defined eligible patient population (219, 252, and 284 patients in Year1, Year2, and Year3, respectively). In the scenario in which miri’s market share derived only from ustekinumab, the model predicted total cost savings of $2.6 million over three years (relative impact=-1.9%), as well as PMPM savings of $0.07 and PMPY savings of $0.85, due to higher estimated average drug costs associated with ustekinumab. DSA results suggested that base-case results were robust to uncertainty in the value of key model parameters.

CONCLUSION
Introducing miri to formulary for moderately-to-severely active UC may offer patients and clinicians an additional therapeutic option to manage this challenging and debilitating condition at minimal added cost to payers. The addition of miri to formulary could be relatively budget neutral or cost saving in some contexts.