Budget impact analysis of including biosimilar adalimumab on formulary: A United States payer perspective.

Background: The biosimilar market is growing rapidly, as evidenced by 41 approvals and 37 launches to date. As adalimumab biosimilars launch in the United States, competition among biosimilar and reference adalimumab will likely increase across multiple reference indications, including rheumatology, dermatology, and gastrointestinal diseases, which may lead to decreased payer costs.

Objective: To evaluate the costs of adding biosimilar adalimumab to a US commercial plan by exploring various utilization and price differential scenarios.

Methods: A 3-year budget impact model for a US commercial plan of 1 million people was developed to assess switching from reference adalimumab or any self-injectable reference tumor necrosis factor (TNF) inhibitor to biosimilar adalimumab. Pharmacy and medical costs were analyzed through high- and low-conversion scenarios from reference adalimumab and the TNF inhibitor class. Price reductions of 5% to 60% relative to reference adalimumab based on previous biosimilar launches were also explored. Short-term medical costs were evaluated as additional simple and complex office visits, with scenarios of half of switch patients having 1 visit up to all switch patients having 10 visits.

Results: In a target population of 1,863 patients, switching from reference adalimumab to biosimilar adalimumab had cumulative cost savings of $5,756,073 with slow conversion (10%-20% over 3 years) and $28,780,365 with fast conversion (50%-100% over 3 years). Similar results were seen when switching from any other self-injectable reference TNF inhibitor. Cost savings more than $1 million were seen with a 10% conversion from reference adalimumab and a 15% price reduction from reference adalimumab. Additional office visit scenarios had a negligible impact on budget, with no changes in per-member-per-month costs until all switch patients had 10 additional complex visits, in which per-member-per-month costs increased by $0.02.

Conclusions: In a hypothetical plan of 1 million lives, use of biosimilar adalimumab in commercial plans can lead to significant cost savings for payers because of increased competition. Greater and faster biosimilar conversion rates from reference adalimumab and other reference TNF inhibitors resulted in decreased costs. Additionally, even with short-term medical expenditures, cost savings were still realized when switching to biosimilar adalimumab.