OBJECTIVES: Biosimilars have emerged as a key component in the drug spending debate, but their uptake in the US has been lower than anticipated. In this study we examined whether US commercial health plans have prioritized coverage of biosimilars relative to their reference products in their coverage policies.

METHODS: We identified coverage policies for biosimilars issued by 17 large US commercial health plans using the Tufts Medical Center Specialty Drug Evidence and Coverage (SPEC) Database. We included all biosimilars available in the US as of September 2019. We considered biosimilars for each approved indication separately. For example, because FDA has approved infliximab-abda for eight indications, it featured in the dataset eight times. We categorized biosimilar coverage as preferred if the health plan placed it ahead of the reference product in its treatment algorithm (i.e. the plan required patients to fail the biosimilar before using the reference product). We categorized biosimilar coverage as non-preferred if the plan placed the reference product ahead of the biosimilar. We categorized biosimilar coverage as on par if the plan did not did not prioritize either the biosimilar or reference product.

RESULTS: Among the 535 biosimilar coverage decisions, we categorized 14% as preferred, 33% as non-preferred, and 53% as on par. Health plans varied as to how they covered biosimilars. Two health plans covered biosimilars as preferred in half or more of their decisions, while six plans covered biosimilars as preferred in only half or fewer of their decisions. Two health plans always covered biosimilars on par with the reference product in each decision.

CONCLUSIONS: We found that the included US commercial health plans varied with regard to how they prioritized coverage of biosimilars products. Our study suggests that the lack of preferred biosimilar coverage may contribute to the lower uptake of biosimilars in the US.