In a recent publication in the journal BioDrugs, researchers sought to investigate factors correlated with biosimilar insurance coverage relative to their reference products by commercial plans in the United States.

The authors noted that this was the first study evaluating the factors associated with U.S. commercial health plan biosimilar coverage.

The authors wrote, “We hypothesize a range of factors, including whether drug indication (pediatric and cancer indications), the intensity of competition, the magnitude of budget impact, availability of the cost-effectiveness evidence, and health plan characteristics, may influence the coverage decisions.”

The primary outcome was determining if the biosimilar coverage was more restrictive than its reference biologic product by indication and commercial payer.

The researchers identified 1,181 coverage decisions for 19 commercially available biosimilars, corresponding to seven reference products and 28 indications from the Tufts Medical Center Specialty Drug Evidence and Coverage (SPEC) database. They also used the Tufts Medical Center Cost-Effectiveness Analysis Registry for cost-effectiveness evidence and the Merative Micromedex RED BOOK for list prices. The coverage restrictiveness was summarized as a binary variable based on the following: If the health plan covers the product, and if covered, the difference of payers’ line of therapy between the biosimilar and its reference product. To investigate the correlation between coverage restrictiveness and several potential drivers of coverage, researchers employed a multivariate logistic regression.

The results revealed that compared with their reference products, health plans enforced coverage exclusions or step-therapy restrictions on biosimilars in 229 decisions, representing 19.4%. Plans were more likely to limit biosimilar coverage for the pediatric population (odds ratio [OR] 11.558; 95% CI, 3.906-34.203), in diseases with U.S. incidence greater than 1,000,000 (OR 2.067; 95% CI, 1.060-4.029), and if the plan did not contract with one of the three prominent pharmacy benefit managers (OR 1.683; 95% CI, 1.129-2.507).

Additionally, compared with the reference product, plans were less likely to enforce boundaries on the biosimilar-indication pairs for the following reasons: If the biosimilar was indicated for cancer treatments; if the product was the first biosimilar; if the biosimilar had two competitors; if the biosimilar could create annual list price savings of more than $15,000 per patient; if the plan limited the biosimilar’s reference product; or if a cost-effectiveness measure did not exist.

The authors noted that they discovered considerable deviation in how biosimilars are covered by U.S. commercial health plans included in the Tufts Medical Center’s SPEC database.

Based on their findings, the authors wrote, “Our study identified a number of factors associated with health plan decision-making related to biosimilar coverage, including cancer treatment, pediatric population, and coverage restriction of the reference products. Future research is needed to identify the effects of such restrictions and other market forces (such as price negotiations by commercial plans and PBMs) on the efficiency of the market and resulting patient access to costly biologic therapies.”

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