2 Research Letters Give Insight Into the Impact of Biosimilars on the Medicare Population

Two research letters, published concurrently in the Journal of the American Medical Association, focused on biosimilars and their role in the Medicare population.

Two research letters, published concurrently in the Journal of the American Medical Association, focused on biosimilars and their role in the Medicare population.

Are Medicare Beneficiaries Seeing Savings From Biosimilars?

First, Jinoos Yazdany, MD, MPH, of University of California, San Francisco, and colleagues reported that “for the more than 43 million beneficiaries with Medicare Part D drug benefits, it is unclear whether biosimilars lower out-of-pocket (OOP) costs given Part D’s complex cost-sharing structure.” In fact, found the authors, patients may be paying more to use a biosimilar.1

Click to read more about biosimilars and the Part D coverage gap.

According to the authors, given the fact that beneficiaries do not receive a 50% manufacturer discount for biosimilars during the Part D coverage gap as they would for reference products (a policy that will change in 2019 as a result of the Bipartisan Budget Act), patients currently see only modest benefits in their OOP spending by using biosimilars.

Analyzing 2017 nationwide benefit design data for all Part D plans, the investigators calculated the mean total cost and OOP cost requirements for patients receiving biosimilar infliximab (Inflectra) and reference infliximab (Remicade). They assumed a standard 8-week dosing regimen to project a maximum annual OOP cost if beneficiaries used no other prescriptions during 2017.

The researchers found that, among 2547 plans, only 10% covered the biosimilar while 96% covered the reference. The biosimilar had a lower mean total cost per 8-week prescription ($2185, for an annual cost of $14,202) than did the reference ($2667, for an annual cost of $17,335). However, all plans that covered the biosimilar products required coinsurance cost-sharing for the product, set at 26.6%, similar to coinsurance cost-sharing for the reference (28.4%). Thus, without coverage gap discounts, patients’ OOP costs for the biosimilar were $5118 (versus $3432 for the reference).

Despite the fact that biosimilar coverage gap discounts will become a reality in 2019, write the authors, the biosimilar “may still not significantly reduce Part D beneficiaries’ out-of-pocket costs given its high price and coinsurance cost-sharing similar to infliximab.”

Biosimilar and Follow-on Filgrastim Use Is on the Rise, but Filgrastim Use is Down Overall

A second research letter, by Steven Kozlowski, MD, of the Center for Drug Evaluation and Research at the FDA, and colleagues, identified Medicare Part B claims for filgrastim between 2014 and 2016 using Healthcare Common Procedure Coding System billing codes.2

The products evaluated were reference filgrastim (Neupogen), biosimilar filgrastim (Zarxio), and follow-on filgrastim (Granix), the last of which was approved prior to the existence of a regulatory pathway for biosimilars in the United States.

The use of any of the 3 filgrastim products decreased by 13% during the study period. However, the monthly administrations of the biosimilar increased to 32% of all filgrastim use, and administrations of the follow-on increased to 16% of all filgrastim use (while use of the reference declined from 97% to 52% of all filgrastim use).

Among those who were given the biosimilar, 22% had previously received the reference, while 73% were new users. According to the authors, the more rapid uptake of the biosimilar compared with slower uptake of the follow-on does not appear to be driven by list prices, as the discount for the follow-on was “similar to or higher than” that of the biosimilar, the researchers noted.

Finally, wrote the authors, the overall decline of filgrastim use in the United States does not mirror the experience of other nations; IMS Health data, they point out, show that UK patients gained expanded access to filgrastim at an earlier stage of therapy after the launch of a biosimilar.


1. Yazdany J, Dudley RA, Lin GA. Out-of-pocket costs for infliximab and its biosimilar for rheumatoid arthritis under Medicare Part D. JAMA. 2018;320(9):931-933. doi:10.1001/jama.2018.7316.

2. Kozlowski S, Birger N, Brereton S. Uptake of the biologic filgrastim and its biosimilar product among the Medicare population. JAMA. 2018;320(9):929-931. doi:10.1001/jama.2018.9014.

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