Biosimilar Market Share Greater in Medicare Advantage Versus Part B

Yoganand Chillarige, MPA

Credit: LinkedIn

Biosimilar use is consistently higher in instances of Medicare Advantage insurance versus traditional Medicare, according to data from a new research letter.¹

Analysis from a team of federal agency and pharmaceutical industry-based investigators showed that biosimilar uptake was, in the cases of some observed products on the market, up to 2-fold greater in Medicare Advantage coverage than traditional Medicare. The new data supplement prior findings showing significant differences in biosimilar use between managed care versus fee-for-service Medicaid, suggesting a need to investigate the various mechanism that which may inform the discrepancy in market share for cost-efficient biosimilars.

Investigators led by Yoganand Chillarige, MPA, of Acumen LLC, sought to analyze differences in biosimilar use between Medicare Advantage (managed care Part C) and traditional Medicare (fee-for-service Part B) by way of biosimilar uptake relative to their reference products. As they noted, more than 40 biosimilar products have been approved by the US Food and Drug Administration (FDA) this year—with experts previously describing to HCPLive a boom of options targeting chronic, “life-changing” diseases.² Similar to Chillarige and colleagues, though, experts have also observed a reticence to embrace the cost-efficient alternatives now on the market.

“Biosimilar products can increase access and reduce treatment costs for chronic and life-threatening diseases,” investigators wrote. “Biosimilar uptake has varied, potentially due to factors such as health care setting, pricing, and market entrance timing. Medicare Advantage tools including preauthorization and payment practices encourage insurers’ use of lower-cost alternatives.”¹

The investigators conducted a cross-sectional study evaluating biosimilar market share for products with ≥1 biosimilar administration up to September 30, 2019, using all available administrative data from traditional Medicare and Medicare Advantage plans from May 2015 – September 2022. Their analysis included 20 biosimilar products across 7 product types, predominately used in Part B and C.

Market share was calculated for each product type by number of biosimilar administrations relative to administrations of their reference products, through 3 years post-biosimilar introduction to the market. Market share was further stratified by indication for bevacizumab and epoeitin alfa.

Chillarige and colleagues observed greater biosimilar uptake in 6 of 7 product types among Medicare Advantage cases versus traditional Medicare; uptake differences ranged from just 1.1-fold greater with trastuzumab, to 2.3-fold greater with epoetin alfa. The median ratio of market share difference from Part C to Part B was 1.3 (range, 0.7 – 2.3).

Regarding bevacizumab, its biosimilar market share was actually lower in Medicare Advance than traditional Medicare. Off-label ophthalmic use of such biosimilars was very low, yet market share was greater in traditional Medicare. On-label oncologic use of such biosimilars was approximately 10% greater in Medicare Advantage than traditional Medicare. “This suggests the apparent greater biosimilar use in traditional Medicare when aggregated across indications is due to the differential dilution of market share by the large overall proportion of ophthalmic usage,” investigators noted.

Regarding epoetin alfa, investigators stratified market share by product use for end-stage kidney disease versus any other use. In each indication, biosimilar market share was still up to 70% greater in Medicare Advantage than traditional Medicare.

The team concluded that biosimilar market share was suggestive of greater frequency in Medicare Advantage versus traditional Medicare, consistent with other observed findings. “One suggested explanation was differential statutory state inflation rebates in managed care vs fee-for-service payers. Implementing the Medicare inflationary rebate may also affect MA and TM biosimilar uptake,” they wrote.

Though the research may have been impacted by population-related differences between persons on traditional Medicare versus Medicare Advantage, the findings highlight the need for further analysis including such covariates and more specific indications of biosimilars.

“Current estimates of biosimilar savings are greater than $20 billion, meaning each percent increase in overall biosimilar uptake could represent hundreds of millions of dollars,” Chillarige and colleagues concluded. “Thus, it is important to validate the increased biosimilar uptake observed in MA and investigate potential mechanisms through which managed care may encourage greater biosimilar use.

References

1. ^{Kozlowski S, Kwist A, McEvoy R, et al. Biosimilar Uptake in Medicare Advantage vs Traditional Medicare. JAMA Health Forum. 2023;4(12):e234335. doi:10.1001/jamahealthforum.2023.4335}
2. ^{Pine L. Breaking Down Barriers: Why Biosimilars Face Resistance in the US Market. HCPLive. Published December 18, 2023. https://www.hcplive.com/view/breaking-down-barriers-why-biosimilars-face-resistance-us-market}