Biosimilar Competition to Herceptin Helped Reduce Price of All Forms of Trastuzumab

A recent study provided new evidence about the effect that the entry of biosimilars has on lowering the price of cancer treatments covered by Medicare.

The study, published in the Journal of Clinical Oncology, examined what happened in fee-for-service (FFS) Medicare after the entry of biosimilar trastuzumab, which has had the most biosimilar competitors for any anticancer biologic. The originator, Herceptin, was approved by the FDA in 1998 to treat human epidermal growth factor receptor 2–positive breast cancer.

The study examined price changes for the originator biologic and biosimilar versions between 2019, when the first biosimilar hit the market, and 2022, by which point 5 biosimilar competitors were available.

The researchers used average sales price (ASP) data from CMS; the ASP includes the average price paid by all purchasers, net of discounts, rebates, and chargebacks, for the originator and each of 5 biosimilars from 2005 to 2022. ASP was adjusted to real 2020 dollars using the Consumer Price Index.

They also estimated the total treatment cost of both forms of trastuzumab from 2005 to 2022, and the analysis also included the number of FFS beneficiaries using either form of trastuzumab from 2010 to 2020.

The study showed:

• The first biosimilar entrant’s price for trastuzumab was 15% lower than the originator brand in 2019.
• In 2022, the price of the fifth biosimilar was 58% lower than Herceptin in 2019.
• By 2022, the originator’s ASP had fallen by 29%, and the decline in the ASP of the lowest-priced biosimilar was even steeper, coming in at 65% lower.
• The combined unweighted mean decrease for all forms of trastuzumab in 2022 was 53% lower than the originator brand in 2019.

By cost, the originator peaked at $89,706 in 2019. With the addition of new competition to the market, the cost fell 29% to $63,592 in 2022.

The cost of the first biosimilar was $13,621 lower than the originator in 2019.

Currently, the mean unweighted biosimilar treatment cost is 40% lower than Herceptin, at $38,173.

Overall, treatment cost was 52% lower, by an average of $45,659, in 2022 compared with the year before biosimilar entry because of a decrease in the originator brand’s price and relatively lower prices for the biosimilar entrants.

The issue of cost for biologic drugs covered under Medicare Part B is of importance because of the rising spending on these therapies; from 2011 to 2020, spending grew by an inflationary adjusted 79% even as FFS enrollment was flat; in 2020, total FFS Medicare Part B spending on biologics for cancer was more than $11 billion.

The authors noted that biosimilars made some gains in market share, and they said this may have been an outcome of the Oncology Care Model (OCM), which ran from July 2016 to June 2022, and which incentivized roviders to use lower-cost treatment options, such as biosimilars. Understanding the impact of the OCM on biosimiliar uptake deserves additional study, they noted.

For the FFS Medicare beneficiaries with an uncapped 20% coinsurance payment for infused cancer drugs like trastuzumab, switching to the biosimilar form would reduce out-of-pocket spending by more than $500 per month.

The authors cautioned that their findings may not be applicable to other biologic cancer drugs covered under Medicare as their study only focused on trastuzumab. This study also doesn't say whether biosimilar treatments overall are more or less effective at reducing other types of health care utilization, as the treatment costs did not include physician services, hospitalizations, surgeries, and other parts of cancer care.

Reference

Horn DH, Alpert AE, Duggan MG, Garcia NA, Jacobsen M. Biosimilar competition and payments in Medicare: the case of trastuzumab. JCO Oncol Pract. Published online January 13, 2023. doi:10.1200/OP.22.00639