Biosimilars are gradually making inroads in the outpatient drug market in the U.S., But Stelara-referenced biosimilars appear to be following the convoluted path that Humira-referenced biosimilars took, with payers and pharmacy benefit managers playing critical roles in terms of market or patient access. The cheapest versions are not necessarily favored.
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If there is one thing that all stakeholders in the prescription drug supply chain can agree on it’s that patients’ out-of-pocket costs for many branded medicines can be prohibitively high. This is particularly true for biologics. When their patents expire, the launch of cheaper biosimilars can lower costs considerably. But the United States market for biosimilars is riddled with barriers that don’t allow it to function optimally. Both drug manufacturers and payers are to blame. Patients suffer as a result, with less access and higher cost-sharing than is warranted.
Biologics are drugs made from living organisms which can activate the immune system to treat, among other things, diabetes, multiple cancers and numerous autoimmune disorders. Biosimilars are biologic products that are highly similar to an already approved reference biologic, with no clinically meaningful differences in safety, purity and potency. Starting in 2015 in the U.S., they first became available in the filgrastim class of drugs, used to help prevent infection in people who have low levels of white blood cells. Since then, they have launched primarily in autoimmune and cancer therapeutic classes, referencing 13 unique reference products.
Biosimilar competition can substantially reduce the cost of expensive biologic medicines. However, biosimilars continue to face challenges unique to the American healthcare system, including persistent and lengthy patent litigation battles and dynamics in the payer or pharmacy benefit manager space which can impede biosimilar entry and often don’t favor uptake of the lowest-priced biosimilars. While biosimilar uptake has gained traction in the past five years after a sluggish start, it’s far from optimal. And the future for biosimilars doesn’t look encouraging. According to IQVIA, 90% of the 118 biologics losing exclusivity in the next decade have no biosimilar candidates in development. There are multiple reasons for this “biosimilar void,” including the relatively high cost of biosimilar development. But a poorly functioning market is likely also at fault, which dims the prospects of sales for biosimilar manufacturers contemplating whether to develop products.
Different kinds of anti-competitive business practices violate the principle that free and fair competition from generic or biosimilar alternatives at (often much) lower prices should follow a defined period of patent exclusivity. In this context, we see in the U.S. that manufacturers of biosimilars are often blocked from entry and the lowest-cost products are usually not preferred by payers.
Patent Litigation
The biosimilar market in the U.S, has been marred by the problem of patent thickets. Described by the economist Carl Shapiro as a “a dense web of overlapping intellectual property rights that a company must hack its way through in order to actually commercialize new technology,” branded biopharmaceutical manufacturers use patent thickets to extend the market exclusivity of their products, often resulting in lengthy patent litigation. They’ve been deployed to prevent biosimilars from entering the market, which can limit patient access to cheaper products, a case in point being Humira (adalimumab), used to treat various autoimmune conditions.
In a legal ruling reported in 2022, a 7th Circuit Court Federal Judge affirmed dismissal of claims challenging AbbVie’s “patent thicket” around Humira (adalimumab). Controversially, the judge explicitly questioned whether there’s anything “wrong with [a product having] 132 patents.” By Easterbrook’s reasoning, building a patent fort to fend off competition in perpetuity is permissible so long as the patents are legitimate. But this forestalls competition.
Humira finally relinquished its monopoly right in the U.S. in 2023. Originally, the biologic was slated to lose its patent in 2018. However, a court tussle in 2017 led to a settlement in which biosimilars could not launch until January 2023. And so, despite getting approval from the Food and Drug Administration before 2023, six adalimumab biosimilars couldn’t launch due to a “compromise” deal struck between Humira’s sponsor and biosimilar manufacturers.
One year after their launch in the U.S., these biosimilars captured under 3% of total adalimumab prescriptions. And Humira still held a remarkable 77% of the market share for adalimumab products in early 2025.
By contrast, in Europe biosimilars that reference Humira have already been on the market for seven years. Within one year of market entrance, adalimumab biosimilars had more than 50% of market share in Germany. And in many European markets by the early 2020s, biosimilars had more than 85% of market share. In Denmark, adalimumab biosimilars captured 95% of market share almost immediately after the patent expiration of Humira in October 2018.
Private-Label Biosimilars
The problem of potentially anti-competitive practices isn’t confined to drug companies’ behavior. Pharmacy benefit managers have at times favored more expensive products over similar or even bioequivalent versions that are cheaper. Warped financial incentives sometimes pervade the pharmaceutical supply chain.
Competitive markets are supposed to boost the availability of lower and lowest price options for consumers. But PBMs may exclude certain lower-cost biosimilar drugs from coverage, instead opting for private-label options that are not the lowest cost. Here, PBMs partner with manufacturers to commercialize their own private-label biosimilars. This happened in April 2024 when the PBM CVS Caremark launched private-label versions of a Humira-referenced biosimilar, while excluding several other biosimilars and branded Humira. In turn, this led to an increase in the number of prescriptions for private-label biosimilars. Two similarly large PBMs followed suit with their own private-label products.
A similar scenario is now playing out with respect to Johnson & Johnson’s branded Stelara (ustekinumab) and referenced biosimilars.
Similar to Humira, Stelara is prescribed for various autoimmune conditions. In 2025, four biosimilars entered the market following legal settlements allowing their entry. Some FDA-approved biosimilars are not yet available for purchase but offer list price discounts ranging from 5% to 95% lower than Stelara’s list or wholesale acquisition cost.
Among the launched biosimilars are private-label versions. For instance, OptumRx, a subsidiary of UnitedHealth Group, introduced a private label Stelara biosimilar named Wezlana through its Nuvaila business. OptumRx offers both high- and low-list priced versions, with the low-list price version being 81% cheaper than Stelara’s WAC. However, this lower-priced version is still more expensive than the unbranded biosimilar offered by independent PBM MedImpact at a 95% discount from Stelara.
The two-price approach adopted by OptumRx underscores the complexities of drug pricing in the U.S. and how it can impact patients negatively. This strategy mirrors the pricing tactics seen with Humira-referenced biosimilars. Amjevita, the first such product launched in 2023, was priced at two different list prices, with discounts of 5% and 55% compared to Humira’s price. Similarly, Yusimry offers an 85% discount but is not included in OptumRx’s formulary.
Employers and health plans working with OptumRx must decide whether to prioritize low net cost or opt for a high WAC with substantial rebates. This choice influences patients with co-insurance, who pay a percentage of the WAC out-of-pocket. The decision-making process is further complicated by the incentives introduced by PBMs, whether favoring high list price biosimilars or private-label versions.
In conclusion, the pharmaceutical market, especially regarding biosimilars, faces challenges related to entrance barriers, information asymmetry, and non-transparent pricing. It is crucial for all stakeholders, including drug makers, payers, and PBMs, to work towards creating a more competitive and transparent market for prescription pharmaceuticals.
