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Psoriasis: Why Biosimilar Drugs Are So Hard to Get
July 2, 2025 – For the more than 8 million Americans with psoriasis, biosimilars promised to drive down costs and improve access to treatment.
But these medications, which are nearly identical to costlier biologics like Enbrel, Humira, Remicade, and Stelara, have faced various obstacles preventing more than a third of them from reaching market.
The FDA says biosimilars have "no clinically meaningful differences" from the pricier name brands, at savings of 15% to 30% – or even more.
Also known as "follow-on" drugs, biosimilars typically come out after the primary patent expires on the original biologic. Like biologics, they are made from living cells.
Yet while 21 biosimilars have been approved for psoriasis, only 13 are currently available.
Among the barriers:
Insurers tend to favor name brands. Health insurers often give biologics preferential treatment on their list of drugs covered, called a formulary. That could be because pharmacy benefit managers negotiate larger rebates with biologic makers, and share that rebate with insurers, said Kavita Y. Sarin, MD, PhD, a professor of dermatology at Stanford Medicine.
You may have to try the biologic first. Insurance plans often require patients to follow "step" therapy. That means trying other treatments (even if you've tried them before) and failing with them before getting approval to use a biosimilar.
Legal battles drag on. Patent disputes over who owns the rights to the drug can delay access to a biosimilar, sometimes by several years.
Most people don't know much about biosimilars. More than 70% of psoriasis patients have a poor understanding of biosimilars, according to an American Academy of Dermatology survey.
The Need for Treatment
The severity of psoriasis, a skin condition, varies greatly, according to the National Psoriasis Foundation. The key cause is an overactive immune system, leading to a rapid increase in skin cell production that forms raised, scaly patches on the skin, ranging in color from red to purple. Those affected report that it itches, burns, and stings. It's linked with other serious health conditions such as heart disease, diabetes, and depression.
Treatment options include light therapy, topicals, nonsteroidal anti-inflammatory drugs, biologics, and biosimilars, among others. Yet support groups and social media communities are full of people looking for more help.
The Long Trail of Approval
The 21 biosimilars approved for psoriasis correspond to reference biologic products Enbrel, Humira, Remicade, and Stelara. The medications adjust the immune system and inhibit the processes that lead to inflammation and increased skin cell production.
But the lag from approval to availability can be long. Adalimumab-atta (Amjevita) was approved in 2016 but did not become available until January 2023. Of the 16 adalimumab biosimilars FDA-approved for skin-related problems, the median time from approval to commercial access was just over a year, Sarin found.
Many biosimilar makers are the same companies – or subsidiaries of the companies – that produce the original biologics, Sarin said, potentially giving them an incentive to delay or control competition. While there's no confirmed evidence of that happening, some biosimilar launches have been delayed after confidential settlements with originator companies. The Preserve Access to Affordable Generics and Biosimilars Act (S. 142), introduced in the U.S. Senate in March 2023, would prohibit such agreements – but the bill has stalled.
Costs of biologics vary. As one example: Two pens of Humira can be $7,300, or $3,650 each, without insurance. A Humira biosimilar pen is listed online at $674.
Biosimilars' Excellent Track Record
"Our research shows that biosimilars are generally safe and effective for treating psoriasis, and doctors can feel confident prescribing them," said Duc Binh Phan, MSc, a research associate at the University of Manchester, U.K., who has evaluated research tracking how well biosimilars and biologics work.
In one paper, he reviewed 16 studies of adalimumab, etanercept, and infliximab, with most evidence suggesting they were like the biologics in effectiveness and safety. One study did find a higher risk of adverse events with an adalimumab biosimilar. That points to the need for more studies to evaluate the real-world effectiveness, he said.
But overall, "they work as well and as safely as the original (or 'originator') biologic drugs and can help more patients access treatment due to their lower cost," Phan said.
He also found that those who switched from a biologic to a biosimilar were more likely to stop treatment, citing mild side effects, reactions where the shot went in, or going back to the original.
That could be due to differences in the injection device or to psychological factors, Phan said. "Some patients might be wary of switching to a drug they perceive as 'cheaper' or not the same, which can affect how well they feel it works."
He also cited the "nocebo effect" – when someone expects a treatment not to work and that leads to a worse experience.
He advises doctors to tailor the treatment to the patient.
It's also worth noting, Phan said, that some may develop an immune response to a biologic drug over time, making the treatment (and its biosimilars) less effective. In that case, switching to a different biologic with a different mode of action might be needed, he said.
He urges ongoing research, as biologics are relatively new.
The Old Switcheroo
Even if you do get a prescribed biosimilar, it could be switched to a different product – another biosimilar or the original biologic – without warning, said Melissa C. Leeolou, a fourth-year medical student at Stanford University who co-authored a report with Sarin.
"Medication substitution can occur when insurers or pharmacy benefit managers change formulary coverage, typically for financial reasons," Leeolou said. "If a biosimilar is designated as interchangeable to a reference biologic by the FDA, pharmacies in some states may substitute it for the reference product without notifying the prescriber [your doctor]."
Even without that designation, the insurer may require a switch by denying coverage for the prescribed product.
If the prescription switches to a less expensive product, any cost savings may go to the insurer or the pharmacy benefit manager, not the patient, Leeolou said. It depends on the plan, Sarin said.
A Patient-Researcher's View
"We're so lucky to have biologics," said Leeolou, a lifelong psoriasis patient. "It's important to know they exist as an alternative and [for patients] to talk to their doctors about them."
Sarin suggests that patients with psoriasis become more aware – not just of access to and the promise of biosimilars, but of the possibility of being switched, once on a biosimilar, from one to another without being alerted.
If that happens to you, you should tell your doctor, who may be able to help you figure out why the switch was made and answer any questions you may have about the new treatment. If coverage was denied, your doctor can request a prior authorization or file an appeal. A prescription marked "dispense as written" may help, but it doesn't always override insurer policies.
