Many Patients Switching to Humira Biosimilars Eventually Switch Back

More than one in eight patients who switched from Humira (adalimumab) to a lower-cost biosimilar eventually returned to the original drug—at times within a month—highlighting the challenges to biosimilar adoption despite growing uptake, according to new research from Truveta.

Humira is a biologic drug used to treat chronic autoimmune conditions such as rheumatoid arthritis, Crohn’s disease, psoriasis and ulcerative colitis.

Since its approval in 2002, Humira has become the world’s top-selling drug—largely due to long-standing market exclusivity and rising prices in the U.S.

In response to concerns about cost and access, the first biosimilar versions of Humira became available in the U.S. in January 2023.

Biosimilars are highly similar to brand-name biologics and are approved by the FDA after demonstrating no clinical differences in safety or efficacy.

They are often priced between 5% and 85% less than the original medication.

Despite these benefits, initial uptake of Humira biosimilars was slow.

However, in April 2024, when CVS Health removed Humira from its formulary for certain patients and designated the biosimilar Hyrimoz (adalimumab-adaz) as the preferred option.

Truveta researchers used this formulary change to assess how patients respond to biosimilar use in the real world.

The new report used electronic health record data from Truveta’s platform to identify 66,720 patients who had previously used Humira and were eligible to switch to a biosimilar.

It was found that by April 2025, 13.3% of those patients—8,876 people—had made the switch.

Monthly switching rates peaked in April 2024, just after the CVS formulary change, and remained significantly higher than in 2023.

Hyrimoz accounted for nearly half of all switches, followed by Simlandi (adalimumab-ryvk) and Hadlima (adalimumab-bwwd).

However, switching didn’t always stick.

Among the 8,594 patients with adequate follow-up data after switching, 13.2% (1,138) eventually returned to bio-originator Humira.

In addition, more than one-third of those who switched back did so within just 30 days—suggesting possible early dissatisfaction, side effects, or discomfort with switching.

A national survey from the Biologics Prescribers Collaborative supports these findings, revealing that about half of patients taking biologics or biosimilars say they know only "a little" about these medications.

Over one-third didn’t realize biosimilars generally cost less, and 55% didn’t know that interchangeable biosimilars can be substituted at the pharmacy level without prescriber involvement.

Despite these knowledge gaps, 91% of patients reported trusting biosimilars, and nearly half said they would consider switching if it lowered their costs—highlighting the importance of patient education in promoting biosimilar adoption.

The Truveta study also found demographic trends in switchback behavior.

Older adults were significantly more likely to revert to Humira, with 20.2% of patients age 65 and older switching back, compared to just 11.7% among those aged 18 to 34.

Women were more likely than men to switch back (14.3% vs. 11.4%), and switchbacks were also more common among patients with rheumatoid arthritis and ankylosing spondylitis.

While there were no major differences by race or urban vs. rural status, rural patients were slightly more likely to switch back within 30 days.

These patterns suggest that patient characteristics—and possibly provider preferences—may shape how comfortable people feel remaining on a biosimilar.

Many patients are still unfamiliar with biosimilars, and surveys indicate that even those who are aware often worry that they’re less safe or effective than the original medication.

Real-world experience may reinforce these concerns.

Nearly 40% of patients who switched back did so within 30 days—before even completing a typical monthly supply of the biosimilar.

This rapid switch suggests that fear, uncertainty or side effects could be driving early discontinuation.

Researchers noted that switching back to Humira was not the norm.

The majority of patients who switched to a biosimilar remained on it, and broader use could help control rising biologic drug costs over time.

The 13.2% switchback rate observed in the U.S. is similar to a 14% switchback rate found in European studies of biosimilars for other biologic drugs.

The authors emphasized the need for better education and shared decision-making between providers and patients when initiating biosimilar treatment.

They also called for further research into why certain groups are more likely to switch back and how healthcare systems can support sustained use of these more affordable alternatives.

These findings highlight that while biosimilar adoption is growing, ongoing hesitancy remains.