Real-world outcomes mixed for Humira biosimilars | AMCP Annual 2026

Real-world evidence on converting patients to biosimilars of Humira (adalimumab) is beginning to offer a clearer picture of what large-scale biologic transitions look like in practice. Panelists on Tuesday at the Academy of Managed Care Pharmacy (AMCP) annual meeting in Nashville shared their experiences with transitioning patients to adalimumab.

The first biosimilars referencing Humira became available in 2023. That year, 10 FDA-approved adalimumab are now on the market. They include both low- and high-concentration formulations and include both low list price/no rebate and high list price with rebate options.

“Real-world studies [of adalimumab biosimilars] show that the real-world outcomes are heterogeneous,” Chelsea P. Renfro, Pharm.D., director of network programs and research at Loopback Health, said during the panel discussion. “Outcomes can vary by disease, state, patient population, and potentially that variability is in part what’s influencing adoption and uptake.”

During the session, leaders from Navitus Health Solutions and Vanderbilt Health discussed how their organizations approached implementation of the Humira biosimilars.

Navitus is a midsize national PBM located in Madison, Wisc., with a 100% pass-through transparent business model. The organization wanted to approach the implementation of the adalimumab biosimilars in a thoughtful way, said Matt Hustad, Pharm.D., senior manager, formulary services at Navitus. “We wanted to make sure that we got it right. We evaluated what's important to patients because ultimately, patients are the ones who are going to be undergoing the actual change. We also solicited an opinion from especially prescribers to understand what was important to both them and their patients.”

What they heard was that the citrate-free formulation of adalimumab was important for patient tolerability, as was the type of device for ease of administration for patients. Navitus also considered patient cost and whether there was financial assistance from manufacturers. On the operational side, the PBM made sure no additional prior authorization was needed to ease the transition for both patients and providers.

But Hustad said it was important to remove Humira from the formulary to ensure that patients were switched. “Product change is very hard for all of us as humans, so if the reference was covered, we did not think that members would have much incentive to move off of that and switch to biosimilars,” he said.

To assess outcomes of the switch, Navitus analyzed data for three commercial plans. At three months, Navitus had achieved a conversion rate of 94%. Twelve-month follow-up data showed that 81% of converted patients remained on biosimilar therapy.

Before the formulary transition, the plan was spending approximately $3 million per month on adalimumab. After biosimilar conversions were completed, costs for the biosimilar cohort dropped to roughly $577,000 per month, a reduction of approximately $2 million monthly. Out-of-pocket costs for patients also fell, from an average of around $5 per fill on the originator to approximately 15 cents on the biosimilar, resulting in more than $14,000 in total patient savings across the study group for the year.

“The adverse event profiles show no statistically significant differences before and after in the adverse events reported; unsurprisingly, injection site reaction is the most commonly reported in the biosimilar group,” said Justin J. Arzt, Pharm.D., PGY2 Specialty Pharmacy Admin and Leadership Resident at Lumicera Health Solutions, the specialty pharmacy of Navitus.

Vanderbilt’s experience

Vanderbilt Specialty Pharmacy fills medications for patients who see Vanderbilt providers and those who have the Vanderbilt University Medical Center Health Plan. They fill oral medications and self-injectable biologics that are billed through the pharmacy benefit; a separate team handles the office-administered medications that are billed through the medical benefit. They also have staff to help patients and providers with benefits, prior authorizations and appeals.

“We really try to be the liaison between our providers and the patients and to hopefully decrease the workload on our providers,” said Julia Pate, Pharm.D., clinical pharmacist at Vanderbilt Specialty Pharmacy at Vanderbilt Health. “With the introduction of biosimilars, there’s been more focus on the medication transition process, and we’ve seen different issues that come up, including formulary change.”

Pate’s team conducted a single center, retrospective, comparative analysis to evaluate the clinical outcomes for patients who switched to an adalimumab biosimilar due to insurance requirements compared with patients who stayed on Humira. Included were patients who were prescribed Humira between January and March 2024 compared with patients who were given the adalimumab biosimilar between January and June 2024, either from an IBD or rheumatology provider at Vanderbilt.

At 12 months post switch, there was no statistically significant association between switching and worsening pain scores in rheumatology patients. In the inflammatory bowel disease population, outcomes were similarly stable, with some patients showing slight quality-of-life score improvements after the transition. But a suboptimal response was seen in about 11% of patients, although patients with IBD were more stable in comparison with rheumatology patients.

Approximately 8% of patients experienced adverse events, with the most common being nausea, rash, fatigue and injection site reaction. About 30% of patients experienced a worsening of symptoms or flares after switching to a adalimumab biosimilar; of these, 78% of patients made another switch, Pate said.

The frequency of switching to a second or even third biosimilar after the initial conversation was surprising. In total, about 67% required another switch to another biosimilar. The most common reason was medication availability/stock issues and insurance issues.

“This opened our eyes, especially in these patients required to switch from the originator to a biosimilar product, and just seeing the frequency at which some patients are having to change multiple times,” Pate said. “It was also very interesting to see the outcome differences in IBD and rheumatology. But this was 2024. As we collect more data, we’ll have a bigger and better picture of what this looks like for patients within Vanderbilt.”