What Real-World Data Show About Moving Patients From Humira to Biosimilars

Biosimilars have been available in the US for nearly a decade, but the pharmacy benefit has remained one of the more difficult settings for adoption. The clinical case for biosimilars is well established: These products are, by definition, highly similar to their reference biologics, with no clinically meaningful differences in safety, purity, or potency.¹

The managed care challenge is different. Plans, prescribers, and patients need to know whether biosimilar transitions can be executed without creating disruption in therapy, dissatisfaction or avoidable discontinuation.

This question became more urgent after adalimumab biosimilars entered the US market in 2023. Humira (AbbVie), the reference adalimumab product, has been one of the most widely used and highest-cost biologics for autoimmune conditions, including rheumatoid arthritis, psoriatic arthritis, Crohn disease, ulcerative colitis, and plaque psoriasis. Biosimilar competition created a clear opportunity to reduce costs, but early US adoption was uneven.²

Nationwide, uptake of adalimumab biosimilars has started low, at 23%, but has now grown to 60%, according to Samsung Bioepis.³ These lower-cost products now exist, but there is still a gap in uptake that points to challenges with benefit design, formulary strategy, and patient-provider communication that prevents moving members from a familiar reference product to a clinically comparable biosimilar.

In many cases, formulary parity and rebate economics limited the practical incentive for patients and prescribers to move from the reference product. For managed care organizations, that makes adalimumab a useful test case: Biosimilars can create savings, but only when plans are willing to make deliberate operational choices that support adoption. Additional 12-month follow-up data from the Navitus transition program provides a longer view of how those operational choices translated into treatment persistence, member satisfaction, and sustained cost savings.⁴

What The Navitus Study Examined

Real-world study findings presented as part of a panel at the Academy of Managed Care Pharmacy 2026 meeting examined what happened when a structured transition program moved established reference adalimumab users to preferred biosimilars. The study included 504 eligible members across 3 commercial plans who had been established on adalimumab before a formulary change.⁴

Initial results assessed biosimilar uptake, therapy gaps, patient out-of-pocket costs, and early discontinuation within 3 months of the transition. A subsequent 12-month analysis evaluated longer-term treatment persistence, attrition patterns, patient satisfaction and gross cost savings compared with continued Humira use.⁴

The study assessed utilization, attrition, and member impact. Importantly, biosimilar transitions cannot be judged solely on whether a formulary change produces lower drug costs. Plans also need to evaluate whether members stay on therapy, whether patients experience gaps in treatment and whether discontinuation is driven by clinical concerns, cost, preference, or missing documentation.

High Uptake Followed By 12-Month Persistence

The transition produced high early adoption and durable 12-month persistence. Within 3 months of the intervention, 94% of members switched to an adalimumab biosimilar. Among the 504 members initially on reference adalimumab, 472 moved to a biosimilar. At 12 months, 64 members were no longer covered, leaving 440 members in the follow-up analysis. Of those, 421 had transitioned to a biosimilar, 3 remained on Humira through an exception to coverage, and 16 discontinued before switching. Among those who moved to a biosimilar, 340 remained on biosimilar therapy at 12 months and 81 discontinued treatment.⁴

Overall, 81% of patients remained on a biosimilar 12 months post-transition. The 12-month analysis also found that 15 patients restarted biosimilar treatment after discontinuing or switching therapy at the 3-month analysis.⁴

The 12-month discontinuation data provided useful context. Across the plans, 62 attrition cases were documented as therapy changes, 9 were related to cost or holding therapy, 5 involved patient or provider preference, and 2 were attributed to adverse effects. Another 19 had no documentation. Compared with the 3-month data, the largest increase was in documented therapy changes, whereas cost or holding therapy and patient or provider preference declined as documented reasons for attrition. Only 12.6% of patients who started out on a biosimilar switched to an alternative specialty treatment.⁴

For payers, these results suggest that discontinuation after a biosimilar transition is not automatically a signal of biosimilar failure. Some members changed to other therapies, some held therapy for other reasons, and some cases lacked enough documentation to determine the cause.

The 12-month analysis also showed variation by pharmacy channel and disease state. Biosimilar attrition was lower among members served by Lumicera, at 17%, than among members served by an unaffiliated health-system specialty pharmacy, at 22%. The highest attrition rates (27%) were observed in dermatology and pediatric gastroenterology. Among the 19% of patients who stopped or switched treatment, the average duration on a biosimilar was 7.5 months.⁴

Early Therapy Gaps Were Usually Short

Treatment disruption is one of the main concerns when a plan moves patients from a reference biologic to a biosimilar. In this study, 336 members had a gap of 7 days or less, 60 had a gap of 8 to 14 days, 26 had a gap of 15 to 21 days, 18 had a gap of 22 to 28 days, and 32 had a gap longer than 28 days. Overall, 71% of members had a therapy gap of 7 days or less.⁴

That finding shows that during the initial conversion period, a structured transition limited disruption for most members. It also gives plan sponsors and health plans a concrete implementation metric to track in future biosimilar transitions.

Savings Reached Patients and Plans

The economic results showed that average monthly patient copay after copay assistance fell from $4.53 on Humira to $0.15 on a biosimilar, a significant reduction.⁴ Those numbers matter because biosimilar savings do not always reach patients directly. A plan may reduce net costs through rebates or formulary contracting without materially changing what members pay at the pharmacy counter. In this case, the transition was associated with both lower member out-of-pocket costs and lower plan spending before rebates.

The 12-month analysis also modeled the broader gross cost impact of the transition. Using wholesale acquisition cost, the analysis projected $1,815,869 in gross monthly savings for 440 patients when biosimilar and alternative specialty therapy costs were compared with continued Humira use. While this wholesale acquisition cost-based figure should be interpreted differently from net plan savings or patient out-of-pocket savings, it reinforces the potential economic value when lower-cost biosimilars replace reference products.

How The Findings Fit With Published Research

These results also align with broader research showing that biosimilar savings depend on active adoption, payer strategy and operational execution. Stanton Mehr wrote in the Journal of Managed Care & Specialty Pharmacy that adalimumab biosimilars had limited US market share in 2023 despite large launch discounts, reflecting the role of formulary decisions and rebate preferences in determining whether biosimilars are actually used.⁵

Manolis and colleagues, also writing in Journal of Managed Care & Specialty Pharmacy, identified payer-provider collaboration as central to biosimilar optimization, including provider confidence, reimbursement confidence and shared savings opportunities.⁶

Policy modeling from Ontario projected that mandatory nonmedical biosimilar substitution could have saved $238.6 million from 2018 to 2020 and that availability of an adalimumab biosimilar could have increased projected 3-year savings to $645.9 million, depending on biosimilar pricing assumptions.⁷

What Still Needs More Research

These findings have some limits to recognize. Claims dates may not perfectly reflect when patients administer medication, which can affect estimates of therapy gaps. Some member experience measures remain limited by available data; for example, 12-month satisfaction results were based on 148 patients with available patient-reported scores. Larger studies and longer follow-up would help further characterize disease-specific persistence, reasons for switching, and real-world outcomes across different specialty pharmacy channels.

Still, the study offers a useful case example for health plans, employers, and pharmacy benefit managers preparing for future biosimilar opportunities. The evidence suggests that when transitions are deliberate and well supported, biosimilars can move from theoretical savings to measurable cost reduction without widespread disruption in care.

Operational Lessons for Managed Care

Taken together, the Navitus data and external research point to a practical conclusion: Biosimilars can reduce costs, but savings are not automatic. Plans need more than product availability. They need clear formulary preference, patient and provider communication, pharmacy coordination, timely prescription conversion, and benefit designs that allow members to see lower costs.

The Navitus transition shows that a structured approach can produce high uptake, short therapy gaps for most members, lower patient costs, plan savings before rebates, and 12-month treatment persistence. At 1 year, 81% of patients remained on a biosimilar, 91% of patients reported being satisfied, and modeled gross monthly savings exceeded $1.8 million for 440 patients compared with Humira.⁴

The long-term savings, high persistence, and high patient satisfaction shows that implementing a biosimilar-forward strategy is best managed when positioned as a longitudinal care transition over a 1-time formulary change for plans and patients to see the largest savings possible.

REFERENCES

1. Biosimilars. Cleveland Clinic. Updated December 19, 2025. Accessed July 21, 2026. https://my.clevelandclinic.org/health/treatments/biosimilars

2. Rome BN, Bhaskar A, Kesselheim AS. Use, spending, and prices of adalimumab following biosimilar competition. JAMA Health Forum. 2024;5(12):e243964. doi:10.1001/jamahealthforum.2024.3964

3. Samsung Bioepis releases second quarter 2026 US biosimilar market report. News release. BusinessWire. April 27, 2026. Accessed July 21, 2026. https://secure.businesswire.com/news/home/20260427670459/en/Samsung-Bioepis-Releases-Second-Quarter-2026-US-Biosimilar-Market-Report

4. Arzt J, Hustad M, Pate J, Renfro CP. Launch to lessons learned: real-world experience with adalimumab biosimilars. Presented at: AMCP 2026. April 14, 2026. Accessed July 21, 2026. https://amcpannual2026.eventscribe.net/index.asp?presTarget=3329496

5. Mehr SR. Sustaining competition for biosimilars on the pharmacy benefit: use it or lose it. J Manag Care Spec Pharm. 2024;30(6):600-603. doi:10.18553/jmcp.2024.30.6.600

6. Manolis CH, Rajasenan K, Harwin W, McClelland S, Lopes M, Farnum C. Biosimilars: opportunities to promote optimization through payer and provider collaboration. J Manag Care Spec Pharm. 2016;22(9 Suppl):3-9. doi:10.18553/jmcp.2016.22.9-a.s3

7. Gomes T, McCormack D, Kitchen SA, et al. Projected impact of biosimilar substitution policies on drug use and costs in Ontario, Canada: a cross-sectional time series analysis. CMAJ Open. 2021;9(4):1055-1062. doi:10.9778/cmajo.20210091