Cost-Efficiency in Action: Denmark's Transition to Biosimilar Adalimumab

A nationwide mandatory switch from originator (Humira) to biosimilar adalimumab in Denmark did not increase total health care costs over 9 months, with hospital costs even decreasing for biosimilar switchers, according to an observational cohort study.1

In Denmark, a national tender system and guidelines have driven high biosimilar uptake, including a mandatory 2018 switch to biosimilar adalimumab based on geographical residence, resulting in significant cost savings.2 However, concerns were raised about potential additional costs from increased health care utilization due to patient education and monitoring.1

The present study, published in Therapeutic Advances in Musculoskeletal Disease, aimed to assess whether the switch led to increased total health care costs, encompassing hospital and primary sector contacts and prescription medicine costs (excluding biologics), while also evaluating changes in health care utilization and the influence of patient and disease characteristics.

“Most previous studies have focused on the direct drug costs and found substantial savings (up to 83% for adalimumab), but it is important to consider the costs associated with healthcare utilization (e.g., additional consultations). Thus, it is reassuring that we found no increased healthcare costs following this nationwide mandatory adalimumab switch,” the authors wrote.

The study was a population-based, observational cohort study utilizing surrogate cluster pseudo-randomization based on geographical regions. It emulated a pragmatic trial by including patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), or axial spondyloarthritis (AxSpA) monitored in the Danish DANBIO registry. Patients switched from originator adalimumab to biosimilar GP2017 (Hyrimoz) or SB5 (Hadlima), following national guidelines. Each patient served as their own control in analyzing health care costs and utilization before and after the switch.

Four Danish databases were searched, and eligible patients had to have switched to a biosimilar between November 1, 2018, and April 30, 2019. The study analyzed health care costs and utilization for 2 9-month periods: 1 before and 1 after the switch, ending on January 31, 2020, to avoid COVID-19–related disruptions. Costs were stratified by disease and biosimilar used and health care utilization was assessed using the number of primary sector contacts and medication use based on defined daily doses (DDD).

The study analyzed data from 1316 patients who switched from originator adalimumab to biosimilar adalimumab products GP2017 (n = 621) or SB5 (n = 695). About half of the patients were women. Most had established disease (median duration, 14 years), were 55 years or older, and had been treated with Humira for over 6 years before switching. During the 180-day follow-up, 33 patients (5.3%) in the GP2017 group and 40 patients (5.8%) in the SB5 group discontinued treatment, and were excluded from the results.

Hospital costs accounted for about 90% of total health care costs before and after the switch, primarily associated with musculoskeletal and connective tissue diseases. The average monthly hospital costs remained similar or decreased after switching, except for a brief increase in the first month post-switch.

Sex, age, type of arthritis, comorbidities, and previous adalimumab treatment history did not significantly affect cost changes. However, the type of biosimilar drug (GP2017 or SB5) significantly influenced health care cost variations.

For the GP2017 group, health care costs decreased 15% for patients with PsA (95% CI, 0.78-0.93) and AxSpA (95% CI, 0.79-0.94), driven by reduced hospital costs. Costs of prescribed non-pain medication increased by 26% in patients with PsA, while primary sector costs rose by 14% in patients with AxSpA.

No significant cost changes were observed for those who switched to SB5. In the SB5 group, prescription medication costs for patients with RA increased by 11% (95% CI, 1.01-1.23), and primary sector costs for patients with AxSpA decreased by 26% (95% CI, 0.56-0.97). Additionally, costs for PsA did not change significantly after switching to SB5.

Limitations included the exclusion of adalimumab medication costs due to non-public pricing and the lack of patient-related or indirect cost analyses. The authors emphasized that their findings reinforce the economic feasibility of biosimilar adoption while underscoring the need for tailored strategies to optimize outcomes.

References

1. Nabi H, Ibsen R, Ibsen M, Kjellberg J, Hetland ML, Glintborg B. Ther Adv Musculoskelet Dis. Published online October 16, 2024. doi:10.1177/1759720X241289391

2. Implementation of biosimilar Adalimumab, Denmark. Medicinrådet. Accessed January 14, 2025. https://medicinraadet.dk/media/svab0lxx/medicinraadets-vurdering-af-ibrugtagning-af-biosimilaer-adalimumab-version-10_adlegacy.pdf