Omalizumab Biosimilar Entry Linked to Expanded Patient Access, Reduced Spending

More than €787 million was spent on omalizumab across 23 European countries in 2024 alone, underscoring the fiscal pressure associated with biologic treatment of severe allergic diseases.1 A newly published budget impact analysis in the Journal of Medical Economics projected that the introduction of an omalizumab biosimilar could generate substantial savings for public payers over the next 5 years, with the potential to expand access to tens of thousands of additional patients.

Omalizumab, marketed as Xolair, is indicated for individuals with severe persistent allergic asthma, chronic spontaneous urticaria (CSU), and chronic rhinosinusitis with nasal polyps (CRSwNP). Although results from clinical trials have demonstrated reductions in exacerbations and improvements in quality of life, acquisition costs remain high. In the UK, annual treatment costs have ranged from £1664 to £26,624 depending on weight-based dosing.2 Across Europe, access has been constrained in some countries because of reimbursement restrictions and cost-effectiveness concerns.

To estimate the financial implications of biosimilar entry following patent expiry in September 2025, investigators developed a 5-year budget impact model from the payer perspective. The model compared a “world without biosimilars,” in which only originator omalizumab was available, with a “world with biosimilars,” in which a lower-cost biosimilar gradually captured market share. Twenty-three countries were included: Austria, Belgium, Bulgaria, Croatia, the Czech Republic, Finland, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, Luxembourg, Norway, Poland, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, and the UK. Countries were selected based on formulary listing, publicly available pricing, and IQVIA volume data.

Drug acquisition costs were derived from national list prices. The base-case analysis assumed that the biosimilar would enter the market at a 30% discount relative to the originator and that originator pricing would remain static—an assumption the authors noted likely underestimated real-world savings, as price erosion commonly occurs after biosimilar entry. Biosimilar uptake was modeled using adalimumab biosimilar adoption as a proxy, and omalizumab volume growth was extrapolated using historical compound annual growth rates between 2021 and 2024.

Under the 30% discount scenario, the model projected first-year savings of approximately €40 million across the 23 countries. Over 5 years, cumulative savings were estimated at €641 million. Germany was projected to realize the largest absolute savings—up to €130 million over 5 years—reflecting higher baseline utilization and spending. In contrast, countries with smaller populations or slower anticipated uptake, such as Luxembourg and Bulgaria, were projected to experience comparatively modest savings.

Investigators translated projected savings into potential access gains. Based on weighted average annual treatment costs across indications—48.37% for CSU, 44.77% for severe allergic asthma, and 6.86% for CRSwNP—the €641 million in cumulative savings could enable treatment of an estimated 96,491 additional patients over 5 years, assuming a full year of therapy per patient.

Sensitivity analyses examined deeper discount scenarios. At a 50% discount, cumulative 5-year savings were projected at approximately €1.04 billion, supporting treatment of an estimated 211,380 additional patients. At a 70% discount, savings increased to €1.44 billion, with the potential to treat up to 479,457 additional patients. Variations in market share uptake and overall market growth had comparatively modest effects on total savings, which ranged from €576 million to €703 million when uptake assumptions were varied by plus or minus 10%.

The authors acknowledged several limitations. The model did not use a prevalence-based approach because of inconsistent country-level epidemiologic data and limited information on treated populations by indication. Uptake projections relied on adalimumab biosimilar experience, which may not fully reflect prescribing behavior in allergic diseases. The analysis also excluded potential switching from other biologics and did not account for downstream cost offsets, such as reductions in hospitalizations or corticosteroid exposure. Administration costs were omitted under the assumption of therapeutic equivalence and similar delivery methods.

Despite these constraints, the analysis suggested that biosimilar entry could meaningfully alter the cost profile of omalizumab in Europe. By lowering acquisition costs, biosimilars may improve cost-effectiveness ratios and influence reimbursement decisions in settings where access has been limited. For payers managing constrained pharmaceutical budgets, the projected savings highlight the role biosimilars may play in expanding access to biologic therapy while moderating expenditure growth.

References

1. Jang M, Lee J, Kwon TS. Budget impact of introducing an omalizumab biosimilar in 23 European countries. J Med Econ. 2025;28(1);1639-1650. doi:10.1080/13696998.2025.2558450
2. Canonica GW, Colombo GL, Rogliani P, et al. Omalizumab for severe allergic asthma treatment in Italy: a cost-effectiveness analysis from PROXIMA study. Risk Manag Healthc Policy. 2020;13:43-53. doi:10.2147/RMHP.S211321