Biosimilars gain ground, cut cancer drug costs

Clinical takeaway: When clinically appropriate, starting eligible patients on oncology biosimilars may help reduce treatment-related costs without sacrificing efficacy, offering meaningful savings for both health systems and patients.

Financial toxicity affects a substantial proportion of patients with cancer and can contribute to medication nonadherence and worse outcomes. Biosimilars were introduced to increase competition and improve affordability, but real-world evidence on their impact on oncology drug spending and patient costs has been limited.

In a retrospective cohort study, researchers analyzed 14,655 patient-drug pairs involving bevacizumab, rituximab, and trastuzumab between 2020 and 2023. Nearly 60% of patients used biosimilars exclusively during their first year of treatment, compared with 32.5% who used only the originator biologic. Just 6.9% switched from an originator to a biosimilar, suggesting that biosimilar uptake occurred primarily at treatment initiation rather than through later switching.

Exclusive biosimilar use was associated with substantially lower costs. Adjusted monthly payer spending averaged $8,959 for biosimilar users versus $12,779 for originator users, a difference of $3,820 per month. Patients receiving biosimilars also experienced lower monthly out-of-pocket costs, averaging $118.90 compared with $158.40 for originator biologics, for savings of nearly $40 per month.

The analysis also found that biosimilar competition reshaped the oncology biologics market. Following biosimilar entry, average sales prices for originator products fell by nearly 4% annually, while their market share declined by about 30% per year across both commercially insured and Medicare populations. Meanwhile, prices for biosimilars dropped even faster, decreasing by more than 12% annually.

“Although the savings were substantially greater for insurers than for patients, even modest reductions in out-of-pocket costs may be meaningful for people facing the financial challenges of cancer care,” said senior author Tina Shih, PhD, of the UCLA Health Jonsson Comprehensive Cancer Center.

Source: Liu X, et al. (2026 Aug 27) JAMA Oncology. Cancer Biologics Utilization After Biosimilar Entry and Financial Implications for Payers and Patients