Do Biosimilars Lower Cancer Drug Costs? UCLA Study Finds

Patients with cancer who used biosimilar versions of common cancer drugs paid less out of pocket, and their insurers paid substantially less, than patients who used the original brand-name biologic drugs, according to a new study led by researchers at the UCLA Health Jonsson Comprehensive Cancer Center.

The findings, published in JAMA Oncology, showed that patients who exclusively used biosimilars had average monthly costs that were $3,820 lower for insurers and $39.50 lower out of pocket compared with patients who exclusively used the original biologic drugs. The results suggest that competition from biosimilars entering the market may be helping to lower the cost of cancer biologic drugs.

What Are Biosimilars?

Biologic drugs, which are complex medicines made from living cells, play a major role in treating cancers such as breast cancer and lymphoma, but their high cost can add to the financial burden of care. Biosimilars are lower-cost versions of these drugs. Unlike generic versions of conventional medications, biosimilars are highly similar to, but not identical to, their original biologic and have no clinically meaningful differences from them.

A federal policy enacted in 2009 created an abbreviated regulatory pathway for biosimilars in the U.S. to increase competition, lower prices and improve access to biologic treatments. By the end of 2024, 13 biosimilars were available for three major cancer biologics: bevacizumab (Avastin), rituximab (Rituxan) and trastuzumab (Herceptin). These drugs are used to treat cancers including breast cancer, lymphoma, colorectal cancer, lung cancer and ovarian cancer.

How Much Do Biosimilars Save Patients and Insurers?

After adjusting for differences among patients and treatment patterns, researchers found average monthly insurer costs were $8,959 for patients who exclusively used biosimilars, compared with $12,779 for those who exclusively used the original biologic — a difference of $3,820 per month.

Patients who exclusively used biosimilars also had lower average monthly out-of-pocket costs: $118.90, compared with $158.40 for those who exclusively used the original biologic, a savings of $39.50 per month.

Researchers also found that biosimilar entry was linked to lower prices and shrinking market share for the original biologics. The average sales price of the three original drugs declined by 3.8% per year after biosimilars entered the market, while their market share dropped by about 30% annually among patients with commercial insurance and 31.5% among those with Medicare Part B. The average sales price of the 12 biosimilars included in the study declined by 12.4% per year.

Among all patient-drug pairs studied, 59.4% of patients exclusively used a biosimilar during their first 12 months of treatment, while 32.5% exclusively used the original biologic. About 6.9% of patients switched from the original biologic to a biosimilar, and 1.2% switched from a biosimilar to the original biologic — suggesting biosimilars were adopted mainly by patients starting treatment rather than by patients switching from an original biologic already in use.

How Was the Study Conducted?

Researchers conducted a retrospective study using health insurance claims data to examine the use and cost of bevacizumab, rituximab and trastuzumab after biosimilars became available for each. The analysis included 14,655 patient-drug pairs involving patients with cancer who started one of the three biologics between 2020 and 2023. Patients had commercial insurance or Medicare-related coverage, and researchers tracked their treatment and costs for 12 months after starting the drug.

Patients were grouped by whether they exclusively used a biosimilar, exclusively used the original biologic, switched from the original biologic to a biosimilar, or switched from a biosimilar to the original biologic. Researchers compared the monthly costs paid by insurers with patients' out-of-pocket payments, which were calculated as the sum of deductibles, copayments and coinsurance. They also tracked changes in average sales price and market share for the original drugs and their biosimilars from before biosimilar entry through 2024.

What This Means for Patients

Researchers said the findings suggest biosimilars could ease some of the financial burden of cancer treatment for patients while creating savings for the health care system overall. Previous research has estimated that financial toxicity may affect as many as half of patients with cancer in the United States, and financial hardship has been linked to skipped or delayed treatment and poorer health outcomes.

"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 — savings that can be used toward other treatment-related expenses or cover living expenses," Tina Shih, PhD, director of the Cancer Health Economics Research Program at the UCLA Health Jonsson Comprehensive Cancer Center and senior author of the study, said in a statement.

Because most patients in the study who received biosimilars started treatment with them rather than switching from an original biologic, the researchers said decisions made at the start of treatment may play an important role in expanding access to lower-cost options.

"The FDA has continued to take regulatory actions aimed at further unlocking biosimilar competition recently," Xiaoyu Liu, first author of the study, said in a statement. "Our study findings offered further evidence to support patients, providers and insurers in their consideration of biosimilars."

The study's first author, Xiaoyu Liu, is a former doctoral student in the Department of Health Policy and Management at the UCLA Fielding School of Public Health. Additional authors include Xiaoyi Xu, MS, and Z. John Lu, PhD, of UCLA.

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