Clinical Results Support Greater Use of Oncology Biosimilars

Presenters at the AMCP Nexus conference explore outcomes data and whether these medications should be substituted for reference products more frequently.

Oncology biosimilars, which cost dramatically less than reference drugs to treat various forms of cancer, have performed well in some clinical trials in terms of both efficacy and safety, but there is still hesitancy to use the medications among many providers and payers, explained presenters during a session at the AMCP Nexus conference in National Harbor, Maryland.

There are 6 categories of approved oncology biosimilars, 3 of which aim at curative care and 3 of which are focused on palliative care, according to the presenters. In total, there are 20 approved oncology biosimilar products available on the market, and their use has steadily increased since 2015.

However, there are 15 additional oncology biosimilars in the pipeline, explained presenter Timothy Mok, PharmD, BCPS, BCOP, a hematology/oncology pharmacy research analyst at Kaiser Pemanente in Oakland, California. Mok noted that many of the biosimilars that will be coming out on the market are targeting “heavy hitters,” such as lung cancer, breast cancer, and multiple myeloma. In terms of clinical trial results, data have shown that oncology biosimilar drugs do stack up against the competition.

As an example, the presenters showed data from 1 clinical trial evaluating biosimilar bevacizumab-awwb to bevacizumab, its reference drug, both for the treatment of several types of cancer, including metastatic colorectal cancer. Results showed the biosimilar to be as effective and safe as the reference drug, with a 1-year overall survival rate that was non-inferior with no serious differences in adverse events (AEs).

In addition, results of a meta-analysis of biosimilars compared to trastuzumab in HER2-positive breast cancer treatment showed no statistical differences in AEs, overall response rate (ORR), or the pathologic complete response. Further, results from another study that looked at the trastuzumab biosimilar trastuzumab-anns showed that the latter demonstrated non-inferiority for invasive HER2-positive breast cancer.

Additionally, a study in the Netherlands looked at rituximab biosimilars for treatment of diffuse large B-cell lymphoma, with results showing no statistical difference in ORR compared with the reference drug. Results of an observational, prospective, single-center study in Italy of rituximab biosimilars in onco-hematology showed that, when evaluating biosimilar switching of 1 product for another, there was a similar safety profile for patients who were switched from or continuously treated with the reference drug when compared to the biosimilar.

According to Theresa Mulvey, MD, director of quality safety and value at Massachusetts General Hospital in Boston, oncologists care about efficacy, safety, and the cost to the system but not as much about cost to patients. Mulvey noted this is because the drugs are part of Medicare Part B and the patients are unlikely to be hugely affected by the cost themselves.

“All oncologists carry some concern about drugs and how much they cost the system,” Mulvey said.

Although there have been very few head-to-head studies, Mulvey explained she has seen a few mild AEs to biosimilars, such as allergic reactions.

“You’re giving these with chemotherapy, and chemotherapy [drugs] have really changed. One could argue that the chemotherapy drugs have gotten better,” Mulvey said.

She noted that the results of a study conducted in late 2019 to early 2020 showed that of 507 health care providers surveyed, less than half had a baseline understanding of the key elements of biosimilars. Additionally, Mulvey noted that patients also typically do not know a great deal about biosimilars, but they care most about efficacy and AEs.

Furthermore, Mulvey explained that the results of another study showed that there is an approximate 2-year lag from approval of biosimilar products to initial use and then a steady increase in usage after that. To get biosimilars used more frequently in practices, Mulvey explained there would need to be changes to consent forms and policies, more patient and provider education, and pharmacy and therapeutic changes, patient and provider education.

“You have to educate your providers, which is a little like herding cats,” Mulvey said. “You have to demonstrate cost savings to your institution to get this implemented.”

While there seem to be cost savings related to using biosimilars, Mulvey noted that there are also a lot of manpower hours and work that needs to be done, as well. This may mean that some oncologists will feel obligated to recommend reference products, Mulvey explained.

Mulvey’s takeaways included:

  • Providers will choose what payers allow and what is on formularies.
  • Few providers will independently choose a biosimilar based on limited data.
  • It is unclear what patients’ perspectives are in terms of biosimilars in oncology.
  • The cost savings related to biosimilars go primarily to health systems and practices.
  • Operationalizing biosimilars is labor-intensive and regulated by state law.


Mok T, Mulvey T. Oncology biosimilars: formulary trends, evidence, and strategies from the payer and patient advocate perspective. Presented at: AMCP Nexus; Gaylord National Convention Center in National Harbor, Maryland: October 13, 2022.