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Clinical Safety Data Show Switching Between Rituximab Biosimilars Does Not Increase Adverse Events
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Key Takeaways
- Switching between rituximab biosimilars does not increase adverse event risk, potentially alleviating safety concerns.
- The study involved 505 patients with hematological malignancies, with 77% receiving biosimilar infusions.
There were 2 main types of switches, including switching to rituximab subcutaneous and switching among different intravenous rituximab treatments.
New clinical safety data show that switching between rituximab biosimilars does not increase the risk of adverse events, according to a study published in Cancers. The study authors said the evidence could alleviate concerns about biosimilar usage and safety.1
Lymphoma, Rituximab, Biosimilar, Hematology | Image Credit: ©freshidea | stock.adobe.com
The introduction of biosimilars has been estimated to reduce treatment costs while increasing access to therapy. Rituximab (Rituxan; Genentech, Biogen) is used as a targeted cancer medication, specifically for certain types of lymphoma or leukemia. It is a monoclonal antibody that targets CD20 proteins, which are found on white blood cells within B cells, according to Cancer Research UK.1,2
There are currently 3 biosimilars of the drug available in the US market: rituximab-abbs (Truxima; Teva), rituximab-pvvr (Ruxience; Pfizer), and rituximab-arrx (Riabni; Amgen). In study findings published in the American Journal of Managed Care, from 2019 to 2021, the overall use of rituximab decreased by more than half, and biosimilar use increased to approximately 60%.3
In the current study, investigators collected information about adverse drug-related reactions related to the use of rituximab as either the reference product or the biosimilar, specifically related to switching among different products. They included patients with onomatological disease, including non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL). There were 13 centers in 8 Italian regions included in the study between March 10, 2018, and June 10, 2022. Treatment included both the intravenous and subcutaneous formulations of the reference product and the intravenous formulation of the biosimilars.1
Investigators gathered clinical information, concomitant medications, previous lines of treatment, number of previous rituximab cycles, and quality of life. Clinical evaluations were conducted 3 months after the administration of rituximab biosimilars and approximately 4 to 6 months after the initial evaluation. Follow-up data was collected up to February 2023. The outcomes included the proportion of individuals experiencing at least 1 adverse reaction (AR) and those experiencing at least 1 grade 3 or higher AR, according to the study authors.1
A total of 800 individuals were recruited, but 85 patients already had data published in the pilot study and were excluded. An additional 82 patients were excluded due to missing data or those who received rituximab prior. In the end, investigators included 505 patients. The patient population received a total of 3681 infusions, with 77% being biosimilars, 19% being rituximab subcutaneous, and 3% being rituximab intravenous. Approximately 78% did not experience any switching and 22% did.1
Investigators found that there were 2 main types of switches, including switching to rituximab subcutaneous and switching among different intravenous rituximab treatments. Overall, investigators reported 16.8% of patients reported ARs, with events more frequently occurring for those with indolent NHL compared with highly malignant NHL and CLL. ARs were significantly associated with age at diagnosis and higher neutrophil count. Of the 124 events reported (approximately 1.5 per patient), 16% were classified as grades 3 to 5. The most commonly reported included general disorders and administration site conditions.1
Investigators reported that there was a higher incidence among patients who did not switch medication at 20.7% compared with 3.5% for those who switched. Events were reported most frequently during the first and second infusions, according to the study investigators.1
