Not only is switching from biosimilars back to reference biologics rare among the VA patient population, but researchers observed no clear trend in rationales for why patients switched back to biosimilars.
In new data presented in an abstract presented at this year’s annual meeting of the International Conference on Pharmacoepidemiology and Therapeutic Risk Management (ICPE), a group of U.S. researchers report that veterans patients primarily switch back to biosimilars. The pharmaceutical view is inconclusive. It refers to biologics due to lack of efficacy or safety of cost-effective options.
Led by Kelly M. Bryan of the Department of Veterans Affairs (VA) Drug Center, researchers conducted a pilot study to identify and quantify the reasons for switching from biosimilars back to reference biologics in a VA patient population. Their study considers real-world applications and outcomes of non-medical switching practices, in which patients stable on a reference biologic product have the opportunity to save on treatment costs through a validated biosimilar option, helping to maintain disease management.
“Returning to originator biologics after non-medical switching occurs frequently and is often viewed as a sign of biosimilar failure,” they wrote. “However, the causes and rates of switching back to originator biologics have not been fully investigated in real-world studies using switching May be incorrect as an efficacy endpoint. “
Bryan and colleagues looked at a cohort of VA patients who took at least 1 of 4 reference biologics between 2019 and 2021: bevacizumab; pegfilgrastim; rituximab monoclonal antibody; or trastuzumab. The team classified each patient’s switching patterns between the reference biologic and biosimilar and charted reentry patterns, which underwent additional review to help identify switching from biosimilars back to the reference biologic. product reasons.
Patients’ reasoning about zigzag was classified into 5 categories, and crude, drug-specific, and cause-specific zigzag rates were calculated separately.
The final evaluation included 18,443 Veteran patients who were taking ≥1 of the 4 identified reference biologics or 1 of the biosimilars. In this cohort, 2137 people (11.6%) switched to a biosimilar; of these, only 49 (2.3%) switched back to the reference biologic—an average of 4.1 switches per person per year. Drug-specific reentry rates ranged from 3.4 to 9.6 per person per year.
Among the 5 categories of reasons for return reported by patients and physicians, “undocumented reason” (n = 26) was the main factor, followed by “incorrect recording of conversion” (n = 8); adverse drug reactions (n = 5); VA Factory biosimilar out-of-stock (n = 7); and provider preference for reference biologic (n = 3).
“Among veterans who switch to biosimilars, switching back to the originator biologic is rare,” the researchers wrote. “Lack of documented reasons for switchback are common, while switchback due to adverse drug reactions is uncommon. .”
The team concluded that based on these findings, it is difficult to assume that reentry is indicative of biosimilar treatment failure. They note that future evaluations, including patterns of additional switching between biologics and biosimilars, may help better differentiate patients’ reasons for pursuing this strategy.
refer to
Pilot evaluation of switching from biosimilars to originator biologics in the Veterans Affairs population: A sign of biosimilar failure? Bryan KM, Her QL, Dong D, Jiang R, et al. Presented at: International Conference on Pharmacoepidemiology and Therapeutic Risk Management (ICPE) 2023 Annual Meeting. Halifax, Canada. August 25-27, 2023.