Approval of Granulocyte Colony Stimulating Factor (G-CSF) Biosimilars and New Injection Device Contributed to Increased Use of G-CSF in Cancer Patients at High Risk for Neutropenia febrile (FN), but many eligible patients continue to do so. not receive preventative treatment, according to a new study.
G-CSF is a growth factor that helps the bone marrow regenerate white blood cells after myelosuppressive chemotherapy and prevent infections.
From 2014 to 2019, the use of G-CSF to prevent FN in high-risk patients increased from 75% to 83% for the commercially insured population and from 75% to 86% for the Medicare population, according to research published by the University of Florida Investigators in JAMA network open in November.
Older age, a high-risk FN regimen, and a history of neutropenia were associated with the use of G-CSF.
However, at the end of 2019, 14% to 17% of patients at high risk for NF who were on chemotherapy had still not received preventative treatment, despite guidelines from the National Comprehensive Cancer Network (NCCN) recommending that they receive primary prophylaxis using G-CSF.
The study authors note that the NCCN offered short-term directions expanding the recommended uses for G-CSF. The organization said that in the context of the COVID-19 pandemic, clinicians may consider giving prophylactic treatment to patients receiving intermediate-risk regimens.
There are 2 G-CSF products for which biosimilars are available: Neupogen (filgrastim) and Neulasta (pegfilgrastim). During the study period, the filgrastim biosimilars Zarxio and Nivestym entered the market. A third competitor to filgrastim (Granix) has also been launched, although it is not officially a biosimilar, as it was approved under a different regulatory pathway.
Two pegfilgrastim biosimilars were approved and launched during the study period: Fulphila and Udenyca. Onpro, a portable pegfilgrastim injection device, has also been launched and represents approximately 50% of the pegfilgrastim market. Onpro uses the reference product (Neulasta), not a biosimilar, and there are no portable biosimilar G-CSF injectors on the market.
“The availability of biosimilar G-CSF presents an opportunity to re-evaluate the cost-effectiveness of prophylactic use of G-CSF in patients receiving myelosuppressive chemotherapy regimens. Evidence shows that the use of biosimilar G-CSF for primary prophylaxis in intermediate-risk patients may be a cost-effective strategy even without risk factors, ”the authors wrote.
Policy initiatives to improve practice, along with decision support tools to reduce overuse and ineffective practices, may have resulted in observed decreases in G-CSF use in patients receiving regimens. at intermediate or low risk of FN in the commercially insured population, according to the study authors. .
Several biosimilars of the long-acting G-CSF filgrastim and pegfilgrastim products were launched between 2015 and 2019, and the portable injector Onpro was launched in 2017, expanding treatment options for patients.
The study, which looked at 119,129 cycles of chemotherapy given to cancer patients from 2014 to 2019, found that the use of filgrastim biosimilar Zarxio exceeded that of filgrastim originally. The biosimilar accounted for 55.6% of all short-acting G-CSF uses in the commercially insured population in Q4 2019 and 22.2% of all short-acting G-CSF uses in the fourth quarter of 2018 in the Medicare population.
Of all long-acting G-CSF uses in the last observable quarter from each data source, Onpro accounted for 44.9% of use in commercial insurance data and 52.4% in Medicare data. . The pegfilgrastim biosimilars experienced rapid initial uptake, accounting for 29.8% of all long-acting G-CSF uses in the fourth quarter of 2019 in the commercial insured population.
Investigators note that the G-CSF market is dominated by long-acting products, primarily the Onpro administration service, where the absorption of biosimilars is lower than that of short-acting therapies.
“Preference for [Onpro] may limit the uptake of long-acting G-CSF biosimilars and jeopardize the potential savings associated with the availability of biosimilars in this therapeutic area. While a simulation study demonstrated cost savings from adopting biosimilars, a variety of barriers exist, ”they wrote.
For example, a biosimilar may not reduce costs for patients given the need for a second clinic visit and the associated costs.
The authors state that the development of biosimilar devices or more aggressive reimbursement or formulary structures may be necessary to stimulate the use of G-CSF biosimilars. Future studies that use real-world data to show the cost savings of pegfilgrastim biosimilars could boost the confidence of payers and clinicians and facilitate wider adoption, they say.