Patient Characteristics and Utilization Patterns of Short-Acting Recombinant Granulocyte Colony-Stimulating Factor (G-CSF) Biosimilars Compared to Their Reference Product

BACKGROUND: Data on short-acting recombinant granulocyte colony-stimulating factor (G-CSF) biosimilar utilization from claims data in the USA are limited. OBJECTIVE: To evaluate patient baseline characteristics and utilization patterns for short-acting G-CSF products with particular focus on the assessment of filgrastim biosimilar usage relative to the originator product. PATIENTS AND METHODS: We examined filgrastim, filgrastim-sndz, and tbo-filgrastim use among adult patients between January 2012 and March 2019 across the five health-plan research partners in the BBCIC Distributed Research Network. The publicly available Sentinel System analytic toolkit was used to perform the distributed analyses. RESULTS: We evaluated over 38 million eligible health-plan members representing more than 88 million person-years of data. We identified 45,204 incident treatment episodes, including 33,118 episodes with filgrastim, 6525 episodes with filgrastim-sndz, and 5,561 episodes with tbo-filgrastim. We observed that the demographic and clinical characteristics of users were comparable across products. While total use of all filgrastim products remained consistent, the proportion of incident episodes of the originator filgrastim steadily decreased since 2014, with filgrastim-sndz and tbo-filgrastim making up the difference. Utilization for the G-CSF biosimilar, filgrastim-sndz, increased from 40 (1%) of 6823 total filgrastim product episodes in 2015, to 2486 (44%) of a total 5668 episodes of filgrastim products in 2018 (partial data for 2018). CONCLUSION: New episodes of short-acting biosimilar filgrastim products have increased over time while the overall number of new users remained flat. Although barriers to biosimilar use in oncology have been noted, uptake has begun and continues to grow.