Increased Use of Non-Originator Filgrastim Could Yield Substantial Savings

February 28, 2019

Biosimilars Team

Switching to either the follow-on biologic (tbo-filgrastim) or biosimilar (filgrastim-sndz) version of the granulocyte colony-stimulating factor (G-CSF) filgrastim would decrease total annual plan costs for a 1 million-member U.S. health plan by almost $0.5 million, with per-member cost savings of $0.04 monthly and $0.48 annually, based on a budget impact analysis published in the January 2019 issue of Journal of Managed Care & Specialty Pharmacy.

G-CSFs are administered to reduce the incidence, severity, and duration of febrile neutropenia in patients undergoing chemotherapy. Short-acting filgrastim is one of the most widely used G-CSFs. For this analysis, the authors developed an interactive budget model to estimate the annual economic cost of increasing utilization of tbo-filgrastim and filgrastim-sndz as a patient-administered (i.e., home-administered) treatment option for patients with nonmyeloid malignancies undergoing myelosuppressive chemotherapy.

Specifically, the model estimated the changes in drug cost associated with a 5% projected increase in market share for tbo-filgrastim (from 5% to 10%) and a 2% increase in market share for filgrastim-sndz (from 10% to 12%), with a corresponding decrease in filgrastim market share from 85% to 78%. Patient self-administration at home was assumed for 20% of patients receiving short-acting G-CSF treatment; all products were purchased through the patient’s pharmacy benefit and were assumed to have tier 3 formulary status with a patient copay of $54 per prescription. The total plan budget impact was calculated using a 1-year time horizon, along with the differences in per member per month and per member per year (PMPY) costs between the current and future scenarios.

Depending on dosage and packaging, the effective annual per-patient drug cost to the plan totaled between:

  • $16,961 and $27,199 for tbo-filgrastim.
  • $16,216 and $26,015 for filgrastim-sndz.
  • $19,134 and $30,663 for filgrastim.

Compared with filgrastim, these costs are 11% lower for tbo-filgrastim and 15% lower for filgrastim-sndz.

The estimated total annual plan cost associated with patient-administered short-acting G-CSFs was $53,298,217 (PMPY = $53.30) in the current scenario and $52,828,832 (PMPY = $52.82) in the future scenario. The model was most sensitive to changes in the percentage of patients self-administering G-CSF at home and to the wholesale acquisition cost for filgrastim.

The authors concluded that concomitantly increasing the use of tbo-filgrastim and filgrastim-sndz and decreasing the use of filgrastim by patients who self-administer short-acting G-CSFs may offer a more affordable option for U.S. payers.


Trautman H, Szabo E, James E, et al. Patient-administered biologic and biosimilar filgrastim may offer more affordable options for patients with nonmyeloid malignancies receiving chemotherapy in the United States: a budget impact analysis from the payer perspective. J Manag Care Spec Pharm. 2019 Jan;25(1):94-101. doi: 10.18553/jmcp.2018.18094. Epub 2018 Aug 7.