Cost Savings With Biologic and Biosimilar Filgrastim Formulations

Granulocyte colony-stimulating factors (G-CSFs) are used to reduce the incidence, severity, and duration of febrile neutropenia (FN) in patients with cancer who are receiving chemotherapy. However, due to historically high costs, these agents are not used in all appropriate patients receiving myelosuppressive chemotherapy. The G-CSFs currently available in the United States include short-acting filgrastim, tbo-filgrastim, and filgrastim-sndz, as well as long-acting pegfilgrastim.

Researchers sought to estimate the budget impact of increasing use of tbo-filgrastim and filgrastim-sndz. The study, published in the Journal of Managed Care & Specialty Pharmacy, indicated that the biologic and biosimilar formulations of the short-acting G-CSF filgrastim resulted in cost savings and are comparable in efficacy and safety.

They developed an interactive budget impact model to estimate the changes in drug cost associated with projected increases in the market share of tbo-filgrastim from 5% to 10% and of filgrastim-sndz from 10% to 12%, with a corresponding decrease in filgrastim market share from 85% to 78% for a 1-million-member health plan of patients with non-myeloid malignancies receiving chemotherapy with a high risk of FN. They assumed that 20% of patients receiving short-acting G-CSF treatment would receive treatment at home. All products were purchased through the patient’s pharmacy benefit and were assumed to have tier 3 formulary status with a per-prescription copay of $54.

Based on the use of 60 doses per year, researchers estimated that the annual effective plan per-patient drug cost total, depending on dosage and packaging, was:

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

The base-case budgetary impact analysis estimated that the total annual plan cost in the current scenario was $53,298,217 for a 1-million-member health plan. Of this, $2,311,211 was attributed to tbo-filgrastim; $46,037,202 to filgrastim; and $4,949,804 to filgrastim-sndz. With a 5% increase in market share for tbo-filgrastim and 2% increase for filgrastim-sndz, as well as a decrease in market share for filgrastim, the estimated total annual plan cost was reduced to $52,828,832—$4,703,546 for tbo-filgrastim; $42,260,349 for filgrastim; and $5,864,937 for filgrastim-sndz.

Researchers estimated that this would results in a total annual plan cost savings of $469,385. Cost savings per member between the current and future scenarios were estimated at $0.04 per-member, per-month and $0.48 per-member, per-year.

“This analysis suggests 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,” the researchers concluded.