Study Evaluates Budget Impact of Filgrastim and Similar Biologics for Treating Neutropenia

Neutropenia, a common complication in patients administered myelosuppressive chemotherapy for nonmyeloid malignancies, is often treated with granulocyte colony-stimulating factors (G-CSFs). A budget impact study comparing home-administration of tbo-filgrastim, filgrastim-sndz, and filgrastim suggests that increasing tbo-filgrastim and filgrastim-sndz utilization for patients who self-administer the drugs may offer a more affordable option for US payers.

Tbo-filgrastim (Granix) and filgrastim-sndz (Zarxio) are, respectively, a follow-on biologic and a biosimilar version of the reference G-CSF filgrastim (Neupogen), with comparable efficacy and safety. Researchers Holly Trautman, PharmD, MS, of Aventine Consulting, Marblehead, MA, and colleagues created a budget impact model to estimate increasing utilization of home (patient)-administered tbo-filgrastim and filgrastim-sndz in patients with nonmyeloid malignancies treated with myelosuppressive chemotherapy from a US payer perspective. They estimated the changes in drug costs associated with projected increases in market share of tbo-filgrastim from 5% to 10% and filgrastim-sndz from 10% to 12%, for a 1-million-member health plan. The overall budget impact was calculated over a 1-year period, along with the difference in per-member, per-year (PMPY) cost between current and future scenarios. One-way sensitivity analyses were also conducted.

It was assumed that 20% of patients receiving short-acting G-CSFs were self-administrating the medications at home. All products were decided upon through pharmacy benefits (Tier 3 formulary status; patient co-pay of $54/prescription). The model assumed syringe replacement rates of 1% for tbo-filgrastim and 5% for filgrastim and filgrastim-sndz because of differences in stability.

The effective annual plan per-patient drug cost totaled between $17,249 and $27,657, depending on dose and presentation, for tbo-filgrastim; between $17,043 and $27,332 for filgrastim-sndz; and between $18,034 and $32,212 for filgrastim. The estimated overall annual plan cost associated with short-acting G-CSFs was $55,920,046 (PMPY, $55.92) in the current scenario and $55,346,277 (PMPY, $55.34) in the future scenario. Estimated cost savings totaled $573,769 (PMPY, $0.58). The authors said the model was most sensitive to changes in the overall proportion of patients self-administering G-CSFs at home and to the wholesale acquisition cost for filgrastim.

Based on their analysis, the authors concluded that the effective annual plan per-patient drug cost for tbo-filgrastim and filgrastim-sndz was 14% to 15% lower than for filgrastim. “Estimated annual US health plan cost savings were in excess of $0.5 million overall, or $0.50 PMPY following small shifts in market shares,” they noted.

The authors presented their findings at the annual meeting of the Academy of Managed Care Pharmacy in Denver, Colorado, March 27-30, 2017.