Cost comparison of filgrastim versus pegfilgrastim and pegfilgrastim biosimilars for inpatient prophylaxis of febrile neutropenia

The Ohio State University Comprehensive Cancer Center (The James) uses daily subcutaneous filgrastim as the inpatient granulocyte colony-stimulating factor of choice. The coordination of care associated with filgrastim can often be a barrier to patient discharge. The purpose of this study was to compare the inpatient cost of daily filgrastim to single dose pegfilgrastim and biosimilars. Adult patients admitted to The James who received at least one dose of filgrastim between June 1, 2021 and August 31, 2021 were retrospectively identified. This study compared the inpatient cost of filgrastim and biosimilars associated with one chemotherapy cycle to the potential inpatient cost of pegfilgrastim and biosimilars based on average sales price (ASP). Additionally, the number and duration of discharge prescriptions for filgrastim was determined. Of the 44 unique patient encounters that met inclusion criteria, 19 received 300-mcg doses of filgrastim and 25 received 480-mcg doses. The median number of doses administered per admission was eight. If each of these patients were to instead receive the most inexpensive biosimilar, pegfilgrastim reference product, the cost would be 216% higher than with filgrastim-sndz. At discharge, 15 patients (34%) received a prescription for filgrastim to be continued for a median duration of 6 days. Based on ASP, pegfilgrastim was more costly than filgrastim. Potential rebates and negotiation power may alter the financial outlook of adding pegfilgrastim to inpatient formulary. Exploration of delays in discharge due to insurance coordination for filgrastim continuation in the outpatient setting may also impact formulary decisions.