Therapeutic Use of Filgrastim for Established Febrile Neutropenia Is Cost Effective Among Patients With Solid Tumors and Lymphomas.

PURPOSE: With the emergence of biosimilar filgrastim to the market, there is a gradual decrease in the listed price of the originator product of filgrastim over the years, and this could have an impact on the cost-effectiveness of filgrastim in the treatment of febrile neutropenia (FN). A cost-effectiveness analysis would allow clinicians to make informed decision when considering the therapeutic filgrastim among low-risk FN patients. This study aims to evaluate the cost-effectiveness of adding therapeutic filgrastim to antibiotics in the treatment of established FN among patients with solid tumors and lymphomas.

METHODS: A decision tree model was created to compare two treatment options for established FN as follows: (1) antibiotics alone (standard care) and (2) antibiotics with therapeutic filgrastim (comparator). The target population was a hypothetical cohort of adult cancer patients with solid tumors or lymphomas hospitalized with FN in Singapore. The analysis was performed from a hospital's perspective over a 21-day time horizon. The main outcome measures included costs, quality-adjusted life year (QALY) and incremental cost-effectiveness ratio (ICER). One-way sensitivity analysis and probabilistic sensitivity analysis were conducted to evaluate the robustness of the results.

FINDINGS: Compared with antibiotics alone, the treatment strategy of antibiotics with therapeutic filgrastim was a dominant choice, incurring a cost saving of US$125 per patient (comparator versus standard care: US$9110 versus US$9235) and additional health benefit of 0.0007 QALY gained per patient (comparator versus standard care: 0.0450 versus 0.0443). Model results were robust against the parameter variations in the one-way sensitivity analyses, but increasing the cost of filgrastim beyond US$87 per injection would increase the ICER to >US$50,000/QALY. Furthermore, the strategy of antibiotics with therapeutic filgrastim was the preferred choice (dominant or cost-effective) in 83.7% of the model iterations at a willingness-to-pay threshold of US$50,000/QALY.

IMPLICATIONS: From a hospital's perspective, the therapeutic filgrastim, in conjunction with antibiotics, in the treatment of FN is cost effective. This provides evidence to support the routine use of filgrastim for the treatment of FN among adult cancer patients with solid tumors and lymphomas.