Patient-Administered Biosimilar and Follow-On Filgrastim Pose Opportunity for Savings

Studies have demonstrated that using follow-on and biosimilar granulocyte colony-stimulating factor (G-CSF) agents can produce cost savings and expand patient access to prophylaxis of febrile neutropenia. Now, a newly published budget impact analysis finds that even greater savings may be possible if patients self-administer these agents at home rather than visiting a provider to receive an injection.

To date, 3 short-acting G-CSF drugs are available in the United States: the innovator product (Neupogen), a follow-on product (tbo-filgrastim, Granix), and a biosimilar (Zarxio). The budget impact analysis sought to estimate the change in cost associated with increased use of Granix and Zarxio from the perspective of a health plan covering 1 million members over a 1-year time horizon.

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Drawing on rates shown in the available literature, the investigators assumed that 45% of eligible patients would use any G-CSF, and 70% of that group would use a short-acting product. Finally, they assumed that 20% of patients would self-administer their drug at home. Drawing on current market share distributions of G-CSFs from IMS Health data, the share of market for self-administered products was assumed to be 4.9% for Granix, 84.7% for Neupogen, and 10.4% for Zarxio. The investigators also projected a future 5% increase in market share for Granix and a 2% increase in market share for Zarxio.

The base-case budgetary impact analysis estimated that the total plan cost for short-acting G-CSF was $53,298,217 for a 1-million-member plan, with Granix costing $2,311,211, Neupogen costing $46,037,202, and Zarxio costing $4,949,804. Assuming the projected future increases for Granix and Zarxio, the total cost dropped to $52,828,832 (with Granix costing $4,703,546, Neupogen costing $42,260,349, and Zarxio costing $5,864,937), resulting in a total plan cost savings of $469,385.

Because Granix can be stored at room temperature for up to 5 days (versus 1 day for Neupogen and Zarxio), it may be subject to less wastage, so the investigators also conducted a scenario analysis evaluating how annual syringe replacement rates (assuming a 1% replacement rate for Granix and 5% replacement rates for the other 2 products) affected costs. The estimated total annual plan cost associated with short-acting G-CSF agents was $55,920,046 in this scenario; however, assuming future increased market share for Granix and Zarxio, the cost dropped to $55,346,277.

The model was most sensitive to changes in the percentage of patients who self-administered their G-CSF agent at home; assuming a 25% increase in home use, total plan costs increased to $66,042,135 for the future scenario, while a 25% reduction in home use led to a decrease to $39,615,529.

“However,” the authors write, “it is important to note that any changes in plan costs associated with a larger number of patients self-administering G-CSF would be largely offset by reduced costs associated with the smaller number of patients undergoing chemotherapy who would receive their short-acting G-CSF treatment directly from a health care provider in an office or other outpatient setting.”

The analysis concluded that the effective annual plan per-patient drug cost was 11% lower for Granix and 15% lower for Zarxio than the cost of the reference, and increased market share of these products could lead to total annual plan cost decreases of nearly $0.5 million. Because replacement due to wastage tempered these savings, increasing the use of Granix and Zarxio over Neupogen for those who self-administer “may offer a more affordable option for US payers.”

Reference

Trautman H, Szabo E, James E, Tang B. 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. [Published online August 7, 2018.] J Manag Care Spec Pharm. doi: 10.18553/jmcp.2018.18094.