A study of granulocyte colony–stimulating factors (G-CSFs) used to prevent neutropenia in patients undergoing chemotherapy found that the Veterans Administration (VA) prescribing and purchasing can minimize its GCSF costs by emphasizing the use of tbo-filgrastim, especially over the originator form of pegfilgrastim.
Outside of the VA system, the pegylated formulation is used more commonly than the short-acting form of filgrastim. However, the cost of pegfilgrastim (prior to introduction of biosimilar versions) was up to 39% more expensive, say researchers from California and South Carolina. Therefore, one very real question in the filgrastim versus pegfilgrastim decision is whether the use of the former should be prescribed over the latter.
The study team evaluated the use of G-CSFs in 23 VA practice sites. The analysis included prescribing patterns and costs of filgrastim (Neupogen®), tbo-filgrastim (Granix®), filgrastim-sndz (Zarxio®), and pegfilgrastim (Neulasta®) use. Based on the VA’s 340B pricing, the researchers found that Granix use would result in the most cost-efficient regimen if all prescribing was switched to this drug ($62,336 per 100 patient episodes). In fact, tbo-filgrastim was the most prescribed GCSF in 78% of the practice sites.
According to these researchers, who presented their results at the annual American Society of Hematology meeting this week, the VA was extremely effective in avoiding use of the more expensive pegfilgrastim (upwards of 75% of prescriptions were not written for pegfilgrastim).
They noted that non-innovator brands of filgrastim are being used for all new patients at each site surveyed. Despite the relatively short treatment episodes, more than one-quarter of practice sites were willing to switch from Neupogen in an existing patient to a biosimilar or follow-on filgrastim.
These filgrastrim versus pegfilgrastim results are unlikely to be replicated outside of the VA, unfortunately. The study team realize that the principal cost savings came from avoiding the use of pegfilgrastim in favor of filgrastim, which is opposite the situation outside of the VA system. Furthermore, they point out that the savings resulting from using Granix versus Neupogen or Zarxio was only slightly greater than 2%. This may be a result of 340B pricing rather than other reimbursement. However, it does go to the question of whether established pegfilgrastim utilization can be reduced, despite its convenience and dosing advantages.
The researchers did not specify, also, what percentage of pegfilgrastim use was in prefilled syringes versus on-body injectors (the most prescribed form today). One also wonders whether the entry into the marketplace of additional filgrastim versus pegfilgrastim biosimilar competition might have an effect, using 340B pricing, on the cost efficiency of G-CSFs.