Analysis of Physicians' Notes Shows Slow Uptake for Filgrastim-sndz

To date, there has been little information available about the uptake of filgrastim-sndz in the United States compared to the use of other granulocyte colony-stimulating factor (G-CSF) agents. In a study funded by Envision Market Access Solutions (part of Envision Pharma Group) and presented at the 22nd Annual International Meeting of The International Society for Pharmacoeconomics and Outcomes Research, researchers sought to identify physicians’ documented G-CSF use, with a particular focus on the use of filgrastim-sndz since its entry into the marketplace.

The first biosimilar approved in the United States, filgrastim-sndz has been approved for 5 of 6 licensed indications for its reference product (including prophylaxis for and treatment of febrile neutropenia in patients undergoing myelosuppressive chemotherapy) and has been available in the US market since September 2015.

The researchers identified mentions of G-CSF agents in physicians’ records of patient consultation as documented in RealHealthData (a transcription database) for the period of January 1, 2016, to March 31, 2017. The records comprise notes from both office visits and healthcare facility consultations, and included physicians’ intentions to treat with a G-CSF at the time of the consultation, a patient’s G-CSF treatment history, or both.

In addition to tabulating occurrences of the names of 4 G-CSF agents, namely pegfilgrastim (Neulasta), filgrastim (Neupogen), tbo-filgrastim (Granix, Neutroval), and filgrastim-sndz (Zarxio, Zarzio), the researchers also evaluated their prophylactic or curative use against neutropenia.

Per the analysis, physicians made 17,770 mentions of G-CSF agents in 2016:

• 56% referenced pegfilgrastim
• 34% referenced filgrastim
• 9.5% referenced tbo-filgrastim
• Less than 1% referenced filgrastim-sndz

In the first quarter of 2017, mentions of filgrastim increased to 39.6% of the total number of G-CSF mentions, while mentions of tbo-filgrastim increased to 12.8%. Pegfilgrastim, however, retained the highest share of the total with 47% of mentions.

The data show that, over the full study period, general practitioners were the most frequent providers to mention pegfilgrastim, filgrastim, and tbo-filgrastim (though hospitalists mentioned tbo-filgratim the most often). Data also demonstrate an influence of location: physicians in Pennsylvania mentioned pegfilgrastim the most often, physicians in Texas noted tbo-filgrastim the most often, and providers in Kansas mentioned filgrastim-sndz the most often.

Explaining that their study provides only a proxy of G-CSF use for specific time periods rather than documented treatment patterns for such agents, the authors state that providers’ notes may have been repeated in cases of patient hospitalization over a period of days. Furthermore, the data do not represent all US states, so the study’s findings are not representative of national trends.

Yet the researchers conclude that, among 21,222 records considered in this study, only 140 mentions (0.7% of total mentions) of filgrastim-sndz were noted in the first 18 months of the product’s entry into the US market, and there was no significant increase in the product’s mentions in the first quarter of 2017 when compared with the 2016 period. The researchers also suggest that differences among mentions of filgrastim-sndz and other G-CSF agents across provider types and geographies may indicate differences in formulary listings and clinical treatment patterns across regions. Increased awareness of biosimilars among clinicians and payers, the authors conclude, may be required in order for filgrastim-sndz to see increased uptake.