Potential and Realized Cost Savings with the Use of the Biosimilar Grastofil Vs Neupogen

Background: Filgrastim was first introduced to the Canadian marketplace as Neupogen^® in 1992 to treat neutropenia caused by chemotherapy regimens. In 2009, the first biosimilar drug was approved for use in Canada, and in March 2016, a biosimilar for filgrastim (Grastofil^®) became available. Biosimilars represent safe, effective, and cost effective alternatives to originator biologic medications. However, although biosimilar medications present opportunities for significant cost savings to the health care system, overall uptake and use of biosimilar medications in North America has been low. The aim of this study was to describe the overall use of the filgrastim products Grastofil^® and Neupogen^® in Canada.

Methods: A retrospective analysis of Canadian drug purchases between July 2016 and June 2018 was performed for the drug filgrastim (Neupogen^®, Grastofil^®). The data used to estimate drug purchases were obtained from IQVIA™, a multi-national healthcare analytics company. Samples from the IQVIA™ Canadian Drugstore and Hospital Purchases (CDH) audit covered greater than 88% of the hospital market and one-third of the retail market. Samples were stratified by region, market size, and type of outlet (e.g. cancer centers, long-term care). For each drug, the total purchase dollar amounts were provided by province on a month by month basis. Potential cost-savings were calculated as a product between the units of each product purchased and the cost difference between Neupogen^® and the biosimilar Grastofil^® on a quarterly basis for each province.

Results: Between July 1^st, 2016 and June 30^th, 2018, Grastofil^® accounted for 27.0% (382,254/1,415,762 units) of filgrastim purchases. During this time period, $62,061,576 was spent on Grastofil^® purchases and $204,152,590 was spent on Neupogen^® purchases. Through use of the biosimilar Grastofil^®, $13,443,873 (37.0%) in savings were realized. Had there been 100% use of the biosimilar Grastofil^®, it would have resulted in $36,348,476 in cost savings. In the first quarter (July to September 2016) Grastofil^® accounted for 1.5% of filgrastim purchases, whereas in the April to June 2018 quarter it increased to 43.6% of filgrastim purchases. The overall percentage of filgrastim units purchased by Canadian province varied substantially. The market share captured by Grastofil^® ranged from a low of 0.08% ($4007/$5,189,623) in the province of Nova Scotia, to a high of 81.62% ($932,864/$1,142,905) in the province of Saskatchewan. Canada's largest province, Ontario, saw Grastofil^® account for 44.7% ($9,047,489/$20,229,421) of purchases during this time period.

Discussion: Although the biosimilar Grastofil^® only accounted for 27% of filgrastim purchases between 2016 and 2018, there was substantial growth over this time period. By the end of June 2018, Grastofil^® accounted for approximately 44% of filgrastim purchases, which is substantially higher than other biosimilar medications currently available in Canada. There are also stark differences between each province, whereas some had little to no use of the biosimilar, whereby in other provinces the purchases of Grastofil^® outnumbered the purchases of Neupogen^®. Had there been exclusive use of the biosimilar, an additional $23 million dollars in savings could have been realized.

Conclusions: The use of biosimilars represents an opportunity for cost savings to be realized in an over-extended health care system. Although there appears to be acceptance for the use of Grastofil^® as the overall purchases trended up from 2016 to 2018, there are still significant cost savings that could be realized by greater use of biosimilar drugs.