Biosimilar Tbo-Filgrastim Poses Unrealized Potential for Cost Savings

In 2008, tbo-filgrastim (Granix) was approved as a biosimilar in Europe. In 2012, it was approved in the United States as a follow-on biologic product to filgrastim. Tbo-filgrastim was less expensive than filgrastim, and clinical information and expert opinion supported similarity between the products. This led the pharmacy and therapeutics committee of a major US health system to approve tbo-filgrastim as the preferred granulocyte-colony stimulating factor (G-CSF) product in March 2014.

A newly published study appearing in the Journal of Managed Care & Specialty Pharmacy was conducted to assess the use of filgrastim and tbo-filgrastim products by comparing baseline characteristics, setting of care, indication for use, and payer type. The study also sought to understand the potential barriers that could arise from conversion to tbo-filgrastim. The researchers found that, although tbo-filgrastim was the preferred G-CSF in the health system, 29% of patients continued to receive reference filgrastim. The system’s conversion to tbo-filgrastim was largely successful, but the researchers note that some extra steps may be needed in order to achieve full conversion to biosimilars.

The researchers conducted a retrospective evaluation of filgrastim and tbo-filgrastim on all patients (n = 204) who received G-CSF between July 2015 and December 2015 at the 2 largest hospitals within the health care system.

Overall, G-CSFs were administered to 204 patients for 261 episodes of care (filgrastim and tbo-filgrastim were used in 65 and 196 episodes of care, respectively). G-CSF was primarily used in the inpatient setting (163 episodes of care, 63%) with 90% of patients using tbo-filgrastim. In the outpatient setting (98 episodes of care, 38%), filgrastim and tbo-filgrastim were each used by 50% of patients. Tbo-filgrastim was the preferred G-CSF by clinical providers for all indications, except for stem cell mobilization. In the outpatient setting, analysis by payers showed that the majority of patients on commercial plans were using filgrastim (58%), while half of Medicare patients were using filgrastim.

Despite their importance and value, biologics like filgrastim are expensive, with a single injection costing between $305 and $515, the study reports. Thus, the use of biosimilars represents an important strategy for providing safe and effective treatment equivalent to the reference drug, but at a lower cost. Despite the reported cost advantages, findings from this study showed that 29% of patients on G-CSF continued to be on filgrastim 2 years after the health system’s pharmacy and therapeutics committee decision. This finding led researchers to conclude that, although the use of biosimilars could have the potential to reduce drug expenditure and increase patient access to high-cost medicines, more needs to be done to educate members of the health care system in order to achieve the full conversion.