didn’t find any clinical differences between the reference product and its biosimilars. But the researchers didn’t find any real cost savings, either. They chalked up the lack of savings to when the study was done—the data are from 2012 to 2017—and biosimilar nascency. Still, for those hoping for cost savings, this is a flickering kind of outcome, not a beacon of hope.
The results, reported in the December 2018 issue of JAMA Oncology, were from a retrospective analysis of claims data from an unnamed commercial insurer, so the usual caveats about research based on claims data must be applied. The researchers looked at data on cancer patients who were prescribed Neupogen or its biosimilars, which at that time included Zarxio (filgrastim-sndz) and Granix (tbo-filgrastim). (Zarxio is often identified as the first FDA-approved biosimilar, but Granix got the OK three years earlier, before the FDA established an approval process for biosimilars.) Filgrastim is a colony-stimulating growth factor that helps cancer patients fight off infections by boosting white blood cell counts. Of the 11,000 patients in the study, a little more than 1,500, or roughly 14%, were treated with a biosimilar rather than Neupogen.
The researchers, led by of HealthCore, a Wilmington, Del., health care research company, didn’t find any statistically significant differences in febrile neutropenia (which filgrastim is supposed to prevent) between the patients prescribed Neupogen and those prescribed a biosimilar. Similarly, their analysis didn’t find any differences in adverse events. So, from purely a clinical perspective, Neupogen provided no real advantage over biosimilars.
But the cost computed on a per-patient basis was virtually the same ($2,516 for Neupogen vs. $2,522 for the biosimilars) and other cuts of the data also showed no separation. When Zarxio and Granix were analyzed separately, some results showed Zarxio to be less costly than Neupogen and Granix more expensive, although statistical significance was lacking in many of those comparisons.
As the authors noted, the results are reassuring if you are concerned about the biosimilars being less effective or having more side effects. If you are looking for savings from biosimilars, your search continues, perhaps to a study that covers a time when more of them are on the market.