Starting in 2017, the Henry Ford Cancer Institute started using follow-on filgrastim (tbo-filgrastim, a product approved prior to the establishment of the biosimilar approval pathway in the United States) and biosimilar filgrastim (Zarxio) in stem cell mobilization prior to transplant.
Biosimilars have been reported to result in similar stem cell yield during hematopoietic stem cell mobilization; in the past, a Canadian study reported that brand-name filgrastim and the biosimilar Grastofil demonstrated similar efficacy for stem cell mobilization and led to a successful CD34+ cell harvest for most patients. Another recent study found no difference in plerixafor use between the patients receiving the brand-name filgrastim versus those receiving the biosimilar Zarxio for mobilization.
However, fewer data are available on the effect of biosimilar use on the length of hospitalization for the transplant procedure, on engraftment, or on long-term survival after the transplant. One recent study sought to add to the body of data by reporting on transplant-specific outcomes related to the use of biosimilars.1
Starting in 2017, the Henry Ford Cancer Institute started using follow-on filgrastim (tbo-filgrastim, a product approved prior to the establishment of the biosimilar approval pathway in the United States) and biosimilar filgrastim (Zarxio) in stem cell mobilization prior to transplant. Researchers at this center conducted a study to evaluate the transplant-specific outcomes of using these agents in the transplant process.
The retrospective study evaluated all 113 patients at the center who received mobilization with granulocyte colony-stimulating factor therapies between 2017 and 2018. Of the 73 patients analyzed, 45% received tbo-filgrastim, 44% received the reference, and the remaining 11% of patients received the biosimilar.
In total, 86% of patients proceeded to transplant. No differences were observed in terms of adequate CD34+ yield among all 3 products, and no difference was observed in mobilization-associated complications, including bone pain and thrombocytopenia. The number of apheresis sessions required to collect an adequate CD34+ yield was not different among the 3 groups.
There were also no significant differences noted between groups with respect to time to neutrophil and platelet engraftment or length of hospital stay, and similar rates of infection, febrile neutropenia, and mucositis were observed in the 3 groups. Finally, relapse rates were similar among the groups.
These findings, note that authors, demonstrate that, among the 3 filgrastim options for pretransplant mobilization protocols, transplant-related outcomes for patients were similar.
1. Neme K, Henkin D, Mikulandric N, et al. Outcomes of tbo-filgrastim, filgrastim-sndz or filgrastim for mobilization in patients undergoing an autologous hematopoietic stem cell transplant: a single center experience. Presented at: American Society of Clinical Oncology Annual Meeting 2019; May 31-June 4, 2019; Chicago, IL. Abstract e19000.