Using Biosimilar Filgrastim Does Not Impact Plerixafor Use in Transplantation Candidates

Patients who are candidates for hematopoietic stem cell transplantation (AHSCT) require adequate collection of stem cells, and granulocyte colony-stimulating factor agents (G-CSFs) are typically used for stem cell mobilization while plerixafor is used to increase the yield of mobilized stem cells. While the biosimilar filgrastim agent Zarxio has become a more widely used, cost-saving G-CSF option in this context, little research has been conducted on whether the use of the biosimilar rather than its reference, Neupogen, has an impact on plerixafor use in patients undergoing AHSCT.

In research scheduled for presentation on December 3 at the 60th Annual Meeting and Exposition of the American Society of Hematology in San Diego, California, researchers will present findings from their retrospective, single-center study of whether there exists a difference in the rate of plerixafor use among patients whose stem cells were mobilized with the biosimilar versus the reference.

Using the Karmanos Cancer Institute’s blood and marrow transplantation database, the researchers collected data on 370 patients who underwent stem cell mobilization for AHSCT between 2015 and 2017. Patients received the biosimilar (n = 173) or reference (n = 197) filgrastim at a dose of 10µg/kg for 5 days, and also received plerixafor if their peripheral CD34+ cell count on the first day of collection was less than 20/µL.

There were no significant difference in the baseline patient characteristics of the patients in the 2 treatment groups other than a slightly lower median white blood cell count prior to mobilization in patients who received the reference filgrastim.

The researchers found that there was no statistically significant difference in plerixafor utilization between the biosimilar and the reference groups, with 45% of the patients receiving the reference requiring plerixafor treatment versus 43% of the patients in the biosimilar group requiring plerixafor (P = .794). Furthermore, there was no difference between the group in the peripheral CD34+ cell count on the first planned day of collection, the number of collected stem cells, the total days of apheresis, the need for a second mobilization, the rate of transplant, or the duration of transplant hospitalization. In fact, in a multivariate analysis, only older age and low platelet count adversely impacted patients’ ability to proceed to transplantation.

The researchers concluded that there was no difference in plerixafor use between the 2 patient groups, and given that the cost of the biosimilar was approximately 50% lower than that of the reference product, using the biosimilar G-CSF agent provided an opportunity for significant cost savings for stem cell mobilization.

Reference

Abdallah N, Kim S, Alavi A, et al. Does use of a biosimilar G-CSF change plerixafor utilization during stem cell mobilization for autologous stem cell transplantation? Presented at: 60th Annual Meeting and Exposition of the American Society of Hematology; December 1-4, 2018; San Diego, California. Abstract 4557. ash.confex.com/ash/2018/webprogram/Paper118400.html.