Real World Clinical Experience of Biosimilar G-CSF (Grastofil) for Autologous Peripheral Blood Stem Cell Mobilization: Single Center Experience in Canada Following Early Adoption.

Vibhuti Aggarwal,Mark Bosch,Julie Stakiw,Mohamed Elemary,Prosanta Mondal,Pat Danyluk,Waleed Sabry

doi:10.3390/curroncol28030148

Abstract

Introduction: Granulocyte colony-stimulating factor (G-CSF) is the first line treatment for mobilization, most commonly using a regimen of daily filgrastim. The use of biosimilars can provide substantial cost savings to the health care system while delivering comparable efficacy outcomes. In 2016, the Saskatchewan Cancer Agency was a leader in Canada, instituting formulary changed from a G-CSF originator product to a cost savings alternative biosimilar for stem cell mobilization prior to autologous stem cell transplant (ASCT) and for engraftment. The purpose of this study was to investigate the clinical comparability of biosimilar G-CSF to its reference product in a real-world clinical setting and to validate use of the biosimilar in mobilization and engraftment—an indication which had been granted by extrapolation. Methods: A retrospective chart review was completed including all patients diagnosed with a hematological malignancy between 2012 and 2018 who underwent ASCT. To assess real-world outcomes across a diverse population, successful CD34+ stem cell collection was compared between patients mobilized with originator filgrastim, Neupogen, and biosimilar filgrastim, Grastofil. Additional comparisons included the number of apheresis required, time to absolute neutrophil count (ANC) engraftment, platelet engraftment, length of hospital stay, and Plerixafor use. Results: 217 patients were mobilized and transplanted during the study period. There was no statistically significant difference in success rate between patients mobilized with biosimilar filgrastim and those who had received originator G-CSF (100% vs. 92.4%, p = 0.075). Neither disease type, nor concurrent chemomobilization regimen resulted in a detectable difference between the two G-CSF products in successful stem cell harvest. Engraftment was highly similar between groups, as demonstrated by ANC recovery (11.6 days Neupogen vs. 11.6 days Grastofil), platelet recovery (14.0 days Neupogen vs. 14.2 days Grastofil), and total length of hospital stay (22.4 days Neupogen vs. 22.3 days Grastofil). No statistically significant difference in adjunctive use of Plerixafor® was observed between Neupogen and Grastofil patients (25.9% vs. 23.4%, p = 0.72). Conclusion: Extrapolation of indications for biosimilars is justified. This real-world evidence builds upon registrational studies to confirm that no clinically meaningful differences were detected between originator Neupogen and biosimilar Grastofil in the setting of PBSC mobilization and engraftment post ASCT. Biosimilars are as safe and effective as originator products. Implementation across all approved indications without hesitation maximizes cost savings to the provincial system, allowing for more optimal allocation of health care resources.

Highlights

Granulocyte colony-stimulating factor (G-CSF) is the first line treatment for mobilization, most commonly using a regimen of daily filgrastim
Patients diagnosed with hematologic malignancies including multiple myeloma (MM), Hodgkin’s disease, and aggressive lymphomas may receive myeloablative therapy followed by autologous stem cell transplant (ASCT) as standard first-line therapy
We evaluated the clinical comparability of biosimilar G-CSF to its reference product for mobilization and engraftment outcomes in a real-world clinical setting and described results in terms of both clinical and practical endpoints, including successful stem cell harvests, adjunctive plerixafor (Mozobil®, Genzyme, Cambridge, MA, USA) use, number of days for apheresis, length of stay in hospital, and days to engraftment

Summary

Introduction

Granulocyte colony-stimulating factor (G-CSF) is the first line treatment for mobilization, most commonly using a regimen of daily filgrastim. In 2016, the Saskatchewan Cancer Agency was a leader in Canada, instituting formulary changed from a G-CSF originator product to a cost savings alternative biosimilar for stem cell mobilization prior to autologous stem cell transplant (ASCT) and for engraftment. To assess real-world outcomes across a diverse population, successful CD34+ stem cell collection was compared between patients mobilized with originator filgrastim, Neupogen, and biosimilar filgrastim, Grastofil. Conclusion: Extrapolation of indications for biosimilars is justified This real-world evidence builds upon registrational studies to confirm that no clinically meaningful differences were detected between originator Neupogen and biosimilar Grastofil in the setting of PBSC mobilization and engraftment post ASCT. Patients diagnosed with hematologic malignancies including multiple myeloma (MM), Hodgkin’s disease, and aggressive lymphomas may receive myeloablative therapy followed by autologous stem cell transplant (ASCT) as standard first-line therapy. Following the patent expiry for Neupogen in 2006, several biosimilar filgrastim products have been approved by global regulatory authorities, with Grastofil® (filgrastim, Apotex, North York, ON, Canada), marketed in the EU as Accofil® (Accord Healthcare, North Harrow, Middlesex, UK) being the first approved biosimilar G-CSF product in Canada [7]

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