Comparison of biosimilar filgrastim versus other G-CSF formulations after autologous stem cell transplantation

Biosimilares/Investigación | Posted 28/11/2014 post-comment

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Introduction
Only limited data have been so far published about the use of biosimilar filgrastim in haematologic recovery after autologous stem cell transplantation (ASCT). Despite the limitation due to retrospective analysis performed on a limited number of patients, all these studies suggest a substantially similar efficacy of biosimilar products, when compared to originators in the febrile neutropenia prophylaxis of lymphoma and myeloma patients post-ASCT. The aim of this study was to compare the biosimilar filgrastim Zarzio with the other available formulations of granulocyte colony-stimulating factor (G-CSF) in terms of efficacy and safety [1].

Research methods
From March 2013 to June 2014, researchers at the Regina Elena National Cancer Institute, Rome, Italy, used biosimilar filgrastim (Zarzio, Sandoz Industrial Products Spa, Rovereto, Italy) at a dosage of 5 mg/kg daily given from day 3 after stem cell infusion for febrile neutropenia prophylaxis and haematologic recovery in 64 consecutive adult patients who underwent ASCT. These patients were retrospectively compared with three historical cohorts: a) 99 consecutive adult patients treated with lenograstim (Myelostim, Italfarmaco Spa, Milano, Italy) at the same dosage and timing in the Institute from January 2009 to February 2013; b) 60 consecutive adult patients treated with pegfilgrastim (Neulasta, Amgen Spa, Milano, Italy) at a dosage of 6 mg single dose at day 3 after stem cell infusion in the Institute from March 2006 to December 2008; and c) 79 consecutive adult patients treated with originator filgrastim (Granulokine, Amgen Spa, Milano, Italy) at a dosage of 5 mg/kg daily given from day 3 after stem cell infusion in the Haematology Unit of Campus Bio-Medico University, Rome, Italy, from May 2008 to June 2014.

Results
The results showed no statistically significant difference among the four patient cohorts. The time of haematologic recovery after stem cell infusion (defined as an absolute neutrophils count > 0.5 x 10⁹/L and a platelets count > 20 x 10⁹/L), the occurrence of fever of unknown origin in neutropenia, documented infectious episodes and the need for intravenous antibiotic treatment were analysed, as well as the number of red blood and platelet transfusions, the days of hospitalization and the transplant-related mortality.

A significantly shorter time to neutrophils and platelet recovery (p = 0.001 and p = 0.007, respectively) was observed, with a consequent lower median number of platelet transfusions (p = 0.001) in the cohort of patients treated with Neulasta, whereas no difference was observed among the other three groups. Moreover, no significant difference among the four patient cohorts for all the other analysed parameters was observed. No difference in terms of drug-related adverse events was observed in the four patient cohorts and no serious adverse events were reported.

Considering the median days of G-CSF injections and assuming a patient median body weight of 60 kg, the estimated cost for each patient was significantly lower in the Zarzio group (approximately Euros 73) when compared with the other groups (approximately Euros 732 for Myelostim, Euros 649 for Granulokine and Euros 660 for Neulasta; p < 0.0001).

Conclusions
It was therefore concluded that biosimilar filgrastim (Zarzio) seems to be substantially equivalent in terms of efficacy and safety to the other G-CSF formulations when used for febrile neutropenia prophylaxis and haematologic recovery after ASCT. The use of biosimilar filgrastim also enables a significant reduction in costs in this setting of utilization. Further prospective randomized studies are warranted to confirm these results.

Conflict of interest
The authors of the research paper [1] declared that there were no conflicts of interest.

Abstracted by Dr Francesco Marchesi, Haematology and Stem Cell Transplantation Unit, Regina Elena National Cancer Institute, Rome, Italy.

Editor’s comment
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Reference
1. Marchesi F, Cerchiara E, Dessanti ML, et al. Comparison between biosimilar filgrastim vs other granulocyte-colony stimulating factor formulations (originator filgrastim, peg-filgrastim and lenograstim) after autologous stem cell transplantation: a retrospective survey from the Rome Transplant Network. Br J Haematol. 2014 Nov 5. doi:10.1111/bjh.13199. [Epub ahead of print]

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