Comparison of trial and real-world data for biosimilar filgrastim Posted 07/09/2018

A study carried out by researchers from Germany compared results from a randomized controlled trial (RCT) of Sandoz’s biosimilar filgrastim and post-approval data on the safety of the biosimilar [1].

Sandoz’s Zarzio (filgrastim) was approved in the European Union back in February 2009 [2] and Zarxio (filgrastim-sndz) was approved in the US in March 2015 [3]. US approval was based on results from PIONEER, a phase III confirmatory trial in breast cancer patients receiving chemotherapy randomized to either Sandoz biosimilar or reference filgrastim.

The authors compared the results from the PIONEER trial to the breast cancer cohort in the MONITOR-GCSF study in order to evaluate Zarxio in an RCT and a real-world practice setting in breast cancer. MONITOR-GSCF was a post-approval, observational study that evaluated the safety of Zarxio in patients with solid or haematological malignancies undergoing chemotherapy.

There were 217 evaluable patients in PIONEER and 466 in MONITOR-GCSF. Febrile neutropenia (FN) was reported in 5.1% of patients from the PIONEER trial vs 6.2% in the MONITOR-GCSF study. All grade adverse events (AEs) were generally reported at a higher level in the PIONEER trial than in the MONITOR-GCSF study. These included musculoskeletal/connective tissue disorders (PIONEER: 261, MONITOR-GCSF: 20); infections/infestations (PIONEER: 31, MONITOR-GCSF: 3); skin/subcutaneous tissue disorders (PIONEER: 258, MONITOR-GCSF: 5) and general disorders/administration site conditions (PIONEER: 673, MONITOR-GCSF: 7). Cycle level results were generally similar between studies.

These data were presented at the American Society of Clinical Oncology’s (ASCO) 2018 Annual Meeting, which was held on 1−5 June 2018 in Chicago, IL, USA.

The authors concluded that ‘Sandoz biosimilar filgrastim prevented FN in an RCT and in real-world practice in breast cancer patients receiving (neo-)adjuvant chemotherapy’. They added that ‘in real-world practice, experiencing AEs may be perceived as unavoidable in order to achieve clinical efficacy. Thus, phase III RCTs remain an effective tool to assess and monitor AEs’.

Conflict of interest
The authors of the abstract [1] reported conflict of interest, including having received honoraria from, having worked in a consulting or advisory role for, or having received research funding from various pharmaceutical companies. Several of the authors also work for Hexal. For full details of the authors’ conflicts of interest, see the abstract [1].

Editor’s comment
It should be noted that data of the study presented in this article was published as an abstract and presented at a conference. These data and conclusions should be considered as preliminary until published in a peer-reviewed journal.

Related article
Real-life data supports efficacy and safety of biosimilar filgrastim

1.  Harbeck N, Yau L, Mathieson N, Krendyukov A. Comparison of efficacy and safety of biosimilar filgrastim in a RCT (PIONEER) and real-world practice (MONITOR-GCSF). American Society of Clinical Oncology (ASCO) 2018 Annual Meeting; 1-5 June 2018; Chicago IL, USA.
2.  GaBI Online - Generics and Biosimilars Initiative. Biosimilars approved in Europe []. Mol, Belgium: Pro Pharma Communications International; [cited 2018 Sep 7]. Available from:
3.  GaBI Online - Generics and Biosimilars Initiative. Biosimilars approved in the US []. Mol, Belgium: Pro Pharma Communications International; [cited 2018 Sep 7]. Available from:

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