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Filgrastim biosimilars: real-world and switching evidence

What the evidence shows

Evidence intelligence

1published study

1trial with repeated switching

1disease covered

1product covered

Studies found1 study, a randomised trial in which breast cancer patients alternated between Neupogen and Zarxio every chemotherapy cycle.
The trialPatients who alternated products every cycle had febrile neutropenia in 3 in 100 against none on continuous Neupogen, within the trial's margin, and infections were the same in both groups. It is the switching evidence behind the first biosimilar approved in the United States.
Products with evidenceZarxio. No published switching study yet in this register for the other filgrastim biosimilars or the Indian and Japanese products.
What is missingNo study from India or the Gulf. No study from routine care, and nothing in stem cell mobilisation or transplant.

Studies

Disease

Product

Trials with repeated switching

Patients switched between Neupogen and the biosimilar more than once, with a control group that stayed on Neupogen. FDA interchangeability decisions rest on this design.

Study	Disease	Switch	Products	Patients switched	Follow-up	What the authors report
Blackwell 2018 Ann Oncol 2018;29(1):244-249 Multicentre (PIONEER trial)	Breast cancer on myelosuppressive chemotherapy	Repeated switches between reference and biosimilar every cycle (biosimilar then reference, or reference then biosimilar) over six cycles	Zarxio	109	6 chemotherapy cycles	Febrile neutropenia 3.4% in the switched patients and 0% on continuous reference across cycles 2 to 6, difference within the non-inferiority margin; infections 9.3% and 9.9%; no clinically meaningful differences in efficacy, safety or immunogenicity.

Blackwell 2018Ann Oncol 2018;29(1):244-249

DiseaseBreast cancer on myelosuppressive chemotherapySwitchRepeated switches between reference and biosimilar every cycle (biosimilar then reference, or reference then biosimilar) over six cyclesProductsZarxioPatients109Follow-up6 chemotherapy cycles

What the authors report

Febrile neutropenia 3.4% in the switched patients and 0% on continuous reference across cycles 2 to 6, difference within the non-inferiority margin; infections 9.3% and 9.9%; no clinically meaningful differences in efficacy, safety or immunogenicity.

No study matches this selection.

Switching evidence is what regulators, tender committees and formulary boards ask for before a change of product. EvySaif prepares interchangeability and switching dossiers and designs real-world studies for biosimilar programmes. Regulatory strategy consulting

Sources

S025Peer-reviewed journal articles on switching between biosimilars and the reference product; the study link on each row opens the paper Primary (published study)

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Data current to September 2026.