Background Prophylactic administration of filgrastim can reduce the risk of febrile neutropenia (FN) in oncological patients undergoing myelosuppressive chemotherapy.

According to approved guidance on biosimilar drugs, clinical comparability can be obtained from results extrapolated from other indications.

Due to this simplified pathway, concerns about safety and effectiveness in some clinical settings may remain.

Purpose To compare the effectiveness and safety of biosimilar filgrastim (B) with the reference medicinal product (RMP) in patients with haematological malignancies treated with the R-CHOP regimen and undergoing primary prophylaxis (PP) with filgrastim.

Materials and Methods A single-centre, retrospective and transversal study was performed: from March 2010 to October 2010 (RMP) and March 2011 to February 2012 (B).

Main endpoints were incidence of FN (per patient and per cycle), time to absolute neutrophil count (ANC) recovery, incidence of NP in first cycle (1stCy), number of hospitalisation days related to FN. Other endpoints and patient-related risk factors for FN were evaluated.

Results The results seem to support equivalence of effectiveness between these drugs. We did not find any safety-related incidents. More patients are being included to increase the sample size and allow statistical significance. These results may further support the use of the more cost-efficient option.

No conflict of interest.