Biosimilar filgrastim treatment patterns and prevention of febrile neutropenia: a prospective multicentre study in France in patients with solid tumours (the ZOHe study)

Background: The ZOHe study was a prospective, non-interventional, multicentre study in France to assess the use of biosimilar filgrastim Zarzio (R) (Sandoz filgrastim) in routine clinical practice in patients at risk of neutropenia-inducing chemotherapy (CT). Methods: Patients >= 18 years undergoing CT for a malignant disease and with a first prescription for Zarzio (R) were enrolled in two cohorts according to tumour type: solid tumour or haematological malignancy; results from the solid tumour cohort are reported here. Analyses primarily described the prescription and use of Zarzio (R) in current practice, and also included identification of factors linked to prescription for primary prophylaxis and comparison of Zarzio (R) use in relation to European Organisation for Research and Treatment of Cancer (EORTC) guidelines. Results: Responses were obtained from 125 physicians and 1179 patients with solid tumours, allowing robust statistical analysis of the data. Use of Zarzio (R) in clinical practice was relatively standardised and followed label indication. The patient profile was in line with EORTC guidelines for granulocyte colony-stimulating factor (G-CSF) febrile neutropenia (FN) prophylaxis, and the majority of patients had >= 1 EORTC factor(s) for increased risk of febrile neutropenia. Some patients (10.8%) received Zarzio (R) despite receiving CT regimens categorised in guidelines as low (<10%) FN risk ('over prophylaxis'). Nearly half of patients' CT regimens did not have a recommended FN risk category. Zarzio (R) was commonly initiated as primary prophylaxis; initiation in Cycle >= 2 of the current line of CT was associated more with a history of neutropenia. The safety profile of Zarzio (R) was confirmed. Conclusions: Use of Zarzio (R) in routine clinical practice is generally in line with EORTC guidelines for prophylaxis of CT-induced neutropenia. Patient-related risk factors appear to be a stronger driver of clinicians' decision to initiate Zarzio (R) than CT risk category for FN. The intrinsic risk of FN associated with a specific CT protocol is often miscategorised by physicians. In contrast to earlier reports of underuse of G-CSF prophylaxis, over prophylaxis is observed in a small subgroup of patients with FN risk of <10%.