Background: The ZOHé study was a prospective, non-interventional, multicentre study in France to assess the use of biosimilar filgrastim Zarzio® (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® 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® in current practice, and also included identification of factors linked to prescription for primary prophylaxis and comparison of Zarzio® 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® 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® 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® 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® was confirmed.
Conclusions: Use of Zarzio® 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® 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%.
Keywords: Biosimilar pharmaceuticals; Chemotherapy; Febrile neutropenia; Filgrastim; Guidelines recommendations; Observational study; Real-world; Solid tumours.