Chemotherapy-induced (febrile) neutropenia prophylaxis with biosimilar filgrastim in solid tumours versus haematological malignancies: Patterns, outcomes and determinants (MONITOR-GCSF study)

Abstract

Background: Chemotherapy-induced neutropenia (CIN) and febrile neutropenia (FN) are common complications of chemotherapy that can lead to hospitalisation or chemotherapy disturbance. Standard of care is guideline-recommended prophylaxis with granulocyte colony-stimulating factors (GCSF) based on the regimen myelotoxicity and patient risk factors. Methods: MONITOR-GCSF is a real-world European study of 1447 cancer patients (pts) receiving CIN/FN prophylaxis with biosimilar filgrastim; 77.2% had solid tumours and 22.8% haematological malignancies. We analysed prophylaxis patterns and CIN/FN outcomes in these cohorts and performed multi-level modelling of predictors of outcomes at the patient and cycle level. Results: Differences in GCSF prophylaxis patterns were observed between cohorts. The solid tumour cohort vs the haematology cohort included significantly more over-pro-phylacted pts (29.7% vs 13.7%) and fewer correctly-prophylacted pts (54.0% vs 65.3%) (P= 0.009 for trend). Of note, 16.3% with solid tumours and 21.0% of haematology pts were under-prophylacted. In 60% of solid tumour pts, GCSF was initiated within the recommended time window vs 42% of haematology pts. Cycle-level analyses revealed higher rates of CIN (all grades) and FN in the haematology cohort, but no dif-ferences in hospitalisation or chemotherapy disturbance. No differences in patient-level outcomes (”ever” during the study) were found, except for FN (9.1% in haematological patients vs. 5.0% with solid tumours). Across patient-and cycle-level analyses, predictors of poor outcomes common to both cohorts included concomitant antibiotic prophylaxis, Eastern Cooperative Oncology Group performance status > =2 at any time, and CIN of any grade in a prior cycle. A GCSF Initiation Score of 1, indicating biosimilar filgrastim initiation within the 24-72 h window, was a common strong predictor of better outcomes. Conclusions: Our analyses illustrate the importance of assuring adequate GCSF support in both haematology and solid tumour pts to prevent CIN/FN and related hospitalisations and chemotherapy disturbances.