Over- and under-prophylaxis for chemotherapy-induced (febrile) neutropenia relative to evidence-based guidelines is associated with differences in outcomes: findings from the MONITOR-GCSF study.

PURPOSE: In the MONITOR-GCSF study of chemotherapy-induced (febrile) neutropenia with biosimilar filgrastim, 56.6% of patients were prophylacted according to amended EORTC guidelines, but 17.4% were prophylacted below and 26.0% above guideline recommendations. METHODS: MONITOR-GCSF is a prospective, observational study of 1447 evaluable patients from 140 cancers centers in 12 European countries treated with myelosuppressive chemotherapy for up to 6 cycles receiving biosimilar GCSF prophylaxis. Patients were classified as under-, correctly-, or over-prophylacted with GCSF relative to guideline recommendations based on their chemotherapy risk, individual risk factors, and type of GCSF prophylaxis (primary versus secondary). RESULTS: Differences between under- (17.4%), correctly- (56.6%), or over-prophylacted (26.0%) groups were found in terms of patient risk factors (age, performance status, history of FN, comorbid conditions) as well as prophylaxis patterns (type of prophylaxis, day of GCSF initiation, and GCSF duration). Rates of chemotherapy-induced neutropenia (CIN) (all grades), FN, and CIN-related hospitalizations were consistently lower in over-prophylacted patients relative to under- and correctly-prophylacted patients. No differences were observed between under- and correctly-prophylacted patients except for CIN/FN-related chemotherapy disturbances. No GCSF safety differences were found between groups (except for headaches). CONCLUSIONS: The real-world evidence provided by the MONITOR-GCSF study indicates that providing GCSF support may yield better CIN, FN, and CIN/FN-related hospitalization outcomes if patients are prophylacted at levels above guideline recommendations. Patients who are under-prophylacted are at higher risk for disturbances to their chemotherapy regimens. Our findings support the guideline recommendation that CIN/FN risk be assessed at the beginning of each chemotherapy cycle.

Chemotherapy-induced (febrile) neutropenia prophylaxis with biosimilar filgrastim in elderly versus non-elderly cancer patients: Patterns, outcomes, and determinants (MONITOR-GCSF study).

BACKGROUND: Myelotoxic chemotherapy is associated with chemotherapy-induced (febrile) neutropenia (CIN/FN). The MONITOR-GCSF study evaluated biosimilar filgrastim (Zarzio®) prophylaxis patterns, associated outcomes, and determinants. We performed stratified analyses comparing elderly and non-elderly patients. METHODS: Comparative (elderly/non-elderly) analysis of demographics and clinical status, prophylaxis, associated CIN/FN outcomes (CIN grade 4 [CIN4], FN, CIN/FN-related hospitalizations and chemodisturbances, composite), and, per hierarchical modeling, determinants thereof evaluated at the patient- and cycle-level. RESULTS: There were no significant differences between both cohorts in prophylaxis initiation/duration and associated outcomes, but proportionately more elderly patients were correctly-prophylacted and fewer over-prophylacted. Common determinants of poor CIN/FN outcomes included concomitant antibiotic prophylaxis, impaired performance status, and any grade CIN in a previous cycle, whereas common determinants of good outcomes included over-prophylaxis and prophylaxis initiation within 24-72h. In the elderly, female gender, liver/renal/cardiovascular disease, secondary prophylaxis, and under-prophylaxis were associated with poorer outcomes. In the non-elderly, CIN4 at baseline or in a prior cycle was associated with poorer CIN/FN outcomes, and higher biosimilar filgrastim dose and, perhaps counter-intuitively, under-prophylaxis with better outcomes. CONCLUSION: Adequate GCSF support is essential for all patients, but especially for elderly patients with serious chronic disease, certainly, if concomitant antibiotic prophylaxis is indicated and if a CIN4 episode occurred in a prior cycle. The potential impact of impaired performance status, especially ECOG≥2 at chemotherapy start or a worsening to such during chemotherapy; under-prophylaxis, including inadequate secondary prophylaxis, should be considered in elderly patients. Timely GCSF initiation and over-prophylaxis is associated with lower rates of adverse CIN/FN events in elderly and non-elderly patients, and should be further evaluated in prospective randomized trials.