Initiation of Biosimilar Filgrastim Within 24-72 Hours of Chemotherapy Reduces Neutropenia

A study published in Supportive Care in Cancer confirmed guideline-indicated recommendations for timing on initiating granulocyte colony-stimulating factors (G-CSFs) to management chemotherapy-induced neutropenia (CIN) and febrile neutropenia. Despite current guidelines recommending G-CSF within 24 to 72 hours following chemotherapy, some studies have indicated that G-CSF given less than 24 hours after chemotherapy may benefit some patients; thus, the researchers conducted the prospective, observational, multicenter, pan-European MONITOR-GCSF study.

Investigators assessed 1,447 chemotherapy-treated patients who received daily biosimilar filgrastim-sndz and classified them based on G-CSF initiation:

• same-day (initiated less than 24 hours after chemotherapy)
• per-guidelines (initiated 24 to 72 hours after chemotherapy)
• late (initiated more than 72 hours after chemotherapy)

Among 1,423 evaluable patients, there were 5,930 chemotherapy cycles, including 795 cycles classified as same-day (13.4%), 3,320 classified as per-guidelines (56.0%), and 1,815 classified as late (30.6%).

There did not appear to be differences among the groups with regard to CIN grade 1 or 4 or febrile neutropenia episodes. There were also no differences in CIN- or febrile neutropenia-related hospitalizations or disruptions in chemotherapy schedules.

Patients in the same-day and per-guidelines groups had statistically similar odds of not experiencing CIN or febrile neutropenia in any given treatment cycle. Patients in the late group had worse odds of experiencing CIN grade 1 or 4, CIN grade 3 or 4, and CIN grade 4 episodes during any treatment cycle.

The researchers concluded that filgrastim given within 24 to 72 hours after chemotherapy is “effective and safe,” but filgrastim administration on the same day as chemotherapy (within 24 hours) may be appropriate for some patients.