The results from a randomized controlled trial were compared with a real-world cohort for the safety and efficacy of a biosimilar to treat chemotherapy-induced neutropenia in patients with breast cancer.
The biosimilar to filgrastim was granted United States Food and Drug Administration (FDA) approval in 2015 for several indications, including the prevention of chemotherapy-induced neutropenia. The approval was based on results from a phase III confirmatory trial (PIONEER) in patients with breast cancer receiving chemotherapy who were randomized to either reference filgrastim or biosimilar filgrastim. After FDA approval, the safety of the biosimilar to filgrastim has been monitored in an observational study (MONITOR-GSCF) in patients with solid or hematological malignancies undergoing chemotherapy.
A group of German researchers performed an analysis to compare the results of PIONEER with the MONITOR-GCSF breast cancer cohort in order to evaluate the biosimilar to filgrastim in a randomized controlled trial and a real-world practice. Results were compared for corresponding endpoints, and patient- and cycle-level comparisons were made between patients in PIONEER and all patients with breast cancer receiving the biosimilar in MONITOR-GCSF.
Results of the analysis were presented at the 2018 American Society of Clinical Oncology (ASCO) Annual Meeting (June 1-5, 2018; Chicago, IL).
Researchers noted that there were 217 evaluable patients in PIONEER and 466 in MONITOR-GCSF. The patient population was generally younger in PIONEER (mean age, 48.9 years) than in MONITOR-GCSF (56.2 years).
Results of the analysis showed that febrile neutropenia was observed in 5.1% vs 6.2% in PIONEER and MONITOR-GCSF, respectively.
However, all grade adverse events were generally reported at a higher level in PIONEER than in MONITOR-GCSF, including musculoskeletal/connective tissue disorders, infections/infestations, skin/subcutaneous tissue disorders, and general disorders/administration site conditions.
Cycle level results were similar between the two studies, authors of the study noted.
The biosimilar to filgrastim prevented febrile neutropenia in a randomized controlled study and in real-world practice in patients with breast cancer receiving chemotherapy, authors concluded.
“In real-world practice, experiencing adverse events may be perceived as unavoidable in order to achieve clinical efficacy,” they added. “Thus phase III randomized controlled trials remain an effective tool to assess and monitor adverse events.”—Zachary Bessette