Hegg, R., Mattar, A., Matos-Neto, J.N., Pedrini, J.L., Aleixo, S.B., Rocha, R.O., . . . van-Eyll-Rocha, S. (2016). A phase III, randomized, non-inferiority study comparing the efficacy and safety of biosimilar filgrastim versus originator filgrastim for chemotherapy-induced neutropenia in breast cancer patients. Clinics, 71, 586–592.
To compare the efficacy and safety of two filgrastim formulations for controlling chemotherapy-induced neutropenia and to evaluate the noninferiority of the test drug against the original
Patients with grade 4 neutropenia were randomized 1:1 to Eurofarma filgrastim or Roche filgrastim. Doses were administered subcutaneously daily 5 mg/kg until absolute neutrophil count was 10,000/mm3 or greater or until the 15th day of the chemotherapy cycle (V14). Only a single event of febrile neutropenia was considered during the study period per patient. Neutrophil counts were drawn every two days.
Phase III, open-label, noninferiority, randomized, two-group trial
To assess the noninferiority of the test drug to the original the 90% confidence interval for the difference in the rates of grade 4 neutropenia between the two groups were initially calculated.
No significant difference (p = 0.9971) in the rate of grade 4 neutropenia existed in the total number of patients in each group during the first chemotherapy cycle.
Risk of bias (no blinding)
The increased surveillance of patients’ neutrophils may have produced better outcomes. The difference between the two drugs was negligible. Strong patient teaching is warranted, regardless of the process of events during the chemotherapy cycle.