Chan, A., Leng, X.Z., Chiang, J.Y., Tao, M., Quek, R., Tay, K., & Lim, S.T. (2011). Comparison of daily filgrastim and pegfilgrastim to prevent febrile neutropenia in Asian lymphoma patients. Asia-Pacific Journal of Clinical Oncology, 7, 75–81.

The study aim was to compare the effectiveness of primary prophylaxis with filgrastim and pegfilgrastim to prevent the incidence of febrile neutropenia in Asian patients with cancer undergoing chemotherapy.  

Data analyzed on intent-to-treat basis from January 2008 and August 2009 identified from the pharmacy prescription database. The G-CSF must have been administered at least 24 hours after chemotherapy administration for primary prophylaxis against febrile neutropenia. Crossover between the two G-CSFs was allowed and the patient was assigned to the treatment group according to the G-CSF used with the first cycle.

• 204 total patients were examined
• 81 received filgrastim, and 123 received pegfilgrastim
• Mean age was 56.7 years (SD = 13.1)  in the  filgrastim group and 55.3 (SD = 14.8) years in the pegfilgrastim group.
• Males outnumbered females, 54% to 46%, respectively
• Patients with non-Hodgkin lymphoma  who underwent chemotherapy
• Primary prophylaxis with filgrastim and pegfilgrastim
   

• Single site  
• Setting type was not specified 
• Location was Singapore
   

Active treatment

Single-center, retrospective study

• Primary end point: Incidence of febrile neutropenia defined as temperature 38.3°C or greater and absolute neutrophil count (ANC) less than 500 mcl.     
• Secondary endpoints: Dose delay of more than three days days or dose reduction of 15% or greater  in subsequent chemotherapy cycles
   

During the first cycle of chemotherapy, six (7.4%) and 11 (8.9%) patients developed FN in the filgrastim and pegfilgrastim arms, respectively (p = 0.8). Across all cycles of chemotherapy treatments, the overall incidence of FN in both arms was much higher than in the first cycle. However, the incidence of FN between the filgrastim group and the pegfilgrastim group remained similar (13.6% in the filgrastim arm versus 16.3% in the pegfilgrastim arm; p = 0.69) across all cycles. More patients in the filgrastim arm experienced treatment delays (8.6%) and chemotherapy dose reductions (4.9%) compared to those who were administered pegfilgrastim (incidence of dose delay = 5.7%, p = 0.25; incidence of dose reduction = 3.3%, p = 0.45) during the first cycle. However, these differences were not statistically significant. The cumulative occurrences of dose delays or dose reductions in all cycles were higher among patients who received pegfilgrastim (absolute difference of dose delay = 2.7%, p = 0.71; absolute difference of dose reduction = 0.7%, p = 1.00). Across all cycles, for regimens that possess a FN risk below 20%, a lower incidence of FN was observed in patients who received filgrastim than those who received pegfilgrastim (12.2 versus 21.4%, respectively; p = 0.31). Similar trends also were observed with the cumulative incidence of treatment delay and chemotherapy dose reduction: patients receiving pegfilgrastim were more likely to suffer from the complications of FN. With regards to the chemotherapy regimens that possess FN risk of 20% or greater, the incidence of FN, treatment delays, and dose reductions all were  similar in both treatment arms (absolute difference in the incidence of FN = 5.6%, p = 0.52; absolute difference in the incidence of dose delays = 0.5%, p = 1.00; absolute difference in the incidence of dose reductions = 4.3%, p = 0.46).

There was no statistically significant difference between filgrastim and pegfilgrastim for the primary prophylaxis of febrile neutropenia in Asian patients undergoing chemotherapy. There was no statistically significant difference between filgrastim and pegfilgrastim with regard to the incidence of dose delays or dose reductions.

Retrospective study that relied on the accuracy of the medical records reviewed.

Filgrastim and pegfilgrastim are equally effective to prevent chemotherapy-induced febrile neutropenia and to prevent dose delays and dose reductions in subsequent cycles.