Risk of chemotherapy-induced febrile neutropenia with early discontinuation of pegfilgrastim prophylaxis in US clinical practice.

PURPOSE: Accumulating evidence suggests that not all cancer chemotherapy patients who receive first-cycle pegfilgrastim prophylaxis continue to receive it in subsequent cycles and that these patients may be subsequently at higher risk of febrile neutropenia (FN). Additional evidence from US clinical practice is warranted. METHODS: Data from two US private healthcare claims repositories were employed. The source population comprised adults who received "intermediate-risk" or "high-risk" chemotherapy regimens for solid cancers or non-Hodgkin's lymphoma and first-cycle pegfilgrastim prophylaxis. From the source population, all patients who did not receive second-cycle pegfilgrastim prophylaxis ("comparison patients") were matched (1:1) to those who received it ("pegfilgrastim patients") based on cancer, regimen, and propensity score. Odds ratios (OR) for FN-broad and narrow definitions-during the second chemotherapy cycle were estimated for comparison patients versus pegfilgrastim patients using generalized estimating equations. RESULTS: A total of 2245 comparison patients (5.3 % of source population) were matched to pegfilgrastim patients; cohorts were well-balanced on baseline characteristics. Second-cycle FN incidence proportions for comparison and pegfilgrastim patients were 3.8 versus 2.2 % based on broad definition and 2.6 versus 0.8 % based on narrow definition; corresponding OR were 1.7 (95 % CI 1.2-2.5, p = 0.002) and 3.5 (95 % CI 2.0-6.0, p < 0.001). Results were similar within cancer/regimen-subgroups and were robust when using alternative methods for confounding adjustment. CONCLUSIONS: In this retrospective evaluation of cancer chemotherapy patients who received first-cycle pegfilgrastim prophylaxis in US clinical practice, a clinically relevant minority did not receive second-cycle prophylaxis. Second-cycle FN odds among this subset were significantly higher than they were among those who continued prophylaxis.

Risk of chemotherapy-induced febrile neutropenia in cancer patients receiving pegfilgrastim prophylaxis: does timing of administration matter?

PURPOSE: Contrary to the approved indication for pegfilgrastim prophylaxis, some patients receive it on the same day as the last administration of chemotherapy in clinical practice, which could adversely impact risk of febrile neutropenia (FN). An evaluation of the timing of pegfilgrastim prophylaxis and FN risk was undertaken. METHODS: A retrospective cohort design and data from two US private health care claims repositories were employed. Study population comprised adults who received intermediate/high-risk chemotherapy regimens for solid tumors or non-Hodgkin's lymphoma (NHL) and received pegfilgrastim prophylaxis in ≥1 cycle; all cycles with pegfilgrastim were pooled for analyses. Odds ratios (OR) for FN during the cycle were estimated for patients who received pegfilgrastim on the same day (day 1) as the last administration of chemotherapy versus days 2-4 from chemotherapy completion. RESULTS: The study population included 45,592 patients who received pegfilgrastim in 179,152 cycles (n = 37,095 in cycle 1); in 12 % of cycles, patients received pegfilgrastim on the same day as chemotherapy. Odds of FN were higher for patients receiving pegfilgrastim prophylaxis on the same day as chemotherapy versus days 2-4 from chemotherapy in cycle 1 (OR = 1.6, 95 % CI = 1.3-1.9, p < 0.001) and all cycles (OR = 1.5, 95 % CI = 1.3-1.6, p < 0.001). CONCLUSIONS: In this large-scale evaluation of adults who received intermediate/high-risk regimens for solid tumors or NHL in US clinical practice, FN incidence was found to be significantly higher among those who received pegfilgrastim prophylaxis on the same day as chemotherapy completion versus days 2-4 from chemotherapy completion, underscoring the importance of adhering to the indicated administration schedule.