Open-label, randomized study of pegfilgrastim vs. daily filgrastim as an adjunct to chemotherapy in elderly patients with non-Hodgkin's lymphoma.

Pegfilgrastim is composed of the protein filgrastim to which a 20-kDa polyethylene glycol (PEG) is covalently bound at the N-terminal residue resulting in decreased renal clearance and increased plasma half-life compared with filgrastim. This open-label, randomized, phase 2 study compared two doses of single administration pegfilgrastim (60 and 100 microg/kg) with daily doses of filgrastim (5 microg/kg/day) or no cytokine treatment after standard CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone) chemotherapy for non-Hodgkin's lymphoma in 50 elderly patients. The primary endpoint was the duration of grade 4 (severe) neutropenia (absolute neutrophil count < 0.5 x 10(9)/l) in cycle 1. Duration of grade 4 neutropenia in cycle 1 was 2.2 (SD 1.2), 1.5 (SD 1.1), 0.8 (1.2) and 5.0 (2.0) days for patients who received pegfilgrastim 60 microg/kg, pegfilgrastim 100 microg/kg, filgrastim 5 microg/kg and no cytokine, respectively. The baseline characteristics of the pegfilgrastim and filgrastim groups were imbalanced with increased bone-marrow involvement and prior therapy in the former. When the treatment groups were balanced for these risk factors, duration of grade 4 neutropenia was comparable with 2.0 and 3.0 vs. 0.6 and 0.5 days for pegfilgrastim 100 microg/kg and filgrastim patients with and without these risk factors, respectively. The incidence of febrile neutropenia (defined as ANC < 0.5 x 10(9)/l and temperature > 38.2degrees C) was low (10% of patients). Pegfilgrastim was well tolerated with a safety profile similar to daily filgrastim. Once per chemotherapy cycle administration of pegfilgrastim was comparable to filgrastim in this clinical setting.

A combined analysis of two pivotal randomized trials of a single dose of pegfilgrastim per chemotherapy cycle and daily Filgrastim in patients with stage II-IV breast cancer.

This combined, retrospective analysis compared once-per-chemotherapy-cycle pegfilgrastim with daily Filgrastim in breast cancer patients undergoing myelosuppressive chemotherapy enrolled in two similarly designed, randomized, double-blind, pivotal trials. On day 2 of each chemotherapy cycle, a single subcutaneous (SC) injection of pegfilgrastim [either 6 mg (n=77) or 100 microg/kg (n=149)] was administered, or daily Filgrastim SC injections (5 microg/kg/day; n=222) were initiated and continued until either absolute neutrophil count (ANC) > or =10 x 10(9)/l after the expected nadir or for up to 14 days, whichever occurred first. Individually, each of these trials demonstrated that a single pegfilgrastim injection per cycle is as effective at reducing the duration of severe neutropenia as daily injections of Filgrastim. Clinical efficacy data from the two trials were combined for analysis (n=448). The risk of febrile neutropenia (FN; absolute neutrophil count <0.5 x 10(9)/l with fever > or =38.2 degrees C) was significantly lower [11% vs 19%, respectively; relative risk = 0.56 (95% confidence interval: 0.35, 0.89)] in patients receiving pegfilgrastim than for those receiving Filgrastim. Trends towards lower risks of hospitalization and intravenous anti-infective use were also observed. These observations were consistent irrespective of risk factors, including age, disease stage, performance status and prior treatment. Pegfilgrastim may offer patients more effective protection against neutropenic complications of chemotherapy with fewer injections and less disruption to their lives.