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Pharmacokinetics and efficacy of pegfilgrastim as hematopoietic support for dose-dense every-2-week chemo-immunotherapy with R-CHOP as first-line therapy in elderly patients with diffuse large B cell lymphoma.

17531 Background: Recently, 6 cycles of R-CHOP-14 have been recommended as reference standard for elderly patients with diffuse large B cell lymphoma (Pfreundschuh, 2004). Pegfilgrastim as a pegylated form of G-CSF has been shown to provide rapid neutrophil recovery and facilitate dose dense chemotherapy schedules with a single administration per chemotherapy cycle. The aim of this study was to analyze pharmacokinetics of a single fixed dose of 6 mg of pegfilgrastim per cycle in a homogenous group of elderly patients with diffuse large B cell lymphoma treated with R-CHOP as first-line therapy in two-weekly intervals.


METHODS
Ten patients with diffuse large B cell lymphoma between the age of 60 and 80 years received a single subcutaneous injection of 6 mg pegfilgrastim 24 h after the administration of R-CHOP chemo-immunotherapy, repeated for 6 to 8 cycles in two-weekly intervals. Pegfilgrastim plasma levels as well as absolute neutrophil counts were measured every other day during the first treatment cycle and twice weekly during all consecutive cycles. Incidence and duration of grade 3/ 4 neutropenia, depth of neutrophil nadir and incidence of febrile neutropenia were assessed.


RESULTS
Median age was 73.4 years. A single 6 mg injection of pegfilgrastim 24 h after the administration of CHOP was effective to allow neutrophil recovery in 69 of 70 (98.6%) two-weekly treatment cycles. Median absolute neutrophil nadir was 0.38 G/l on day 9. Grade 3/ 4 granulocytopenia occurred in all ten patients. Mean duration of grade 3/4 neutropenia (< 1.0 G/l) was two days. Febrile neutropenia occurred in one patient. Plasma levels of pegfilgrastim remained elevated during the neutropenic phase. At the start of hematologic recovery, plasma concentrations of pegfilgrastim decreased rapidly as a result of clearance by the neutrophils. Median pegfilgrastim trough plasma level was 0.43 ng/ml on the day preceding the next application.


CONCLUSIONS
A single fixed dose of 6 mg of pegfilgrastim given once per cycle of R-CHOP-14 is effective in supporting neutrophil recovery to safely allow two-weekly drug administration in previously untreated elderly patients with diffuse large B cell lymphoma. [Table: see text].