The purpose of this study is to provide data on the safety and efficacy of pegfilgrastim when administered on the same day versus the next day of chemotherapy, as measured by the duration of grade 4 neutropenia.

This was a multicenter, double-blind, randomized, phase 2 study of pegfilgrastim given either the same day as or the day after a chemotherapy regimen consisting of cyclophosphamide, doxorubicin, vincristine, prednisone, and rituximab (R-CHOP).

Chemotherapy was administered every 21 days for up to 6 cycles in subjects with aggressive non-Hodgkin's lymphoma (NHL; mantle cell or diffuse large B-cell lymphoma). Subjects were administered R-CHOP on day 1 of each cycle. All subjects were randomized to 1 of 2 treatment arms: arm A subjects were administered pegfilgrastim 6 mg on day 1 of each cycle (within 4 hours of chemotherapy completion); arm B subjects were administered pegfilgrastim 6 mg on day 2 of each cycle (at least 24 hours after chemotherapy completion). All subjects were administered placebo on the day they did not receive pegfilgrastim. A total of 77 subjects were enrolled at 24 centers across the US. Protocol treatment duration for subjects was up to 18 weeks (6 three-week cycles).

Inclusion Criteria: - Histologically proven mantle cell lymphoma or histologically proven diffuse large B-cell non-Hodgkin's lymphoma (NHL) according to the REAL classification - Measurable and/or evaluable disease - Previously untreated patients Exclusion Criteria: - Burkitt's or B-lymphoblastic lymphoma - Central nervous system (CNS) involvement - Active infection requiring treatment with systemic anti-infectives within 72 hours of chemotherapy - Prior malignancy within the last 5 years - T-cell lymphoma or history of indolent lymphoma - Prior bone marrow or stem cell transplantation - Known sensitivity to E. coli derived drug products