Phase II study of a single pegfilgrastim injection as an adjunct to chemotherapy to mobilize stem cells into the peripheral blood of pretreated lymphoma patients

Background and Objectives. The aim of this study was to evaluate the efficacy of pegfilgrastim, in combination with salvage chemotherapy, in mobilizing CD34⁺ stem cells into the peripheral blood of pretreated lymphoma patients. Design and Methods. This was an open-label phase II study including 25 pretreated patients (Hodgkin's disease=4; aggressive non-Hodgkin's lymphoma=21). The primary end-point of the study was the successful mobilization of a target cell dose of 2×10⁶ CD34⁺ cells/kg in lymphoma patients receiving ifosfamide, epirubicin and etoposide (IEV) chemotherapy and a fixed dose (6 mg) of pegfilgrastim given as single subcutaneous injection. Results. Following chemotherapy, all patients had grade 4 neutropenia that lasted a median of 1.5 days (1-3). Pegfilgrastim treatment was well tolerated and only 2/25 patients required pain-control medication. CD34⁺ cells were mobilized in all patients. The median (range) peak value of peripheral blood CD34⁺ cells after IEV chemotherapy and pegfilgrastim was 141×10⁶/L (12.8-386) and occurred almost invariably on day +14 (13-16). Twenty-three of the 25 patients underwent a single standard volume leukapheresis to collect a median of 8.7×10 ⁶ CD34⁺ cells/kg (1.78-17.3). Twenty four/25 patients (96%) reached the target cell dose of 2×10⁶ CD34⁺ cells/kg. High concentrations of circulating CD34⁺ cells (> 50×10⁶/L) were observed for several days after the achievement of the peak value. All the study patients were transplanted with their pegfilgrastim-mobilized CD34⁺ cells and showed a rapid and sustained engraftment after high-dose chemotherapy. Interpretation and Conclusions. Our results show that pegfilgrastim as an adjunct to chemotherapy is a predictable and highly effective mobilization regimen in pretreated lymphoma patients.