Phase II Study of a Single Pegfilgrastim Injection as Adjunct to Chemotherapy to Mobilize Stem Cells into Peripheral Blood of Resistant/Relapsed Lymphoma Patients.

The primary end point of the study was the successful mobilization of a target cell dose of 2 x 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. An open-label phase II study including 25 relapsed or refractory patients (Hodgkin’s disease=4; aggressive non-Hodgkin’s lymphoma=21) was conducted to evaluate the efficacy of pegfilgrastim, in combination with salvage chemotherapy, mobilizing CD34⁺ stem cells into peripheral blood. Following chemotherapy, all patients had grade 4 neutropenia with a median duration 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/microL (12.8–386) and occurred almost invariably on day +14 (13–16). Twenty three/25 patients underwent a single apheresis to collect a median of 8.7 CD34⁺cells/Kg (1.8–17.3). Twenty four/25 patients (96%) reached the target cell dose of 2 x 10⁶ CD34⁺ cells/kg. High concentrations of circulating CD34⁺ cells (> 50/microL) were observed for several days after the achievement of the peak value. All patients have been transplanted with pegfilgrastim-mobilized CD34⁺ cells and all of them showed a rapid and sustained engraftment after high-dose chemotherapy. Our results show that pegfilgrastim as adjunct to chemotherapy is a predictable and highly effective mobilization regimen in lymphoma patients