Peg-Filgrastim after Autologous Peripheral Blood Stem Cell Transplantation in Hematological Malignancies.

Abstract

ASCO guidelines recommend the use of granulocyte-colony stimulating factors (G-CSF) as adjuvant agents after autologous peripheral blood stem cell transplantation (PBSCT), for shortening the period of severe neutropenia and reducing the related risk of life-threatening infections. The recently available pegylated formulation of G-CSF (peg-filgrastim) could have some potential advantages in phase of recovery after PBSCT, such as self-regulation mechanisms, particularly useful when neutropenia duration is unforeseeable, possible reduction/standardization of growth factor costs and possibility of more manageable outpatient treatments. We investigated the effects of a single s.c. injection of peg-filgrastim (6 mg) on day 3 in 11 patients (8 with multiple myeloma, MM; 2 with non-Hodgkin's lymphomas, NHL; 1 with acute myeloid leukemia, AML) planned to receive autologous PBSCT. Mean age was 55 years (range 24–65). In 7 patients PBSCT was performed as consolidation in first complete or partial remission, while 4 patients received the procedure as salvage treatment for chemo-sensitive disease. Conditioning regimens were intermediate/high dose melphalan in MM, BEAM protocol in NHL and TBI plus cyclophosphamide in AML. For comparison, we selected a group of 11 historical controls matched for age, type and status of disease, conditioning regimen, and number of CD34+ stem cells infused, who had received standard daily s.c. administration of G-CSF (300 mcg/d) from day 5 to neutrophil recovery after autologous PBSCT. No adverse events occurred in patients treated with peg-filgrastim. Bone pain was the only side effect referred by one patient. There was no difference between the two groups in terms of median time to hemoglobin recovery, days of febrile neutropenia and number of red cell or platelet transfusions received. However, the median times to neutrophil > 0.5 x 109/L (10 days, range 9–13 vs 12 days , range 11–14, p < 0.000) and platelet > 20 x 109/L (10 days, range 8–15 vs 13 days, range 12–20, p < 0.003) were significantly shorter in peg-filgrastim group. The median number of G-CSF injections in controls was 12 (range 9–20), so that the mean cost of this drug for single patient was 1,764 euros, as compared to 910 euros for patients receiving peg-filgrastim. We conclude that peg-filgrastim and G-CSF have comparable safety and efficacy profiles in patients affected by hematological malignancies who undergo autologous PBSCT. In this specific setting of patients, peg-filgrastim could be cost-effective. Whether peg-filgrastim may be also superior in reducing the periods of neutropenia and thrombocytopenia, requires to be confirmed and further investigated in larger studies.