Pegfilgrastim compared to lenograstim after allogeneic peripheral blood stem-cell transplantation from unrelated donors

[Comparative study on the efficacy and safety between pegfilgrastim (PEG-rhG-CSF) and recombinant human granulocyte colony-stimulating factor in promoting hematopoietic recovery after allogeneic hematopoietic stem cell transplantation after hematological malignancy]

Objective: To observe the efficacy and safety between Pegfilgrastim (PEG-rhG-CSF) and Recombinant human granulocyte colony stimulating factor (rhG-CSF) in hematological malignancy after allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Methods: 157 patients after allo-HSCT were enrolled in this study from June 2015 to November 2016. Two agents of G-CSF were used to stimulate hematopoietic recovery after transplantation. There were 65 cases in PEG-rhG-CSF and 92 cases in rhG-CSF groups. Patients in PEG-rhG-CSF group were given a single subcutaneous dose of 6 mg on the first day and +8 d, while cases in rhG-CSF group were given in dose of 5 μg·kg(-1)·d(-1) by subcutaneous injection from +1 d continuing to neutrophils more than 1.5×10(9)/L, and then the indicators and survival rates in two groups after transplantation were compared. Results: ①There were no significant differences of the neutrophil implantation time[13.5 (8-12) d vs 13 (9-24) d, P=0.393] and platelet implantation time [14 (9-160) d vs 14 (9-92) d, P=0.094] between PEG-rhG-CSF and rhG-CSF groups respectively. There were no significant differences in terms of neutropenia period (P=0.435) , number of cases who got fever during neutropenia (P=0.622) , and the median time of fever in neutropenia period (P=0.460) , respectively between the two groups. There were no significant differences of erythrocyte and platelet transfusions (P=0.074, P=0.059) within 1 month after transplantation. ②There were no significant differences with regard to the incidences of acute GVHD[23.1% (15/65) vs 34.8% (32/92) , P=0.115], chronic GVHD[20.0% (13/65) vs 32.6% (32/92) , P=0.081], Ⅱ-Ⅳdegree of acute GVHD[30.0% (13/65) vs 30.4% (30/92) , P=0.287] and extensive chronic GVHD[9.2% (6/65) vs 20.7% (19/92) , P=0.135] between PEG-rhG-CSF and rhG-CSF groups. ③There were no significant differences in terms of disease free survival (DFS) (62.5% vs 61.4%, P=0.478) and overall survival (OS) (67.4% vs 67.3%, P=0.718) between PEG-rhG-CSF and rhG-CSF groups. ④There was no significant difference of the non-relapse mortality (NRM) between PEG-rhG-CSF and rhG-CSF groups[20.5% (95%CI 11.4%-37.0%) vs 32.6% (95%CI 22.2%-47.9%) , P=0.141]. The relapse rate was not statistically significant[14.9% (95%CI 7.4%-29.8%) vs 10.0% (95%CI 5.0%-20.0%) , P=0.299]. Conclusion: Compared with rhG-CSF, PEG-rhG-CSF could reduce the times of injection. There were no differences in terms of hematopoietic recovery, the incidence of GVHD, relapse rate, DFS and OS rates after allo-HSCT between two groups.

Design Rationale and Development Approach for Pegfilgrastim as a Long-Acting Granulocyte Colony-Stimulating Factor

Filgrastim, a recombinant methionyl human granulocyte colony-stimulating factor (G-CSF) (r-metHuG-CSF), is efficacious in stimulating neutrophil production and maturation to prevent febrile neutropenia (FN) in response to chemotherapy. Because of its relatively short circulating half-life, daily filgrastim injections are required to stimulate neutrophil recovery. In an effort to develop a long-acting form of filgrastim that was as safe and efficacious as filgrastim but had a longer in vivo residence time, a number of strategies were considered. Ultimately, fusion of filgrastim to polyethylene glycol (PEG) was selected. Following extensive analysis of conjugation chemistries as well as in vitro and in vivo characterization of a panel of PEGylated proteins, a construct containing a 20 kDa PEG moiety covalently conjugated to the N-terminus of filgrastim was chosen for advancement as pegfilgrastim. Pegfilgrastim is primarily cleared by neutrophils and neutrophil precursors (rather than the kidneys), meaning that clearance from the circulation is self-regulating and pegfilgrastim is eliminated only after neutrophils start to recover. Importantly, addition of PEG did not alter the mechanism of action and safety profile compared to filgrastim. Clinical evaluation revealed that a single 6 mg dose effectively reduces the duration of neutropenia and risk of FN in patients receiving chemotherapy. This work demonstrates the benefit of using PEGylation to generate pegfilgrastim, which allows for once-per-chemotherapy cycle administration while maintaining similar safety and efficacy profiles as those for multiple daily administration of filgrastim. Approaches that may provide advances for therapeutic agonists of G-CSF receptor are also discussed.

Prevention of febrile neutropenia in chemotherapy-treated cancer patients: Pegylated versus standard myeloid colony stimulating factors. Do we have a choice?

The pertinent literature on clinical studies comparing the respective value of myeloid colony stimulating factors to pegfilgrastim as a prevention of febrile neutropenia in chemotherapy-treated cancer patients has been reviewed. Pegfilgrastim is definitely not inferior to filgrastim or other myeloid colony stimulating agents with respect to duration of grade IV neutropenia and delivery of full chemotherapy dose on time; several comparative studies indicate a trend to less frequent febrile neutropenia with pegfilgrastim.