Use of filgrastim for stem cell mobilisation and transplantation in high-dose cancer chemotherapy

Signaling through TLR5 mitigates lethal radiation damage by neutrophil-dependent release of MMP-9

Acute radiation syndrome (ARS) is a major cause of lethality following radiation disasters. A TLR5 agonist, entolimod, is among the most powerful experimental radiation countermeasures and shows efficacy in rodents and non-human primates as a prophylactic (radioprotection) and treatment (radiomitigation) modality. While the prophylactic activity of entolimod has been connected to the suppression of radiation-induced apoptosis, the mechanism by which entolimod functions as a radiomitigator remains poorly understood. Uncovering this mechanism has significant and broad-reaching implications for the clinical development and improvement of TLR5 agonists for use as an effective radiation countermeasure in scenarios of mass casualty resulting from accidental exposure to ionizing radiation. Here, we demonstrate that in contrast to radioprotection, neutrophils are essential for the radiomitigative activity of entolimod in a mouse model of lethal ARS. Neutrophils express functional TLR5 and rapidly exit the bone marrow (BM), accumulate in solid tissues, and release MMP-9 following TLR5 stimulation which is accompanied by an increase in the number of active hematopoietic pluripotent precursors (HPPs) in the BM. Importantly, recombinant MMP-9 by itself has radiomitigative activity and, in the absence of neutrophils, accelerates the recovery of the hematopoietic system. Unveiling this novel TLR5-neutrophil-MMP-9 axis of radiomitigation opens new opportunities for the development of efficacious radiation countermeasures to treat ARS following accidental radiation disasters.

Differential role of r-met-hu G-CSF on male reproductive function and development in prepubertal domestic mammals

The understanding of mammalian spermatogenesis niche factors active during sexual development may be leveraged to impact reproduction in farm animals. The aim of this study was to evaluate the effects of r-met-hu/G-CSF (filgrastim) on prepubertal sexual development of guinea pigs (Cavia porcellus) and ram lambs (Ovis aries). Individuals of both species were administered r-met-hu/G-CSF daily for 4 days. During and after administration protocols, testicular function and development were assessed through hematological responses, hormonal profiles (gonadotropins, testosterone and cortisol) testicular morphometry and germ cell kinetics. As expected, r-met-hu/G-CSF acutely mobilized white-lineage blood cells in both species. LH was increased by r-met-hu/G-CSF in guinea pigs (P<0.01) but T remained unchanged. In ram lambs gonadotropins and T increased in dose-response fashion (P<0.01) while cortisol values were stable and similar in treated and control animals (P>0.05). In guinea pigs there were no differences in testicular weights and volumes 2-mo after r-met-hu/G-CSF application (P>0.05). However, ram lambs showed a dose-response effect regarding testis weight (P<0.05). 66.66% of ram lambs had initial testes not yet in meiosis or starting the first spermatogenic wave. After 60-days only 25% of control animals were pubertal while all treated animals (1140-μg) had reached puberty. We propose an integrated hypothesis that G-CSF can stimulate spermatogenesis through two possible ways. 1) r-met-hu/G-CSF may go through the brain blood barrier and once there it can stimulate GnRH-neurons to release GnRH with the subsequent release of gonadotrophins. 2) a local testicular effect through stimulation of steroidogenesis that enhances spermiogenesis via testosterone production and a direct stimulation over spermatogonial stem cells self-renewal. In conclusion, this study shows that r-met-hu/G-CSF differentially affects prepubertal sexual development in hystricomorpha and ovine species, a relevant fact to consider when designing methods to hasten sexual developmental in mammalian species.

Mobilization and collection of CD34(+) cells for autologous transplantation of peripheral blood hematopoietic progenitor cells in children: analysis of two different granulocyte-colony stimulating factor doses

INTRODUCTION

The use of peripheral hematopoietic progenitor cells (HPCs) is the cell choice in autologous transplantation. The classic dose of granulocyte-colony stimulating factor (G-CSF) for mobilization is a single daily dose of 10μg/kg of patient body weight. There is a theory that higher doses of granulocyte-colony stimulating factor applied twice daily could increase the number of CD34(+) cells collected in fewer leukapheresis procedures.

OBJECTIVE

The aim of this study was to compare a fractionated dose of 15μg G-CSF/kg of body weight and the conventional dose of granulocyte-colony stimulating factor in respect to the number of leukapheresis procedures required to achieve a minimum collection of 3×10(6) CD34(+) cells/kg body weight.

METHODS

Patients were divided into two groups: Group 10 - patients who received a single daily dose of 10μg G-CSF/kg body weight and Group 15 - patients who received a fractioned dose of 15μg G-CSF/kg body weight daily. The leukapheresis procedure was carried out in an automated cell separator. The autologous transplantation was carried out when a minimum number of 3×10(6) CD34(+) cells/kg body weight was achieved.

RESULTS

Group 10 comprised 39 patients and Group 15 comprised 26 patients. A total of 146 apheresis procedures were performed: 110 (75.3%) for Group 10 and 36 (24.7%) for Group 15. For Group 10, a median of three (range: 1-7) leukapheresis procedures and a mean of 8.89×10(6) CD34(+) cells/kg body weight (±9.59) were collected whereas for Group 15 the corresponding values were one (range: 1-3) and 5.29×10(6) cells/kg body weight (±4.95). A statistically significant difference was found in relation to the number of apheresis procedures (p-value <0.0001).

CONCLUSIONS

To collect a minimum target of 3×10(6) CD34(+) cells/kg body weight, the administration of a fractionated dose of 15μg G-CSF/kg body weight significantly decreased the number of leukapheresis procedures performed.

Chemotherapy-Induced Neutropenia in HIV Positive Patients with Lymphoma: Comparison of Pegfilgrastim with Daily Filgrastim Administration

We retrospectively compared the incidence of neutropenia in two groups of HIV patients with lymphoma, who underwent chemotherapy supported by once-per-cycle administration of pegfilgrastim or by daily subcutaneous injection of filgrastim, respectively. Our findings indicate that pegfilgrastim and filgastrim produce similar results in preventing both neutropenia and febrile neutropenia.

Review and revision of clinical practice of using G-CSF after autologous and allogeneic hematopoietic stem cell transplantation at UCSD

There was no consensus on the optimal use of G-CSF after hematopoietic stem cell transplantation. In this study, the practice of using G-CSF, based on the CD34(+) cell number, at the University of California, San Diego Blood and Marrow Transplant Unit (UCSD BMT) was evaluated by performing a five-year retrospective analysis of data from patients undergoing autologous and allogeneic transplantation. Various outcomes, such as time to neutrophil and platelet engraftment and length of post-transplant hospital stay are assessed in relation to use of G-CSF and number of CD34(+) cells infused. It has been found that the use of G-CSF is associated with faster neutrophil engraftment and shorter length of post-transplant hospital stay without affecting time to platelet engraftment in patients undergoing autologous transplantation. In addition, the number of CD34(+) cells do not influence outcomes in autologous and allogeneic transplant patients if they are treated with G-CSF. As a result of this evaluation, the G-CSF protocol at UCSD BMT Unit is revised. The main change is to implement the use of G-CSF in all patients undergoing autologous transplantation regardless of the number of CD34( +) cells. No changes in the allogeneic transplantation protocol are made as a result of this analysis.

Optimal use of G-CSF administration after hematopoietic SCT

After hematopoietic SCT (HSCT), G-CSF is commonly used to enhance stem cell engraftment to minimize the morbidity and mortality associated with prolonged neutropenia. However, there is no consensus on the optimal use of G-CSF after high-dose chemotherapy followed by HSCT. This review was performed to evaluate the evidence regarding the use of G-CSF after autologous and allogeneic HSCT. Studies investigating the use of G-CSF in comparison to control (observation or placebo), early vs delayed initiation of G-CSF, and other approaches driven by patient-specific parameters to identify optimal use of G-CSF have been reviewed. Various outcomes such as neutrophil and platelet engraftment, post-transplant length of hospital stay, post-transplant complications such as infection and GVHD, and survival have been assessed. Finally, we provide the level of evidence for each of the outcomes analyzed while evaluating strategies for using G-CSF in patients undergoing autologous or allogeneic HSCT.

Efficacy of single dose pegfilgrastim in enhancing the mobilization of CD34+ peripheral blood stem cells in aggressive lymphoma patients treated with cisplatin-aracytin-containing regimens

Systematic data on the ability of pegfilgrastim to mobilize stem cells after chemotherapy are scarce. We evaluated the efficacy of a single 6 mg dose of pegfilgrastim for mobilizing peripheral blood stem cells (PBSC) in aggressive lymphoma patients. Between July 2004 and October 2005, 17 aggressive non-Hodgkin's lymphoma and 11 poor-risk Hodgkin's lymphoma were treated with cycles containing cisplatin-aracytin. At the end of chemotherapy, the patients received 6 mg of pegfilgrastim. Duration of grade 4 neutropenia, adverse events, time to neutrophil recovery, peak and harvest of CD34+ cells were recorded. Twenty-seven out of 28 patients harvested a median of 17.3 x 10(6)/CD34+ cells (range 2.5-28.9) after a median of 9 days (range 8-12 days), with a single apheresis procedure in 25 cases. All patients had grade 3-4 neutropenia, median duration 3 days. The only adverse event was mild bone pain. To date, 13 patients have been autografted with a median of 15.4 x 10(6) CD34+ pegfilgrastim-mobilized cells per kg (range 2.5-28.9) with rapid and sustained engraftment. Mobilization, harvesting and autografting of pegfilgrastim-mobilized PBC can be successfully achieved in pretreated patients with aggressive lymphoma.

Evidence-based guidelines for the management of neutropenia following outpatient hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) involves the transfer of stem cells to establish hematopoiesis in patients who have received myeloablative chemotherapy with or without whole body irradiation. Following high-dose therapy and HSCT, all patients experience a period of neutropenia. Outpatient care delivery models place expanded responsibilities on patients and their families for the management of this treatment side effect. Proactive management of neutropenia is critical to decrease the depth and duration of neutropenia following HSCT, limit exposure to opportunistic and nosocomial pathogens, and ensure prompt intervention should febrile neutropenia or infection develop. Patient and family education, psychosocial support, and coordination of care are key nursing responsibilities.