Treatment of chemotherapy-induced neutropenia by subcutaneously administered granulocyte colony-stimulating factor with optimization of dose and duration of therapy

Pegfilgrastim in Supportive Care of Hodgkin Lymphoma

Simple Summary

Pegfilgrastim, the pegylated form of filgrastim (recombinant human GCSF) is widely adopted as supportive care for preventing neutropenia or febrile neutropenia episodes during chemotherapy. Neutropenia is directly cause of potentially severe infections and indirectly cause of treatment delivery delay. No guidelines address the pegfilgrastim role in the specific setting of Hodgkin lymphoma (HL). Since HL is a young-adult disease and shows mostly a very a favorable outcome after chemotherapy, treatment delay or dose reduction could potentially affect negatively the outcome. The aim of our review is to explore the current scientific literature on pegfilgratim use in HL, evaluating both observational than prospective trial. Moreover, analyzing the latter, we aim to define some practical suggestion about primary prophylaxis with pegfilgrastim in HL.

Abstract

Neutropenia and febrile neutropenia are common and potentially life-threating events associated with chemotherapy treatment in Hodgkin lymphoma (HL). Neutropenia-related infectious events could be an issue both for direct clinical consequences and for delay in treatment delivery, affecting final outcomes in a potentially highly curable disease. Pegfilgrastim is the pegylated form of filgrastim, the recombinant form of human G-CSF, capable of prevent and mitigate neutropenic effects of chemotherapy, when adopted as primary prophylaxis in several hematological malignancies. No updated version of major international guidelines provides clear indication on prophylaxis use of pegfilgrastim in HL to prevent febrile neutropenia episodes in HL. Moreover, to date, scarce and non-uniform clinical experiences evaluating pegfilgrastim as prophylaxis in HL are present in the literature. Herein, we propose a brief summary of the literature data about efficacy and safety of the use of pegfilgrastim as primary prophylaxis in HL during chemotherapy treatment.

Pegfilgrastim for primary prophylaxis of febrile neutropenia in multiple myeloma

Multiple myeloma (MM) survival rates have been substantially increased thanks to novel agents that have improved survival outcomes and shown better tolerability than treatments of earlier years. These new agents include immunomodulating imide drugs (IMiD) thalidomide and lenalidomide, the proteasome inhibitor bortezomib (PI), recently followed by new generation IMID pomalidomide, monoclonal antibodies daratumumab and elotuzumab, and next generation PI carfilzomib and ixazomib. However, even in this more promising scenario, febrile neutropenia remains a severe side effect of antineoplastic therapies and can lead to a delay and/or dose reduction in subsequent cycles. Supportive care has thus become key in helping patients to obtain the maximum benefit from novel agents. Filgrastim is a human recombinant subcutaneous preparation of G-CSF, largely adopted in hematological supportive care as "on demand" (or secondary) prophylaxis to recovery from neutropenia and its infectious consequences during anti-myeloma treatment. On the contrary, pegfilgrastim is a pegylated long-acting recombinant form of granulocyte colony-stimulating factor (G-CSF) that, given its extended half-life, can be particularly useful when adopted as "primary prophylaxis," therefore before the onset of neutropenia, along chemotherapy treatment in multiple myeloma patients. There is no direct comparison between the two G-CSF delivery modalities. In this review, we compare data on the two administrations' modality, highlighting the efficacy of the secondary prophylaxis over multiple myeloma treatment. Advantage of pegfilgrastim could be as follows: the fixed administration rather than multiple injections, reduction in neutropenia and febrile neutropenia rates, and, finally, a cost-effectiveness advantage.

Neuroprotection through G-CSF: recent advances and future viewpoints

Granulocyte-colony stimulating factor (G-CSF), a member of the cytokine family of hematopoietic growth factors, is 19.6 kDa glycoprotein which is responsible for the proliferation, maturation, differentiation, and survival of neutrophilic granulocyte lineage. Apart from its proven clinical application to treat chemotherapy-associated neutropenia, recent pre-clinical studies have highlighted the neuroprotective roles of G-CSF i.e., mobilization of haemopoietic stem cells, anti-apoptotic, neuronal differentiation, angiogenesis and anti-inflammatory in animal models of neurological disorders. G-CSF is expressed by numerous cell types including neuronal, immune and endothelial cells. G-CSF is released in autocrine manner and binds to its receptor G-CSF-R which further activates numerous signaling transduction pathways including PI3K/AKT, JAK/STAT and MAP kinase, and thereby promote neuronal survival, proliferation, differentiation, mobilization of hematopoietic stem and progenitor cells. The expression of G-CSF receptors (G-CSF-R) in the different brain regions and their upregulation in response to neuronal insult indicates the autocrine protective signaling mechanism of G-CSF by inhibition of apoptosis, inflammation, and stimulation of neurogenesis. These observed neuroprotective effects of G-CSF makes it an attractive target to mitigate neurodegeneration associated with neurological disorders. The objective of the review is to highlight and summarize recent updates on G-CSF as a therapeutically versatile neuroprotective agent along with mechanisms of action as well as possible clinical applications in neurodegenerative disorders including AD, PD and HD.

Differential role of segments of α-mating factor secretion signal in Pichia pastoris towards granulocyte colony-stimulating factor emerging from a wild type or codon optimized copy of the gene

BACKGROUND

The methylotrophic yeast, Pichia pastoris has been widely used for the production of human therapeutics, but production of granulocyte colony-stimulating factor (G-CSF) in this yeast is low.The work reported here aimed to improve the extracellular production of G-CSF by introducing mutations in the leader sequence and using a codon optimized copy of G-CSF. Bioinformatic analysis was carried out to propose an explanation for observed effect of mutations on extracellular G-CSF production.

RESULTS

Mutations in the pro-region of the α-mating type (MAT) secretory signal, when placed next to a codon optimized (CO)-GCSF copy, specifically, the Δ57-70 type, led to highest G-CSF titre of 39.4 ± 1.4 mg/L. The enhanced effect of this deletion was also observed when it preceded the WT copy of the gene. Deletion of the 30-43 amino acids in the pro-peptide, fused with the wild type (WT)-GCSF copy, completely diminished G-CSF secretion, while no effect was observed when this deletion was in front of the CO-GCSF construct. Also, Matα:Δ47-49 deletion preceding the WT-GCSF dampened the secretion of this protein, while no effect was seen when this deletion preceded the CO-GCSF copy of the gene. This indicated that faster rates of translation (as achieved through codon optimization) could overcome the control exercised by these segments. The loss of secretion occurring due to Δ30-43 in the WT-GCSF was partially restored (by 60%) when the Δ57-70 was added. The effect of Δ47-49 segment in the WT-GCSF could also be partially restored (by 60%) by addition of Δ57-70 indicating the importance of the 47-49 region. A stimulatory effect of Δ57-70 was confirmed in the double deletion (Matα:Δ57-70;47-49) construct preceding the CO-GCSF. Secondary and tertiary structures, when predicted using I-TASSER, allowed to understand the relationship between structural changes and their impact on G-CSF secretion. The Δ57-70 amino acids form a major part of 3rd alpha-helix in the pre-pro peptide and its distortion increased the flexibility of the loop, thereby promoting its interaction with the cargo protein. A minimum loop length was found to be necessary for secretion. The strict control in the process of secretion appeared to be overcome by changing the secondary structures in the signal peptides. Such fine tuning can allow enhanced secretion of other therapeutics in this expression system.

CONCLUSIONS

Among the different truncations (Matα:Δ57-70, Matα:Δ47-49, Matα:Δ30-43, Matα:Δ57-70;30-43, Matα:Δ57-70;47-49) in pro-peptide of α-MAT secretion signal, Matα:Δ57-70 fused to CO-GCSF, led to highest G-CSF titre as compared to other Matα truncations. On the other hand, Matα:Δ30-43 and Matα:Δ47-49 fused to the WT-GCSF dampened the secretion of this protein indicating important role of these segments in the secretion of the cargo protein.

Review of oncological emergencies in small animal patients

Oncological emergencies can occur at any time during the course of a malignancy and need to be recognized promptly to maximize successful outcomes. Emergencies are characterized as chemotherapy-induced, paraneoplastic syndromes, or directly related to the neoplasm. Prompt identification with treatment of these emergencies can prolong survival and improve quality of life, even in the setting of terminal illness. This review aims to educate the reader on the pathophysiology, clinical presentation and treatment of some of these emergencies, and to review the current veterinary literature to help educate veterinarians in primary and tertiary facilities to know how to diagnose and treat these serious conditions.

The Role of Granulocyte Colony-Stimulating Factor (Filgrastim) in Maintaining Dose Intensity during Conventional-Dose Chemotherapy with Abvd in Hodgkin's Disease

Background

The aim of the study was to evaluate the role and potential benefit of granulocyte colony-stimulating factor (G-CSF, Filgrastim), administered following cytotoxic chemotherapy with the ABVD regimen in Hodgkin's disease, in maintaining cycle schedule and dose intensity and in decreasing neutropenia and number of infections.

Patients and Methods

Twenty-two patients affected by high-risk Hodgkin's disease (14 localized and 8 diffuse), aged 15 to 69 years (median, 34), were given ABVD chemotherapy for a total of 6 courses (for the purpose of this study, each single course of chemotherapy was considered as two 15-day periods). No patient was given G-CSF after the first cycle. After each cycle, G-CSF was administered only for: 1) absolute neutrophil count < 1 × 109/L between cycles; 2) delay in cycle schedule due to an absolute neutrophil count < 1 × 109/L on the planned day of treatment; or 3) fever or a documented infection, regardless the absolute neutrophil count. Once administered, G-CSF was maintained in the subsequent cycles.

Results

Seventeen of 22 patients (77%) required the administration of G-CSF (5 μg/kg b.w.; a median of 5 doses/cycle); most of them (13/17) before the 5th dose of chemotherapy. The main reason for introducing G-CSF into therapy was neutropenia during the interval between courses (n = 4) or on the planned day of treatment (n = 11). Comparing 112 courses where G-CSF was not administered with 124 where it was, in the latter group we observed: 1) a significantly lower (P = 0.0002) incidence of cycle delays (0 vs 13), with a median delay of 7 days (5 to 11). The main reason for cycle delay was neutropenia (n = 13); 2) a greater dose intensity delivered to the patients while on G-CSF (100% vs 95.2±8.8%; P = 0.0001); 3) an absolute neutrophil count significantly higher at day 8 (P<0.0001) and day 15 (P< 0.0001); 4) a significantly lower (P = 0.0003) incidence of neutropenia (2 vs. 17). No difference in the incidence of infections was observed between the two groups of cycles (P = 0.5889), but the duration and severity of the same were greater during chemotherapy without G-CSF, requiring antibiotic therapy and causing cycle delay.

Conclusions

In conclusion, our data suggest the use of Filgrastim in Hodgkin's disease also during conventional-dose chemotherapy with ABVD. It is not required from the first dose of therapy, but as soon as neutropenia appears between cycles or on the planned day of treatment. Then, its use allows maintenance of the chemotherapy schedule and dose intensity. It also decreases frequency, duration and severity of neutropenia and its sequelae.

TLR2 agonism reverses chemotherapy-induced neutropenia in Macaca fascicularis

Neutropenia is a common consequence of radiation and chemotherapy in cancer patients. The resulting immunocompromised patients become highly susceptible to potentially life-threatening infections. Granulocyte colony-stimulating factor (G-CSF) is known to stimulate neutrophil production and is widely used as a treatment of chemotherapy-induced neutropenia. A small-molecule G-CSF secretagogue without a requirement for refrigerated supply chain would offer a more convenient and cost-effective treatment of chemotherapy-induced neutropenia. Bacterial lipopeptides activate innate immune responses through Toll-like receptor 2 (TLR2) and induce the release of cytokines, including G-CSF, from macrophages, monocytes, and endothelial. Pam₂CSK₄ is a synthetic lipopeptide that effectively mimics bacterial lipoproteins known to activate TLR2 receptor signaling through the TLR2/6 heterodimer. Substrate-based drug design led to the discovery of GSK3277329, which stimulated the release of G-CSF in activated THP-1 cells, peripheral blood mononuclear cells, and human umbilical vein endothelial cells. When administered subcutaneously to cynomolgus monkeys (Macaca fascicularis), GSK3277329 caused systemic elevation of G-CSF and interleukin-6 (IL-6), but not IL-1β or tumor necrosis factor α, indicating a selective cytokine-stimulation profile. Repeat daily injections of GSK3277329 in healthy monkeys also raised circulating neutrophils above the normal range over a 1-week treatment period. More importantly, repeated daily injections of GSK3277329 over a 2-week period restored neutrophil loss in monkeys given chemotherapy treatment (cyclophosphamide, Cytoxan). These data demonstrate preclinical in vivo proof of concept that TLR2 agonism can drive both G-CSF induction and subsequent neutrophil elevation in the cynomolgus monkey and could be a therapeutic strategy for the treatment of chemotherapy-induced neutropenia.

Impact of recommended weight-based dosing of granulocyte-colony stimulating factors in acute leukemia and stem cell transplant patients

PURPOSE

Febrile neutropenia (FN) is a major risk factor for infection-related morbidity and mortality. The National Comprehensive Cancer Network recommends the prophylactic use of granulocyte-colony stimulating factors (G-CSF), dosed at 5 mcg/kg and rounded to the nearest vial size. A previous medication use evaluation conducted within a multi-hospital healthcare system demonstrated that only 67% of patients were started on appropriate weight-based dosing. The purpose of this study was to evaluate the effect of appropriate weight-based G-CSF dosing in patients on clinical outcomes.

METHODS

A retrospective chart review of patients with acute leukemia or stem cell transplant recipients who received G-CSF from May 2009 to September 2015 was conducted. Patient admissions were reviewed in regards to neutropenia length, incidence of FN, length of stay, and final disposition (alive or deceased). Admissions were divided into one of three weight-based dosing groups of under 5 mcg/kg, recommended 5 mcg/kg within a 10% range, and over 5 mcg/kg which were named under, recommended, and over, respectively.

RESULTS

Ninety-four admissions were included. Average age of this patient population was 58 years old, and the majority of patients were male (53%) and Caucasian (55%). Majority of patients had been diagnosed with acute myeloid leukemia (91%). Data showed average duration of neutropenia was around 10 days regardless if the patient received under 5 mcg/kg, the recommended 5 mcg/kg or over 5 mcg/kg G-CSF (10.1 ± 6.7 days, 8.9 ± 9.2 days, 10.1 ± 9.1 days, respectively). Length of stay was similar for patients regardless of initial G-CSF dose (29.6 ± 16.0 days, 29.1 ± 18.4 days, and 24.5 ± 17.0, respectively). However, the incidence of FN was significantly greater for those who received under 5 mcg/kg of G-CSF (87% for under, 68% for recommended, and 54% for over).

CONCLUSIONS

In this retrospective analysis, variations from the recommended 5 mcg/kg G-CSF dose did not significantly impact length of neutropenia, length of stay, nor mortality. However, patients who received under the 5 mcg/kg of G-CSF dose may be at a greater risk of FN.

A clinical and economic drug usage evaluation of prophylactic G-CSF in non-Hodgkin's lymphoma

Objective. To identify if prophylactic granulocyte colony-stimulating factor (G-CSF) delivers the same clinical outcome and level of cost-effectiveness in general clinical use as it has under controlled clinical trial conditions in patients with non-Hodgkin's lym phoma.

Method. A 6-month prospective study of all patients eligible to receive prophylactic G-CSF for supportive treatment for non-Hodgkin's lymphoma was performed. Outcomes measured included occur rence of febrile neutropenia, length of hospital stay, and cost of admission. The critical values of key pharmacoeconomic parameters were calculated for this patient group and compared with the actual values obtained.

Results. The use of G-CSF in all 99 courses, for 35 patients, complied with funding guidelines. Pro phylactic G-CSF was prescribed most frequently for chemotherapy courses which were most likely to result in febrile neutropenia. The percentage of che motherapy courses associated with febrile neutrope nia in patients who did not receive G-CSF increased significantly with treatment intensity. Prophylactic G-CSF appeared to be cost-effective for patients re ceiving high intensity chemotherapy but not for other patients.

Conclusion. Clinicians at our institute use G- CSF where clinical benefits are most likely to be obtained. The use of prophylactic G-CSF is more cost-effective than using therapeutic G-CSF to treat febrile neutropenia in high risk patients. The contin ued funding of prophylactic G-CSF for non-Hodgkin's lymphoma is justified clinically and economically in patients receiving intensive chemotherapy.

An evaluation of the stability of granulocyte colony stimulating factor on short-term storage and delivery from an elastomeric infusion system

Aim. To evaluate the stability of granulocyte col ony stimulating factor (G-CSF) (lenograstim) on the 14-day storage and delivery from an elastomeric infusion system (infusion device).

Methods. Infusion devices were filled with two different concentrations of G-CSF and stored for various times at 4°C under sterile conditions. Samples of G-CSF solution were then released through the infusion device and bioassayed on the G-CSF dependent murine cell line G-NFS-60.

Results. There was no statistically significant loss of bioactivity of G-CSF throughout storage and delivery from the devices for the maximum 14-day period tested at either concentration of G-CSF.

Conclusion. The devices can be filled with G-CSF and stored at 4°C for up to 14 days under sterile conditions without loss of biological activ ity, suggesting that these devices are compatible with this biological material and suitable for its short-term storage.

Associations between hematopoietic growth factors and risks of venous thromboembolism, stroke, ischemic heart disease and myelodysplastic syndrome: findings from a large population-based cohort of women with breast cancer

PURPOSE

To determine the risk of venous thromboembolism (VTE), stroke, ischemic heart disease, and myelodysplastic syndrome (MDS) in association with the receipt of colony-stimulating factors (CSFs) and/or erythropoiesis-stimulating agents (ESAs) in women with breast cancer.

METHODS

We studied 77,233 women with breast cancer aged ≥65 in 1992-2009 from the Surveillance, Epidemiology, and End Results-Medicare linked data with up to 19 years of follow-up.

RESULTS

Incidence of VTE increased from 9 cases in women receiving no chemotherapy and no CSFs/ESAs to 22.79 cases per 1,000 person-years in those receiving chemotherapy with CSFs and ESAs. Women with chemotherapy who received both CSFs and ESAs (adjusted hazard ratio and 95 % confidence interval 2.01, 1.80-2.25) or received ESAs without CSFs (2.03, 1.74-2.36) were twice as likely to develop VTE than those receiving no chemotherapy and no CSFs/ESAs, whereas those receiving CSF alone without ESA were 64 % more likely to have VTE (1.64, 1.45-1.85). Risk of MDS was significantly increased by fivefold in patients receiving ESA following chemotherapy.

CONCLUSIONS

Receipts of CSFs and ESAs were significantly associated with an increased risk of VTE in women with breast cancer. Use of ESAs was significantly associated with substantially increased risks of MDS. These findings support those of previous studies.

Clinical safety of tbo-filgrastim, a short-acting human granulocyte colony-stimulating factor

The recombinant human granulocyte colony-stimulating factor (G-CSF) known as filgrastim (Tevagrastim(®), Ratiograstim(®), Biograstim(®)) in Europe (approved in 2008) and tbo-filgrastim (Granix(®)) in the USA (approved in 2012; Teva Pharmaceutical Industries Ltd., Petach Tikva, Israel) is indicated to reduce the duration of severe neutropenia in patients with non-myeloid malignancies receiving myelosuppressive anti-cancer drugs associated with a clinically significant incidence of febrile neutropenia. This article presents pooled clinical data for tbo-filgrastim compared with Neupogen(®) (Amgen, Thousand Oaks, CA, USA) as well as tbo-filgrastim post-marketing safety data. The safety and efficacy of tbo-filgrastim were evaluated in three phase III studies in 677 patients receiving myelosuppressive chemotherapy and study drug (348 patients with breast cancer, 237 with lung cancer, 92 with non-Hodgkin lymphoma). In each study, the efficacy of tbo-filgrastim was similar to that of Neupogen. Overall, 633 (93.5 %) patients receiving the study drug experienced 6093 treatment-emergent adverse events (AEs), most of which were related to chemotherapy. Adverse events related to the study drug (tbo-filgrastim or Neupogen) were experienced by 185 (27.3 %) patients; 19 (2.8 %) had severe drug-related AEs, 5 (0.7 %) had drug-related serious AEs, and 6 (0.9 %) discontinued the study due to drug-related AEs. Overall, the most common drug-related AEs were bone pain (7.1 %), myalgia (4.0 %), and asthenia (4.4 %). The post-marketing safety profile of tbo-filgrastim was consistent with that observed during the clinical studies. The availability of tbo-filgrastim, a G-CSF with safety and efficacy comparable to those of Neupogen, provides physicians with an alternative treatment option for supportive care of patients with non-myeloid malignancies receiving myelosuppressive chemotherapy.

Differential sensitivity of lipegfilgrastim and pegfilgrastim to neutrophil elastase correlates with differences in clinical pharmacokinetic profile

To assess the basis of the different half-lives of long-acting human granulocyte colony-stimulating factor (G-CSF) drugs, the effect of neutrophil elastase on lipegfilgrastim and pegfilgrastim was investigated. Sensitivity to human neutrophil elastase (HNE) was evaluated by incubating the drugs with HNE followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Drugs were also incubated with isolated human neutrophils followed by Western blot analysis. Lipegfilgrastim was more resistant to degradation with HNE or neutrophils than pegfilgrastim and appeared more intact on SDS-PAGE gels and Western blots. Lipegfilgrastim retained more functional activity than pegfilgrastim after incubation with HNE (67% vs ∼ 9%, respectively) or neutrophils (80% vs ∼ 4%, respectively) as assessed in an NFS-60 cell-based [(3) H]-thymidine incorporation assay. The binding and affinity of untreated lipegfilgrastim and pegfilgrastim for G-CSF receptors were evaluated using an NFS-60 competitive G-CSF receptor-binding assay and surface plasmon resonance. Untreated drugs were also evaluated in the functional NFS-60 thymidine incorporation assay. G-CSF receptor binding, receptor affinity, and functional activity were comparable between untreated drugs. The results showed a greater resistance to neutrophil elastase degradation and concomitant retention of functional activity of lipegfilgrastim compared with pegfilgrastim, which potentially explains the clinical observations of a longer half-life of lipegfilgrastim versus pegfilgrastim.

Risks of Venous Thromboembolism, Stroke, Heart Disease, and Myelodysplastic Syndrome Associated With Hematopoietic Growth Factors in a Large Population-Based Cohort of Patients With Colorectal Cancer

PURPOSE

To determine the relationship between the receipt of colony-stimulating factors (CSFs) with erythropoiesis-stimulating agents (ESAs) and the risk of developing venous thromboembolism (VTE), stroke, heart disease, and myelodysplastic syndrome (MDS) in patients with colorectal cancer.

METHODS

We studied 80,925 patients diagnosed with colorectal cancer at age ≥ 65 years in 1992-2009 from the nationwide 16 areas of the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked data. Cumulative incidence and the time to events Cox hazard regressions were used to explore the risks of outcomes in association with the receipt of CSFs and ESAs.

RESULTS

Patients who received chemotherapy (CT) with both CSF and ESA were 58% more likely to develop VTE than those who received CT without CSF and ESA (hazard ratio, 1.58; 95% confidence interval, 1.43-1.76). The risk of stroke appeared to be not associated with the use of CSF and ESA, whereas the risk of heart disease was only significantly elevated in those patients who did not receive CT but received ESA. The risk of acute myeloid leukemia or MDS was significantly increased 4- to 9-fold in patients who received ESA, regardless of receipt of CT or CSF.

CONCLUSION

The use of ESAs was significantly associated with a substantially increased risk of MDS in patients with colorectal cancer. The use of CSFs and ESAs was also significantly associated with a moderately increased risk of VTE and a slightly elevated risk of heart disease.

A thorough QT study to assess the effects of tbo-filgrastim on cardiac repolarization in healthy subjects

Tbo-filgrastim is a recombinant human granulocyte colony-stimulating factor approved by the US Food and Drug Administration to reduce the duration of severe neutropenia in patients with nonmyeloid malignancies receiving myelosuppressive anticancer drugs associated with a clinically significant incidence of febrile neutropenia. We assessed the effect of tbo-filgrastim on cardiac conduction and repolarization in healthy subjects. A three-arm, parallel-group, active- and placebo-controlled, double-blind study randomized healthy adults to a single 5 μg/kg intravenous tbo-filgrastim infusion, a single intravenous placebo infusion, or a single 400 mg moxifloxacin oral dose. The primary end point was placebo-corrected time-matched change from baseline in QT interval corrected using a QT individual correction (QTcI) method. Secondary end points included heart rate, PR interval, QRS duration, change in electrocardiogram patterns, correlation between QTcI change from baseline (milliseconds) and tbo-filgrastim serum concentrations, and safety variables. A total of 145 subjects were enrolled (50 tbo-filgrastim, 50 placebo, 45 moxifloxacin). Peak placebo-corrected change from baseline for QTcI with tbo-filgrastim was 3.5 milliseconds, with a two-sided 95% upper confidence interval of 7.2 milliseconds, demonstrating no signal for any tbo-filgrastim effect on QTc. Concentration-effect modeling showed no evidence of an effect of tbo-filgrastim on cardiac repolarization. Tbo-filgrastim produced no clinically significant changes in other electrocardiogram parameters. Tbo-filgrastim was well tolerated.

An open-label, randomized, multicenter dose-finding study of once-per-cycle pegfilgrastim versus daily filgrastim in Chinese breast cancer patients receiving TAC chemotherapy

A chemotherapy regimen of docetaxel, doxorubicin and cyclophosphamide (TAC) has been accepted as a standard care because of their superior clinical benefit in early-stage breast cancer patients, but with a higher risk of neutropenia. Pegfilgrastim is a once-per-cycle therapy for prophylactic neutrophil support and neutropenia prevention. There was still a lack of direct evidences for finding an optimal fixed dose of pegfilgrastim in Chinese breast cancer patients receiving TAC regimen. An open-label, randomized, phase II study was designed to compare the effects of pegfilgrastim with filgrastim. Eighteen centers in China enrolled 171 eligible female breast cancer patients with cycles of TAC chemotherapy treatment, randomized into four arms, received a single subcutaneous injection of pegfilgrastim (60, 100 or 120 µg/kg) per chemotherapy cycle or daily subcutaneous injections of filgrastim 5 µg/kg 24 h after chemotherapy. Efficacy and safety were analyzed. In ITT population, the mean duration of grade 3+ neutropenia (neutrophil count <1.0 × 10(9)/l) was 2.09, 1.53 and 1.73 days in patients who received pegfilgrastim 60, 100 and 120 µg/kg/cycle, respectively, and 1.69 days in patients who received 5 µg/kg/day filgrastim (P = 0.043). The incidence of grade 3+ neutropenia was 76, 83 and 74 % for doses of pegfilgrastim and 90 % for filgrastim (P = 0.409). The results for febrile neutropenia, time to neutrophil recovery and neutrophil profile were also not significantly different between arms. The safety profiles of pegfilgrastim and filgrastim were similar. A single dose of 100 µg/kg once-per-cycle administration of pegfilgrastim provided neutrophil support and a safety profile comparable to daily subcutaneous injections of filgrastim in Chinese breast cancer patients receiving TAC chemotherapy.

Neutrophil contribution to spinal cord injury and repair

Spinal cord injuries remain a critical issue in experimental and clinical research nowadays, and it is now well accepted that the immune response and subsequent inflammatory reactions are of significant importance in regulating the damage/repair balance after injury. The role of macrophages in such nervous system lesions now becomes clearer and their contribution in the wound healing process has been largely described in the last few years. Conversely, the contribution of neutrophils has traditionally been considered as detrimental and unfavorable to proper tissue regeneration, even if there are very few studies available on their precise impact in spinal cord lesions. Indeed, recent data show that neutrophils are required for promoting functional recovery after spinal cord trauma. In this review, we gathered recent evidence concerning the role of neutrophils in spinal cord injuries but also in some other neurological diseases, highlighting the need for further understanding the different mechanisms involved in spinal cord injury and repair.

G-CSF and G-CSFR are highly expressed in human gastric and colon cancers and promote carcinoma cell proliferation and migration

Background:

Granulocyte colony-stimulating factor (G-CSF) is a pro-inflammatory cytokine that stimulates myeloid stem cell maturation, proliferation, and migration into circulation. Despite being a known growth factor, the impact of G-CSF on solid tumours has not been well examined. G-CSF receptor (G-CSFR) is expressed by some tumours, and thus the aim of this study was to examine the expression and impact of G-CSF and G-CSFR on gastrointestinal tumours.

Methods:

In this study, G-CSF expression was examined in human gastric and colon tumours and by tumour-derived stromal myofibroblasts and carcinoma cells. G-CSFR expression was examined on carcinoma cells isolated from human tissues. The effects of G-CSF on gastric and colon carcinoma cell proliferation, migration, and signalling were examined.

Results:

G-CSFR was highly expressed in 90% of human gastric and colon carcinomas. G-CSF was also found to be highly produced by stromal myofibroblasts and carcinoma cells. Exposure of carcinoma cells to G-CSF led to increased proliferation and migration, and expansion of a sub-population of carcinoma cells expressing stem-like markers. These processes were dependent on ERK1/2 and RSK1 phosphorylation.

Conclusions:

These data suggest that the G-CSF/R axis promotes gastric and colorectal cancer development and suggest they are potential tumour targets.

Temporal and Geographic Variations in the Receipt of Colony-Stimulating Factors and Erythropoiesis-Stimulating Agents in a Large Retrospective Cohort of Older Women With Breast Cancer From 2000 to 2009

The purpose of this study was to use the most recent national data for a large cohort of patients diagnosed with breast cancer to evaluate temporal trend of receiving hematopoietic growth factors from 2000 to 2009 and to examine significant factors associated with increasing trends and geographic variations. We identified 26,130 women aged 65-89 years who were diagnosed with breast cancer and received chemotherapy in 2000-2009 from the Surveillance, Epidemiology, and End Results (SEER)-Medicare data. Colony-stimulating factors (CSFs) were identified if there was a claim from the following procedure codes: filgrastim, pegfilgrastim, or sargramostim. Erythropoiesis-stimulating agents (ESAs) were identified if there was a claim from the following procedure codes: epoetin or darbepoetin. Overall, 51.7% of patients with breast cancer received CSFs, which increased from 21.7% in 2000 to 63.2% in 2009. The percentage of patients receiving pegfilgrastim increased from 2.7% in 2000 to 19.5% in 2003 and then continuously to 49.7% in 2009. The overall percentage of patients receiving ESAs was 39.3%, which increased from 26.4% in 2000 to 60.8% in 2006, and then decreased significantly from 40.7% in 2007 to 12.9% in 2009. The receipt of both CSFs and ESAs differed significantly across different geographic areas. The receipt of CSFs continued to increase from 2000 to 2009, and pegfilgrastim started to replace filgrastim since 2003. The receipt of ESAs increased until 2006 and then declined substantially due to the black box warning. There were substantial geographic variations in the use of these hematopoietic growth factors.

Neutrophil dynamics after chemotherapy and G-CSF: the role of pharmacokinetics in shaping the response

Chemotherapy has profound effects on the hematopoietic system, most notably leading to neutropenia. Granulocyte colony stimulating factor (G-CSF) is often used to deal with this neutropenia, but the response is highly variable. In this paper we examine the role of pharmacokinetics and delivery protocols in shaping the neutrophil responses to chemotherapy and G-CSF. Neutrophil responses to different protocols of chemotherapy administration with varying dosages, infusion times, and schedules are studied through a mathematical model. We find that a single dose of chemotherapy produces a damped oscillation in neutrophil levels, and short-term applications of chemotherapy can induce permanent oscillations in neutrophil level if there is a bistability in the system. In addition, we confirm previous findings [Zhuge et al., J. Theor. Biol., 293(2012), 111-120] that when periodic chemotherapy is given, there is a significant period of delivery that induces resonance in the system and exacerbates the corresponding neutropenia. The width of this resonant period peak increases with the recovery rate after a single chemotherapy, which is given by the real part of the dominant eigenvalue pair at the steady state, and both are determined by a single cooperativity coefficient in the feedback function for the neutrophils. Our numerical studies show that the neutropenia caused by chemotherapy can be overcome if G-CSF is given early after chemotherapy but can actually be worsened if G-CSF is given later, consistent with results reported in Zhuge et al. (2012). The nadir in neutrophil level is found to be more sensitive to the dosage of chemotherapy than that of the G-CSF. Furthermore, dependence of our results with changes in key pharmacokinetic parameters as well as initial functions are studied. Thus, this study illuminates the potential for destructive resonance leading to neutropenia in response to periodic chemotherapy, and explores and explains why the timing of G-CSF is so crucial for successful reversal of chemotherapy induced neutropenia.

The potential role of recombinant hematopoietic colony-stimulating factors in preventing infections in the immunocompromised host

Hematopoietic colony-stimulating factors coordinate the proliferation and maturation of bone marrow and peripheral blood cells during normal hematopoiesis. Most of these factors are now available as recombinant human colony-stimulating factors, and preclinical and clinical testing is proceeding rapidly. Granulocyte and granulocyte/macrophage colony-stimulating factors have been the most extensively studied to date. In human clinical trials, granulocyte colony-stimulating factor improves neutrophil counts and function, reduces episodes of febrile neutropenia, improves neutrophil recovery after disease- or treatment-induced myelosuppression, and reduces the number of serious infections in several neutropenic disease states. Granulocyte/macrophage colony-stimulating factor has similar biological properties but may also improve eosinophil proliferation and function, and platelet cell recovery after myelotoxic bone marrow injury, Interleukin-1 boosts the effects of granulocyte colony-stimulating factor and granulocyte/macrophage colony-stimulating factor, but also may promote the resolution of established infections in conjunction with antibiotics. The therapeutic realities and future therapeutic implications of these agents for the therapy of infections, cancer and hemopoietic disorders are discussed.

G- and GM-CSF in oncology and oncological haematology

Administration of G- and GM-CSF increases the neutrophil counts in a number of clinical situations. GM-CSF shows the additional effect of increasing the number of monocytes and eosinophil granulocytes. Both G- and GM-CSF affect of neutrophil functions, in the case of GM-CSF there are some potentially negative effects on neutrophil migration and adhesiveness. The clinical relevance of the various effects on mature haematopoietic cells is not fully understood. Clinical data with G-CSF treatment indicate that increased levels of neutrophil granulocytes following cytotoxic chemotherapy may translate into clinical benefit such as a decreased rate of neutropenic infection and an increased cytotoxic chemotherapy dose even though the data are conflicting and the risk of "laboratory cosmetics" is apparent. Regarding treatment with GM-CSF following chemotherapy, the clinical benefit is unclear. The clinical benefit of GM-CSF-induced monocytes and eosinophils is unknown. G- and GM-CSF accelerates neutrophil recovery following autologous or allogeneic BMT. The influence on neutropenic infections is, however, less impressive. Pretreatment with G- or GM-CSF increases the yield of peripheral stem cell harvest, thereby reducing the number of leukaphereses needed. Transplantation of G- and GM-CSF primed autologous peripheral stem cells tends to reduce the period of post-transplant cytopenia, particularly thrombocytopenia, in comparison with traditional ABMT. In patients with MDS, G- and GM-CSF appear to increase the number of neutrophil granulocytes and there is some evidence that patients with severe infectious problems will benefit from this treatment. However, little influence was seen on the main clinical problems with these patients, which are anaemia and thrombocytopenia. In conclusion, G- and GM-CSF are two different proteins with different properties in vivo and in vitro. GM-CSF has, compared with G-CSF, more complex pharmacological effects and a more trouble-some side-effect profile. Early clinical development indicates that both compounds have a substantial influence on the levels of certain blood cells. Whether the increases in different blood cells translate into long-term clinical benefit for greater patient groups is the focus of ongoing research. The effects of G- and GM-CSF may be potentiated by other cytokines, an area which is presently being explored.

Mathematical model for G-CSF administration after chemotherapy

Granulocyte-colony stimulating factor (G-CSF) is used clinically for treating chemotherapy-induced neutropenia (low neutrophil levels). Here we present a delay differential equation model for the regulation of neutrophil production that accounts for the effects of G-CSF. Using a combination of analysis and numerical simulations, we use this model to study the effects of delaying G-CSF treatment following chemotherapy for two recombinant forms of G-CSF (filgrastim and pegfilgrastim). We also examine the consequences of varying the duration of filgrastim treatment. We found that varying the starting day or the duration of G-CSF treatment can lead to different qualitative responses in the neutrophil count. These changes can be explained by the coexistence of two stable solutions in the mathematical model.

Impact of primary prophylaxis with granulocyte colony-stimulating factor on febrile neutropenia and mortality in adult cancer patients receiving chemotherapy: a systematic review

PURPOSE

Randomized controlled trials (RCTs) of prophylactic granulocyte colony-stimulating factors (G-CSF) have demonstrated a significant reduction in febrile neutropenia (FN) after systemic chemotherapy. Several RCTs have been published recently that investigate the impact of G-CSF on mortality and relative dose-intensity (RDI).

METHODS

A comprehensive systematic review and meta-analysis of all reported RCTs comparing primary prophylactic G-CSF with placebo or untreated controls in adult solid tumor and malignant lymphoma patients was undertaken without language restrictions, using electronic databases, conference proceedings, and hand-searching techniques. Two reviewers extracted data independently. Summary estimates of relative risk (RR) with 95% CIs were estimated based on the method of Mantel-Haenszel and DerSimonian and Laird.

RESULTS

Seventeen RCTs were identified including 3,493 patients. For infection-related mortality, RR reduction with G-CSF compared with controls was 45% (RR = 0.55; 95% CI, 0.33 to 0.90; P = .018); for early mortality (all-cause mortality during chemotherapy period), it was 40% (RR = 0.60; 95% CI, 0.43 to 0.83; P = .002); and for FN, it was 46% (RR = 0.54; 95% CI, 0.43 to 0.67; P < .001). Average RDI was significantly higher in patients who received G-CSF compared with control patients (P < .001). Bone or musculoskeletal pain was reported in 10.4% of controls and 19.6% of G-CSF patients (RR = 4.03; 95% CI, 2.15 to 7.52; P < .001). Significant reductions in FN with G-CSF were observed in studies allowing secondary G-CSF prophylaxis in controls and in the three trials with concurrent prophylactic antibiotics in both treatment arms.

CONCLUSION

Prophylactic G-CSF reduces the risk of FN and early deaths, including infection-related mortality, while increasing RDI and musculoskeletal pain. There are insufficient data to assess the impact of G-CSF on disease-free and overall survival.

Concurrent cisplatin-based chemoradiation for cervical carcinoma: tumor response, toxicity, and serum cytokine profiles

PURPOSE

To evaluate the relation between tumor response, treatment toxicity, and serum cytokine profiles in patients with cervical cancer receiving cisplatin-based chemoradiation.

PATIENTS AND METHODS

Forty-two patients with cervical carcinoma receiving chemoradiation were recruited. Hemogram, biochemistry profile, cytokine levels, tumor size, and toxicity were assessed weekly.

RESULTS

The absolute neutrophil count decreased accompanied by an increase in serum levels of G-CSF during chemoradiation. The sudden elevation of serum TGF-beta 1 and VEGF levels after the first fraction of brachytherapy accompanied with the development of greater radiation therapy (RT) morbidity. Lower pretreatment TGF-beta 1 and VEGF levels are associated with tumor response to chemoradiation.

CONCLUSION

The serial changes in serum cytokines during chemoradiation may correlate with tumor regression and treatment morbidity.

Temporal and geographic variation in the use of hematopoietic growth factors in older women receiving breast cancer chemotherapy: findings from a large population-based cohort

PURPOSE

Hematopoietic growth factors have played a major role in preventing infection and shortening the duration of neutropenia in patients receiving cancer chemotherapy. Little information is available on how these growth factors are used in patients with cancer outside the clinical trial setting. We performed descriptive and exploratory analyses on the patterns and correlates of the use of hematopoietic growth factors in community-dwelling elderly patients.

PATIENTS AND METHODS

We identified 5,843 women from the Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked data cohorts who were diagnosed with breast cancer at age 65 or older in 1992 to 1999 from the 11 SEER areas and received chemotherapy.

RESULTS

Overall, 17.3% of the elderly women with breast cancer chemotherapy received filgrastim and 6.8% received epoetin. The use of the growth factors increased significantly over time from 1992 to 1999 (P < .001 for trend). Compared with patients diagnosed in 1992 to 1994, patients diagnosed in 1998 to 1999 were more than five times and 65 times more likely to receive filgrastim and epoetin, respectively, after controlling for other factors such as age and comorbidity. There also was substantial geographic variation in the use of hematopoietic growth factors, ranging from 10.6% in Seattle to 22.9% in Atlanta. Significant predictors of growth factors included patient age, race, tumor stage, and comorbidity.

CONCLUSION

There were substantial temporal and geographic variations in the use of hematopoietic growth factors among patients receiving chemotherapy for breast cancer. The nationwide and population-based Medicare claims provide potential for examining the effectiveness, medical costs, and cost effectiveness of hematopoietic growth factors in the community.

Prophylactic granulocyte colony-stimulating factor in patients receiving dose-intensive cancer chemotherapy: a meta-analysis

PURPOSE

Several studies have evaluated the efficacy of the recombinant colony-stimulating factors in reducing the severity and duration of neutropenia and the risk of infection associated with dose-intensive cancer chemotherapy. We performed a meta-analysis to define better the magnitude of this effect and to assess the generalizability of the results among different diseases and types of treatment.

MATERIALS AND METHODS

We used electronic databases and citation lists to identify controlled clinical trials of the prophylactic efficacy of the colony-stimulating factors on neutropenic complications. We selected randomized trials of the use of recombinant colony-stimulating factors before the onset of fever or neutropenia following systemic chemotherapy for solid tumors or malignant lymphomas.

RESULTS

We identified eight controlled trials (n = 1144 patients) of prophylactic colony-stimulating factors, including five trials of filgrastim (recombinant granulocyte colony-stimulating factors) and three studies of lenograstim (glycosylated granulocyte recombinant colony-stimulating factors). Five trials were double-blind and placebo-controlled; three included untreated controls. Use of recombinant colony-stimulating factors was associated with a reduced risk of febrile neutropenia (odds ratio [OR] = 0.38; 95% confidence interval [CI]: 0.29 to 0.49), documented infection (OR = 0.51; 95% CI: 0.36 to 0.73), and infection-related mortality (OR = 0.60; 95% CI: 0.30 to 1.22), but a greater risk of bone pain (OR = 2.9; 95% CI: 1.6 to 4.8).

CONCLUSION

In this meta-analysis, recombinant colony-stimulating factors were effective in reducing the risk of febrile neutropenia and documented infection associated with several malignancies and dose-intensive treatment regimens.

Rapid down modulation of P-selectin glycoprotein ligand-1 (PSGL-1, CD162) by G-CSF in humans

BACKGROUND

In vitro and animal studies suggest a critical role for P-selectin glycoprotein ligand-1 (PSGL-1) in the regulation of WBC adhesion and neutrophil counts. As WBC activation decreases PSGL-1 expression on WBCs in vitro, the effects of G-CSF on PSGL-1 expression were examined.

STUDY DESIGN AND METHODS

Two different G-CSF doses (1 and 5 microg/kg IV) were compared with high-dose dexamethasone (1 mg/kg twice daily) and placebo in a randomized, double-blind, four-way cross-over trial in eight healthy volunteers. Surface expression of WBC adhesion molecules was quantified by flow cytometry.

RESULTS

Both G-CSF and dexamethasone led to a delayed down regulation of L-selectin. In contrast, G-CSF rapidly down regulated PSGL-1 expression on neutrophils within 90 minutes, whereas neither dexamethasone nor placebo had an effect. Similarly, incubation of WBCs with clinically relevant G-CSF concentrations (60 microg/L) for 90 minutes down modulated PSGL-1 expression on neutrophils and enhanced CD11b expression, compatible with a direct PSGL-1 down regulation by G-CSF-induced neutrophil activation. Similar to G-CSF, GM-CSF down regulated PSGL-1 in vitro. Both drugs induced shedding of soluble PSGL-1, supporting the concept that proteolytic cleavage is a potential mechanism of PSGL-1 down regulation on neutrophils.

CONCLUSION

G-CSF, but not dexamethasone, down regulates PSGL-1 expression on the surface of neutrophils in humans. This could also partly explain the synergistic effects when both drugs are combined for optimal mobilization of neutrophils for clinical granulocyte transfusion programs.

Recombinant human interleukin-3 administered concomitantly with chemotherapy in patients with relapsed small cell lung cancer

Although recombinant human interleukin-3 (rhIL-3) shortens both the duration of chemotherapy-induced neutropenia and thrombocytopenia, its effect on nadir counts is limited. Concurrent administration of rhIL-3 and chemotherapy may enhance this effect. However, simultaneous administration of other hematopoietic growth factors and chemotherapy has resulted in enhanced myelosuppression. We investigated whether concomitant administration of rhIL-3 and chemotherapy would result in enhanced myelosuppression. Twelve patients with relapsed small cell lung cancer received vincristine, ifosfamide, mesna, and carboplatin on day 1 every four weeks. RhIL-3 was administered subcutaneously on days 1-14 during cycle 1 at doses of 4 (three patients) or 8 micrograms/kg/day (nine patients). During cycle 2 patients received only chemotherapy. No significant difference in leukocyte (1.4 +/- 1.0 vs. 0.9 +/- 0.4 x 10(9)/l (mean +/- SD), neutrophil (0.5 +/- 0.6 vs. 0.2 +/- 0.2 x 10(9)/l), and platelet (64 +/- 60 vs. 38 +/- 58 x 10(9)/l) nadir counts were demonstrated. The hemoglobin nadir level was significantly higher during cycle 1 (6.5 +/- 1.1 vs. 5.5 +/- 0.9 mmol/l, P = 0.05). Both leukocyte and platelet recovery were significantly enhanced in the rhIL-3 cycle. There was no significant difference in chemotherapy postponement or platelet transfusions. As a result of severe headaches, rhIL-3 administration was discontinued in one patient at 8 micrograms. RhIL-3 during this chemotherapy regimen for relapsed small cell lung cancer did not enhance myelotoxicity but did improve bone marrow recovery. This observation may increase the application of rhIL-3, for instance in combination with other hematopoietic growth factors.

Early suppressive effects of chemotherapy on recovery of bone marrow megakaryocyte precursors: possible relationship to platelet recovery

This study utilized a recently developed culture and quantitation system to detect megakaryocyte precursors in CD34+ bone marrow cells from normal donors and breast cancer patients treated with 5-fluorouracil, leucovorin, adriamycin and cyclophosphamide (FLAC). Bone marrow was obtained from patients before and then after their first cycle of FLAC once blood cell counts had recovered. CD34+ cells were isolated and placed in liquid culture with growth factors to stimulate proliferation and lineage commitment. Absorbance values from an enzyme-linked immunosorbent assay were used to quantitate expression of platelet glycoprotein GPIIb/IIIa. There was an increase in absorbance with increasing numbers of cells seeded per culture that was associated with an increase in the number of megakaryocyte lineage cells produced. After 10 days in liquid culture, absorbance values for expression of GPIIb/IIIa from 2,000 normal donor and pre-chemotherapy CD34+ marrow cells were > or = 1.0. Absorbance values from cultures of post-chemotherapy CD34+ cells from four patients were similar to values from pre-chemotherapy CD34+ cells. In contrast, absorbance values from cultures of post-chemotherapy CD34+ cells from two other patients were low (absorbance < 0.5). Low absorbance values for GPIIb/IIIa expression indicate that megakaryocyte production from those CD34+ cells was reduced. Both of those patients developed prolonged thrombocytopenia and platelet nadirs of less than 20,000/microl during FLAC chemotherapy. In contrast, only one out of four patients whose cultures of post-chemotherapy CD34+ cells had absorbance values > or = 1.0 developed platelet nadirs less than 20,000/microl. These results suggest that low platelet nadirs and delayed platelet recovery may be associated with suppressive effects of chemotherapy on recovery of megakaryocyte precursors.

Effect of granulocyte and granulocyte macrophage colony stimulating factors (G-CSF and GM-CSF) on neonatal neutrophil functions

Although there are many studies on the effect of granulocyte and granulocyte-macrophage colony stimulating factors (G/GM-CSF) on adult neutrophil functions, there is little information regarding their influence on neonatal cells. We studied the in vitro effect of G/GM-CSF on neutrophil chemotaxis, polarization, and superoxide anion generation in 47 neonates compared with 35 adults. We found that G-CSF and GM-CSF significantly enhanced the chemotaxis of newborn infants' neutrophils, normalizing their chemotactic defect [from 35 +/- 7 cells/field (mean +/- SE) to 49 +/- 5 cells/field with G-CSF, p < 0.05 and to 55 +/- 4 cells/field with GM-CSF, p < 0.001]. It is notable that the maximal neutrophil response to the cytokines was observed particularly in the newborn infants with severe impairment in their chemotactic activity. Statistical analysis of the data showed a significant inverse correlation, which supported this observation (r = -0.6, p < 0.02 for G-CSF; r = -0.76, p < 0.001 for GM-CSF). The reduced polarization of neonatal compared with adult cells [71 +/- 5% versus 86 +/- 2% (mean +/- SE), p < 0.05], was corrected by CSF-priming (to 87 +/- 4% with G-CSF and to 92 +/- 2% with GM-CSF, p < 0.05). In addition, the neutrophil superoxide generation was significantly improved in both groups following the CSF-priming. GM-CSF and G-CSF gave comparable results in all functions studied except that GM-CSF improved superoxide release to a greater extent. This study shows a significant improvement of the neonatal neutrophil functions following in vitro CSF-priming and contributes to a better understanding of the neonatal neutrophil behavior when treated with G/GM-CSF.

Leukocyte behavior in a free-flap model following chemotherapy and application of granulocyte colony-stimulating factor (GCSF)

Free-flap reconstruction following tumor resection and chemotherapy is used increasingly in sarcoma patients. Granulocyte colony-stimulating factor (GCSF) is used to stimulate polymorphnuclear leukocytes (PMNs). In this study we used a free-flap model to investigate PMN behavior after chemotherapy and GCSF stimulation. Eighteen Lewis rats were divided into three groups: (1) chemotherapy + vehicle; (2) chemotherapy + GCSF; and (3) control. Group 1 received vinblastine; group 2 received vinblastine plus 300 microg rhGCSF. Blood was drawn for total white cell and PMN counts for 9 days. Free-flap surgery was simulated by isolating the cremaster muscle on its pedicle and anastomosing the artery. Leukocyte-endothelium interaction was assessed by observation of leukocytes rolling and sticking. Leukocyte sequestration was measured by counting leukocytes in the lungs and the abdomen. We found that leukocyte rolling and sticking were significantly increased, while sequestration was decreased in the chemotherapy + GCSF group. We conclude that leukocytes-endothelium interaction after chemotherapy and GCSF administration is increased in the microcirculation. This augments the risk of microvascular compromise and subsequent flap failure, as capillary flow may be altered.

Granulocyte colony-stimulating factor ameliorates toxicity of intensification chemotherapy for acute lymphoblastic leukemia

BACKGROUND

Intensification chemotherapy improves the prognosis for children with acute lymphoblastic leukemia (ALL), but results in considerable morbidity, primarily due to myelosuppression with resultant neutropenia. Recombinant granulocyte colony-stimulating factor (G-CSF) shortens neutropenia following intensive chemotherapy, but potential benefits in the therapy of ALL remain inadequately explored. Accordingly, a randomized, crossover study was undertaken to clarify this issue.

PROCEDURE

Seventeen children with acute lymphoblastic leukemia or T-cell non-Hodgkin lymphoma and treated on standard protocols were randomized to receive G-CSF following either the first or second intensification blocks of chemotherapy. G-CSF was administered as a single daily subcutaneous injection of 5 mcg/kg from day 9 following the start of intensification therapy, and continued until the neutrophil count exceeded 0.5 x 10(9)/l for 3 days. Study endpoints were days of neutropenia (neutrophils < 1 x 10(9)/l) and severe neutropenia (neutrophils < 0.5 x 10(9)/l), days in hospital, days of fever, and days on antibiotics.

RESULTS

There were significant reductions in the duration of neutropenia (95% confidence interval 3.8-8 days, P = 0.0001), severe neutropenia (95% confidence interval 1.8-7.4 days, P = 0.002), and days in hospital (95% confidence interval 0.9-6.3 days, P = 0.01) for children receiving G-CSF. Overall, the duration of neutropenia was longer following the second block (95% confidence interval 2.2-6.4 days, P = 0.0003), but this difference was abolished by G-CSF, and children, receiving G-CSF after the second intensification were more likely to restart maintenance chemotherapy on schedule (P = 0.05).

CONCLUSIONS

G-CSF reduces the hematological toxicity of intensification chemotherapy and may allow improved compliance with treatment scheduling.

Chemotherapy dose-intensification for pediatric patients with Ewing's family of tumors and desmoplastic small round-cell tumors: a feasibility study at St. Jude Children's Research Hospital

PURPOSE

To evaluate the feasibility of dose-intensification for patients with Ewing's family of tumors (EFT) and desmoplastic small round-cell tumors.

PATIENTS AND METHODS

From February 1992 to June 1996, we treated 53 consecutive patients on our Ewing's protocol. Induction comprised three cycles of ifosfamide/etoposide on days 1 to 3 and cyclophosphamide (CTX)/doxorubicin on day 5, followed by granulocyte colony-stimulating factor. Local control using surgery and/or radiotherapy started at week 9 along with vincristine/dactinomycin. Maintenance included four alternating cycles of ifosfamide/etoposide and doxorubicin/CTX, with randomization to one of two CTX dose levels to determine the feasibility of dose-intensification during maintenance.

RESULTS

Patients had a median age of 13.4 years (range, 4.5 to 24.9 years); 34 patients were male and 43 patients were white. Nineteen patients presented with metastatic disease, 29 had tumors greater than 8 cm in diameter, and 26 had primary bone tumors. These patients received 155 induction cycles, 91% of which resulted in grade 4 neutropenia, 68% in febrile neutropenia, and 68% in grade 3 to 4 thrombocytopenia. During maintenance, grade 4 neutropenia and grade 3 to 4 thrombocytopenia occurred in 81% and 85% of cycles, respectively. Thirty-five patients (66%) completed all therapy, only 13 without significant delays; three developed secondary myeloid malignancies. The toxicity and time to therapy completion were similar in both CTX arms. Estimated 3-year survival and event-free survival were 72%+/-8% and 60%+/-9%, respectively.

CONCLUSION

Although intensifying therapy seems feasible for 25% of patients on this study, toxicity was considerable. Therefore, the noninvestigational use of dose-intensification in patients with EFT should await assessment of its impact on disease-free survival.

The economics of febrile neutropenia: implications for the use of colony-stimulating factors

The occurrence of fever and neutropenia following cancer chemotherapy generally prompts hospitalisation for evaluation and treatment. Colony-stimulating factors (CSFs) have been shown to reduce the risk of febrile neutropenia (FN) and the need for hospitalisation in such patients. This study was undertaken to obtain estimates of the actual institutional costs associated with FN and the impact of these costs on threshold estimates for the appropriate use of CSFs. Total hospital expenditures for patients admitted with FN over a 2 year period were studied. A cost allocation function was utilised to allocate all direct costs for non-revenue-generating support centres to revenue-generating service centres as indirect costs. A cost accounting function was then utilised to allocate direct and indirect costs for each service centre to the charge code level. Two groups of patients were defined based on diagnostic codes to represent the spectrum of patients with FN. Total hospital costs were estimated and incorporated into a cost model for the use of CSFs. Variation in the total cost of hospitalisation for FN relates primarily to differences in the average length of stay. The daily cost of hospitalisation was comparable in the groups studied, averaging between US$1675 and US$1892. Incorporation of these cost estimates into the cost model yielded FN risk threshold projections for CSF use in the range of 20-25%. Preliminary studies suggest that incorporation of non-medical, indirect and intangible costs into the CSF decision models will further decrease FN risk threshold projections. Total hospitalisation cost estimates for managing patients with FN are greater than those previously reported, reducing projected FN risk thresholds for CSF use.

The Effect of Hematopoietic Growth Factors on Platelet Aggregability

We compared the in vitro effect of thrombopoietin (TPO) on platelet aggregation to other hematopoietic growth factors (HGFs): granulocyte colony stimulating factor (G- CSF), granulocyte macrophage colony stimulating factor (GM- CSF), interleukin-3 (IL-3), interleukin-6 (IL-6), and erythro poietin (EPO). The platelet aggregation response of the venous blood of eight volunteers with differing aggregation patterns was characterized by a platelet aggregation (PA) score that provided numerical assessment of an individual's platelet ag gregation tendency to adenosine diphosphate (ADP). The method for analysis of the data included constructing regres sion lines for each participant's PA score versus the HGF con centration (range of 0.5 nG/mL to 100 nG/mL) and calculating the regression coefficients for the slope and the Y axis inter cept. We demonstrated that the proposed method resulted in accurate assessment of the HGF effect or lack of it on the platelet aggregation response. Within the concentration range evaluated, the influence of IL-6 and G-CSF on platelet aggrega bility was insignificant and the effects of GM-CSF and IL-3 were almost undetectable. In contrast, the potentiating effect of TPO on platelet activation was dose dependent with significant enhancement for all responder types. The concentrations of TPO utilized in our in vitro experiments were in pathophysi ological range, indicating that its impact on platelet aggregation may have clinical relevance, and that monitoring platelet func tion in conjunction with TPO treatment might be advisable. Investigation of the possible synergistic effect of HGF combi nations is warranted.

Effect of escalating doses of recombinant human granulocyte colony-stimulating factor (filgrastim) on circulating neutrophils in healthy subjects

The safety profile, tolerability, pharmacodynamics, and pharmacokinetics of four doses of recombinant human granulocyte colony-stimulating factor (filgrastim) were assessed in healthy volunteers in a double-masked, placebo-controlled, parallel-group trial. Healthy subjects received subcutaneous injections of filgrastim 75 microg (n = 8), 150 microg (n = 4), 300 microg (n = 4), 600 microg (n = 8), or placebo (n = 6) daily for 10 consecutive days. Blood samples were drawn daily immediately before the injection and on days 1 and 10 serially throughout the day. Increased absolute neutrophil counts (ANCs) were seen within 90 minutes of drug administration in subjects in all dose groups, peaking approximately 12 hours after administration. This increase was dose related in subjects in the three lower dose groups. The time to peak ANC on day 10 was approximately 9 hours, with a daily ANC profile in all four dose groups that was similar to the profile on day 1. In all dose groups, ANCs were near baseline within 48 hours of discontinuation of filgrastim. Mild, reversible thrombocytopenia was reported in 4 of 10 subjects in the highest dose group. Two subjects in the filgrastim 600-microg group were withdrawn for adverse events. Filgrastim had a good safety profile and caused dose-related increases in ANC when administered to healthy volunteers for up to 10 days.

G-CSF after autologous hemopoietic stem cell transplantation in malignant lymphoma

Forty-eight autografted patients were studied after treatment with granulocyte-colony stimulating factor (G-CSF) and were compared with a historical series of 24 patients autografted with bone marrow (BM) without G-CSF. When the patients were divided on the basis of G-CSF administration, type of lymphoma and the source of hemopoietic stem cells, no significant difference was found in the median number of infused BM cells, duration of febrile episodes, platelet and hemoglobin recovery, or in the number of transfusions. The patients receiving peripheral blood (PB) + G-CSF had significantly shorter median durations of antibiotic therapy, hospital stay and polymorphonucleate (PMN) recovery. When the Hodgkin disease (HD) and non-Hodgkin lymphoma (NHL) cases were considered separately, a significant difference between those receiving and those not receiving G-CSF was observed only in the HD group. The advantage offered by PB + G-CSF over BM + G-CSF was far more evident in the NHL group than in HD. It can be concluded that G-CSF improves the outcome of BM transplant in HD, and that the use of PB + G-CSF adds a further advantage; conversely, in NHL, PB + G-CSF is strikingly superior to BM + G-CSF, but the addition of G-CSF adds little advantage.