Clinical use of granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor in neutropenia associated with malignancy

Construction of Recombinant Human GM-CSF and GM-CSF-ApoA-I Fusion Protein and Evaluation of Their Biological Activity

In this study, two strains of the yeast P. pastoris were constructed, one of which produced authentic recombinant human granulocyte-macrophage colony-stimulating factor (ryGM-CSF), and the other was a chimera consisting of ryGM-CSF genetically fused with mature human apolipoprotein A-I (ApoA-I) (ryGM-CSF-ApoA-I). Both forms of the cytokine were secreted into the culture medium. The proteins’ yield during cultivation in flasks was 100 and 60 mg/L for ryGM-CSF and ryGM-CSF-ApoA-I, respectively. Both forms of recombinant GM-CSF stimulated the proliferation of human TF-1 erythroleukemia cells; however, the amount of chimera required was 10-fold that of authentic GM-CSF to induce a similar proliferative effect. RyGM-CSF exhibited a 2-fold proliferative effect on BFU-E (burst-forming units—erythroid) at a concentration 1.7 fold less than non-glycosylated E. coli-derived GM-CSF. The chimera together with authentic ryGM-CSF increased the number of both erythroid precursors and BMC granulocytes after 48 h of incubation of human bone marrow cells (BMCs). In addition, the chimeric form of ryGM-CSF was more effective at increasing the viability of the total amount of BMCs, decreasing apoptosis compared to the authentic form. ryGM-CSF-ApoA-I normalized the proliferation, maturation, and segmentation of neutrophils within the physiological norm, preserving the pool of blast cells under conditions of impaired granulopoiesis. The chimera form of GM-CSF exhibited the properties of a multilinear growth factor, modulating the activity of GM-CSF and, perhaps, it may be more suitable for the normalization of granulopoiesis.

Prophylactic colony-stimulating factors in children receiving myelosuppressive chemotherapy: A meta-analysis of randomized controlled trials

BACKGROUND

The colony-stimulating factors (CSFs) are widely utilized to prevent neutropenic complications in both adults and children, but randomized controlled trials in the pediatric setting have reported varied results. A systematic review of the literature and meta-analysis were conducted to definitively assess the impact of prophylactic CSFs on the risk of febrile neutropenia (FN) in pediatric oncology patients.

METHODS

MEDLINE was searched and references hand-searched through July 2004 for randomized controlled trials of prophylactic G-CSF or GM-CSF in pediatric oncology patients. Objectives, outcomes, and quality of the 16 included studies were extracted by two reviewers. Weighted summary estimates of relative risks (RR) were calculated for FN and documented infection (DI). Mean differences in hospitalization, antibiotic use, and duration of neutropenia were calculated.

RESULTS

FN occurred in 68% of 400 controls and 59% of 404 CSF patients. The estimated RR was 0.88 [0.81-0.97; (P=0.01)] favoring the CSFs for leukemia and high grade lymphoma studies and 0.71 [0.51-0.97; (P=0.03)] for solid tumor studies. DI occurred in 25% of controls and 20% of CSF patients for an estimated RR of 0.80 [0.61-1.06; (P=0.12)]. The mean decrease in duration of neutropenia was 3.5 days [2.2-4.7; (P<0.0001)]. Mean decreases favoring CSF use were also observed for hospital stay of 1.7 days [0.9-2.5 (P<0.01)] and antibiotic use of 2.0 days [0.4-3.6; P=0.02].

CONCLUSIONS

Prophylactic CSFs significantly decrease the incidence of FN and the durations of severe neutropenia, hospitalization, and antibiotic use in pediatric cancer patients, but they do not significantly decrease documented infections.

Colony stimulating factors for prevention of myelosupressive therapy induced febrile neutropenia in children with acute lymphoblastic leukaemia

BACKGROUND

Acute lymphoblastic leukaemia (ALL) is the most common cancer in childhood and febrile neutropenia is a potentially life-threatening side effect of its treatment. Current treatment consists of supportive care plus antibiotics. Clinical trials have attempted to evaluate the use of colony-stimulating factors (CSF) as additional therapy to prevent febrile neutropenia in children with ALL. The individual trials do not show whether there is significant benefit or not. Systematic review provides the most reliable assessment and the best recommendations for practice.

OBJECTIVES

To evaluate the safety and effectiveness of the addition of G-CSF or GM-CSF to myelosuppressive chemotherapy in children with ALL, in an effort to prevent the development of febrile neutropenia. Evaluation of number of febrile neutropenia episodes, length to neutrophil count recovery, incidence and length of hospitalisation, number of infectious disease episodes, incidence and length of treatment delays, side effects (flu-like syndrome, bone pain and allergic reaction), relapse and overall mortality (death).

SEARCH STRATEGY

The search covered the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CANCERLIT, LILACS, and SciElo. We manually searched records of conference proceedings of ASCO and ASH from 1985 to 2003 as well as databases of ongoing trials. We consulted experts and scanned references from the relevant articles.

SELECTION CRITERIA

We looked for randomised controlled trials (RCTs) comparing CSF with placebo or no treatment as primary or secondary prophylaxis to prevent febrile neutropenia in children with ALL.

DATA COLLECTION AND ANALYSIS

Two authors independently selected, critically appraised studies and extracted relevant data. The end points of interest were:* Primary end points: number of febrile neutropenia episodes and overall mortality (death) * Secondary end points: time to neutrophil count recovery, incidence and length of hospitalisation, number of infectious diseases episodes, incidence and length of treatment delays, side effects (flu-like syndrome, bone pain and allergic reaction) and relapse. We conducted a meta-analysis of these end points and expressed the results as Peto odds ratios. For continuous outcomes we calculated a weighted mean difference and a standardised mean difference. For count data, meta-analysis of the logarithms of the rate ratios using generic inverse variance was employed.

MAIN RESULTS

We scanned more than 5500 citations and included six studies with a total of 332 participants in the analysis. There were insufficient data to assess the effect on survival. The use of CSF significantly reduced the number of episodes of febrile neutropenia episodes (Rate Ratio = 0.63; 95% confidence interval (CI) 0.46 to 0.85; p =0.003, with substantial heterogeneity), the length of hospitalisation (weighted mean difference (WMD) = -1.58; 95% CI -3.00 to -0.15; p = 0.03), and number of infectious diseases episodes (Rate Ratio=0.44; 95%CI 0.24 to 0.80; p=0.002). In spite of these results, CSF did not influence the length of episodes of neutropenia (WMD = -1.11; 95% CI -3.55 to 1.32; p = 0.4) or delays in chemotherapy courses (Rate Ratio=0.77; 95%CI 0.49 to 1,23; p=0.28) .

AUTHORS' CONCLUSIONS

Children with ALL treated with CSF benefit from shorter hospitalisation and fewer infections. However, there was no evidence for a shortened duration of neutropenia nor fewer treatment delays, and no useful information about survival. The role of CSF regarding febrile neutropenia episodes is still uncertain. Although current data shows statistical benefit for CSF use, substantial heterogeneity between included trials does not allow this conclusion.

The role of colony-stimulating factors and granulocyte transfusion in treatment options for neutropenia in children with cancer

Children with cancer receiving anticancer therapy always experience neutropenia, and as a result often develop serious neutropenic infections that cause morbidity and/or mortality. Intensive chemotherapy with improved supportive care for neutropenia contribute to the recent advances in treatment outcome in children with cancer. Recombinant human granulocyte colony-stimulating factor (G-CSF) and recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) can shorten the duration and decrease the severity of neutropenia, and thus support intensive chemotherapy. Both G-CSF and GM-CSF stimulate proliferation and maturation of myeloid progenitor cells and are thus used to help mobilization of peripheral blood progenitor cells, and after stem-cell transplantation. The American Society of Clinical Oncology 2000 Guidelines recommended that colony-stimulating factors (CSFs) can be administered as a primary prophylaxis with a chemotherapy regimen if previous experiences with chemotherapy regimens have shown that the incidence of febrile neutropenia (neutropenic fever) is > or =40%. The routine use of CSFs for secondary prophylaxis or for patients with afebrile neutropenia is not recommended in order to avoid the overuse of CSFs. The use of a CSF may be considered in children with febrile neutropenia with a neutrophil count <100/microL, uncontrolled primary disease, pneumonia, hypotension, multiorgan dysfunction (sepsis syndrome), or invasive fungal infection. Although these guidelines are generally applicable to children with cancer, further studies on CSFs are certainly needed in pediatric oncology. The recent advances in granulocyte collection, using healthy volunteer donor stimulation with G-CSF and/or dexamethasone to yield large numbers of granulocytes has made granulocyte transfusion a more realistic option. Granulocyte transfusion has shown promising results in treating children with severe neutropenic infection; however, controlled trials are warranted to clarify the efficacy and cost-effectiveness of this procedure.

Myeloid progenitors protect against invasive aspergillosis and Pseudomonas aeruginosa infection following hematopoietic stem cell transplantation

Myelotoxic treatments for oncologic diseases are often complicated by neutropenia, which renders patients susceptible to potentially lethal infections. In these studies of murine hematopoietic stem cell transplantation (HSCT), cotransplantation of lineage-restricted progenitors known as common myeloid progenitors (CMP) and granulocyte-monocyte progenitors (GMP) protects against death following otherwise lethal challenge with either of 2 pathogens associated with neutropenia: Aspergillus fumigatus and Pseudomonas aeruginosa. Cotransplantation of CMP/GMP resulted in a significant and rapid increase in the absolute number of myeloid cells in the spleen, most of which were derived from the donor CMP/GMP. Despite persistent peripheral neutropenia, improved survival correlated with the measurable appearance of progenitor-derived myeloid cells in the spleen. A marked reduction or elimination of tissue pathogen load was confirmed by culture and correlated with survival. Localization of infection by P aeruginosa and extent of disease was also assessed by in vivo bioluminescent imaging using a strain of P aeruginosa engineered to constitutively express a bacterial luciferase. Imaging confirmed that transplantation with a graft containing hematopoietic stem cells and CMP/GMP reduced the bacterial load as early as 18 hours after infection. These results demonstrate that enhanced reconstitution of a tissue myeloid pool offers protection against lethal challenge with serious fungal and bacterial pathogens.

A laboratorian’s perspective on evaluation and implementation of new laboratory tests

New assay development should be directed toward answering fundamental clinical questions. Caveats that must be considered before initiating assay development projects are: New assays should allow the clinician to interact with and treat a patient more effectively, thereby improving medical outcome; and new assays should facilitate recapture of system resources, enabling cost savings or reinvestment of resources. Defining the clinical questions and consideration of the caveats permit a means of prioritizing assay development activities. Laboratorians are faced with evaluating several types of development activities that lead to assay implementation in routine clinical testing. Assays can be prioritized for up-grading to newer cost-effective technologies, provided the changes maintain or improve analytical and clinical performance. Predicting which research assay will have future value is difficult when clinical performance is not fully validated. However, such assay development has the greatest potential for changing the delivery of healthcare by a clinician.