Comparison of sargramostim and filgrastim in the treatment of chemotherapy-induced neutropenia

Colony stimulating factors for prophylaxis of chemotherapy-induced neutropenia in children

INTRODUCTION

Febrile neutropenia (FN) is one of the complications of chemotherapy that can increase the risk of infection and mortality. Granulocyte colony-stimulating factors (G-CSFs) are used in practice to prevent and treat episodes of neutropenia. The use of G-CSFs in children with cancer has not been studied much for primary prophylaxis of FN.

AREAS COVERED

Current data suggest that G-CSFs have a similar pharmacokinetic profile in children and adults. Clinical trials published from 2002 to 2021 using G-CSFs in pediatric cancer patients were reviewed. All evaluated clinical trials used a dosage of 5 mcg/kg of filgrastim daily until neutrophil recovery or a single dose of 100 mcg/kg pegfilgrastim. Filgrastim demonstrated the benefit in decreasing the duration of fever, hospital stay, and antibiotic use in high-risk neuroblastoma patients. Pegfilgrastim showed similar efficacy in reducing the occurrence of FN and infections, with bone pain as an adverse effect.

EXPERT OPINION

Filgrastim 5 mcg/kg/day or pegfilgrastim 100 mcg/kg single dose is appropriate when given at least 24 hours or after the chemotherapy in pediatric patients who weigh 45 kg or more. More prospective randomized trials are necessary to further investigate the efficacy and safety of G-CSFs in children with different types of cancer.

Repurposing Pharmaceuticals Previously Approved by Regulatory Agencies to Medically Counter Injuries Arising Either Early or Late Following Radiation Exposure

The increasing risks of radiological or nuclear attacks or associated accidents have served to renew interest in developing radiation medical countermeasures. The development of prospective countermeasures and the subsequent gain of Food and Drug Administration (FDA) approval are invariably time consuming and expensive processes, especially in terms of generating essential human data. Due to the limited resources for drug development and the need for expedited drug approval, drug developers have turned, in part, to the strategy of repurposing agents for which safety and clinical data are already available. Approval of drugs that are already in clinical use for one indication and are being repurposed for another indication is inherently faster and more cost effective than for new agents that lack regulatory approval of any sort. There are four known growth factors which have been repurposed in the recent past as radiomitigators following the FDA Animal Rule: Neupogen, Neulasta, Leukine, and Nplate. These four drugs were in clinic for several decades for other indications and were repurposed. A large number of additional agents approved by various regulatory authorities for given indications are currently under investigation for dual use for acute radiation syndrome or for delayed pathological effects of acute radiation exposure. The process of drug repurposing, however, is not without its own set of challenges and limitations.

Use of molecularly-cloned haematopoietic growth factors in persons exposed to acute high-dose, high-dose rate whole-body ionizing radiations

Exposure to acute, high-dose, high dose-rate whole-body ionizing radiations damages the bone marrow resulting in rapid decreases in concentrations of blood cells, especially lymphocytes, granulocytes and platelets with associated risks of infection and bleeding. In several experimental models including non-human primate radiation exposure models giving molecularly cloned haematopoietic growth factor including granulocyte/macrophage colony-stimulating factor (G/M-CSF; sargramostim) and granulocyte colony-stimulating factor (G-CSF; filgrastim and pegylated G-CSF [peg-filgrastim]) accelerates bone marrow recovery and increases survival. Based on these data these molecules are US FDA approved for treating victims of radiation and nuclear incidents, accident and events such as nuclear terrorism and are included in the US National Strategic Stockpile. We discuss the immediate medical response to these events including how to estimate radiation dose and uniformity and which interventions are appropriate in different radiation exposures settings. We also discuss similarities and differences between molecularly cloned haematopoietic growth factors.

Utilization of G-CSF and GM-CSF as an alternative to discontinuation in clozapine-induced neutropenia or leukopenia: A case report and discussion

Clozapine remains the definitive gold standard for treatment-resistant schizophrenia despite limitations in use because of hematological abnormalities. Neutropenia or leukopenia are often treated with interruption of clozapine treatment, frequently resulting in clinical decompensation, hospitalization, increased burden to patient care, and increased risk of suicide. Colony-stimulating factors, including granulocyte colony-stimulating factors and granulocyte-macrophage colony-stimulating factors, are cytokines that stimulate proliferation and differentiation of myeloid precursor cells. Their use in the prevention and treatment of clozapine-associated neutropenia presents an alternative to clozapine discontinuation in certain cases. We present a case report of successful periodic granulocyte-macrophage colony-stimulating factor use with clozapine in a patient with treatment-resistant schizophrenia, as well as discussion of a practical approach to patients with possible clozapine-induced neutropenia or leukopenia.

Multiple sclerosis onset after granulocyte macrophage colony-stimulating factor withdrawal

A 51-year old woman with stage III melanoma participated in a phase II clinical trial in which she received subcutaneous rhGM-CSF injections for 3 years. She was in remission by the end of the trial. Seven months after discontinuing GM-CSF she had her first MS event. The unique timeline of rh-GM-CSF injections in a melanoma trial, during which yearly MRI scans showed subtle stable demyelination followed by RRMS onset shortly after discontinuation of treatment, may provide some insight on the role of GM-CSF in MS.

Comparative effectiveness of pegfilgrastim, filgrastim, and sargramostim prophylaxis for neutropenia-related hospitalization: two US retrospective claims analyses

OBJECTIVE

Few studies have compared the effectiveness of filgrastim (FIL), pegfilgrastim (PEG), and sargramostim (SAR) to reduce the risk of febrile neutropenia (FN) associated with myelosuppressive chemotherapy (M-CT). Two large commercial database analyses were separately conducted to examine the incidence of neutropenia-related and all-cause hospitalizations associated with FIL, PEG, and SAR prophylaxis for patients receiving M-CT for non-Hodgkin lymphoma (NHL), Hodgkin lymphoma, or solid tumors.

METHODS

Separate retrospective US claims database analyses utilized patient data from January 1, 2004 to April 30, 2010 using the HealthCore Integrated Research Database (HIRD(SM)) and January 1, 2001 to August 31, 2009 using OptumInsight's (formerly Ingenix) database. Patients were ≥18 years old and treated with M-CT for NHL, Hodgkin lymphoma, and solid tumors. All identified M-CT cycles with prophylactic (first 5 days of cycle) FIL, PEG, or SAR were included in the analysis. Patterns of administration and incidence rates of all-cause and neutropenia-related hospitalization were examined on a per-cycle basis.

RESULTS

In total, 9330 and 8762 patients with cancer, representing 30,264 and 24,215 chemotherapy cycles (28,189 and 22,649 (PEG), 1669 and 1351 (FIL), 406 and 215 (SAR)) from the HIRD(SM) and OptumInsight databases, respectively, were included in the separate database analyses. Both the HIRD(SM) and OptumInsight analysis showed that SAR and FIL prophylaxis had a higher risk of neutropenia-related hospitalization (SAR: OR = 3.48 [95%CI = 2.11, 5.74] and 2.81 [1.62, 4.87]; FIL: 1.78 [1.28, 2.48] and 2.36 [1.82, 3.06], respectively) and all-cause hospitalization (SAR: 2.18 [1.41, 3.36] and 2.41 [1.58, 3.68]; FIL:1.57 [1.25, 1.97] and 1.95 [1.60, 2.38], respectively) vs PEG.

LIMITATIONS

Medical claims do not contain information about chemotherapy dose, and hospitalizations were not validated against the patient's chart.

CONCLUSION

In this comparative effectiveness study, use of PEG was associated with a lower risk of neutropenia-related and all-cause hospitalizations compared to use of FIL or SAR prophylaxis.

Comparison of hospitalization risk and associated costs among patients receiving sargramostim, filgrastim, and pegfilgrastim for chemotherapy-induced neutropenia

BACKGROUND

Sargramostim is a granulocyte-macrophage-colony-stimulating factor (GM-CSF). Unlike filgrastim and pegfilgrastim, which are granulocyte-colony-stimulating factors (G-CSFs), sargramostim activates a broader range of myeloid lineage-derived cells. Therefore, GM-CSF might reduce infection risk more than the G-CSFs. This study compared real-world infection-related hospitalization rates and costs in patients using G/GM-CSF for chemotherapy-induced neutropenia.

METHODS

This retrospective matched-cohort study analyzed nationally representative health insurance claims in the United States from 2000 through 2007. The sample population included patients who received chemotherapy and G/GM-CSF. G/GM-CSF treatment episodes began with the first administration of G/GM-CSF and ended when a subsequent administration was >28 days after a prior administration. Sargramostim patients were matched 1:1 with filgrastim and pegfilgrastim patients based on gender and birth year. Outcomes included infection-related hospitalization rates and the associated costs. Hospitalization rates were analyzed using univariate and multivariate Poisson methods; covariates included myelosuppressive agents received, tumor type, anemia, and comorbidities.

RESULTS

A total of 990 sargramostim-filgrastim and 982 sargramostim-pegfilgrastim matched pairs were analyzed. Cohorts were similar with regard to age, gender, and comorbid conditions. Several differences were observed with regard to tumor type, anemia, and chemotherapy, but no systematic trends were apparent. Sargramostim patients experienced a 56% lower risk of infection-related hospitalizations compared with filgrastim and pegfilgrastim patients. Infection-related hospitalization costs were 84% and 62% lower for sargramostim patients compared with patients treated with filgrastim and pegfilgrastim, respectively.

CONCLUSIONS

Among patients with or at risk for chemotherapy-induced neutropenia, these data indicated that use of sargramostim was associated with a reduced risk of infection-related hospitalization and lower associated costs compared with filgrastim or pegfilgrastim.

HIV and other lentiviral infections cause defects in neutrophil chemotaxis, recruitment, and cell structure: immunorestorative effects of granulocyte-macrophage colony-stimulating factor

Patients with HIV infection exhibit deficits in bacterial and fungal clearance, and possibly depressed innate immunity. In this study, we observed that neutrophils from HIV-infected patients have a profound defect in chemotaxis in response to endogenous (IL-8) and bacterial (fMLP) chemoattractants, which was directly correlated with peripheral CD4(+) lymphocyte levels but not plasma viral load. A similar chemotactic defect was observed in the feline immunodeficiency virus (FIV) model of HIV infection. Intravital microscopy of FIV-infected animals revealed marked impairment in the in vivo recruitment of leukocytes; specifically integrin-dependent neutrophil adhesion and emigration induced by bacterial products. Treatment of FIV-infected animals with GM-CSF re-established both neutrophil recruitment (rolling, adhesion, and emigration) and in vitro chemotaxis to the levels seen in uninfected animals. This restoration of neutrophil responses was not due to GM-CSF-mediated priming. Rather, HIV and FIV infections resulted in defective neutrophil development, with an ensuing reduction in neutrophil granularity and chemotactic receptor expression. GM-CSF therapy restored neutrophil granularity, implying restoration of normal neutrophil development. Together, our findings underscore the fundamental defects in innate immunity caused by lentivirus infections, while also indicating that GM-CSF may be a potential immunorestorative therapy for HIV-infected patients.