The effects of dose and route of administration on the pharmacokinetics of granulocyte-macrophage colony-stimulating factor

Development of an extended half-life GM-CSF fusion protein for Parkinson's disease

Transformation of CD4+ T cell effector to regulatory (Teff to Treg) cells have been shown to attenuate disease progression by restoring immunological balance during the onset and progression of neurodegenerative diseases. In our prior studies, we defined a safe and effective pathway to restore this balance by restoring Treg numbers and function through the daily administration of the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF). These studies were conducted as a proof-of-concept testing in Parkinson's disease (PD) preclinical models and early phase I clinical investigations. In both instances, they served to ameliorate disease associated signs and symptoms. However, despite the recorded efficacy, the cytokine's short half-life, low bioavailability, and injection site reactions proved to be limitations for any broader use. To overcome these limitations, mRNA lipid nanoparticles encoding an extended half-life albumin-GM-CSF fusion protein were developed for both mouse (Msa-GM-CSF) and rat (Rsa-GM-CSF). These formulations were tested for immunomodulatory and neuroprotective efficacy using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and human wild-type alpha-synuclein (αSyn) overexpression preclinical models of PD. A single dose of the extended half-life mouse and rat mRNA lipid nanoparticles generated measurable GM-CSF plasma cytokine levels up to four days. Increased Treg frequency and function were associated with a resting microglial phenotype, nigrostriatal neuroprotection, and restoration of brain tissue immune homeostasis. These findings were substantively beyond the recorded efficacy of daily recombinant wild-type GM-CSF with a recorded half-life of six hours. Mechanistic evaluation of neuropathological transcriptional profiles performed in the disease-affected nigral brain region demonstrated an upregulation of neuroprotective CREB and synaptogenesis signaling and neurovascular coupling pathways. These findings highlight the mRNA-encoded albumin GM-CSF fusion protein modification linked to improvements in therapeutic efficacy. The improvements achieved were associated with the medicine's increased bioavailability. Taken together, the data demonstrate that mRNA LNP encoding the extended half-life albumin-GM-CSF fusion protein can serve as a benchmark for PD immune-based therapeutics. This is especially notable for improving adherence of drug regimens in a disease-affected patient population with known tremors and gait abnormalities.

Granulocyte-macrophage colony-stimulating factor mRNA and Neuroprotective Immunity in Parkinson's disease

Restoring numbers and function of regulatory T cells (Tregs) is a novel therapeutic strategy for neurodegenerative disorders. Whether Treg function is boosted by adoptive cell transfer, pharmaceuticals, or immune modulators, the final result is a robust anti-inflammatory and neuronal sparing response. Herein, a newly developed lipid nanoparticle (LNP) containing mRNA encoding granulocyte-macrophage colony-stimulating factor (Gm-csf mRNA) was developed to peripherally induce Tregs and used for treatment in preclinical Parkinson's disease (PD) models. Administration of Gm-csf mRNA to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice and rats overexpressing alpha-synuclein produced dose-dependent increases in plasma GM-CSF levels and peripheral CD4+CD25+FoxP3+ Treg populations. This upregulation paralleled nigrostriatal neuroprotection, upregulated immunosuppression-associated mRNAs that led to the detection of a treatment-induced CD4+ T cell population, and decreased reactive microgliosis. The current findings strengthen prior works utilizing immune modulation by harnessing Gm-csf mRNA to augment adaptive immune function by employing a new delivery platform to treat PD and potentially other neurodegenerative disorders.

Neuroprotective Activities of Long-Acting Granulocyte-Macrophage Colony-Stimulating Factor (mPDM608) in 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine-Intoxicated Mice

Loss of dopaminergic neurons along the nigrostriatal axis, neuroinflammation, and peripheral immune dysfunction are the pathobiological hallmarks of Parkinson's disease (PD). Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been successfully tested for PD treatment. GM-CSF is a known immune modulator that induces regulatory T cells (Tregs) and serves as a neuronal protectant in a broad range of neurodegenerative diseases. Due to its short half-life, limited biodistribution, and potential adverse effects, alternative long-acting treatment schemes are of immediate need. A long-acting mouse GM-CSF (mPDM608) was developed through Calibr, a Division of Scripps Research. Following mPDM608 treatment, complete hematologic and chemistry profiles and T-cell phenotypes and functions were determined. Neuroprotective and anti-inflammatory capacities of mPDM608 were assessed in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated mice that included transcriptomic immune profiles. Treatment with a single dose of mPDM608 resulted in dose-dependent spleen and white blood cell increases with parallel enhancements in Treg numbers and immunosuppressive function. A shift in CD4+ T-cell gene expression towards an anti-inflammatory phenotype corresponded with decreased microgliosis and increased dopaminergic neuronal cell survival. mPDM608 elicited a neuroprotective peripheral immune transformation. The observed phenotypic shift and neuroprotective response was greater than observed with recombinant GM-CSF (rGM-CSF) suggesting human PDM608 as a candidate for PD treatment.

Immunotherapy for Parkinson's disease

With the increasing prevalence of Parkinson’s disease (PD), there is an immediate need to interdict disease signs and symptoms. In recent years this need was met through therapeutic approaches focused on regenerative stem cell replacement and alpha-synuclein clearance. However, neither have shown long-term clinical benefit. A novel therapeutic approach designed to affect disease is focused on transforming the brain’s immune microenvironment. As disordered innate and adaptive immune functions are primary components of neurodegenerative disease pathogenesis, this has emerged as a clear opportunity for therapeutic development. Interventions that immunologically restore the brain’s homeostatic environment can lead to neuroprotective outcomes. These have recently been demonstrated in both laboratory and early clinical investigations. To these ends, efforts to increase the numbers and function of regulatory T cells over dominant effector cells that exacerbate systemic inflammation and neurodegeneration have emerged as a primary research focus. These therapeutics show broad promise in affecting disease outcomes beyond PD, such as for Alzheimer’s disease, stroke and traumatic brain injuries, which share common neurodegenerative disease processes.

Intraperitoneal administration of fosfomycin, metronidazole, and granulocyte-macrophage colony-stimulating factor in patients undergoing appendectomy is safe: a phase II clinical trial

We aimed to investigate the safety of intraperitoneal administration of the combination of fosfomycin, metronidazole, and recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) in patients undergoing appendectomy. We conducted a prospective phase II clinical trial in 14 otherwise healthy men suffering from uncomplicated appendicitis. After appendectomy, the trial treatment was administered intraperitoneally and left in the abdominal cavity. Trial treatment consisted of 4 g fosfomycin, 1 g metronidazole, and 50 µg rhGM-CSF in a total volume of 500 ml. Safety was evaluated through white blood cell count where a toxic effect was predefined. We evaluated harms and adverse events, repeated biochemical markers, vital signs, and length of stay. White blood cell count did not drop below the toxic range. The recorded harms were dizziness, discomfort when breathing deeply, no flatus, and bloating. Adverse events included three patients with diarrhoea after discharge and one patient with a hypotensive episode. No serious adverse events or infectious complications occurred. Intraperitoneal administration of fosfomycin, metronidazole, and rhGM-CSF was safe in otherwise healthy men undergoing laparoscopic appendectomy. There were some possible harms and adverse events but we were unable to assess if they were related to anaesthesia, surgery, or the trial treatment.

Randomised controlled trial of GM-CSF in critically ill patients with impaired neutrophil phagocytosis

BACKGROUND

Critically ill patients with impaired neutrophil phagocytosis have significantly increased risk of nosocomial infection. Granulocyte-macrophage colony-stimulating factor (GM-CSF) improves phagocytosis by neutrophils ex vivo. This study tested the hypothesis that GM-CSF improves neutrophil phagocytosis in critically ill patients in whom phagocytosis is known to be impaired.

METHODS

This was a multicentre, phase IIa randomised, placebo-controlled clinical trial. Using a personalised medicine approach, only critically ill patients with impaired neutrophil phagocytosis were included. Patients were randomised 1:1 to subcutaneous GM-CSF (3 μg/kg/day) or placebo, once daily for 4 days. The primary outcome measure was neutrophil phagocytosis 2 days after initiation of GM-CSF. Secondary outcomes included neutrophil phagocytosis over time, neutrophil functions other than phagocytosis, monocyte HLA-DR expression and safety.

RESULTS

Thirty-eight patients were recruited from five intensive care units (17 randomised to GM-CSF). Mean neutrophil phagocytosis at day 2 was 57.2% (SD 13.2%) in the GM-CSF group and 49.8% (13.4%) in the placebo group, p=0.73. The proportion of patients with neutrophil phagocytosis≥50% at day 2, and monocyte HLA-DR, appeared significantly higher in the GM-CSF group. Neutrophil functions other than phagocytosis did not appear significantly different between the groups. The most common adverse event associated with GM-CSF was fever.

CONCLUSIONS

GM-CSF did not improve mean neutrophil phagocytosis at day 2, but was safe and appeared to increase the proportion of patients with adequate phagocytosis. The study suggests proof of principle for a pharmacological effect on neutrophil function in a subset of critically ill patients.

Granulocyte-macrophage colony-stimulating factor gene based therapy for acute limb ischemia in a mouse model

BACKGROUND

Granulocyte-colony-stimulating factor (GM-CSF) is a pleiotropic factor for hematopoiesis that stimulates myeloblasts, monoblasts and mobilization of bone marrow stem cells. Therefore, the GM-CSF gene is a potential candidate for vessel formation and tissue remodeling in the treatment of ischemic diseases.

METHODS

A new mouse limb ischemia was established by surgery and gene transfer was performed by injection of 100 microg of a plasmid carrying GM-CSF. Muscle force and weight, histology, capillary density, circulating stem cells and monocytes were determined after 3-4 weeks.

RESULTS

More than 60% of nontreated ischemic animals showed gangrene below the heel after 4 weeks, whereas the GM-CSF gene-treated animals showed only darkening of nails or toes. These animals demonstrated a full recovery of the affected muscles in terms of weight, force and muscle fiber structure, but the muscles of nontreated ischemic animals lost approximately 50% weight, 86% force and their regular structure. When the GM-CSF gene was injected into the contralateral limb, only partial loss was observed, demonstrating a distant effect of GM-CSF. The capillary density in the GM-CSF-treated group was 52% higher in relation to the nontreated group. Blood analysis by flow cytometry showed that the GM-CSF-treated group had 10-20% higher levels of circulating monocytes and Sca-1(+).

CONCLUSIONS

We conclude that the direct administration of GM-CSF gene in limb ischemia had a strong therapeutic effect because it promoted the recovery of muscle mass, force and structure by mobilizing therapeutic cells and augmenting the number of vessels.

Influence of varying doses of granulocyte-macrophage colony-stimulating factor on pharmacokinetics and antibody-dependent cellular cytotoxicity

Recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) is used in immunotherapy for correction of neutropoenia. The optimal dose for activation of immune functions and the pharmacokinetics following repeated administrations is less analysed in depth. In this study, the pharmacokinetics and the effects on haematological functions and antibody-dependent cellular cytotoxicity (ADCC) were analysed in 50 patients with metastatic colorectal carcinoma receiving monoclonal antibody based therapy in combination with Escherichia coli-derived GM-CSF (molgramostim) administered s.c. once daily for 10 days every month over a period of 4 months. Thirty-three patients received a GM-CSF dose of 200-250 microg/m(2)/day. Seventeen patients received GM-CSF doses varying between 65 and 325 microg/m(2)/day in the different treatment cycles. Serum GM-CSF concentration was measured (ELISA) before and 3-4 h after (peak serum concentration) GM-CSF administration days 1, 5 and 10. Prior to therapy, GM-CSF was not detectable in serum. Following repeated daily administrations, the peak serum concentration of GM-CSF gradually decreased on days 5 and 10 compared to day 1 (P < 0.05). During a 10-day treatment cycle, the total number of leukocytes, neutrophils, eosinophils, monocytes and lymphocytes increased. A dose-dependent increment in total white blood cell count and neutrophils was observed. The total numbers of GM-CSF receptor (alpha-subunit) expressing cells (granulocytes and monocytes) increased significantly during treatment while a transient decline in expression intensity was observed at day 5, suggesting a receptor-mediated removal of GM-CSF as a mechanism for the elimination of GM-CSF from circulation. ADCC of peripheral mononuclear cells was decreased at day 10 compared to baseline. An inverse correlation between the dose and ADCC was noted. The data might indicate that high doses of GM-CSF may have a negative impact on ADCC.

Granulocyte and granulocyte macrophage colony-stimulating factors as therapy in human and veterinary medicine

Granulocyte colony-stimulating factors (G-CSFs) and granulocyte macrophage colony-stimulating factors (GM-CSFs) are endogenous cytokines that regulate granulocyte colonies and play a major role in the stimulation of granulopoiesis (neutrophils, basophils and eosinophils) and in the regulation of microbicidal functions. There are numerous pathological conditions in which neutrophils are decreased, the most common being neutropenia associated with cancer chemotherapy, which increases the risk of serious microbial infections developing with the potential for high morbidity and mortality. New methods in molecular biology have led to the identification and cloning of CSF genes and biopharmaceutical production. Since then, CSFs have been widely used for the prevention and treatment of neutropenia associated with cancer chemotherapy, for mobilising haematopoietic cell precursors, and for other neutropenia-related pathologies. This review focuses on the use of CSFs within both human and veterinary medicine. Clinical applications, pharmacology, tolerability and the potential role of these factors in veterinary medicine are considered.

Effect of granulocyte-macrophage colony-stimulating factor on the immune response of circulating monocytes after severe trauma

OBJECTIVE

Severe injury compromises functions of the antigen-presenting immune cells, resulting in an increased vulnerability toward bacterial sepsis. Support of the immune capabilities contributes a desirable therapeutic option in high-risk patients. Factors possessing immunostimulating properties such as granulocyte-macrophage colony-stimulating factor (GM-CSF) may serve as potential tools to compensate immunosuppression caused by severe trauma. In the present study, therefore, GM-CSF was examined with regard to its capacity to overcome trauma-induced down-regulation of immune functions.

DESIGN

Prospective clinical experimental study.

SETTING

University hospital intensive care unit and research facility.

PATIENTS

Severely injured patients with >25 points on the Injury Severity Score.

INTERVENTIONS

Blood samples of severely injured patients were incubated in vitro with 10 ng/mL GM-CSF for 6 hrs.

MEASUREMENTS

Human leukocyte antigen (HLA)-DR expression on monocytes was analyzed by flow cytometry, lipopolysaccharide-induced tumor necrosis factor (TNF)alpha and interleukin-10 production of blood samples was measured by means of enzyme-linked immunoabsorbent assay.

MAIN RESULTS

Compared with blood specimens of healthy donors, ex vivo endotoxin-induced TNF alpha production and HLA-DR expression on monocytes were significantly reduced in blood of trauma patients. Ex vivo treatment of blood specimens with GM-CSF increased HLA-DR expression and TNF alpha production stimulated by lipopolysaccharides in both healthy volunteers and patients on day 1 after trauma. Blood samples of patients with an uneventful recovery showed nearly normal TNF alpha synthesis and HLA-DR expression after 2-3 wks, whereas TNF alpha production and HLA-DR expression of patients with sepsis and multiple organ failure remained at low levels. In the sepsis/multiple organ failure group, GM-CSF also enhanced HLA-DR expression and TNF alpha production, although the levels of the volunteers' blood were not reached.

CONCLUSIONS

The presented data show that trauma- and sepsis-induced depression of monocyte functions can be counteracted by GM-CSF in vitro, suggesting that this substance may serve as support of immune functions in severely injured patients.

A potential role of macrophage activation in the treatment of cancer

One of the functions of macrophages is to provide a defense mechanism against tumor cells. In the last decades the mechanism of tumor cell killing by macrophages have been studied extensively. The tumor cytotoxic function of macrophages requires stimulation either with bacterial cell wall products such as lipopolysaccharide (LPS) or muramyldipeptide (MDP) or with cytokines such as interferon-gamma (IFN-gamma) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Activated macrophages secrete several substances that are directly involved in tumor cell killing i.e. tumor necrosis factor (TNF) and nitric oxide (NO). On the other hand, substances are secreted that are able to stimulate tumor cell growth, depending on the stage and the nature of the tumor. Several clinical trials have been performed aiming at the activation of macrophages or dendritic cells, a subpopulation of the macrophages. In this review we will summarize and discuss experimental studies and clinical trials based on the activation of macrophages.

Recombinant anti-human HER2/neu IgG3-(GM-CSF) fusion protein retains antigen specificity and cytokine function and demonstrates antitumor activity

Anti-HER2/neu therapy of human HER2/neu-expressing malignancies such as breast cancer has shown only partial success in clinical trials. To expand the clinical potential of this approach, we have genetically engineered an anti-HER2/neu IgG3 fusion protein containing GM-CSF. Anti-HER2/neu IgG3-(GM-CSF) expressed in myeloma cells was correctly assembled and secreted. It was able to target HER2/neu-expressing cells and to support growth of a GM-CSF-dependent murine myeloid cell line, FDC-P1. The Ab fusion protein activated J774.2 macrophage cells so that they exhibit an enhanced cytotoxic activity and was comparable to the parental Ab in its ability to effect Ab-dependent cellular cytotoxicity-mediated tumor cell lysis. Pharmacokinetic studies showed that anti-HER2/neu IgG3-(GM-CSF) is stable in the blood. Interestingly, the half-life of anti-HER2/neu IgG3-(GM-CSF) depended on the injected dose with longer in vivo persistence observed at higher doses. Biodistribution studies showed that anti-HER2/neu IgG3-(GM-CSF) is mainly localized in the spleen. In addition, anti-HER2/neu IgG3-(GM-CSF) was able to target the HER2/neu-expressing murine tumor CT26-HER2/neu and enhance the immune response against the targeted Ag HER2/neu. Anti-HER2/neu IgG3-(GM-CSF) is able to enhance both Th1- and Th2-mediated immune responses and treatment with this Ab fusion protein resulted in significant retardation in the growth of s.c. CT26-HER2/neu tumors. Our results suggest that anti-HER2/neu IgG3-(GM-CSF) fusion protein is useful in the treatment of HER2/neu-expressing tumors.

The potential for monocyte-mediated immunotherapy during infection and malignancy--Part II: in vivo activation by exogenous cytokines and clinical applications

The monocyte system exhibits a range of immunological mechanisms that may be harnessed for therapeutic effect against infection and malignancy. The advent of novel therapies aimed at treating infection and malignancy is complemented by a resurgence of clinical interest in immunotherapeutic programmes to treat diseases by modification or direct augmentation of host immunity. Cytokines such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and IFN-gamma modulate the function of monocytes and have been used to experimentally probe the immunotherapeutic potential of monocytes against micro-organisms and malignancy. However, monocytes rarely act alone but communicate with other leukocytes involved in cell-mediated immunity. In particular monocytes cooperate with the T-helper (Th1 and Th2) sub-populations of peripheral lymphocytes. Moreover, sub-populations of monocytes, as identified by the co-expression of membrane-associated CD14 and CD16, have been shown to exist. At the preclinical level, this provides a unique opportunity to explore the effect of immunotherapeutic strategies on the function of monocyte sub-populations against infectious or malignant challenge and may allow immunotherapeutic strategies to be targeted towards specific monocyte sub-populations. Preclinical and clinical studies in human subjects suggest that GM-CSF and other cytokines such as IFN-gamma are the most promising biological response modifiers for augmenting monocyte-mediated immunity. In this review, the immunotherapeutic potential of the monocyte system will be discussed in the context of combating microbial and malignant disease.

Decrease in arterial oxygen partial pressure within the first 24 h of rhGM-CSF administration in AML patients

GM-CSF may induce pulmonary complications, such as dyspnea with temporary decreases in oxygen saturation described as first dose effect for higher dosages of intravenous rhGM-CSF. This study investigated possible pulmonary disturbances in adult de novo AML patients receiving yeast rhGM-CSF 24 h prior to chemotherapy under phase II/III conditions. Eighteen patients were monitored for 22 treatment episodes. GM-CSF was given s.c. 1 q.d., 2 q.d. or continuously i.v. at 250 micrograms/m2/d 24 h prior to induction chemotherapy (TAD9, n = 18) and consolidation (TAD9, n = 4). Spirometry, bodyplethysmography, single breath-diffusion capacity (DLCO) and arterial blood gas analyses were obtained prior to GM-CSF, and repeated after 24 h. Pulse oxymetric oxygen saturation (saO2) was registered continuously for the first 16 h within day 1 of rhGM-CSF treatment. Patients were aged 21-75 years. The saO2 monitoring did not reveal any first dose effect. PaO2 values decreased from 78.9 mmHg before GM-CSF to 72.8 mmHg after 24 h (p < 0.01, maximum shift 15 mmHg). PaO2 shifts occurred mainly with pre-existing lowered paO2, but otherwise were independent of age, the route of GM-CSF administration, leukocyte levels, or increase of leukocytes with GM-CSF. Increases in AaDO2 reflected the paO2 shifts (p < 0.05). No dyspnea corresponded to these changes. DLCO values did not decrease significantly after 24 h. Summarily, contemporary dosage of yeast rhGM-CSF avoids short-term oxygen desaturations, but leads to clinically benign impairment in oxygen tension, based on ventilation/perfusion mismatches. This should be taken into account for patients starting at subnormal paO2.

Pharmacokinetics of recombinant human granulocyte-macrophage colony-stimulating factor: the effects of zidovudine

Recombinant human granulocyte-macrophage colony-stimulating factor (rHu GM-CSF) enhances bone marrow production of and stimulates granulocytes, macrophages, and eosinophils. Granulocyte-macrophage colony-stimulating factor may be used concomitantly with zidovudine in human immunodeficiency virus (HIV)-positive patients to minimize zidovudine-associated neutropenia. This open-label, randomized, placebo-controlled study was performed to evaluate the pharmacokinetic disposition of rHu GM-CSF in HIV-positive, asymptomatic patients in the absence and presence of concomitant zidovudine administration. Eight participants received rHu GM-CSF (5 micrograms/kg subcutaneously) daily for 4 days in combination with placebo or zidovudine (200 mg orally every 8 hours) in a randomized, crossover fashion, with each study period separated by a 3-day washout phase. Pharmacokinetic blood sampling was performed over 16 hours on days 1 and 4 of both treatment periods, and subsequent analysis of serum was performed using an enzyme-linked immunosorbent assay. Pharmacokinetic results of rHu GM-CSF at steady state (days 4 of periods I and II) in the absence (placebo) and presence of zidovudine included apparent total body clearance, half-life, and apparent volume of distribution, all of which were not significantly altered with concomitant administration of zidovudine. Mean pharmacokinetic results of rHu GM-CSF after the first dose (days 1 of periods I and II) were similar to steady-state values; however, total body clearance was significantly increased at steady state compared with the results of the first dose. Concurrent administration of zidovudine does not influence the pharmacokinetic disposition of rHu GM-CSF after single or multiple doses.

Levels of recombinant human granulocyte colony-stimulating factor in serum are inversely correlated with circulating neutrophil counts

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is effective in countering chemotherapy-induced neutropenia. However, serum rhG-CSF levels cannot be maintained throughout the course of rhG-CSF therapy. The drop in serum rhG-CSF levels may vary with the duration of rhG-CSF administration or with the circulating neutrophil counts. We investigated the relationship between serum G-CSF levels and circulating neutrophil counts and the pharmacokinetics of rhG-CSF for patients with lung cancer who had been treated with myelosuppressive chemotherapy and then with subcutaneous rhG-CSF (lenograstim, 2 micrograms per kg of body weight per day). Twelve patients were randomly assigned to four groups with different rhG-CSF therapy schedules. Serum G-CSF levels were measured by an enzyme immunoassay method. Serum G-CSF levels during the rhG-CSF therapy greatly exceeded endogenous G-CSF levels and were mainly due to the presence of exogenous rhG-CSF rather than increased levels of endogenous G-CSF. Despite the duration of rhG-CSF administration, serum G-CSF levels during rhG-CSF therapy were inversely correlated with circulating neutrophil counts (r2 = 0.73, P < 0.0001). The value for the area under the concentration-time curve of rhG-CSF on the day of neutrophilia was lower than that on the day of neutropenia (P < 0.05). Our results suggest that the fall in serum G-CSF levels during rhG-CSF therapy may result from increased clearance and/or decreased absorption of rhG-CSF, two processes related to circulating neutrophil counts.

Effects of granulocyte-macrophage colony stimulating factor produced in Chinese hamster ovary cells (regramostim), Escherichia coli (molgramostim) and yeast (sargramostim) on priming peripheral blood progenitor cells for use with autologous bone marrow after high-dose chemotherapy

Peripheral blood progenitor cells (PBPCs) were collected without prior association with chemotherapy but after the administration of granulocyte-macrophage colony-stimulating factor (GM-CSF) produced in Chinese hamster ovary cells (CHO-GM, regramostim), Escherichia coli (E. coli-GM, molgramostim), or yeast (Yeast-GM, sargramostim) and used in conjunction with autologous bone marrow after high-dose chemotherapy in 69 patients with breast cancer or melanoma. The mean peripheral white blood cell (WBC) counts increased by 2.2 to 2.7-fold after regramostim, 4.5 to 7.3-fold after molgramostim and 4.3-fold after sargramostim. All patients underwent three leukaphereses. The mean (+/- standard error) total nucleated pheresed cells per kg x 10(8) were 4.15 +/- 0.56, 15.10 +/- 1.77 and 7.24 +/- 1.00 for patients receiving regramostim, molgramostim or sargramostim respectively. The mean (+/- standard error) granulocyte-macrophage colony-forming units per kg x 10(4) mobilized into the PB were 8.75 +/- 3.63, 71.03 +/- 17.85, and 65.11 +/- 18.74 for patients receiving regramostim, molgramostim, or sargramostim respectively. The total mean (+/- standard error) CD34+ cells per kg x 10(7) collected by three leukaphereses were 3.28 +/- 1.62, 1.34 +/- 0.51 and 2.57 +/- 1.93, for patients receiving regramostim, molgramostim or sargramostim respectively. The use of either molgramostim- or sargramostim-primed PBPCs led to complete elimination of absolute leukopenia with a WBC count under 100/mm3 in 64% and 77% of patients treated, respectively. Patients receiving molgramostim-primed PBPCs required fewer red blood cells transfusions than patients receiving regramostim-primed PBPCs (p = 0.0062). Our data indicate that PBPCs collected without prior association with chemotherapy but after either molgramostim or sargramostim with autologous bone marrow support and GM-CSF shorten the hematopoietic recovery after myeloablative chemotherapy in patients with breast cancer or melanoma.

Pharmacokinetics of recombinant human granulocyte-macrophage colony-stimulating factor in children after intravenous and subcutaneous administration

Despite its widespread use, only limited pharmacokinetic data exist for recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF), especially in children. We evaluated the pharmacokinetics of rhGM-CSF in children who had undergone intensive multiagent chemotherapy: 11 children with refractory solid tumors received 500-1500 micrograms/m2 of rhGM-CSF (sargramostim) as a daily 2-h intravenous (iv) infusion, and seven children received subcutaneous (sc) rhGM-CSF at 1500-2000 micrograms/m2/d in two daily injections for 2 weeks. Serum samples obtained before and after rhGM-CSF administration were analyzed for granulocyte-macrophage colony-stimulating factor (GM-CSF) by a bioassay and by ELISA. Concentrations measured by the two methods were highly correlated (r2 = 0.89, p < 0.001). Following 2-h iv infusions, the concentration-time data were best described by a two-compartment, first-order elimination model. The median (range) for rhGM-CSF systemic clearance (CI) was 49 mL/min/m2 (range, 15-118 mL/min/m2), terminal half-life (t1/2) was 1.6 h (range, 0.9-2.5 h), and the time the GM-CSF concentration was > 1 ng/mL was 9 h (range, 6-13 h). The CI was not dose dependent or related to patient age. The absolute neutrophil count day 14 of GM-CSF was significantly related to GM-CSF dosage and platelet count on day 1. There was a weak correlation between AUC and duration of neutropenia (p = 0.05). The sc concentration-time data were best described by a one-compartment model with first-order absorption and elimination. Median apparent clearance was 72 mL/min/m2 (range, 27-231 mL/min/m2) and t1/2 was 2.3 h (range 0.7-3.8 h).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of granulocyte-macrophage colony stimulating factor produced in Chinese hamster ovary cells (regramostim), Escherichia coli (molgramostim) and yeast (sargramostim) on priming peripheral blood progenitor cells for use with autologous bone marrow after high-dose chemotherapy

Peripheral blood progenitor cells (PBPCs) were collected without prior association with chemotherapy but after the administration of granulocyte-macrophage colony-stimulating factor (GM-CSF) produced in Chinese hamster ovary cells (CHO-GM, regramostim), Escherichia coli (E. coli-GM, molgramostim), or yeast (Yeast-GM, sargramostim) and used in conjunction with autologous bone marrow after high-dose chemotherapy in 69 patients with breast cancer or melanoma. The mean peripheral white blood cell (WBC) counts increased by 2.2 to 2.7-fold after regramostim, 4.5 to 7.3-fold after molgramostim and 4.3-fold after sargramostim. All patients underwent three leukaphereses. The mean (+/- standard error) total nucleated pheresed cells per kg x 10(8) were 4.15 +/- 0.56, 15.10 +/- 1.77 and 7.24 +/- 1.00 for patients receiving regramostim, molgramostim or sargramostim respectively. The mean (+/- standard error) granulocyte-macrophage colony-forming units per kg x 10(4) mobilized into the PB were 8.75 +/- 3.63, 71.03 +/- 17.85, and 65.11 +/- 18.74 for patients receiving regramostim, molgramostim, or sargramostim respectively. The total mean (+/- standard error) CD34+ cells per kg x 10(7) collected by three leukaphereses were 3.28 +/- 1.62, 1.34 +/- 0.51 and 2.57 +/- 1.93, for patients receiving regramostim, molgramostim or sargramostim respectively. The use of either molgramostim- or sargramostim-primed PBPCs led to complete elimination of absolute leukopenia with a WBC count under 100/mm3 in 64% and 77% of patients treated, respectively. Patients receiving molgramostim-primed PBPCs required fewer red blood cells transfusions than patients receiving regramostim-primed PBPCs (p = 0.0062). Our data indicate that PBPCs collected without prior association with chemotherapy but after either molgramostim or sargramostim with autologous bone marrow support and GM-CSF shorten the hematopoietic recovery after myeloablative chemotherapy in patients with breast cancer or melanoma.

Clinical implications of cytokine and soluble receptor measurements in patients with newly-diagnosed aggressive non-Hodgkin's lymphoma

Serum levels of 13 different cytokines and receptors were measured serially in 78 patients with aggressive non-Hodgkin's lymphoma (NHL) treated by 4 cycles of an intensive multi-agent chemotherapy regimen. Recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) was administered subcutaneously in 36 of these patients from day + 5 to day + 18 after each chemotherapy. Statistically significantly higher pretreatment levels of interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), the soluble IL-2 receptor (sIL-2r), the soluble transferrin receptor (sTf-r), and neopterin, were observed in NHL patients as compared to controls (p < 0.001 for all molecules). sIL-2r and sTf-r levels correlated with tumor burden (p < 0.001 and p = 0.003, respectively) whereas IL-6 was higher in patients presenting B symptoms (p < 0.001). Cytokine levels progressively declined to normal ranges in responding patients, while they remained elevated in non-responders. Relapsed patients also presented increased concentrations of several molecules. During the administration of GM-CSF, we observed the drastic increase of sIL-2r, while lower elevations were recorded for a number of cytokines, including IL-8, tumor necrosis factor-alpha, interleukin-1 beta, IL-6, and IL-2. However, upon completion of the induction treatment, cytokine/receptor levels were comparable among individuals with the same type of response, whether or not they had received GM-CSF. No single parameter was found to be of prognostic significance, but the combination of elevated IL-10 and of sIL-2r greater than 3000 U/ml selected a subgroup of 7 patients who failed induction treatment (p = 0.002). These results demonstrate that cytokine and soluble receptor measurements can provide valuable informations for a better management of NHL, in terms both of markers to monitor disease activity and of prognostic indicators.

Granulocyte-macrophage colony stimulating factor in acute non-lymphocytic leukaemia

BACKGROUND

Granulocyte-macrophage colony stimulating factor (GM-CSF) is required to maintain and to regulate granulocyte and monocyte productions. It is potentially useful for accelerating and enhancing haemopoietic recovery and neutrophil function.

RESULTS

In acute non-lymphocytic leukaemia (ANLL) the dependence of blast cells on GM-CSF and its role in the development and maintenance of leukaemia are still poorly defined. In vitro exposure of fresh leukaemic blast cells to a wide range of concentrations of GM-CSF leads to a stimulation of cell proliferation in the majority of cases but does not induce any detectable maturation.

CONCLUSIONS

Granulocyte-macrophage colony stimulating factor may be used in the management of ANLL and the myelodysplastic syndrome (MDS) with the aim of: (i) accelerating the recovery of normal haemopoiesis; (ii) increasing cell killing by chemotherapy; and (iii) inducing cell maturation. Therefore the application of GM-CSF can potentially improve treatment outcome in ANLL and is worth testing in a clinical setting.

Detection of soluble interleukin-2 receptor and interleukin-10 in the serum of patients with aggressive non-Hodgkin's lymphoma. Identification of a subset at high risk of treatment failure

BACKGROUND

This study explores the ability of the combined detection of soluble IL-2 receptor (sIL-2r) and interleukin-10 (IL-10) to predict treatment failure in patients with aggressive non-Hodgkin's lymphoma (NHL) and to evaluate the modifications in cytokine measurements induced by the therapeutic administration of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF).

METHODS

Serum levels of sIL-2r and IL-10 were measured serially in 93 patients with newly diagnosed aggressive NHL treated with four courses of a multiagent chemotherapy regimen. GM-CSF was administered subcutaneously in 39 of these patients from day +5 to day +18 after each chemotherapy course.

RESULTS

Pretreatment levels of sIL-2r were greatly elevated in patients with NHL compared with control subjects (P < 0.001), significantly correlating with the Ann Arbor stage (P < 0.001) and beta 2-microglobulin (beta 2-m) concentrations (r = 0.552, P = 0.004). IL-10 was detected in 37 patients at diagnosis, with no correlation with clinicohematologic parameters, and was not detected in the control sample (P < 0.001). Cytokine and receptor levels progressively declined to normal ranges in responding patients, whereas they remained elevated in nonresponders. During administration of GM-CSF, the authors observed an increase of sIL-2r, whereas lower elevations were recorded for IL-10. However, on completion of the induction treatment, cytokine/receptor levels were comparable in patients with the same type of response, whether or not they had received GM-CSF. In the five patients who were investigated at relapse, the levels of sIL-2r, beta 2-m, and lactic dehydrogenase were found to be elevated. IL-10 concentrations were high in three of these patients: two already had detectable levels at presentation, whereas one tested positive only on recurrence. No single parameter was associated with response to therapy, but the combination of elevated IL-10 and sIL-2r concentrations greater than 3000 U/ml resulted in a subset of eight patients who failed induction chemotherapy (P < 0.001). In addition, six of eight patients with high IL-10 and beta 2-m concentrations greater than 3.3 mg/l had an unfavorable outcome (P = 0.003). A multivariate regression model was used to identify sIL-2r (P = 0.004) and beta 2-m (P = 0.043) as the covariates that amplified the prognostic ability of IL-10.

CONCLUSIONS

sIL-2r and IL-10 measurements provide valuable information for better management of patients with NHL as markers to monitor disease activity and as prognostic indicators.

Analysis of radiolabeled CHO cell-derived rHuGM-CSF pharmacokinetics and biodistribution in rhesus monkeys following intravenous and subcutaneous injection

The purpose of these studies was to examine the biodistribution and pharmacokinetics of radiolabeled human CHO cell-derived rHuGM-CSF in normal Rhesus monkeys (Macaca mulatta) following intravenous (i.v.) and subcutaneous (s.c.) injection. A dual radioisotope tracer technique was utilized to monitor the behavior of rHuGM-CSF in vivo. Recombinant HuGM-CSF was radiolabeled with I-123 (a 13.2 h half-life, 140 KeV pure gamma emitting radionuclide detected using gamma scintigraphic imaging) using a mild chloramine T reaction. A separate preparation of rHuGM-CSF radiolabeled with S-35 methionine by bioincorporation in tissue culture was mixed with the I-123-labeled protein, permitting comparison of data obtained from the two radiolabels. Two dose levels of rHuGM-CSF were used for i.v. bolus (15 and 300 micrograms/kg) and s.c. (10 and 100 micrograms/kg) studies. The results of these studies demonstrated that the co-administered I-123 rHuGM-CSF and S-35 rHuGM-CSF followed similar blood elimination kinetics after i.v. or s.c. injection. Following i.v. bolus injection, rHuGM-CSF was found to rapidly distribute to all central body cavity high blood flow organs, followed by rapid uptake in the kidneys and elimination in the urine. There were no differences in the pharmacokinetic values obtained for I-123- and S-35-labeled rHuGM-CSF nor for the two dose levels examined. Following, s.c. injection, I-123- and S-35-labeled rHuGM-CSF were found to reach maximal plasma levels after approximately 16 h. The primary route of elimination was the urine. Monkeys previously exposed to rHuGM-CSF were found to have circulating antibodies to rHuGM-CSF. Studies in these animals revealed a significantly altered distribution and clearance of radiolabeled rHuGM-CSF, with the majority of the injected activity being cleared by the liver.

Endogenous haemopoietic growth factors in neutropenia and infection

Haemopoietic growth factors (HGFs) are being administered to patients with neutropenic fever; however, little is known about the endogenous HGF response in these patients. Specific assays were used to study four HGFs, granulocyte (G-) CSF, granulocyte-macrophage (GM-) CSF, macrophage (M-) CSF and interleukin (IL-) 6 levels in the blood of patients with neutropenic fever (46 episodes). For comparison, levels were also measured in three control populations: normals (20), afebrile neutropenic (14), and bacteraemic but not neutropenic patients (20). In febrile patients, levels of G-CSF (median, range) (0.46, < 0.10-142 ng/ml). IL-6 (0.054, 0.005-24.3 ng/ml) and M-CSF (18.5, 9.9-79.1 ng/ml) were elevated compared with afebrile subjects (< 0.10, < 0.10-1.62 ng/ml). (0.008, 0.002-0.024 ng/ml) and (6.45, < 5.0-31.3 ng/ml) respectively. GM-CSF was not elevated (< 0.02, < 0.02-8.0 ng/ml) compared with afebrile subjects (0.021, < 0.02-0.20 ng/ml). Variables significantly associated (P < 0.05) with elevated cytokine levels were determined by multiple regression analyses. Factors associated with G-CSF elevation were fever, neutropenia, pathogen type and raised bilirubin and creatinine. In contrast, neutropenia was not associated with IL-6 elevation although there was an association between IL-6 elevation and fever, Gram-negative and fungal infections and raised creatinine and bilirubin. M-CSF elevation was associated with fever, renal impairment and known pathogen. Elevated G-CSF and IL-6 levels normalized rapidly (hours-days) with the resolution of infection, whereas M-CSF concentrations remained elevated for up to 10 d. Cytokine levels remained elevated in septic neutropenic patients who did not recover. In summary, G-CSF, IL-6 and M-CSF levels were significantly elevated in sepsis. In contrast, GM-CSF levels were not elevated. These studies should assist the development of therapeutic strategies using HGFs in the treatment of sepsis.

A pilot study of low-dose recombinant human granulocyte-macrophage colony-stimulating factor in chronic neutropenia

Recombinant human granulocyte macrophage colony stimulating factor (rhGM-CSF) is under investigation for the treatment of a wide range of haematological disorders. At commonly used doses of > 120 micrograms/m2/d, extramedullary toxicity is common. We report the effects of low-dose (LD) rhGM-CSF in patients with chronic neutropenia related to HIV infection, myelodysplastic syndrome and idiopathic neutropenia. Nine patients with a mean pre-treatment neutrophil count of 0.6 x 10(9)/l (range 0.2-1.4 x 10(9)/l) received daily rhGM-CSF at doses of between 5 and 15 micrograms/m2. Eight patients responded with a mean post-treatment ANC of 3.2 x 10(9)/l (range 1.9-4.6 x 10(9)/l). There was no significant therapy-related morbidity. We conclude that in chronic neutropenia, LD rhGM-CSF is an acceptable treatment which has important cost/benefit implications.

Comparative pharmacokinetics of single-dose administration of mammalian and bacterially-derived recombinant human granulocyte-macrophage colony-stimulating factor

Pharmacokinetics of recombinant human non-glycosylated bacterially-synthesized (E. coli) granulocyte-macrophage colony-stimulating factor (GM-CSF) were studied following single intravenous (i.v.) and subcutaneous (s.c.) bolus injection, and compared to equivalent doses of glycosylated mammalian-derived CHO-GM-CSF. Each route of administration gave a different GM-CSF concentration-time profile. The highest peak serum concentrations (Cmax) were observed following i.v. bolus injection. After i.v. administration, a two-phase decline in concentration was noted for both types of GM-CSF with a significantly shorter t1/2 alpha of 7.8 minutes for the E. coli GM-CSF versus 20.0 min for the CHO-GM-CSF, while no significant difference was observed for the terminal phase. Following s.c. administration of equivalent doses, a higher peak serum concentration was observed in the E. coli-treated patients and, again, a faster elimination where pretreatment serum levels were reached after 16-20 h, versus more than 48 h after administration of CHO-GM-CSF. Although the non-glycosylated E. coli GM-CSF thus seems to undergo a faster elimination that the glycosylated CHO-GM-CSF no significant difference could be demonstrated in the in vivo effect of corresponding doses of the two compounds with respect to stimulation of granulopoiesis--with reservation for small patient numbers and a large individual variations in response.

Granulocyte-macrophage colony-stimulating factor. Preliminary observations on the influences of dose, schedule, and route of administration in patients receiving cyclophosphamide and carboplatin

BACKGROUND

In an attempt to learn how best to administer granulocyte-macrophage colony-stimulating factor (GMCSF), the authors performed a Phase I study of this agent. They were interested in the influences of dose, schedule, and route of administration on the effects of GMCSF in patients receiving standardized 1-day regimens of cyclophosphamide (CYCLO) and carboplatin (CBDCA).

METHODS

Between June 1988 and March 1991, 57 patients with advanced cancer received GMCSF in association with CYCLO 1 g/m2 plus CBDCA 225-700 mg/m2. After the first dose escalation to 300 mg/m2 of CBDCA, patients who had previously received chemotherapy or radiation therapy were excluded. GMCSF was administered in three different doses, five different schedules, and by two different routes. Altogether, 17 different treatment groups were observed. In addition, 24-hour GMCSF serum concentration curves were charted in four patients.

RESULTS

Using four sequential groups of three patients each who had received myelosuppressive treatment, treatment with CYCLO 1 g/m2 and CBDCA 225 mg/m2, the apparent superiority of daily subcutaneous injection over 30-minute daily IV infusion of GMCSF was demonstrated graphically. Subsequently, the authors observed apparent enhancement of GMCSF effects beyond those produced by the initially selected 20-day basic 10 micrograms/kg daily SC regimen beginning 2 days after chemotherapy. When administered SC every 12 hours for 14 days beginning the day after chemotherapy, GMCSF appeared to ameliorate the severity of both leukopenia and thrombocytopenia. These effects permitted escalation of the CBDCA dose to 700 mg/m2 (with 1 g/m2 of CYCLO) before cytotoxic tolerance limits were reached. Graphic small group comparisons suggest that GMCSF given SC in doses of 5 micrograms/kg twice daily may produce comparable leukocyte and platelet support after chemotherapy with lower toxicity than occurs from higher doses. Prechemotherapy priming with GMCSF twice daily for an additional 4 days (days -6 to -3) seems to ameliorate postchemotherapy cytopenias further but at the cose of some increased risk of GMCSF toxicity. Although most of the toxic effects of moderate-dose GMCSF are controlled by antihistamines and ibuprofen, oral glucocorticoids (e.g., prednisone, 10 mg twice daily during the second week of GMCSF administration) may be required in patients with serositis, pulmonary infiltrates, or severe skin eruptions.

CONCLUSIONS

Our observations suggest that GMCSF should be administered SC in doses of approximately 5 micrograms/kg every 12 hours for 10-14 days beginning the day after chemotherapy. Prechemotherapy priming with these same doses for four additional days (days -6 to -3) may additionally ameliorate postchemotherapy leukopenia and thrombocytopenia, but with increased risk of toxicity.

Myelosuppressive effects of cytosine arabinoside (Ara-C) on growth factor-dependent human long-term bone marrow cultures (LTBMC)

Freshly isolated human mononuclear cells (5 x 10(6)) were incubated in a Dexter-type long-term bone marrow culture (LTBMC) system to study myelosuppressive effects of cytosine arabinoside (Ara-C) in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin 3 (IL-3). Differential counts (dc) of the nonadherent cell (nac) populations, starting with culture initiation, were performed weekly. After one week of simultaneous incubation of LTBMCs with either cytokine (100 ng/ml) and Ara-C (1 microgram/ml), nac numbers were markedly reduced compared to controls. Dc after week 1 of culture demonstrated significant decreases of all myeloid cell fractions except for macrophages, which remained unaffected. Growth factor-dependent LTBMCs exposed to Ara-C showed recovery of promyelocytic, metamyelocytic, and polymorphonuclear cell numbers up to control values (cultures without Ara-C exposure) in weeks 3 to 6. Intriguingly, high-proliferative, early myeloid progenitor cells (myeloblasts) appeared at high rates only in IL-3-dependent LTBMCs with and without Ara-C exposure. Nac numbers in LTBMCs exposed to Ara-C alone declined rapidly; after two weeks of culture only negligible numbers of viable nac were maintained. Plating experiments of nac in the presence of GM-CSF were performed weekly. Granulocyte-macrophage colony-forming units (CFU-GM) yields for nac from IL-3 LTBMCs were consistently higher than those for nac from GM-CSF LTBMCs. Ara-C exposure reduced CFU-GM numbers generated with nac from GM-CSF LTBMCs to 10% of GM-CSF controls (week 1). However, CFU-GM numbers grown with nac from Ara-C exposed GM-CSF-dependent LTBMCs recovered above control levels after week 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical pharmacokinetic studies of a human haemopoietic growth factor, GM-CSF

The pharmacokinetics of glycosylated recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) was studied following intravenous (i.v.) and subcutaneous (s.c.) bolus injection of rhGM-CSF, 8 micrograms kg-1 employing a sensitive radioimmunoassay. After a single i.v. bolus injection, an initial high serum level of rhGM-CSF was observed, followed by a rapid decrease that occurred in two phases with a half-life (t1/2) alpha of 20.0 +/- 5 min and a t1/2 beta of 68.3 +/- 8 min. Following s.c. bolus injection the absorption was more prolonged. Peak serum concentrations did not occur until about 15-20 h, and were followed by a more protracted elimination than by the i.v. route. In all patients the single rhGM-CSF injection led to an increase in peripheral white blood cells (WBC), after a temporary drop of 2-5 h duration. The increase in WBC was of longer duration after s.c. than after i.v. bolus treatment. Since the subcutaneous administration leads to prolonged serum concentration of rhGM-CSF and prolonged increase in peripheral WBC, it seems preferable to i.v. bolus injection, and as effective as continuous i.v. infusion.

The Florey Lecture, 1991. The colony-stimulating factors: discovery to clinical use

The four colony-stimulating factors, GM-GSF, G-CSF, M-CSF and Multi-CSF, are specific glycoproteins with a likely common ancestral origin which interact to regulate the production, maturation and function of granulocytes and monocyte-macrophages. Each has been purified and produced in active recombinant form. Animal studies have shown the ability of injected CSF to increase the production and functional activity of granulocytes and macrophages in vivo and to enhance resistance to infections. These studies have led to the current extensive clinical use of CSFs to promote the formation and function of granulocytes and macrophages in a wide variety of disease situations in which there is an associated risk of serious infections. Although our knowledge of the control of haemopoiesis remains incomplete, the approaches used to develop the CSFs can be used to extend this knowledge, with the promise of the introduction into clinical medicine of additional effective therapeutic agents.