Effect of granulocyte colony stimulating factor on neutropenia induced by cytotoxic chemotherapy

Purification and characterization of two recombinant human granulocyte colony-stimulating factor glycoforms. Pharmacokinetic and activity studies of single-dose administration in mice

Two recombinant human granulocyte colony-stimulating factor (rhG-CSF) isoforms were isolated from the medium conditioned by an engineered Chinese hamster ovary (CHO) cell line. The two rhG-CSFs were characterized and were found to differ in the carbohydrate structure attached to Thr-133. The glycoform, referred to as Peak 1, contains the O-linked glycan Neu5Ac(alpha 2-3)Gal(beta 1-3)GalNAc; the Peak 2 glycoform contains the O-linked glycan Neu5Ac(alpha 2-3)Gal(beta 1-3)[Neu5Ac(alpha 2-6)]GalNAc. The two glycoforms displayed a similar biological activity in cultures of a mouse 32D C13 cell line and human bone-marrow myelo-monocytic progenitor cells (CFU-GM). In the latter test both glycoforms displayed a higher activity than nonglycosylated rMet-hG-CSF from Escherichia coli. The pharmacokinetic profile and activity of the two rhG-CSF glycoforms and of a mixture of them (Pool) were investigated in mice treated with a single injection of rhG-CSF at the doses of 125 micrograms and 250 micrograms/kg, given via the intravenous (i.v.) and the subcutaneous (s.c.) route, respectively. The plasma concentration profiles obtained were similar for all three substances and did not show any relevant differences in absorption or elimination. The pharmacokinetic parameters indicate that the three substances have similar area under the curve (AUCs), volumes of distribution, and terminal half-life. Furthermore, our data indicate a high bioavailability of the two different glycoforms of rhG-CSF when given to mice via the s.c. route either singularly or as a mixture. Detectable levels of rhG-CSF persisted for more than 8 h in the i.v. and more than 24 h in the s.c. route of administration. All three substances induced early neutrophilia in mice. All rhG-CSF-treated mice developed a two-four-fold rise in neutrophil counts as early as 4 h after the intravenous and 2 h after the subcutaneous injection. Relatively high levels of neutrophils were maintained for at least 8 and 24 h after i.v. and s.c. administration, respectively.

Erythropoietin addition to granulocyte colony-stimulating factor abrogates life-threatening neutropenia and increases peripheral-blood progenitor-cell mobilization after epirubicin, paclitaxel, and cisplatin combination chemotherapy: results of a randomized comparison

PURPOSE AND METHODS

The ability of granulocyte colony-stimulating factor (G-CSF) plus erythropoietin (EPO) treatment was compared in a randomized fashion with that of G-CSF treatment alone in promoting hematologic recovery and peripheral-blood progenitor-cell (PBPC) mobilization in previously untreated patients with advanced ovarian cancer who underwent their first course of epirubicin, paclitaxel, and cisplatin (ETP) chemotherapy during a phase II study of intensive outpatient ETP chemotherapy followed by high-dose carboplatin, etoposide, and melphalan (CEM) late intensification with PBPC support.

RESULTS

Comparative analysis of hematologic recovery of 50 randomized patients, after ETP chemotherapy, showed that life-threatening neutropenia occurred in 88% of the patients treated with G-CSF alone, whereas it occurred in only 4% of patients treated with G-CSF + EPO. Significantly different WBC and polymorphonuclear leukocyte (PMN) counts were observed in the two distinct arms on the day of WBC nadir (P <.0001 and P <.0001, respectively). Moreover, the addition of EPO to G-CSF increased PBPC mobilization and collection as compared with that in G-CSF-treated patients (P =.0009 and P =.0026, respectively), who required a significantly higher number of leukaphereses than G-CSF + EPO-treated patients (P =.0076) to obtain the planned minimum dose of PBPCs. Qualitative analysis by cloning assay of PBPCs collected in both arms revealed that G-CSF- and G-CSF + EPO-mobilized PBPCs have comparable in vitro functional properties.

CONCLUSION

This randomized comparison revealed that EPO significantly increases most of the hematologic effect produced by G-CSF administration after chemotherapy. This biologic property of EPO translated in vivo into a global improvement of patients' hematologic status.

Pharmacokinetics of glycosylated recombinant human granulocyte colony-stimulating factor (lenograstim) in healthy male volunteers

AIMS

The aim of this open, randomised, crossover, parallel-group study was to compare the pharmacokinetics and neutrophil responses of lenograstim when administered subcutaneously (s.c.) and intravenously (i.v.).

METHODS

A total of 27 healthy male volunteers was recruited. Lenograstim doses (0.5, 2, 5, or 10 microg kg(-1)) were administered s.c. or i.v. once-daily for 5 days, and then, after a 10-day washout period, vice versa for a further 5 days. Lenograstim concentrations and absolute neutrophil counts (ANCs) were measured predosing and postdosing on days 1 and 5.

RESULTS

Maximum serum concentrations of lenograstim were higher following i.v. dosing (mean 5.2-185.5 vs 0.7-30.0 ng ml(-1) after s.c. dosing on day 1) and attained sooner (median 0.5-0.8 vs 4.7-8.7 h on day 1). However, apparent elimination half-lives of lenograstim were longer following s.c. dosing (mean 2.3-3.3 vs 0.8-1.2 h after i.v. dosing on days 1 and 5). ANCs increased in a dose-dependent manner with both routes of lenograstim, but more prolonged rises and higher ANC peaks were attained following s.c. doses. ANCs peaked on day 6 following 5 microg kg(-1) s.c. doses (mean peak=26.3x10(9) cells l(-1)), but on day 2 after 5 microg kg(-1) i.v. doses (mean peak = 12.4 x 10(9) cells l(-1)). Irrespective of route, the most common adverse events were headaches and back/spine pain; at doses of up to 5 microg kg(-1) these were mild and generally well tolerated.

CONCLUSIONS

While supporting the use of both s.c. and i.v. administered lenograstim to treat neutropenia, these results demonstrate that neutrophil responses are more sustained and prolonged with the s.c. route.

The efficacy of recombinant thrombopoietin in murine and nonhuman primate models for radiation-induced myelosuppression and stem cell transplantation

Radiation-induced pancytopenia proved to be a suitable model system in mice and rhesus monkeys for studying thrombopoietin (TPO) target cell range and efficacy. TPO was highly effective in rhesus monkeys exposed to the mid-lethal dose of 5 Gy (300 kV x-rays) TBI, a model in which it alleviated thrombocytopenia, promoted red cell reconstitution, accelerated reconstitution of immature CD34+ bone marrow cells, and potentiated the response to growth factors such as GM-CSF and G-CSF. In contrast to the results in the 5 Gy TBI model, TPO was ineffective following transplantation of limited numbers of autologous bone marrow or highly purified stem cells in monkeys conditioned with 8 Gy TBI. In the 5 Gy model, a single dose of TPO augmented by GM-CSF 24 h after TBI was effective in preventing thrombocytopenia. The strong erythropoietic stimulation may result in iron depletion, and TPO treatment should be accompanied by monitoring of iron status. This preclinical evaluation thus identified TPO as a potential major therapeutic agent for counteracting radiation-induced pancytopenia and demonstrated pronounced stimulatory effects on the reconstitution of immature CD34+ hemopoietic cells with multilineage potential. The latter observation explains the potentiation of the hematopoietic responses to G-CSF and GM-CSF when administered concomitantly. It also predicts the effective use of TPO to accelerate reconstitution of immature hematopoietic cells as well as possible synergistic effects in vivo with various other growth factors acting on immature stem cells and their direct lineage-committed progeny. The finding that a single dose of TPO might be sufficient for a clinically significant response emphasizes its potency and is of practical relevance. The heterogeneity of the TPO response encountered in the various models used for evaluation points to multiple mechanisms operating on the TPO response and heterogeneity of its target cells. Mechanistic mouse studies made apparent that the response of multilineage cells shortly after TBI to a single administration of TPO is quantitatively more important for optimal efficacy than the lineage-restricted response obtained at later intervals after TBI and emphasized the importance of a relatively high dose of TPO to overcome initial c-mpl-mediated clearance. Further elucidation of mechanisms determining efficacy might very well result in a further improvement, e.g., following transplantation of limited numbers of stem cells. Adverse effects of TPO administration to myelosuppressed or stem cell transplanted experimental animals were not observed.

In vitro and in vivo expansion of stem cell populations

Expansion of hemopoietic stem cells occurs in vivo following transplantation of limited numbers of bone marrow cells or of highly purified stem cells. Stem cell expansion can in principle be achieved in vitro and also be promoted in vivo by growth factor treatment, notably with thrombopoietin. Advances in identification of stromal elements, growth factors and culture conditions that stimulate immature hemopoietic stem cell proliferation may result in effective stem cell expansion protocols and contribute to efficient retrovirally mediated gene transfer. In vivo expansion of immature cells by growth factor treatment may both be a valid alternative and an adjuvant to in vitro expansion.

Purification and characterization of recombinant human granulocyte colony-stimulating factor (rhG-CSF) derivatives: KW-2228 and other derivatives

Various derivatives of recombinant human granulocyte colony-stimulating factor (rhG-CSF) have been overproduced in Escherichia coli with the strong, inducible trp promoter. A derivative designated as KW-2228 in which the amino acids were replaced at five positions showed more potent granulopoietic activity and stability than those of wild-type both in vitro and in vivo. The purification involved a sequential renaturation process and three-step chromatography. Refolding succeeded in very high yield using a urea system. The purity of KW-2228 was greater than 99% as measured by SDS-PAGE and HPLC analysis. According to circular dichroism and nuclear magnetic resonance spectroscopy, rhG-CSF and KW-2228 have very similar conformations. This suggests that the substitution of five amino acids does not appreciably change the conformation of hG-CSF. KW-2228 ([Ala1, Thr3, Tyr4, Arg5, and Ser17]-hG-CSF) and derivative A ([Ala1, Thr3, Tyr4, Arg5]-hG-CSF) are easily crystallized and they show similar in vitro activity. On the other hand, neither rhG-CSF nor derivative B ([Ser17]-hG-CSF) are crystallized under the same conditions. Thus, the four amino acid substitution (Ala1, Thr3, Tyr4, Arg5) of the N-terminal sequence may facilitate crystallization. The change of Cys17 to Ser may not influence the stability and activity of hG-CSF.

A randomized, placebo-controlled trial of granulocyte colony-stimulating factor administration to newborn infants with neutropenia and clinical signs of early-onset sepsis

OBJECTIVE

To determine whether recombinant human granulocyte colony-stimulating factor (G-CSF) administration: 1) accelerates production of neutrophils; 2) increases bone marrow stored and precursor neutrophils; and 3) is safe in newborn infants with neutropenia and clinical signs of early-onset sepsis.

STUDY DESIGN

We randomized 20 infants with neutropenia and clinical signs of early-onset sepsis in the first 3 days of life to receive G-CSF (10 microg/kg/d) or placebo for 3 days. Entry criteria included neutropenia as defined by Manroe criteria, an elevated immature to total neutrophil ratio [(I/T) >/=0.25], and a requirement for ventilatory support. Cultures were obtained and antibiotics initiated on all study infants. Circulating absolute neutrophil count (ANC), I/T ratio, bone marrow neutrophil storage pool (NSP) and neutrophil proliferative pool (NPP), and plasma G-CSF concentrations were evaluated. Also, severity of illness as determined using the Score for Neonatal Acute Physiology (SNAP), morbidity, and mortality were recorded.

RESULTS

Circulating ANC increased in both G-CSF and placebo recipients by day 1. Also, the I/T neutrophil ratio decreased in both G-CSF and placebo recipients. There were no significant differences in the ANC or I/T ratio between the two groups during the study period. Similarly, bone marrow NSP and NPP did not differ between G-CSF and placebo recipients at study entry or day 2. No differences were observed in the secondary outcome measures including severity of illness, morbidity, and mortality.

CONCLUSIONS

Administration of recombinant G-CSF to infants with neutropenia and clinical signs of early-onset sepsis did not increase circulating ANC, or bone marrow NSP and NPP compared with placebo. No differences were observed between G-CSF and placebo recipients in severity of illness, morbidity, or mortality. No adverse effects of G-CSF administrations were noted.

Randomized multicentre trial of filgrastim as an adjunct to combination chemotherapy for Hodgkin's disease. West of Scotland Lymphoma Group

This study was intended to ascertain whether the adjunctive administration of filgrastim (r metHuG-CSF, Amgen) would influence the dose intensity of chemotherapy or the morbidity of myelosuppression in patients receiving MOPP or MOPP/EVAP hybrid chemotherapy for Hodgkin's disease. In a prospective randomized trial, two regimens for the treatment of Hodgkin's disease were compared. The substudy described here randomized patients receiving either regimen to receive filgrastim on the days when chemotherapy was not administered. During chemotherapy, parameters of myelosuppression were documented, including dose delays, the severity and duration of neutrophil and platelet nadirs, infective episodes, and resulting hospital admissions. In the MOPP arm, 13/25 eligible patients, and, in the MOPP/EVAP arm, 12/22 eligible patients, received filgrastim. The use of filgrastim made no statistically significant difference to the administered dose intensity for either MOPP (P = 0.57, 95% confidence interval (CI) 15-point increase to 8-point reduction) or MOPP/EVAP (P = 0.53; 95% CI 7-point increase to 11-point reduction). In patients receiving MOPP, filgrastim reduced the median duration of leucopenia (P = 0.007) and the severity of the white blood cell nadir (P = 0.036); however, no statistically significant effect (at the 5% level) was seen in platelet or haemoglobin nadirs, the number of days of in-patient hospitalization, the number of admissions for infective complications, the incidence, grade or duration of infections, or the incidence of febrile neutropenia. In patients receiving MOPP/EVAP, filgrastim had no significant effect on the duration or depth of leucopenia but was associated with a reduction in the median haemoglobin (P = 0.002) and platelet nadirs (P = 0.015). No effect on the above listed sequelae of myelosuppression was influenced by the administration of filgrastim. This study, although small, suggests that the routine use of filgrastim, aimed at influencing the administered dose intensity of conventional dose chemotherapy in Hodgkin's disease, is not warranted.

High-dose cytarabine-containing chemotherapy with or without granulocyte colony-stimulating factor for children with acute leukemia

We sought to determine the role of granulocyte colony-stimulating factor (G-CSF) as an adjunct therapy in high-dose cytarabine-containing chemotherapy (HD C/T) for children with acute leukemia. Seventeen patients, aged 9 months to 18 years old, 8 ALL and 9 AML, were treated with cytarabine (Ara-C) 1 g/m2 q12h for 8 doses with mitoxantrone, idarubicin, VP-16, or asparaginase. A total of 71 courses of HD C/T was given. G-CSF was not used in 14 courses (Group A). Prophylactic G-CSF was given in 57 courses (Group B) as 200 microg/m2/d SC started one day after the completion of HD C/T and continued until the neutrophil recovery was maintained. The incidences of sepsis per course in Group A and Group B were 35.7% (5/14) and 40.4% (23/57), respectively. While 2 patients in Group A died of sepsis or pneumonia, none in Group B died. The mortality and delay in chemotherapy were fewer in Group B (P = 0.037 and 0.0006, respectively, Fisher exact test). There was a shorter average number of days of neutrophil <500/cumm, antibiotic usage, fever, and hospital stay in Group B (11, 8, 5, 17 days in Group B vs. 21, 17, 10, 37 days in Group A; P = 0.0001, log-rank test; 0.0006, 0.0023, 0.0001, Wilcoxon rank sum test, respectively). The incidence of neutropenic fever was lower in Group B, but the difference did not reach statistical significance (P = 0.06, Fisher exact test). We conclude that G-CSF as an adjunct therapy in HD C/T is effective in reducing mortality, days of neutropenia, antibiotic usage, fever, hospital stay, and frequency of delay in chemotherapy. The efficacy of this treatment approach requires further testing in a randomized, controlled trial.

Assessing the value of a new pharmaceutical. A feasibility study of contingent valuation in managed care

OBJECTIVES

The authors assessed the feasibility and construct validity of the contingent valuation method for measuring the monetary value to healthy enrollees in a health maintenance organization of a new drug, filgrastim, as prophylaxis against febrile neutropenia after chemotherapy treatment for cancer.

METHODS

A random sample of 220 enrollees from a closed-panel staff-model health maintenance organization who did not have cancer were interviewed. Chemotherapy, febrile neutropenia and filgrastim were described by video and decision board. Questions were asked in two different scenarios: (1) User-based: Assuming they were at the point of consumption and about to receive chemotherapy, what is the maximum they would be willing to pay to receive filgrastim? and (2) Insurance-based: Given they were at risk of cancer in the future, what is the maximum they would be willing to pay in additional monthly insurance premiums to add filgrastim to the plan? In a second insurance scenario where respondents were told that filgrastim was covered, what is the minimum reduction in premium that persons were willing to accept to relinquish coverage of the drug? A 2 x 2 factorial design was used to contrast two bidding algorithms to test for starting point bias and two 5-yearly prior risks of cancer, 1/200 versus 1/100. Main effects were tested by ANCOVA controlling for age, sex, health, and income.

RESULTS

Demographics of experimental cells were similar. No evidence was found of significant starting point bias. For user-based questions, as expected, willingness-to-pay increases with febrile neutropenia risk reduction, but at a declining marginal rate. Despite careful presentation of information to respondents, willingness-to-pay for insurance was higher in the lower prior risk group. Consistent with previous contingent valuation studies, the authors of the present study found evidence that willingness-to-accept exceeds willingness-to-pay for coverage of the same benefit.

CONCLUSIONS

An insurance-based contingent valuation study is feasible in a health maintenance organization. Construct validation evidence was encouraging, with the exception of the test for prior risk of cancer; however, this was a between-person contrast and may have been confounded by other factors.

Cyclophosphamide, Doxorubicin, Vincristine, Prednisone Dose Intensification With Granulocyte Colony-Stimulating Factor Markedly Depletes Stem Cell Reserve for Autologous Bone Marrow Transplantation

Hematopoietic growth factors allow dose escalation of chemotherapy. This approach may potentially reduce the quality and quantity of hematopoietic stem cells. The capacity of stem cells recovered after dose intensification to support myeloablative therapy is unknown. In patients with previously untreated advanced follicular lymphoma, trilineage hematopoietic engraftment was compared in two sequential trials of induction therapy (standard dose cyclophosphamide, doxorubicin, vincristine, prednisone [CHOP] without growth factors or dose intensification CHOP supported by granulocyte colony-stimulating factor [G-CSF ]) followed by identical myeloablative therapy and autologous stem cell support. Neutrophil, platelet, and red blood cell (RBC) engraftment were compared on days 100, 180, and 360 after stem cell reinfusion. Despite similar patient characteristics including reinfusion of comparable numbers of marrow mononuclear cells, after stem cell transplantation, a highly significant prolongation of neutrophil and platelet engraftment was seen in patients who received high dose CHOP and G-CSF in comparison to standard dose CHOP. These findings suggest that dose intensified chemotherapy and G-CSF recruited stem cells into a proliferative phase and that G-CSF allowed retreatment at a time when stem cells were susceptible to damage by cytotoxic therapy. Such inadequate hematologic engraftment after myeloablative therapy might be avoided by either shortening the time that growth factor support is administered, lengthening the interval between cycles, or attempting to repetitively harvest additional stem cells either from the marrow or peripheral blood. Therefore, intensification of chemotherapy with growth factor support must be used with caution if stem cells are to be used to support myeloablative therapy.

Cyclophosphamide, Doxorubicin, Vincristine, Prednisone Dose Intensification With Granulocyte Colony-Stimulating Factor Markedly Depletes Stem Cell Reserve for Autologous Bone Marrow Transplantation

Hematopoietic growth factors allow dose escalation of chemotherapy. This approach may potentially reduce the quality and quantity of hematopoietic stem cells. The capacity of stem cells recovered after dose intensification to support myeloablative therapy is unknown. In patients with previously untreated advanced follicular lymphoma, trilineage hematopoietic engraftment was compared in two sequential trials of induction therapy (standard dose cyclophosphamide, doxorubicin, vincristine, prednisone [CHOP] without growth factors or dose intensification CHOP supported by granulocyte colony-stimulating factor [G-CSF ]) followed by identical myeloablative therapy and autologous stem cell support. Neutrophil, platelet, and red blood cell (RBC) engraftment were compared on days 100, 180, and 360 after stem cell reinfusion. Despite similar patient characteristics including reinfusion of comparable numbers of marrow mononuclear cells, after stem cell transplantation, a highly significant prolongation of neutrophil and platelet engraftment was seen in patients who received high dose CHOP and G-CSF in comparison to standard dose CHOP. These findings suggest that dose intensified chemotherapy and G-CSF recruited stem cells into a proliferative phase and that G-CSF allowed retreatment at a time when stem cells were susceptible to damage by cytotoxic therapy. Such inadequate hematologic engraftment after myeloablative therapy might be avoided by either shortening the time that growth factor support is administered, lengthening the interval between cycles, or attempting to repetitively harvest additional stem cells either from the marrow or peripheral blood. Therefore, intensification of chemotherapy with growth factor support must be used with caution if stem cells are to be used to support myeloablative therapy.

The impact of Filgrastim schedule variation on hematopoietic recovery post-chemotherapy

BACKGROUND

A phase 2 trial was done to study effects of varying treatment schedule of Filgrastim (r-metHuG-CSF) on hematologic recovery following chemotherapy.

PATIENTS AND METHODS

Forty-six patients with extensive small-cell carcinoma of the lung were randomized to receive one of three Filgrastim schedules following cyclophosphamide, doxorubicin, and etoposide (CAE) chemotherapy for up to six cycles of treatment. Chemotherapy was delivered on days 1-3 of each 21-day cycle with Filgrastim initiated at 5 micrograms/kg/day subcutaneously (SC) beginning on day 4, day 6, or day 8 and continuing until post-nadir neutrophil recovery.

RESULTS

During the first cycle of chemotherapy, the duration of neutropenia was similar for all three schedules; however, the pattern of absolute neutrophil count (ANC) recovery differed. In subsequent cycles of treatment, an improvement in the severity of neutropenia occurred in patients on the day-4 and day-6 schedules compared with the first cycle of chemotherapy. By contrast, patients on the day-8 schedule continued to experience neutropenia similar to that seen in cycle one. Patients on the day-8 schedule also experienced a greater magnitude of grade IV thrombocytopenia in later cycles of treatment.

CONCLUSION

Timing of Filgrastim administration post-chemotherapy has profound effects on hematologic recovery. Delay of Filgrastim until day 8 was associated with suboptimal hematologic recovery compared with administration of Filgrastim on day 4 or day 6. Initiation of Filgrastim on day 4 or day 6 showed a similar pattern of hematologic recovery. Beginning Filgrastim on day 6 is associated with a decrease in the total dose of Filgrastim administered.

The Efficacy of Single-Dose Administration of Thrombopoietin With Coadministration of Either Granulocyte/Macrophage or Granulocyte Colony-Stimulating Factor in Myelosuppressed Rhesus Monkeys

Thrombopoietin (TPO) was evaluated for efficacy in a placebo-controlled study in rhesus monkeys with concurrent administration of either granulocyte/macrophage colony-stimulating factor (GM-CSF) or granulocyte CSF, (G-CSF). Rhesus monkeys were subjected to 5 Gy total-body irradiation (TBI), resulting in 3 weeks of profound pancytopenia, and received either TPO 5 μg/kg intravenously (IV) at day 1 (n = 4), GM-CSF 25 μg/kg subcutaneously (SC) for 14 days (n = 4), TPO and GM-CSF (n = 4), G-CSF 10 μg/kg/d SC for 14 days (n = 3), TPO and G-CSF (n = 4), or placebo (carrier, n = 4; historical controls, n = 8). Single-dose IV treatment with TPO 1 day after TBI effectively counteracted the need for thrombocyte transfusions (provided whenever thrombocyte levels were <40 × 109/L) and accelerated platelet reconstitution to normal levels 2 weeks earlier than placebo controls. TPO/GM-CSF was more effective than single-dose TPO alone in stimulating thrombocyte regeneration, with a less profound nadir and a further accelerated recovery to normal thrombocyte counts, as well as a slight overshoot to supranormal levels of thrombocytes. Monkeys treated with TPO/GM-CSF uniformly did not require thrombocyte transfusions, whereas those treated with GM-CSF alone needed two to three transfusions, similar to the placebo-treated monkeys, which required, on average, three transfusions. Also, reticulocyte production was stimulated by TPO and further augmented in monkeys treated with TPO/GM-CSF. TPO alone did not stimulate neutrophil regeneration, whereas GM-CSF shortened the period of neutrophil counts less than 0.5 × 109/L by approximately 1 week; TPO/GM-CSF treatment elevated the neutrophil nadir, but did not further accelerate recovery to normal values. TPO also augemented the neturophil response to G-CSF, resulting in similar patterns of reconstitution following TPO/G-CSF and TPO/GM-CSF treatment. TPO/GM-CSF resulted in significantly increased reconstitution of CD34+ bone marrow cells and progenitor cells such as GM-CFU and BFU-E. Adverse effects of combining TPO with the CSFs were not observed. It is concluded that (1) a single IV administration of TPO is sufficient to prevent severe thrombocytopenia following myelosuppression, (2) TPO/G-CSF and TPO/GM-CSF treatment result in distinct response patterns, with TPO/GM-CSF being superior to TPO/G-CSF in stimulating thrombocyte and erythrocyte recovery while being equivalent in stimulating neutrophil recovery; and (3) TPO significantly improves the performance of CSFs in alleviating severe neutropenia.

The Efficacy of Single-Dose Administration of Thrombopoietin With Coadministration of Either Granulocyte/Macrophage or Granulocyte Colony-Stimulating Factor in Myelosuppressed Rhesus Monkeys

Thrombopoietin (TPO) was evaluated for efficacy in a placebo-controlled study in rhesus monkeys with concurrent administration of either granulocyte/macrophage colony-stimulating factor (GM-CSF) or granulocyte CSF, (G-CSF). Rhesus monkeys were subjected to 5 Gy total-body irradiation (TBI), resulting in 3 weeks of profound pancytopenia, and received either TPO 5 μg/kg intravenously (IV) at day 1 (n = 4), GM-CSF 25 μg/kg subcutaneously (SC) for 14 days (n = 4), TPO and GM-CSF (n = 4), G-CSF 10 μg/kg/d SC for 14 days (n = 3), TPO and G-CSF (n = 4), or placebo (carrier, n = 4; historical controls, n = 8). Single-dose IV treatment with TPO 1 day after TBI effectively counteracted the need for thrombocyte transfusions (provided whenever thrombocyte levels were <40 × 109/L) and accelerated platelet reconstitution to normal levels 2 weeks earlier than placebo controls. TPO/GM-CSF was more effective than single-dose TPO alone in stimulating thrombocyte regeneration, with a less profound nadir and a further accelerated recovery to normal thrombocyte counts, as well as a slight overshoot to supranormal levels of thrombocytes. Monkeys treated with TPO/GM-CSF uniformly did not require thrombocyte transfusions, whereas those treated with GM-CSF alone needed two to three transfusions, similar to the placebo-treated monkeys, which required, on average, three transfusions. Also, reticulocyte production was stimulated by TPO and further augmented in monkeys treated with TPO/GM-CSF. TPO alone did not stimulate neutrophil regeneration, whereas GM-CSF shortened the period of neutrophil counts less than 0.5 × 109/L by approximately 1 week; TPO/GM-CSF treatment elevated the neutrophil nadir, but did not further accelerate recovery to normal values. TPO also augemented the neturophil response to G-CSF, resulting in similar patterns of reconstitution following TPO/G-CSF and TPO/GM-CSF treatment. TPO/GM-CSF resulted in significantly increased reconstitution of CD34+ bone marrow cells and progenitor cells such as GM-CFU and BFU-E. Adverse effects of combining TPO with the CSFs were not observed. It is concluded that (1) a single IV administration of TPO is sufficient to prevent severe thrombocytopenia following myelosuppression, (2) TPO/G-CSF and TPO/GM-CSF treatment result in distinct response patterns, with TPO/GM-CSF being superior to TPO/G-CSF in stimulating thrombocyte and erythrocyte recovery while being equivalent in stimulating neutrophil recovery; and (3) TPO significantly improves the performance of CSFs in alleviating severe neutropenia.

Clinical trial of recombinant granulocyte colony-stimulating factor for chemotherapy-induced neutropenia patients with oral cancer

PURPOSE

This study was undertaken to evaluate the efficacy and toxicity of recombinant human granulocyte colony-stimulating factor (rhG-CSF) in reducing neutropenia in patients with oral cancer undergoing intensive chemotherapy.

MATERIALS AND METHODS

Patients with chemotherapy-induced neutropenia (< 1 x 10(9)/L) were divided into two groups: control group (n = 13) and rhG-CSF administration group (n = 16). rhG-CSF was administered subcutaneously at a dose of 75 micrograms/day on consecutive days. Peripheral blood cell counts and oral complications were investigated in each group.

RESULTS

The duration of neutropenia and absolute neutrophil nadir counts were significantly improved by administration of G-CSF. No consistent effect on thrombocytopenia was noted. Administration of rhG-CSF also reduced the duration and degree of oral complications associated with chemotherapy-induced neutropenia. Intolerable side effects associated with administration of rhG-CSF were not observed.

CONCLUSION

It was concluded that rhG-CSF is effective in shortening the duration of neutropenia after chemotherapy at a dose of 75 micrograms/day.

Phase 1 safety trial of Filgrastim (r-metHuG-CSF) in non-neutropenic patients with severe community-acquired pneumonia

The objectives of the present study were to: (1) evaluate the safety of Filgrastim therapy in non-neutropenic patients with severe community-acquired pneumonia; (2) determine the absolute neutrophil count (ANC) response to various dosages of Filgrastim in non-neutropenic patients with active infection; and (3) describe the impact of therapy with Filgrastim in combination with antibiotics on selected pneumonia-related clinical parameters. The study design was an open-label, dose-ranging, clinical trial, set in the General Clinical Research Unit of a large, public community hospital. The study population consisted of 30 patients who had presented to the Emergency Department with severe, community-acquired pneumonia. One of five dosages (75, 150, 300, 450 or 600 micrograms day-1) of Filgrastim (r-metHuG-CSF) was given subcutaneously daily for 10 days, until discharge or until the absolute neutrophil count > 75 x 10(9) l(-1), whichever was earlier. Vital signs, pulse oximetry, arterial blood gases, daily complete blood counts with differential, serum chemistries, coagulation profiles, electrocardiograms, chest radiographs, plasma G-CSF concentrations and duration of hospitalization were measured. There was no evidence of Filgrastim-related lung injury or evidence of extra-pulmonary toxicity. There was no apparent dose-response effect of Filgrastim on pneumonia-related clinical variables. Dosages of Filgrastim between 150 and 600 micrograms day-1 had similar effects on increasing the ANC. Filgrastim appeared to be safe in non-neutropenic patients with severe, community-acquired pneumonia when given in dosages of 75-600 micrograms day-1 in combination with appropriate antibiotic therapy. Further study is needed to determine the effect of Filgrastim on morbidity, mortality and duration of symptoms in this patient population.

Continuous hepatocyte growth factor supply prevents lipopolysaccharide-induced liver injury in rats

We present a rat model in which continuous supply of hepatocyte growth factor (HGF) prevents liver injury induced by carbon tetrachloride (CCl4) and E. coli 011:B4 lipopolysaccharide (LPS). Rat fibroblasts genetically modified to secrete rat HGF were implanted in syngenic rat spleen 7 days before administration of the hepatotoxins. Rats with HGF-secreting fibroblasts in the spleen showed a dramatic resistance to CCl4- and LPS-induced liver injury. In the LPS-induced liver injury model, blood chemical analysis revealed that the increase in serum glutamic oxalacetic transaminase level and the decrease in blood sugar level were remarkably suppressed in rats with HGF-secreting cells in the spleen. Most importantly, their survival rate was greatly improved compared to other control groups of rats. Thus our results indicate a new role of HGF in liver protection during endotoxemia and convey important clinical implications for developing new therapeutic modalities in the treatment of liver failure caused by endotoxemia.

Use of Hematopoietic Growth Factors in the Neonatal Intensive Care Unit

Recombinant hematopoietic growth factors have emerged as valuable treatments for a variety of medical conditions. Recently, their applications have reached the neonatal intensive care unit, where they offer new therapeutic options for problems as common as anemia of prematurity, or as catastrophic as neonatal sepsis. When facing bacterial infection, it is known that newborn infants are capable of increasing their serum G-CSF concentrations. However, their response does not reach the concentrations that adults are able to achieve, and frequently neutropenia complicates the picture of neonatal sepsis. Although Phase III clinical trials are still in progress, published animal studies, case reports, and Phase I trials suggest that neonates with a variety of neutropenias experience a rapid elevation in their blood neutrophil concentration following administration of rG-CSF, without significant adverse effects. Although many factors contribute to the development of the “anemia of prematurity,” one of the major factors is the inability of preterm infants to generate an erythropoietin (Epo) response appropriate to their degree of anemia. On the basis of this fact, administration of rEpo to preterm neonates to treat or to prevent the anemia of prematurity has been the subject of multiple clinical studies, and it is now clear that rEpo administration to this population can indeed result in lower transfusion requirements, with only occasional and mild adverse effects. Neonatal thrombocytopenia is also a frequent clinical problem, which in most patients develops without a clear underlying cause. Recent studies, quantifying circulating megakaryocyte progenitors in the peripheral blood of thrombocytopenic neonates, suggest that impaired megakaryocytopoiesis may be the main underlying mechanism of many cases of thrombocytopenia. On the basis of this finding, it is tempting to speculate that recombinant thrombopoietin, the newly discovered physiological stimulator of platelet production, will be of clinical relevance in the treatment of thrombocytopenic neonates.

Effect of granulocyte colony-stimulating factor on the candidacidal activity of polymorphonuclear neutrophils and their collaboration with fluconazole

The effect of granulocyte colony-stimulating factor (GCSF) treatment of polymorphonuclear neutrophils (PMN) in vitro was studied with respect to their candidacidal activity. The candidacidal activity of PMN was found to be significantly increased when they were pretreated with GCSF. Fluconazole (1 microg/ml) was found to be highly fungistatic (90%) for Candida albicans Sh27 and collaborated with PMN for significantly increased killing. Collaborative killing by PMN significantly increased when they were treated with GCSF before and after fungal exposure. The enhancing activities of GCSF required optimization of the GCSF dose and were thus inoculum and strain dependent.

Human granulocyte colony-stimulating factor after induction chemotherapy in children with acute lymphoblastic leukemia

BACKGROUND

Recombinant human granulocyte colony-stimulating factor PO1 CA-20180ilgrastim) hastens the recovery from neutropenia after P30 CA-21765emotherapy, but its role in the management of childhood leukemia is unclear.

METHODS

We randomly assigned 164 patients with acute lymphoblastic leukemia (age range, 2 months to 17 years) to receive placebo or G-CSF (10 microg per kilogram of body weight per day subcutaneously), beginning one day after the completion of remission-induction therapy and continuing until the neutrophil count was greater than or equal to 1000 per cubic millimeter for two days. The clinical and laboratory effects of this therapy were documented for 21 days. The area under the plasma G-CSF concentration-time curve was measured on days 1 and 7 in both groups.

RESULTS

Responses to the growth factor could be assessed in 148 patients (73 in the G-CSF group and 75 in the placebo group). G-CSF treatment did not significantly lower the rate of hospitalization for febrile neutropenia (58 percent in the G-CSF group vs. 68 percent in the placebo group; relative risk, 0.85; 95 percent confidence interval, 0.59 to 1.16), increase the likelihood of event-free survival at three years (83 percent in both groups), or decrease the number of severe infections (five in the G-CSF group vs. six in the placebo group). Patients treated with G-CSF had shorter median hospital stays (6 days vs. 10 days, P=0.011) and fewer documented infections (12 vs. 27, P=0.009). The median total costs of supportive care were similar in the G-CSF and placebo groups ($8,768 and $8,616, respectively). Among patients who did not have febrile neutropenia during the first week of G-CSF or placebo injections, higher systemic exposure to the growth factor on day 7 was significantly related to a lower probability of subsequent hospitalization (P=0.049).

CONCLUSIONS

G-CSF treatment had some clinical benefit in children who received induction chemotherapy for acute lymphoblastic leukemia, but it did not reduce the rate of hospitalization for febrile neutropenia, prolong survival, or reduce the cost of supportive care.

Genetic Influences Determining Progenitor Cell Mobilization and Leukocytosis Induced by Granulocyte Colony-Stimulating Factor

The mechanisms involved in the mobilization of progenitor cells into the blood by granulocyte colony-stimulating factor (G-CSF ) and other cytokines are poorly understood. To identify important influences on this complex process, in vivo murine models were used. Granulocyte-macrophage colony-stimulating factor (GM-CSF ) transgenic, Max41 transgenic, W/WV, Mpl-null, GM-CSF receptor (β chain)-null mice, wild-type littermate controls, and six inbred strains of mice were injected with 200 μg/kg/d G-CSF for 5 days. Three parameters of response were monitored: white blood cell count (WCC), peripheral blood progenitor cell (PBPC) numbers, and spleen weight. In all genotypes studied, G-CSF induced increases in these three parameters. However, PBPC mobilization in W/WV and Mpl-null mice was only 30% and 9%, respectively, of that observed in wild-type mice. In contrast, perturbations of GM-CSF signalling had no demonstrable effect on in vivo responses to G-CSF. Broad variability was evident between inbred strains for each parameter of the response to G-CSF. A 10-fold range in response was observed for circulating progenitor cell numbers, similar to that observed for normal human subjects receiving G-CSF. The interstrain differences were in the distribution of mature and progenitor cells between peripheral blood, bone marrow, and spleen rather than in the total numbers of these cells in the body. Results of an F2 intercross of low-responding C57BL/6 and intermediate-responding SJL mice indicated that regulation of progenitor cell mobilization is a complex genetic trait, that there is a correlation between this trait and WCC response (r2 = .5), and that this approach may serve as a useful model for the identification of genes involved in the mobilization process.

Effect of granulocyte-macrophage colony-stimulating factor on chemotherapy-induced oral mucositis in non-neutropenic cancer patients

The aim of this study was to assess prospectively the efficacy of granulocyte-macrophage colony-stimulating factor (GM-CSF) in the management of chemotherapy-induced oral mucositis in non-neutropenic cancer patients. In a prospective open study, 30 cancer patients with chemotherapy-induced, neutropenia-independent oral mucositis were treated with GM-CSF (Schering Plough Corp, Kenilworth, NJ) prepared as a mouthwash solution (5-10 micrograms ml-1). GM-CSF was administered within 24 hours of occurrence of oral mucositis x 4 to 6 times daily. Systemic GM-CSF was not permissible. Oral mucositis was graded according to the modified Radiation Therapy Oncology Group criteria. Six patients were subsequently excluded as they experienced neutropenia during GM-CSF therapy. The remaining 24 patients were all evaluable. Most patients had either Grade 3 or 4 gross (76%) or functional (54%) mucositis. The mean +/- SEM gross oral mucositis scores for all 24 patients combined decreased from 3.08 +/- 0.18 at baseline to 2.04 +/- 0.19 (p < 0.0001) after 2 days, 0.92 +/- 0.16 (p < 0.0001) after 5 days, and 0.25 +/- 0.09 (p < 0.0001) after 10 days of therapy. Likewise, the mean +/- SEM functional oral mucositis scores decreased from 2.71 +/- 0.18 at baseline to 1.58 +/- 0.19 (p < 0.0001) after 2 days, 0.75 +/- 0.16 (p < 0.0001) after 5 days, and 0.17 +/- 0.08 (p < 0.0001) after 10 days of therapy. The duration of severe oral mucositis was also shortened as Grade 0 or 1 (gross mucositis score) was evident in seven (29%), 20 (83%), and 24 (100%) patients by the 2nd, 5th, and 10th day of therapy, respectively. Similarly, Grade 0 or 1 (functional mucositis score) reported in 13 (54%), 19 (79%), and 24 (100%) by the 2nd, 5th, and 10th day of therapy respectively. It was found that GM-CSF mouthwash as used in this study has a significant recuperative efficacy on the severity, morbidity, and duration of chemotherapy-induced oral mucositis. A large randomized, placebo-controlled study is warranted to ascertain that benefit and determine the optimal dosages and schedule.

Pharmacokinetics of intravenous recombinant human granulocyte colony-stimulating factor (rhG-CSF) in children receiving myelosuppressive cancer chemotherapy: clearance increases in relation to absolute neutrophil count with repeated dosing

Limited evidence suggests increased efficacy of rhG-CSF by subcutaneous (SQ) compared with intravenous (IV) administration. To examine the possibility that rapid elimination of IV rhG-CSF could substantially shorten the duration of systemic exposure and could explain a difference in pharmacodynamics, we characterized the pharmacokinetic profile of IV rhG-CSF for comparison to that previously reported for SQ administration. Twelve children were randomly assigned to receive 10 or more days of IV rhG-CSF at dosages of 5 or 10 microg/kg a day beginning 24 hr after chemotherapy. Enzyme-linked immunosorbent assay (ELISA) was used to measure rhG-CSF concentrations in timed serum samples on days 1 and 10. Pharmacokinetic parameters were estimated by nonlinear, least squares regression. All serum concentration-time profiles were best described by a two-compartment model of elimination. Mean t1/2beta values ranged from 3.68 +/- 0.86 to 22.4 +/- 12.0 hr. ANC was correlated with log CLT (r = 0.72, P < 0.05), and inversely with log dose-adjusted AUC (r = 0.75, P < 0.05) and log dose-adjusted Cmax (r = -0.65, P < 0.05). Estimated duration of serum rhG-CSF concentrations above 1 ng/ml exceeded 24 hr for all but the 5 microg/kg cohort on day 1. Pharmacokinetic parameters of IV rhG-CSF are similar to those previously reported for SQ administration in children treated with myelosuppressive cancer chemotherapy. Daily IV administration should be a suitable alternative route of administration in this patient population.

Granulocyte colony-stimulating factor receptor expression on human transitional cell carcinoma of the bladder

Receptors for granulocyte colony-stimulating factor (G-CSFRs) have been confirmed on the cell surfaces of several non-haematopoietic cell types, including bladder cancer cells. This observation has naturally led to the hypothesis that the expression of G-CSFR on these cells may enhance their growth by G-CSF. In this study, the expression of G-CSFR was determined in both established human bladder cancer cell lines and primary bladder cancers. We studied five different human bladder cancer cell lines (KU-1, KU-7, T-24, NBT-2 and KK) and 26 newly diagnosed bladder tumours. G-CSFR mRNA expressions on cultured cell lines were determined using the reverse transcriptase polymerase chain reaction (RT-PCR) method. Furthermore, the G-CSFR binding experiments on the cultured cell lines were conducted using the Na(125)I-labelled G-CSF ligand-binding assay method. Moreover, the G-CSFR mRNA expressions on primary bladder tumour specimens were assessed using the in situ RT-PCR method. Three out of the five cultured cell lines (KU-1, NBT-2 and KK) exhibited G-CSFR mRNA signals when the RT-PCR method was used. The G-CSFR binding experiments showed an equilibrium dissociation constant (K[d]) of 490 pM for KU-1, 340 pM for NBT-2 and 103 pM for KK cells. With in situ RT-PCR, the tumour cells of 6 out of 26 primary bladder tumour specimens (23.1%) presented positive G-CSFR mRNA signals. Thus, in this study, G-CSFR expression was frequently observed on bladder cancer cells. Therefore, the clinical use of G-CSF for patients with bladder cancer should be selected with great care.

Neutralising antibodies to the granulocyte colony-stimulating factor receptor recognise both the immunoglobulin-like domain and the cytokine receptor homologous domain

To define regions of the granulocyte colony-stimulating factor (G-CSF) receptor that are important for ligand binding, neutralising monoclonal antibodies to the human receptor have been produced. Eleven antibodies recognised six different receptor epitopes. Antibodies from three of the epitope groups were able to detect the receptor by western blotting but did not inhibit G-CSF binding. The other three antibody groups inhibited G-CSF binding either completely (groups 1 and 2) or partially (group 3). All the antibodies inhibited proliferation of BA/F3 cells expressing the G-CSF receptor to varying extents. By using human-marine chimeric receptors, the binding sites of the antibodies were mapped to the immunoglobulin-like domain (groups 1 and 3), the cytokine receptor homologous domain (group 2) or the fibronectin type III domains (groups 4 to 6). These results show that the immunoglobulin-like and cytokine receptor homologous domains of the receptor are important for ligand binding and subsequent signalling.

Hematopoietic growth factors in cancer patients with invasive fungal infections

Hematopoietic growth factors have been used in prophylaxis and treatment of neutropenic febrile episodes. Granulocyte colony-stimulating factor (G-CSF) and granulocyte macrophage colony-stimulating factor (GM-CSF) are the most common growth factors in clinical use. Both successfully shorten the duration of neutropenia following myelo-suppressive or myeloablative chemotherapy. The influence of G-CSF and GM-CSF on documented infections and mortality from infections is less obvious. There is no clear evidence that treatment with growth factors reduces the incidence of fungal infections. Since mortality is not affected, considerations of morbidity and cost effectiveness currently dominate the indication for use of growth factors. At current costs, their use is indicated in prophylaxis when the likelihood of developing neutropenic febrile episodes following chemotherapy is 40% or more.

Thrombopoietic effects of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) in patients with advanced cancer

BACKGROUND

Pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) is a potent stimulator of megakaryocyte colony formation and platelet production. It is likely to be useful in the management of severe thrombocytopenia. To determine its clinical activity and safety, we gave it to patients with advanced cancer before chemotherapy.

METHODS

Patients were randomly assigned to receive either PEG-rHuMGDF or placebo in a three to one ratio. PEG-rHuMGDF was given at a dose of 0.03, 0.1, 0.3, or 1.0 microgram/kg body weight. The study drug or placebo were administered daily by subcutaneous injection for up to 10 days or until a target platelet count was reached.

FINDINGS

17 patients, median age 59 years, received either PEG-rHuMGDF (13 patients) or placebo (four patients). PEG-rHuMGDF produced a dose-dependent increase in platelet counts. Patients given placebo. 0.03, and 0.1 microgram/kg of PEG-rHuMGDF had median increases in platelet counts of 16%, 12%, and 39%. Those receiving 0.3 and 1.0 microgram/kg of PEG-rHuMGDF had an increase in blood platelets of between 51% and 584%. Platelets rose from day 6 of PEG-rHuMGDF administration and continued to rise after stopping the drug. The platelet count peaked between days 12 and 18 and remained above 450 x 10(9)/L for up to 21 days. There were no alterations in white-blood-cell count or haematocrit, and low toxicity. Platelets taken from patients during PEG-rHuMGDF administration and at the time of peak platelet count were morphologically and functionally normal.

INTERPRETATION

The potency with which PEG-rHuMGDF stimulates platelet production and its low toxicity indicate that this is likely to be a useful agent for the management of thrombocytopenia.

Pharmacokinetics and pharmacodynamics of a recombinant human granulocyte colony-stimulating factor

Granulocyte colony-stimulating factor (G-CSF), a hematopoietic growth factor, is a clinically effective drug used to promote neutrophil recovery in patients with chemo- or radiotherapy-induced neutropenia. We have reviewed the pharmacokinetic and pharmacodynamic properties of three kinds of G-CSFs: E. coli derived G-CSF, CHO-derived G-CSF, and mutein G-CSF. The clearances of G-CSFs are saturable and autoinducible in experimental animals and humans. That is, the systemic clearances of G-CSFs decrease as the dose injected increases and approaches a constant value. Both saturable and nonsaturable processes are involved in G-CSF elimination. Also, the systemic clearances of G-CSFs are increased by repeated administration of G-CSF. Although the relative bioavailability of G-CSFs after subcutaneous administration is approximately 60%, the increase in peripheral white blood cells or neutrophils is greater than that after intravenous administration at the same dose. The effects of G-CSFs seem to be time dependent rather than AUC dependent, considering that mean residence time of G-CSFs in the plasma is longer after subcutaneous administration than that after intravenous administration. There is a slight difference in the pharmacokinetics of E-coli- and CHO-G-CSF although they seem to be pharmacologically equivalent. The correlation between G-CSF clearance and peripheral neutrophil counts in the patients suggests that G-CSF receptors contribute to G-CSF clearance. Quantitative pharmacokinetic analysis using mutein G-CSF shows that the G-CSF receptor plays a major role in saturable G-CSF clearance, and that this saturable process accounts for approximately 80% of the total clearance at low doses. That is, the degradation following the receptor-mediated endocytosis in bone marrow might be a major clearance system of G-CSF at a physiological blood level. The G-CSF receptor in bone marrow might work not only as a signal transducer for differentiation and proliferation of granulopoietic precurcer cells but as a regulator of G-CSF levels in blood. In addition, at high doses, glomerular filtration in the kidneys is the major process for nonsaturable G-CSF clearance. At present, polyethylene glycol derivatives of G-CSF are being developed to reduce the frequency of G-CSF administration.

Low-dose recombinant human granulocyte colony-stimulating factor therapy in children with symptomatic chronic idiopathic neutropenia

OBJECTIVES

To prospectively define the lowest possible doses of recombinant human granulocyte colony-stimulating factor (rhG-CSF) that would benefit selected children with chronic idiopathic neutropenia whose disease was severe enough to interfere appreciably with quality of life.

STUDY DESIGN

The efficacy of low-dose rhG-CSF therapy was investigated in six children with symptomatic chronic idiopathic neutropenia. All patients received rhG-CSF, 5 micrograms/kg subcutaneously, as a single daily dose until an absolute neutrophil count (ANC) above 1.5 x 10(9)/L was observed. The rhG-CSF dosage interval and amount were then increased and decreased, respectively, in an alternating fashion until the lowest rhG-CSF dose that would maintain the ANC above 1.0 x 10(9)/L (1000/mm3) was reached.

RESULTS

Although the minimal dose requirements varied, all patients were able to maintain a mean ANC > 1.0 x 10(9)/L during a mean follow-up period of 14 months at doses ranging from 1.0 microgram/kg once weekly to 5.0 micrograms/kg every other day. Administration of rhG-CSF resulted in resolution of all preexisting chronic infections, reduction in the frequency of new infectious episodes, and discontinuation of prophylactic antibiotics. In all patients the ANC decreased to pretreatment values when further reduction or discontinuation of rhG-CSF therapy was attempted. By identifying the minimal effective dose in each patient, we were able to reduce the treatment cost by a mean of 81% compared with daily dosage at 5 micrograms/kg.

CONCLUSIONS

Recombinant human granulocyte colony-stimulating factor therapy at low doses (< or = 5 micrograms/kg) every 2 to 7 days to symptomatic children with chronic idiopathic neutropenia is effective and no more costly than supportive treatment with antibiotics.

Heterogeneous effects of G-CSF and GM-CSF on cell growth and ara-C cytotoxicity in childhood leukemias which express myeloid markers

It is uncertain if acute lymphoblastic leukemia (ALL) cells expressing myeloid makers can respond to granulocyte colony-stimulating factor (G-CSF) and granulocyte macrophage colony-stimulating factor (GM-CSF). We investigated the effects of G-CSF (0.01 microgram/ml) and GM-CSF (0.01 microgram/ml) on [3H]thymidine (TdR) uptake, and the cytotoxicity of 1-beta-D-arabinofuranosylcytosine (ara-C) in leukemia cells from 17 pediatric patients. ALL cells without myeloid markers did not respond to G-CSF or GM-CSF. On the other hand, these cytokines enhanced the [3H]TdR uptake and cell growth, not only of AML cells but also of ALL cells expressing myeloid antigens. However, G-CSF and GM-CSF did not always enhance the growth inhibitory effect of the cell cycle specific drug ara-C when the cells were co-cultured with the drug. There was no relationship between cell growth and the amount of [3H]TdR incorporation or the intracellular ara-CTP level. These results indicate the heterogeneous effects of G-CSF and GM-CSF on cell growth and ara-C sensitivity in childhood leukemia cells.

Recent progress and current problems in treatment of invasive fungal infections in neutropenic patients

Invasive fungal infections, including disseminated candidiasis and invasive pulmonary aspergillosis, are important causes of morbidity and mortality in neutropenic patients. The recent development of fluconazole, itraconazole, lipid formulations of amphotericin B, and recombinant cytokines have expanded our therapeutic armamentarium. Clinical trials have elucidated new strategies for utilizing these compounds in the prevention and treatment of opportunistic mycoses. The population of more severely immunocompromised patients, however, continues to expand and the spectrum of drug-resistant fungi, including but not limited to Candida spp, Fusarium spp, Zygomycetes, and dematiaceous moulds, continues to evolve, thus presenting new challenges to recent therapeutic advances. Development of new antifungal chemotherapeutic agents and novel approaches for augmentation of host response will be required to meet these new mycologic challenges.

Granulocyte colony-stimulating factor and modulation of inflammatory cells in sepsis

Although antimicrobial therapy has been the central clinical strategy for patients with sepsis and multiple organ failure, the survival rate in these patients remains low because their host defense mechanisms usually are compromised. Various inflammatory cytokines recently have been shown to play important roles in normal host defense mechanisms and in sepsis and its sequelae. Cytokine modulation therapies, which have focused on the downregulation of the inflammatory response, have not been shown to benefit these patients. This article examines the role of granulocyte colony-stimulating factor as a proinflammatory mediator and a potential adjuvant treatment in patients with severe infection.

Kinetics of serum granulocyte-colony stimulating factor (G-CSF) concentration and G-CSF receptor expression during G-CSF treatment of cyclophosphamide-treated mice

We analyzed the kinetics of leukocyte number, serum granulocyte colony stimulating factor (G-CSF) concentration, and G-CSF receptor expression in mice after recombinant human (rh) G-CSF treatment. Intraperitoneal (i.p.) injection with 200 mg/kg of cyclophosphamide (CP) induced a transient decrease of leukocyte number in blood and spleen. Daily i.p. inoculation of a low dose of rhG-CSF (1 microgram/kg/day) from day 1 of CP injection for 8 days resulted in a significant increase of spleen cell number from day 5 to day 8, while serum rhG-CSF concentration decreased to an undetectable level on day 7. Furthermore, daily i.p. inoculation of high dose rhG-CSF (100 micrograms/kg/day) for 5 days to CP-injected mice induced a significant increase of leukocytes from day 3 to day 6 in both peripheral blood and spleen, and the increase was higher than that observed after low dose G-CSF treatment. In the course of the high dose rhG-CSF treatment, however, serum rhG-CSF concentration decreased from day 3, which is earlier than the decrease of serum rhG-CSF seen after low dose rhG-CSF treatment. A reverse transcription-polymerase reaction analysis of mRNA expression showed that spleen cells from high dose rhG-CSF-treated mice on day 4 and day 6 expressed more than 10 times higher levels of membrane G-CSF receptors than did those obtained before rhG-CSF treatment. All these results suggest that decrease of serum G-CSF during daily G-CSF treatment does not always indicate neutralization of G-CSF, but implies that the inoculated G-CSF is still stimulating granulocytes and their precursors by binding to membrane G-CSF receptors which are up-regulated by G-CSF treatment. This observation is important when we measure pharmacokinetics of G-CSF in patients chronically injected with G-CSF.

Changes in granulocyte colony-stimulating factor concentration in patients with trauma and sepsis

OBJECTIVE

To better understand the role of granulocyte colony-stimulating factor (G-CSF) after the inflammatory response.

DESIGN

Serum G-CSF concentrations were measured serially in 19 trauma and 15 sepsis patients. Changes in G-CSF concentration were compared with those in the neutrophil ratio, phagocytic and bactericidal activities, and other cytokines.

MEASUREMENTS AND MAIN RESULTS

G-CSF concentrations in trauma patients were elevated on day 1, but quickly decreased within 7 days. G-CSF reached its maximum 3 hours after injury, parallel with peaks of interleukin-6 (IL-6) and IL-8, but not of tumor necrosis factor-alpha (TNF-alpha). In sepsis patients, G-CSF as well as TNF-alpha, IL-6, and IL-8 concentrations were markedly elevated at diagnosis and remained high during the course of the illness. These levels decreased significantly in the 11 survivors. Up to 3 days after the trauma, nonsegmented neutrophil ratios were higher than those thereafter. Neutrophil phagocytic and bactericidal activities remained normal during the course of disease in both conditions.

CONCLUSIONS

These results suggest that G-CSF plays an important role in the maturation and maintenance of function of neutrophils during the inflammatory response to trauma and sepsis.

Combined administration of recombinant human megakaryocyte growth and development factor and granulocyte colony-stimulating factor enhances multilineage hematopoietic reconstitution in nonhuman primates after radiation-induced marrow aplasia

This study compared the therapeutic potential of recombinant, native versus pegylated megakaryocyte growth and development factor (rMGDF and PEG-rMGDF, respectively), as well as that of the combined administration of PEG-rMGDF and r-methionyl human granulocyte colony-stimulating factor (r-metHuG-CSF) on hematopoietic reconstitution after 700 cGy, 60Co gamma, total body irradiation in nonhuman primates. After total body irradiation, animals received either rMGDF, PEG-rMGDF, r-metHuG-CSF, PEG-rMGDF and r-metHuG-CSF or HSA. Cytokines in all MGDF protocols were administered for 21-23 d. Either rMGDF, PEG-rMGDF, or PEG-rMGDF and r-metHuG-CSF administration significantly diminished the thrombocytopenic duration (platelet count (PLT) < 20,000 per microliter)to o.25, 0, 0.5 d, respectively, and the severity of the PLT nadir (28,000, 43,000, and 30,000 per microliter, respectively) as compared with the controls (12.2 d duration, nadir 4,000 per microliter), and elicited an earlier PLT recovery. Neutrophil regeneration was augmented in all cytokine protocols and combined PEG-rMGDF and r-metHuG-CSF further decreased the duration of neutropenia compared with r-metHuG-CSF alone. These data demonstrated that the administration of PEG-rMGDF significantly induced bone marrow regeneration versus rMGDF, and when combined with r-metHuG-CSF significantly enhanced multilineage hematopoietic recovery with no evidence of lineage competition.

Comparison of two strategies for the treatment of radiogenic leukopenia using granulocyte colony stimulating factor

PURPOSE

Radiation-induced leukopenia can cause a delay or discontinuation of radiotherapy. This complication can be overcome with the use of granulocyte colony-stimulating factor (G-CSF). However, an uncertainty exists regarding the mode of application of G-CSF in patients treated with radiotherapy. For this reason, the efficacy of two strategies for the administration of G-CSF in irradiated patients was compared in a prospective randomized clinical study.

METHODS AND MATERIALS

Forty-one patients who developed leukopenia (< 2.5 x 10(9) per liter) while undergoing radiotherapy were treated with G-CSF at a daily dose of 5 microg/kg. The first group received single injections of G-CSF as required (n = 21). The second group received G-CSF on at least 3 consecutive days (n = 20). An analysis was made of the changes in leukocyte counts, the number of days on which radiotherapy had to be interrupted, and the side effects of growth-factor treatment.

RESULTS

An increase in leukocyte values in the peripheral blood was observed in all patients treated with G-CSF. In the group which received G-CSF when required, two injections (range: 1-8) were administered in most cases. In the second group, most of the patients received three injections (range: 3-9). The average duration of therapy interruptions due to leukopenia was 4.8 days (0-28) in the first therapy arm and 2.5 (0-20) in the second arm. The variance in the duration of therapy interruptions between the two groups was not significant (p = 0.2). Radiotherapy had to be terminated in two patients due to thrombocytopenia but the application of G-CSF did not seem to be a reason of decreasing platelet counts.

CONCLUSIONS

Our results reveal that G-CSF is safe and effective in the treatment of radiation-induced leukopenia regardless of the mode of application. Because the calculated difference related to radiation treatment interruptions has no clinical relevance, both approaches examined in our study appear reasonable.

Chemotherapy and neutropenia

Myelosuppression is the most common toxicity associated with the administration of dose-intensive cytotoxic chemotherapy. The basic understanding of neutrophil biology and the physiology of chemotherapy-induced neutropenia has advanced tremendously in the past 2 decades. Concordantly, the ability to reduce the morbidity associated with neutropenia has improved. Adjunctive cytokine and progenitor cell support of hematologic recovery after myelosuppressive therapy have proved to be models of translational research and have led to novel therapeutic initiatives for patients with cancer and hematologic malignancies. In this article, fundamental aspects of neutrophil production are discussed, and the clinical development of hematopoietic cytokines active on cells of the leukocyte lineages is presented.

A randomised study comparing granulocyte-colony stimulating factor (G-CSF) with G-CSF plus thymostimulin in the treatment of haematological toxicity in patients with advanced breast cancer after high dose mitoxantrone therapy

54 patients with advanced breast cancer were randomised into a prospective, non-blinded, controlled trial to receive: mitoxantrone 28 mg/m2 intravenous day 1 and granulocyte-colony stimulating factor (G-CSF) 5 micrograms/kg/day subcutaneously days 2 to 16 (n = 27) or the same regimen plus thymostimulin (TS) 50 mg/day intramuscular at days 2 to 16 (n = 27). The median time to reach a neutrophil count greater than 0.5 x 10(9)/l was lower in the G-CSF+TS treated group (9.13 versus 3.24 days; P < 0.0005). More patients experienced neutropenic fever in the G-CSF group than in the G-CSF+TS group (59.3% versus 22.2%, P = 0.0119). The incidence, duration and severity of clinically or bacteriologically documented infection were lower in patients who received TS. 16 patients (59.3%) in the G-CSF group contracted infection, and 4 patients (14.8%) receiving G-CSF+TS (P = 0.0016). These data indicate that the combination of G-CSF and TS is well-tolerated and may enhance haematological recovery following myelosuppressive chemotherapy in patients with advanced breast cancer.

Effects of polar glycopeptidolipids of Mycobacterium chelonae (pGPL-Mc) on haematopoietic regeneration and resistance to infection of sublethally irradiated mice

The influence of polar glycopeptidolipids of Mycobacterium chelonae (pGPL-Mc) treatment on the reversal of irradiation-induced leukopenia (granulocytopenia, monocytopenia) and thrombocytopenia and its ability to protect mice against lethal infections were investigated in this study. The administration of pGPL-Mc to irradiated mice significantly accelerated the recovery of leukocyte and thrombocyte numbers in the peripheral blood. Granulocytes and monocytes were the principal cells of the leukocyte population that responded to the potent stimulus of this product. The reversal of granulocytopenia and monocytopenia in treated mice was achieved on day 14 and reached a peak value on day 20. Responses in mice receiving 100 mg/kg of pGPL-Mc was about 40-fold compared to controls and about 4-fold compared to the rhG-CSF-treated group. Normal levels of thrombocytes were reached by day 17 in mice treated with 100 mg/kg and by day 20 in those receiving 25 mg/kg of pGPL-Mc. The administration of pGPL-Mc to mice with irradiation-induced granulocytopenia was characterized by highly significant protection of these animals against lethal Klebsiella pneumoniae or Escherichia coli infections. Therefore, pGPL-Mc appears to possess a considerable potential for improvement of the outcome of radiotherapy and may contribute to the successful avoidance of irradiation-induced toxicities.

Granulocyte-Macrophage Colony-Stimulating Factor in Newly Diagnosed Adult Patients with Acute Lymphoblastic Leukemia Treated with Conventional Chemotherapy

Twenty consecutive adult patients with newly diagnosed acute lymphoblastic leukemia (ALL) were treated with conventional therapy consisting of daunorubicin, vincristine, prednisone and L-asparaginase in standard doses. Granulocyte-macrophage colony-stimulating factor (GM-CSF) was administered at a single subcutaneous daily dose of 5 microgram per kilogram body weight for fourteen days starting on day 7 of chemotherapy. Twenty two adult patients with acute lymphoblastic leukemia and similar risk characteristics who received the same chemotherapeutic regimen without GM-CSF served as a historical control group. The complete remission rate and the rate of early mortality were similar in both groups of patients. Patients treated with GM-CSF showed significantly faster neutrophil recovery above 0.5 × 10(9)/L than the control patients (P < 0.005). The incidence of febrile episodes and the rate of documented infection were similar in the two groups of patients.

A possible mechanism of increase in serum alkaline phosphatase activity in rats given granulocyte colony-stimulating factor

Recombinant human granulocyte colony-stimulating factor (G-CSF) at a dose of 1 to 300 micrograms/kg/day was administered intravenously to rats daily for 13 weeks. Serum alkaline phosphatase (ALP) activity increased dose-dependently with leukocytosis. Most of the increased leukocytes were segmented neutrophils, and neutrophil alkaline phosphatase (NAP) scores were elevated markedly. Serum ALP activity correlated very well with the segmented neutrophil counts, and the coefficient of correlation was more than 0.97 in both sexes. Pathological examinations revealed splenomegaly and a marked increase in neutrophils in the red pulp of the spleen. In the spleen, phagocytosis of neutrophils by macrophages was observed. These data indicate that the increased ALP was of neutrophil origin. Serum ALP activity may be increased by the direct release of ALP from the high number of neutrophils into the blood, or by the leakage of ALP into the blood mainly from the spleen where many neutrophils are pooled and destroyed by the macrophage system.

Cytokines and bone marrow transplantation

This article summarizes the various current uses of cytokines, and bone marrow and peripheral blood stem cell transplantation for cancer treatment. Interferons, interleukin-2 and hematopoietic growth factors are extensively used for the treatment of hematopoietic as well as nonhematopoietic malignancies, either as the main therapeutic agents or as an adjuvant. Research on gene therapy using cytokines is in progress. Stem cell transplantation is also discussed in the context of gene therapy of cancer. Gene therapy is expected to become a future modality in cancer treatment.

A single-blind, randomised, vehicle-controlled dose-finding study of recombinant human granulocyte colony-stimulating factor (lenograstim) in patients undergoing chemotherapy for solid cancers and lymphoma

This study evaluated the effect of glycosylated recombinant human granulocyte colony-stimulating factor (rHuG-CSF; lenograstim) on neutrophil granulocyte counts and on cells of other haematopoietic lineages in 66 patients with solid cancer or lymphoma who received myelosuppressive chemotherapy. Beginning 1 day after completion of chemotherapy, patients received lenograstim (at dosages of 0.5, 2, 5 or 10 micrograms/kg) or vehicle subcutaneously once daily for 14 consecutive days. Compared with vehicle, lenograstim significantly accelerated neutrophil recovery after chemotherapy in a dose-dependent manner. Mean neutrophil counts recovered to > 1.0 x 10(9) cells/l by day 13 in the vehicle group compared with days 11, 10, 8 and 7 in the 0.5, 2, 5 and 10 micrograms/kg lenograstim groups, respectively. Doses of 0.5 and 2 micrograms/kg of lenograstim had a significant effect on the duration of neutropenia (< 1.0 x 10(9) cells/l), the area under the absolute neutrophil count (ANC) curve and the time to ANC nadir. The dose of 5 micrograms/kg additionally decreased the total area of neutropenia and gave the narrowest range of values for all neutrophil parameters, while the 10 micrograms/kg dose brought no added benefit. A dose-response effect of lenograstim on time to neutrophil recovery was observed both for patients who received chemotherapy on a single day (n = 35) and for those who received chemotherapy over several days (n = 29). Based on these findings, a dose of 5 micrograms/kg/day was chosen for further trials.

Critical influence of timing of administration of granulocyte colony-stimulating factor on antibacterial effect in experimental endocarditis due to Pseudomonas aeruginosa

The effect of human recombinant granulocyte colony-stimulating factor (hrG-CSF) in rabbits with aortic endocarditis due to Pseudomonas aeruginosa was investigated. hrG-CSF significantly increased the number of polymorphonuclear neutrophils in blood and in cardiac vegetations and the expression of the adhesin molecule CD11b on the surface of polymorphonuclear neutrophils compared with those of animals that had not received hrG-CSF. When treatment was started 72 h after bacterial challenge, hrG-CSF alone had no antibacterial effect and did not enhance the efficacy of ciprofloxacin when used in combination, even with the higher dosing regimen used (50 micrograms/kg of body weight subcutaneously every 12 h for 4 days), in terms of number of positive blood cultures, bacterial counts in vegetations, and survival. In contrast, when treatment was started 30 min prior to bacterial challenge, hrG-CSF (50 micrograms/kg injected every 12 h) decreased bacterial titers in vegetations 72 h later (6.5 +/- 0.9 versus 7.9 +/- 0.9 log10 CFU/g of vegetation for hrG-CSF and controls, respectively; P = prophylactic administration of hrG-CSF did not increase the antibacterial effect of ciprofloxacin. We concluded that the antibacterial effect of hrG-CSF in experimental endocarditis was related to the timing of its administration since hrG-CSF demonstrated a significant but transient antimicrobial effect only when treatment was initiated before bacterial challenge.