Emerging clinical uses for GM-CSF

Cell-cell signalling in the regulation of blood cell formation and function

Blood cell formation is continuous in adult life and requires complex regulatory control to achieve the necessary cell proliferation, differentiation commitment and maturation. Much of this control is achieved by specific glycoprotein haemopoietic regulators, more than 20 of which have now been identified and produced in recombinant form. For the granulocyte-macrophage lineage, major regulators are the colony stimulating factors (CSF) that are produced by many cell types dispersed throughout the body. The production of CSF is rapidly increased in response to induction signals, most usually of microbial origin, representing a demand-generated signalling system designed to activate and generate cells to rapidly eliminate the micro-organisms. The CSF not only control cell division but certain aspects of differentiation commitment, maturation initiation and functional activation. These multiple responses are initiated by signals arising from different regions of the cytoplasmic domains of the CSF membrane receptors. Less well understood are the signalling systems controlling the special gene activation events required to initiate the formation of the first haemopoietic cells and the specialized microenvironmental cells needed to support haemopoietic cells as they respond to haemopoietic regulators.

Effect of granulocyte-macrophage colony-stimulating factor treatment on phenotype, cytokine release and cytotoxicity of circulating blood monocytes and monocyte-derived macrophages

We studied phenotype, function and differentiation of mononuclear phagocytes in 11 cancer patients treated subcutaneously with 10O microg/kg recombinant human (rhu) GM-CSF for 7 d. The rhuGM-CSF treatment induced (1) a 5.9-fold increase in the number of blood monocytes (MO), (2) a decrease of CD14bright/CD16bright cells with a diminution of the mean fluorescence intensity (MFI) of CD14, and (3) a decrease of MO cellular cytotoxicity. In patients' sera, tumour necrosis factor (TNF)-alpha, interleukin (IL)-10, IL-12, neopterin, macrophage-colony-stimulating factor (M-CSF), and IL-1 receptor antagonist (IL-1RA) increased, whereas GM-CSF and granulocyte-colony-stimulating factor (G-CSF) decreased after an initial peak. In whole blood samples the lipopolysaccharide (LPS)-stimulated release of TNF-alpha, IL-6 and IL-1RA increased initially, whereas IL-1beta, IL-10 and IL-12 decreased. During differentiation from MO to macrophages (MAC), interferon (IFN)-gamma-stimulated tumour cytotoxicity increased, but both MO and MAC were less cytotoxic upon rhuGM-CSF treatment. The differentiation-associated increase of LPS-induced TNF-alpha, IL-1RA and IL-10 secretion was reduced by the rhuGM-CSF treatment, and the expression of CD14 on MAC as well as the proportion of CD14+/CD16+, CD14+/MAX.1+ and CD14+/CD71+ cells in 7-d cultured MAC declined. We interpret these findings as (1) an increase of immature MO upon rhuGM-CSF therapy, (2) a priming effect on the LPS-induced proinflammatory cytokine repertoire of MO, and (3) an impact of rhuGM-CSF on the capacity of MO to differentiate to MAC in vitro.

[Haematopoietic growth factors and solid tumors]

Haematopoietic growth factors are glycosylated proteins involved in the differentiation of pluripotent stem cells into committed progenitor cells, which eventually give rise to distinct haematopoietic cell lineages. Three recombinant hematopoietic growth factors--G-CSF, GM-CSF and erythropoietin--are currently commercially available for clinical use. G-CSF and GM-CSF are lineage-specific growth factor that regulate the production and function of granulocytic and monocytic cells. They have been shown to reduce the incidence of febrile neutropenia. Primary prophylactic administration is reserved for patients in which the expected incidence of febrile neutropenia is greater than 40% without haematopoietic growth factor. After a documented occurrence of febrile neutropenia in an earlier cycle, the secondary prophylactic administration of G-CSF or GM-CSF may be considered. However, in the absence of clinical data supporting maintenance of chemotherapy dose-intensity, dose reduction should be considered as an alternative to the use of haematopoietic growth factors. G-CSF and GM-CSF also shorten the period of neutropenia in patients undergoing high-dose chemotherapy with autologous bone marrow support. Erythropoietin is currently approved for treatment of anemia associated with cisplatin-based chemotherapy with the aim to reduce transfusion requirements.

Effect of recombinant human granulocyte-macrophage colony-stimulating factor on HIV-related leukopenia: a randomized, controlled clinical study

OBJECTIVE

To assess the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) on white blood cell (WBC) count and on the rate of opportunistic infections in a large and selected population of leukopenic HIV-positive patients compared with non-treated controls.

DESIGN

Open-label, randomized, comparative clinical study.

SETTING

University hospitals and AIDS centres.

PATIENTS AND METHODS

One hundred and twenty-three leukopenic HIV-positive patients received recombinant human GM-CSF (300 microg subcutaneously daily for 1 week, and 150 microg subcutaneously two times weekly for 11 weeks thereafter); the control group comprised 121 non-treated leukopenic HIV-positive patients. A complete blood cell count with differential, platelet count, reticulocyte count, and CD4+ and CD8+ T-cell subset counts were performed in both patient groups at baseline and at weeks 1, 12 and 24.

RESULTS

The administration of GM-CSF resulted in a significant increase of WBC count in patients compared with non-treated controls. Total leukocyte count increased by 22% at week 1 and by 65% at week 12 compared with baseline levels; a 20% increase of total leukocyte count was still present at week 24. Increases of neutrophils, eosinophils and monocytes were responsible for the majority of the increase in WBC count. Opportunistic infections occurred in 61.7% of GM-CSF-treated patients and in 72% of the patients of the control group (relative risk, 0.86; 95% confidence interval, 0.72-1.03; P = 0.123). Mild flu-like side-effects were observed in most patients receiving GM-CSF, although they were not sufficiently severe to warrant withdrawal from the study.

CONCLUSIONS

GM-CSF was well tolerated and biologically active in leukopenic HIV-positive patients, with a significant, although time-limited, increase of WBC count compared with non-treated patients. The administration of this growth factor should be considered in ameliorating the myelosuppression observed with some cell-cycle-specific antiviral and anti-neoplastic agents.

Autologous transplantation with peripheral blood stem cells in children and young adults after myeloablative treatment: nonrandomized comparison between GM-CSF and G-CSF for mobilization

Recombinant human granulocyte-monocyte colony-stimulating factor (rhGM-CSF) was compared with recombinant granulocyte colony-stimulating factor (rhG-CSF) in 34 patients for mobilization of peripheral blood stem cells (PBSC) and for posttransplantation use. Peripheral blood stem cell mobilization was initiated by a single 1 h infusion of cyclophosphamide (4 g/m2) in all patients, followed by either a continuous infusion of rhGM-CSF (250 micrograms/m2/day) in 17 patients (group A) or a daily subcutaneous injection of rhG-CSF (10 micrograms/kg/day) in 17 patients (group B). PBSC were collected using a Fenwal CS 3000 continuous flow blood cell separator in one to three sessions. All patients suffered from various childhood malignancies. No difference in the number of collected cells among both groups was found. A mean of 2.7 x 10(8)/kg mononuclear cells (MNC) and of 7.9 x 10(4)/kg CFU-GM (colony-forming unit-granulocyte-macrophage) were collected in group A. In group B, 2.3 x 10(8)/kg MNC and 11.8 x 10(4)/kg CFU-GM were collected. In 33 patients, PBSC were reinfused after myeloablative therapy. Patients of group A (n = 17) were treated with rhGM-CSF (250 micrograms/m2/day) starting day +1, and patients in group B (n = 16) were treated with rhG-CSF (10 micrograms/kg/day) i.v. All patients showed a rapid and complete hematopoietic recovery without significant differences in both groups. Time to achieve 0.5 x 10(9)/L granulocytes was 10.9 days in group A and 11 days in group B.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Efficacy of recombinant human granulocyte-macrophage colony-stimulating factor for chemotherapy-induced leukopenia in patients with non-small-cell lung cancer

To assess the feasibility and efficacy of rhGM-CSF in ameliorating chemotherapy-induced leukopenia in patients with advanced non-small-cell lung cancer, we conducted a double-blind placebo controlled phase III study in a multicenter setting. Patients were eligible if they had cytologically or histologically proven cancer, no prior chemotherapy, stage IIIB or IV disease, an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, an age of less than 76 years, and no symptomatic brain metastasis, disseminated bone metastasis, or previous vertebral/pelvic irradiation. The chemotherapy regimen consisted of mitomycin given at 8 mg/m2 on day 1, cisplatin given at 100 mg/m2 on day 1, and vindesine given at 3 mg/m2 i.v. on days 1 and 8 (MVP). If the granulocyte nadir count recorded after the first cycle of MVP was less than 1,000/mm3, patients were randomly assigned to receive recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) or placebo during the second cycle of MVP. The dose of rhGM-CSF was 125 micrograms/m2 given daily s.c. for 14 consecutive days starting on day 2. Of the 52 patients enrolled, 45 were evaluable. The nadir of granulocytes was significantly lower in the placebo group (P = 0.007). The period during which the granulocyte count was less than 1,000/mm3 was significantly longer in the placebo group (median, 6 vs 10 days; P = 0.04). The incidence of adverse effects related to rhGM-CSF, such as fever (> or = 38 degrees C) and skin rash, was significantly higher in the rhGM-CSF group (P = 0.011). The rate of response to chemotherapy did not significantly differ between the two groups. In conclusion, rhGM-CSF reduced the duration of chemotherapy-induced granulocytopenia. The clinical usefulness of this agent may be deminished because of the adverse effects encountered when it is used in combination with a moderately myelotoxic chemotherapy regimen.

Recombinant human granulocyte-macrophage colony-stimulating factor in acquired or chemotherapy-induced neutropenia. An open clinical trial

This prospective open trial evaluated the efficacy and tolerability of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) in patients with established neutropenia, considering as the main endpoint the clinical benefit to the patients regarding clearing of infection or resuming chemotherapy as initially planed. Adult patients (n = 28) with absolute neutrophil counts (ANC) < 10(9)/1 for 21 days were given a fixed dose (400 micrograms) of rhGM-CSF subcutaneously, for a total of 35 cycles. Causes of neutropenia were chemotherapy for acute leukaemia, lymphoma, myeloma and solid tumours, complications after bone marrow transplantation (BMT), and neutropenia associated with AIDS. Response (ANC to > 10(9)/l) occurred in 83% of rhGM-CSF cycles (29/35). Median time to response was 2.4 days (mean 6.7 days). Kinetics of response was dependent on diagnosis and treatment history. Fever abated with increasing ANC in 13/17 patients (76%) who entered the trial with hyperpyrexia. Treatment with rhGM-CSF allowed chemotherapy to be resumed on schedule in 7/9 relevant cycles. Toxicity was mild, leading to treatment interruption in only two cycles. In conclusion, rhGM-CSF was well tolerated and associated with a rise in ANC which appeared to result in immediate clinical benefit, including resolution of infection and resumption of scheduled chemotherapy.

Comparison of 5 vs 10 micrograms/kg per day of GM-CSF following dose-intensified chemotherapy with cisplatin, etoposide, and ifosfamide in patients with advanced testicular cancer

Despite the increasing use of granulocyte-macrophage colony-stimulating factor (GM-CSF) for the treatment of chemotherapy-induced neutropenia, few studies have focused on the activity and toxicity of the different clinically used dosages of GM-CSF. Forty-four patients with "poor-risk" (advanced disease, according to the Indiana University classification) testicular cancer were treated with a dose-intensified chemotherapy regimen of cisplatin (30 mg/m2), etoposide (200 mg/m2), and ifosfamide (1.6 g/m2), given on days 1-5 for a total of four cycles at planned intervals of 21 days. Patients (pts) received GM-CSF, either 10 (22 pts; 70 cycles evaluable) or 5 micrograms/kg body wt. daily s.c. (22 pts; 72 cycles evaluable), starting the first day after chemotherapy for 10 consecutive days. Overall, 34 patients (78%) achieved a favorable response (CR or PR with negative tumor markers), six patients (14%) failed this chemotherapy regimen, and four patients (9%) died of therapy-related complications. The durations of both neutropenia and thrombocytopenia increased with the number of treatment cycles given. The duration of granulocytopenia after the fourth PEI cycle was significantly shorter for patients receiving 10 micrograms/kg than for those with 5 micrograms/kg per day of GM-CSF (9 vs 13 days; p < 0.05). The median duration of thrombocytopenia < 20,000/microliters after the fourth cycle of PEI was also significantly reduced in favor of patients receiving 10 micrograms/kg of GM-CSF (4 vs 9 days; p < 0.02). However, there were no differences in the frequency of severe infections or in the achieved dose intensity. Five patients (11%) discontinued GM-CSF due to side effects (three anaphylactoid-type reactions, one myalgia and fever, one cutaneous toxicity). No difference in the frequency of side effects was seen between patients receiving 5 and those receiving 10 micrograms/kg per day of GM-CSF. The dose of 5 micrograms/kg per day of GM-CSF may be sufficient to ameliorate neutropenia following standard-dose chemotherapy, while higher dosages of GM-CSF may be advantageous in patients receiving repetitive cycles of dose-intensified chemotherapy.

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.

Southwestern Internal Medicine Conference: clinical use of hematopoietic growth factors

The hematopoietic growth factors, granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF), have been cloned, produced in bacteria and yeast, and approved for clinical use in the treatment of neutropenia. Both factors stimulate the proliferation and maturation of neutrophil progenitors and enhance the effector functions of mature cells by interaction with specific receptors on the cell surface. Serum levels of G-CSF correlate inversely with the neutrophil count, suggesting that G-CSF may be the normal homeostatic regulator of the neutrophil count, while GM-CSF is generally undetectable in the serum and appears under normal physiologic conditions to act locally at inflammatory sites. Phase I and II clinical trials with these factors demonstrated minimal toxicity for G-CSF and mild to moderate dose-dependent toxicity for GM-CSF. Recent clinical trials, including double-blind, randomized studies, support a role for these growth factors in the treatment of chronic neutropenias, such as Kostmann's syndrome, acquired immune deficiency syndrome (AIDS), aplastic anemia, and myelodysplasia, as well as in acute neutropenias, such as cyclic neutropenia, chemotherapy-induced neutropenia, and bone marrow transplantation.

Bone marrow myeloid cell kinetics during treatment of small cell carcinoma of the lung with chemotherapy not associated and associated with granulocyte-macrophage colony-stimulating factor

Information on the kinetics of bone marrow (BM) myeloid precursors (BMMP) is required for integrating cancer chemotherapy with granulocyte-macrophage colony-stimulating factor (rhGM-CSF), with the aim of reducing neutropenia. Using bivariate flow-cytometric analysis of the in vivo incorporation of bromode-oxyuridine (BUDR) vs DNA content we have studied the kinetics of BMMP in 21 patients with SCLC during the first of six chemotherapy courses (etoposide, epirubicin, and cis-platinum, days 1-3, every 21 days), given alone (eight patients) or followed by rhGM-CSF (10 micrograms/kg/day s.c., days 4-14) as BM rescue (eight patients) or both preceded (days -17 to -7, as BM priming) and followed by rhGM-CSF (five patients). At 11-14 days after the start of these therapies there was an increase in the baseline proliferative activity of proliferating BMMP and a shortening in the time needed by the metamyelocyte to mature and to leave the marrow. Both effects were greater and were maintained to a significantly greater degree a week later in patients who received chemotherapy plus rhGM-CSF rescue than in those who received chemotherapy alone or rhGM-CSF priming alone. At day 11-14 the pretreatment median cell production rate of pBMMP was increased by 340%, 150%, and 183% and the maturation time was reduced by 80%, 45%, and 57%, respectively, in the three groups. A week later, the corresponding figures were 206%, 111%, and 157% and 50%, 18%, and 45%. Hence, an identical rhGM-CSF schedule is more effective in increasing the neutrophil production by BMMP when given following chemotherapy as BM rescue than before it as BM priming. In both the rescue and the priming schedule, the increase in proliferative activity of BMMP just at the end of rhGM-CSF stimulation was linked to both an increase in the labeling index and a reduction in duration of S-phase (TS), while a week later it was linked solely to reduction in TS. This could actually reduce one of the two kinetic targets of subsequently administered cytostatics, i.e., a high LI and a long time spent in S phase. From this study, accurate kinetic data can be obtained with the in vivo BUDR technique that are useful in scheduling rhGM-CSF.

Effect of monoclonal antibody 17-1A and GM-CSF in patients with advanced colorectal carcinoma--long-lasting, complete remissions can be induced

Antibody-dependent cellular cytotoxicity (ADCC) is considered to be one of the effector functions of unconjugated monoclonal antibodies (MAbs) in tumor therapy. The antitumor activity of MAbs might therefore be augmented if the cytotoxic capability of the effector cells could be increased. In an in vitro system, the killing capacity of MAb was significantly enhanced by pre-treatment of the effector cells with granulocyte-macrophage colony-stimulating factor (GM-CSF). Based on these findings, the therapeutic effect of the combination of mouse MAb 17-1A (IgG2a) and GM-CSF was evaluated in 20 patients with metastatic colorectal carcinoma (CRC). The patients received GM-CSF for 10 days and a single i.v. infusion of MAb 17-1A on day 3 of the cycle. Four cycles were given at 1-monthly intervals. There was a continuous increase in blood monocytes and lymphocytes during all 4 GM-CSF cycles. Neutrophils and eosinophils were also significantly augmented but in a biphasic manner and the cell counts on day 10 of cycle IV were significantly lower than in cycles I and II. GM-CSF-related side-effects were of no major clinical importance. During the third cycle, an immediate-type allergic reaction (ITAR) against MAb 17-1A occurred in most patients, necessitating reduction of the MAb dose as well as of the infusion rate. Two patients achieved complete remission. One patient had a minor response, and 3 other patients were considered to have stable disease > 3 months.

Agar capillary clonogenic microassays for cellular immunocytotoxic activities in human leukaemia and lymphoma

Current concepts of immunotherapeutic approaches in leukemias and lymphomas using activated cytotoxic lymphocytes and macrophages are briefly reviewed. Defective cellular immunocytotoxic activities and effects of interleukins and chemotherapeutic drugs thereupon are discussed. In vitro assays to measure lymphokine-activated killer (LAK) and natural killer (NK) cell activities suffer from various problems, depending on the quality of the endpoints. Our clonogenic microassay for LAK cell activity, using agar-containing glass capillaries, avoids some of the potential artifacts and offers several advantages that are discussed. As an example the stimulatory effect of low mafosfamide concentrations on the LAK cell activity versus K562 human myeloid leukemia cells is demonstrated. Thus, our clonogenic LAK microassay provides a valid tool for preclinical screening of immunomodulatory agents.

Empiric treatment of localized infections in the febrile neutropenic patient with monotherapy

Empiric therapy is necessary for febrile, neutropenic patients in order to minimise morbidity and mortality. Certain agents are now available for monotherapy which offer comparable success to combinations of either an aminoglycoside with a beta-lactam or two beta-lactams. However, no regimen offers complete treatment under all circumstances in all patients. It is also apparent that febrile, neutropenic patients comprise a more heterogeneous group than just those with bacteraemia, clinically apparent infection and unexplained fever. Localized infections occur in just under a third of cases at the onset of fever and a similar number will develop during the course of fever. Mortality is higher in infections that are accompanied by bacteraemia and also those that develop subsequently, especially when related to the lung. The aetiological agent also differs with each type of infection as does the duration of fever and symptoms. Consequently modifications are required more often. The length of treatment may also differ. Therefore, during the first 3-4 days of empiric therapy, every effort should be made to identify incipient localized infections in addition to detecting bacteraemia. Changes in therapy can then be based on objective grounds rather than continued fever offering more patients individual treatment than is possible when relying only on the temperature chart.

Reduction of infection rates in cancer patients associated with the use of haematopoietic growth factors

As the risk of infection associated with chemotherapy is related to the depth of the fall in neutrophil counts, protection from neutropenia has been used as an endpoint for growth factors in this setting. However, the functional status of these and other myeloid cells are also important. Therefore, more direct measurements of clinical improvement will also be useful. Several studies have suggested that the use of granulocyte-macrophage colony-stimulating factor (GM-CSF) can result in improvements in hospital stay, days of fever, antibiotic use and thrombocytopenia. Similar findings have been confirmed by our own work which indicates that GM-CSF not only shortens the period of leukopenia, but also reduces the complications of infection. More sensitive and appropriate endpoints should be included in future trials, including rate of and survival from infection as well as overall and disease-free survival.

Current issues in cancer. Biological therapy

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The side-effect profile of GM-CSF

Granulocyte-macrophage colony-stimulating factor (GM-CSF), a pleiotropic molecule which displays a broad range of haematopoietic activities, has become available for clinical evaluation in various patient groups. It has been shown to be effective in preventing or reversing neutropenia. Adverse effects of GM-CSF, however, are dose related. Appropriate dose, route and schedules for GM-CSF in various clinical settings have recently been defined, the usual range being 5-10 micrograms/kg/day either by 4-6 h intravenous infusion or by subcutaneous injection. At such doses, adverse effects are predominantly mild-to-moderate in nature, occur in 20-30% of patients and usually comprise fever, myalgia, malaise, rash and injection site reaction. Early trials using very high doses of GM-CSF were often associated with marked adverse effects, which in rare cases proved severe (pericarditis and thrombosis). Similarly, a so-called "first-dose reaction", defined as a syndrome of hypoxia and hypotension after the initial but not subsequent doses of GM-CSF, was observed in certain predisposed patients following doses above 10 micrograms/kg/day. Subsequent trials have established that intravenous bolus or short infusions of GM-CSF are more likely to promote adverse effects. Certain patient groups, for example those with myelodysplastic syndrome, acute myeloid leukaemia, inflammatory disease, autoimmune thrombocytopenia or malfunctional immunological responsiveness, require careful clinical monitoring in order to avoid potential complications following the administration of GM-CSF. With the current appropriate administration and doses of GM-CSF, the benefit:risk ratio has been greatly improved.