Treatment of anaemia in myelodysplastic syndromes with prolonged administration of recombinant human granulocyte colony-stimulating factor and erythropoietin

Treatment with recombinant human erythropoietin (rhEPO) improves anaemia in approximately 20% of the patients with myelodysplastic syndromes (MDS). Recent reports suggest that a combination treatment with rhEPO plus recombinant human granulocyte colony-stimulating factor (rhG-CSF) given for up to 18 weeks may result in a higher erythroid response rate than with rhEPO alone. We investigated the potential advantage of an even more prolonged schedule of combined rhG-CSF and rhEPO treatment to obtain and maintain stable responses. In a phase II study, 33 patients with MDS [17 with refractory anaemia (RA), eight with RA with ringed sideroblasts (RARS), eight with RA with excess blasts (RAEB) with bone marrow blast counts less than 20%] were scheduled to receive at least 36 weeks of combined therapy with rhG-CSF and rhEPO. Seventeen of 28 evaluable patients demonstrated an erythroid response [61%; 95% confidence interval (CI) 41-78] after 12 weeks of treatment. The erythroid response rate was 80% (20 of 25 evaluable patients; 95% CI 59-93) after 36 weeks. Seven of these responses developed between week 12 and week 36, whereas two initially responding patients became refractory. The cytokine therapy was generally well tolerated. Nineteen of the 20 patients responding after 36 weeks continued to be treated with both cytokines. After 1 year and 2 years of continuous combined treatment, 50% of the initially included patients showed a continuing response. Our results suggest that a prolonged combination treatment with rhG-CSF and rhEPO is highly effective in achieving a stable and long-lasting erythroid response in many patients with MDS and low blast count.     

A phase II trial of recombinant human granulocyte colony-stimulating factor in the myelodysplastic syndromes

We conducted a phase II study of the intravenous administration of a glycosylated recombinant human granulocyte colony-stimulating factor (rhG-CSF) for 7-14 d in 41 patients with the myelodysplastic syndromes (MDS). Administration of rhG-CSF elicited striking rises in both leucocyte and neutrophil counts in the majority of the patients irrespective of the FAB subtypes of MDS. The rises in neutrophil counts were dose dependent and 5 micrograms/kg/d of rhG-CSF yielded approximately an 8-fold increase in neutrophil counts. Leucocytes and neutrophil counts started to increase shortly after the first injection of 5 micrograms/kg, was maintained at significantly elevated levels during 14 d of treatment, and returned to the pretreatment levels within several days following discontinuation of rhG-CSF. The action of rhG-CSF was specific for neutrophils since leucocytosis was due exclusively to neutrophilic increase associated with an increased marrow myeloid maturation. There were no consistent changes in the monocyte, eosinophil, lymphocyte, platelet or reticulocyte counts. After treatment, the percentage of marrow blast cells was reduced in eight of 13 evaluable patients with refractory anaemia with an excess of blasts (RAEB) or RAEB in transformation (RAEB-t). No patients developed acute leukaemia during the treatment or in the immediate follow-up period. The treatment was well tolerated with only minimal toxicity. The results suggest that rhG-CSF is a safe and effective way to promptly improve neutropenia in MDS patients.     

Combination Therapy With Recombinant Human Granulocyte Colony-Stimulating Factor and Erythropoietin in Aplastic Anemia

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) and erythropoietin (rhEPO) were used to treat patients with aplastic anemia (AA). In terms of effects on erythrocyte recovery, the combined use of rhG-CSF and rhEPO showed a favorable response in 6 of 14 (42.9%) patients with moderate AA following 10 weeks treatment and in 3 of 14 (21.4%) patients thereafter. However, the response was poor in patients with severe AA (3/13). A favorable response in severe AA was observed in 1 of 13 (7.7%) patients following 10 weeks treatment and in 2 of 13 (15.4%) patients thereafter. The overall effect on erythrocytes was observed in 44.4% patients. A dose of 400 μ/m² G-CSF was sufficient to cause an increase in neutrophil count and 100 IU/kg rhEPO appeared to be sufficient to cause an increase in erythrocyte count. In 6 of 27 (22.2%) patients, a trilineage response was observed. Interestingly, a delayed and long-lasting effect was obtained in 5 of 27 (18.5%) patients. These results suggest that rhG-CSF can synergize with rhEPO in erythrocyte response, especially in patients with moderate AA.     

Recombinant human granulocyte colony-stimulating factor repairs the abnormalities of neutrophils in patients with myelodysplastic syndromes and chronic myelogenous leukemia

We examined the in vitro effect of recombinant human granulocyte colony- stimulating factor (rhG-CSF) on neutrophil anomalies in 20 patients with myelodysplastic syndromes (MDS) and eight patients with chronic myelogenous leukemia (CML). Neutrophil alkaline phosphatase (NAP) activity was determined in nine MDS patients and eight CML patients by a scoring method. NAP scores were decreased in six of the nine patients with MDS and in all of the patients with CML. In all patients with these diseases, NAP scores increased by incubating the blood with rhG- CSF. An increase in NAP scores by rhG-CSF was observed even at a concentration of 1 U/mL in patients with MDS but was observed only at higher concentrations (1,000 to 10,000 U/mL) in patients with CML. Significant increases in NAP scores occurred at 12 hours' incubation in patients with MDS, whereas the increase was more gradual in patients with CML. This time course difference was thought to be due mainly to the difference in cell populations of circulating myeloid cells between MDS patients and CML patients. Induction of NAP activity by rhG-CSF in patients with both these diseases was suppressed by the addition of inhibitors of RNA or protein synthesis. Neutrophil superoxide anion (O2- ) production induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP) was determined in the other 11 patients with MDS. This neutrophil function was decreased in seven of the 11 patients with MDS, normal in two patients, and increased in two patients. Preincubation with rhG-CSF caused a significant increase in fMLP-induced O2- production in nine of the 11 patients with MDS. rhG-CSF enhanced this neutrophil function in a time- and dose-dependent manner, and maximal stimulation was observed at 2,000 to 4,000 U/mL of rhG-CSF and at five to ten minutes' incubation. The present results show that rhG-CSF is able to repair at least in part the neutrophil anomalies in these patients, and our data, especially for patients with MDS, suggest the clinical usefulness of rhG-CSF for this preleukemic disorder.     

Clinical study of rhG-CSF (KRN8601) in patients with myelodysplastic syndrome]

A clinical study of rhG-CSF (KRN8601) in patients with myelodysplastic syndrome (MDS) was performed to investigate the hematopoietic effects and the increase of neutrophils. The rhG-CSF was administered daily by intravenous infusion over 30 min. to 21 patients with MDS (PARA = 11, RAEB = 4, RAEB in T = 6). The dose was escalated stepwise from 50 to 400 microgram/m2 every week. Within one week to 26 days after commencement of rhG-CSF administration, the increases of absolute neutrophil counts in peripheral blood were observed in all patients. Treatment with rhG-CSF enhanced normal marrow myeloid cell differentiation and maturation in 3 of 9 PARA patients and in 3 of 4 RAEB patients. None of patients changed to acute leukemia attributable to rhG-CSF, but one of RAEB patient and two of RAEB in T patients progressed to leukemic phase in 21 days or two months after treatment. Minor side effects or abnormal laboratory findings were observed in 3 patients (14.3%). These results suggested that treatment with rhG-CSF was well tolerated and effective for improving the neutropenia between 50 to 400 micrograms/m2 in patients with MDS.     

Efficacy of recombinant human granulocyte colony-stimulating factor on neutropenia in patients with AIDS.

The efficacy of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on neutropenia was evaluated in 14 patients with AIDS and AIDS-related complex (ARC). In all patients, including 11 neutropenic patients, 100 or 200 micrograms/m2 of rhG-CSF significantly increased the neutrophil counts. The response was greater in patients with higher neutrophil counts before the treatment, and was also dose-dependent. Although the effect seemed to be less potent, the agent also increased the neutrophil counts even when zidovudine (azidothymidine, AZT) and other myelosuppressive antiviral agents were administered simultaneously. These observations indicate that rhG-CSF may be beneficial in preventing and treating some secondary infections, and will make it easier to continue therapy with antiviral agents in patients with AIDS or ARC.     

Treatment of aplastic anemia with KRN8601 (rhG-CSF)]

Thirty-nine patients with severe or moderate aplastic anemia received treatment with recombinant human granulocyte colony-stimulating factor (rhG-CSF). The first group of eight patients received rhG-CSF in doses of 100 to 400 micrograms/m2/d by a daily 30-minute intravenous infusion for one or two weeks. Doses up to 400 micrograms/m2/d were well tolerated and resulted in increases of neutrophil counts in 5 out of 8 patients. We gave rhG-CSF (400 micrograms/m2/d) to the second group of 26 patients by a daily 30-minute intravenous infusion for two weeks. The treatment resulted in an increase of neutrophil counts in 15 out of 26 patients (3.1 to 29.5 fold). Further, higher doses (800 or 1,200 micrograms/m2/d) were administered in 5 patients who did not respond to the dose of 400 micrograms/m2/d. The treatment increased the neutrophil counts in 3 out of 5 patients. The third group of five patients received rhG-CSF subcutaneously in doses of 20 to 400 micrograms/m2/d. An increase of neutrophil counts was noted in all five patients. Differential counts of bone marrow aspirate revealed an increase of myeloid: erythroid ratios. However, the responses were transient and neutrophil counts returned to basal levels within 1 approximately 2 weeks after discontinuing treatment. No severe toxicity due to rhG-CSF was observed. These results suggest that rhG-CSF is effective on stimulating granulopoiesis in patients with aplastic anemia. This treatment will be particularly useful for the patient with aplastic anemia suffering from bacterial or fungal infections.     

Additive effects of human recombinant interleukin-11 and granulocyte colony-stimulating factor in experimental gram-negative sepsis

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is widely used to promote granulocyte recovery from a variety of pathologic states. Recombinant human interleukin-11 (rhIL-11) has recently become available clinically as a platelet restorative agent after myelosuppressive chemotherapy. Preclinical data has shown that rhIL-11 limits mucosal injury after chemotherapy and attenuates the proinflammatory cytokine response. The potential efficacy of combination therapy with recombinant human forms of rhIL-11 and rhG-CSF was studied in a neutropenic rat model of Pseudomonas aeruginosa sepsis. At the onset of neutropenia, animals were randomly assigned to receive either rhG-CSF at a dose of 200 micrograms/kg subcutaneously every 24 hours for 7 days; rhIL-11 at 200 micrograms/kg subcutaneously every 24 hours for 7 days; the combination of both rhG-CSF and rhIL-11; or saline control. Animals were orally colonized with Pseudomonas aeruginosa 12.4.4 and then given a myelosuppressive dose of cyclophosphamide. rhG-CSF resulted in a slight increase in absolute neutrophil counts (ANC), but did not provide a survival advantage (0 of 12, 0% survival) compared with the placebo group (1 of 12, 8% survival). rhIL-11 was partially protective (4 of 10, 40% survival); the combination of rhG-CSF and rhIL-11 resulted in a survival rate of 80% (16 of 20; P <.001). rhIL-11 alone or in combination with rhG-CSF resulted in preservation of gastrointestinal mucosal integrity (P <.001), lower circulating endotoxin levels (P <.01), and reduced quantitative levels of P. aeruginosa in quantitative organ cultures. These results indicate that the combination of rhIL-11 and rhG-CSF is additive as a treatment strategy in the prevention and treatment of experimental Gram-negative sepsis in immunocompromised animals. This combination may prove to be efficacious in the prevention of severe sepsis in neutropenic patients.     

Combination therapy for radiation-induced bone marrow aplasia in nonhuman primates using synthokine SC-55494 and recombinant human granulocyte colony-stimulating factor

Combination cytokine therapy continues to be evaluated in an effort to stimulate multilineage hematopoietic reconstitution after bone marrow myelosuppression. This study evaluated the efficacy of combination therapy with the synthetic interleukin-3 receptor agonist, Synthokine- SC55494, and recombinant methionyl human granulocyte colony-stimulating factor (rhG-CSF) on platelet and neutrophil recovery in nonhuman primates exposed to total body 700 cGy 60Co gamma radiation. After irradiation on day (d) 0, cohorts of animals subcutaneously received single-agent protocols of either human serum albumin (HSA; every day [QD], 15 micrograms/kg/d, n = 10), Synthokine (twice daily [BID], 100, micrograms/kg/d, n = 15), rhG-CSF (QD, 10 micrograms/kg/d, n = 5), or a combination of Synthokine and rhG-CSF (BID, 100 and 10 micrograms/kg/d, respectively, n = 5) for 23 days beginning on d1. Complete blood counts were monitored for 60 days postirradiation and the durations of neutropenia (absolute neutrophil count < 500/microL) and thrombocytopenia (platelet count < 20,000/microL) were assessed. Animals were provided clinical support in the form of antibiotics, fresh irradiated whole blood, and fluids. All cytokine protocols significantly (P < .05) reduced the duration thrombocytopenia versus the HSA-treated animals. Only the combination protocol of Synthokine + rhG-CSF and rhG-CSF alone significantly shortened the period neutropenia (P < .05). The combined Synthokine/rhG-CSF protocol significantly improved platelet nadir versus Synthokine alone and HSA controls and neutrophil nadir versus rhG-CSF alone and HSA controls. All cytokine protocols decreased the time to recovery to preirradiation neutrophil and platelet values. The Synthokine/rhG-CSF protocol also reduced the transfusion requirements per treatment group to 0 among 5 animals as compared with 2 among 5 animals for Synthokine alone, 8 among 5 animals for rhG-CSF, and 17 among 10 animals for HSA. These data showed that the combination of Synthokine, SC-55494, and rhG-CSF further decreased the cytopenic periods and nadirs for both platelets and neutrophils relative to Synthokine and rhG-CSF monotherapy and suggest that this combination therapy would be effective against both neutropenia and thrombocytopenia consequent to drug- or radiation- induced myelosuppression.     

Monosomy 7 and activating RAS mutations accompany malignant transformation in patients with congenital neutropenia

Individuals with severe forms of congenital neutropenia suffer from recurrent infections. The therapeutic use of recombinant human granulocyte colony-stimulating factor (rhG-CSF) to increase the neutrophil count is associated with fewer infections and an improved quality of life. However, the long-term effects of this new therapy are largely unknown. In particular, it is unclear if myeloid leukemia, a known complication of some forms of congenital neutropenia, will occur with increased frequency among patients who receive long-term treatment with hematopoietic growth factors. We report 13 patients with congenital disorders of myelopoiesis who developed leukemic transformation with either myelodysplastic syndrome (MDS) or acute myelogenous leukemia (AML) and 1 who acquired a clonal cytogenetic abnormality without evidence of MDS or AML while receiving rhG-CSF. The bone marrows of 10 patients showed monosomy 7 and 5 had activating RAS mutations. These abnormalities were not detected in pretreatment bone marrows and cessation of rhG-CSF was not associated with either clinical improvement or cytogenetic remission. We conclude that patients with severe forms of congenital neutropenia are at relatively high risk of developing MDS and AML. The occurrence of monosomy 7 and RAS mutations in these cases suggests that the myeloid progenitors of some patients are genetically predisposed to malignant transformation. The relationship between therapeutic rhG-CSF and leukemogenesis in patients with severe chronic neutropenia is unclear.     

Treatment of aplastic anemia in children with recombinant human granulocyte colony-stimulating factor

Twenty children (aged 1 to 17 years) with severe or moderate aplastic anemia were treated with recombinant human granulocyte colony- stimulating factor (rhG-CSF) at a dose of 400 micrograms/m2 per day administered as a 30-minute intravenous (IV) infusion daily for 2 weeks. This treatment increased the neutrophil counts (2.7- to 28.0- fold) in 12 of the 20 patients. Increasing doses (800 or 1,200 micrograms/m2 per day) were administered to five patients who had not responded to the initial dose, and three showed an increase in neutrophil count. Differential counts of bone marrow (BM) aspirates showed an increase in the myeloid/erythroid ratio. The response was transient, however, and the neutrophil count returned to baseline within 2 to 10 days of discontinuing treatment. No severe toxicity attributable to rhG-CSF was observed. The results suggest that this agent is effective in stimulating granulopoiesis in children with aplastic anemia. Our study also indicates that rhG-CSF will be particularly useful in managing patients with aplastic anemia complicated by bacterial or fungal infection.     

Clinical effects of recombinant human granulocyte colony-stimulating factor in leukemia patients: a phase I/II study

A phase I/II study of recombinant human granulocyte colony-stimulating factor (rhG-CSF) in 24 leukemia patients was conducted at our institute. Recombinant human G-CSF (50-200 micrograms/m2/day) was administered i.v. In seven allogeneic bone marrow transplantation (BMT) recipients, treatment with rhG-CSF was started 5 days after BMT. Neutrophils began to increase within 3 days after the start of rhG-CSF administration in five of seven patients. The mean duration necessary for recovery of neutrophils to greater than 500/microliters was 11.3 days after BMT with rhG-CSF; 26.8 days is the figure for recovery without rhG-CSF from Japanese historical data. In seven out of eight patients who received rhG-CSF administration after the first remission-induction chemotherapy, the neutrophil counts increased from less than 300/microliters to greater than 4000/microliters within 10 days. Blasts did not increase in all patients including four acute nonlymphocytic leukemia (ANLL) patients. Severe infections such as septicemia and pneumonia, which were unable to be controlled by antibiotics only, were successfully treated with rhG-CSF and antibiotics. rhG-CSF either stimulated or inhibited myeloid leukemic cells in some refractory cases. Mild bone pain occurred in one patient while receiving rhG-CSF i.v. rhG-CSF seems to have the ability to shorten the period of neutropenia, prevent infections after allogeneic BMT and remission-induction chemotherapy for acute leukemia, and support therapy for infections.     

Pentoxifylline,Ciprofloxacin and Dexamethasone Improve the Ineffective Hematopoiesis in Myelodysplastic Syndrome Patients

Twenty-five patients with a diagnosis of myelodysplastic syndromes (MDS) were randomized to either begin therapy with pentoxifylline, ciprofloxacin and dexamethasone (PCD) immediately (10 patients) or after a 12 week observation period (control arm, 15 patients). PCD was administered with the goal of suppressing cytokine-induced excessive intramedullary apoptosis of hematopoietic cells. No marked fluctuations of blood counts were noted during the period of observation. Twenty-two patients completed at least 12 weeks of therapy: 18/22 showed some type of hematologic response, 9/18 showing an improvement in absolute neutrophil count only (p = < 0.001) and 9/18 showing multi-lineage responses. No unique category of MDS responded better, however 19/25 patients had refractory anemia (RA)/RA with ringed sideroblasts. The median time to response was 6 weeks and 3/18 responding patients maintained their responses beyond a year. We conclude that hematologic improvement in response to PCD therapy supports the validity of this unique anti-cytokine approach. Future trials should combine PCD therapy with established approaches (growth factors/chemotherapy) and also should focus on identifying more effective ways of suppressing the pro-apoptotic cytokines in MDS.     

Pentoxifylline, Ciprofloxacin and Dexamethasone Improve the Ineffective Hematopoiesis in Myelodysplastic Syndrome Patients; Malignancy

Twenty-five patients with a diagnosis of myelodysplastic syndromes (MDS) were randomized to either begin therapy with pentoxifylline, ciprofloxacin and dexamethasone (PCD) immediately (10 patients) or after a 12 week observation period (control arm, 15 patients). PCD was administered with the goal of suppressing cytokine-induced excessive intramedullary apoptosis of hematopoietic cells. No marked fluctuations of blood counts were noted during the period of observation. Twenty-two patients completed at least 12 weeks of therapy: 18/22 showed some type of hematologic response, 9/18 showing an improvement in absolute neutrophil count only (p = < 0.001) and 9/18 showing multi-lineage responses. No unique category of MDS responded better, however 19/25 patients had refractory anemia (RA)/RA with ringed sideroblasts. The median time to response was 6 weeks and 3/18 responding patients maintained their responses beyond a year. We conclude that hematologic improvement in response to PCD therapy supports the validity of this unique anti-cytokine approach. Future trials should combine PCD therapy with established approaches (growth factors/chemotherapy) and also should focus on identifying more effective ways of suppressing the pro-apoptotic cytokines in MDS.     

The COP-BLAM III therapy of non-Hodgkin's lymphoma]

COP-BLAM III therapy was given to 18 patients with non-Hodgkin's lymphoma, and the therapeutic effects as well as adverse effects of the treatment were examined. Of the 18 patients 16 had a complete remission (CR) and 2 showed an partial remission (PR) with a total response rate of 100%. In terms of the stage of disease, CR was achieved in all patients in stage III and in 11 of 13 patients in stage IV. Patients with neutrophil counts less than 1,000/microliters were given rhG-CSF (1.5 micrograms/kg/day, sc), which significantly shortened the duration of neutropenia and decreased the number of days with episodes of fever when compared with those not given rhG-CSF, consequently facilitating the treatment without prolonging the dosing intervals. No serious infection was observed. Adverse effects included neutropenia of less than 1,000/microliters in 6 of the 18 patients (33.3%), thrombocytopenia less than 5 x 10(4)/microliters in 3 (16.7%), nausea and vomiting in 8 (44.4%), peripheral neuropathy in 4 (22.2%) and stomatitis in 4 (22.2%). There were no fatalities caused by the treatment. The above findings indicate that COP-BLAM III therapy is capable inducing high frequency of complete remissions in non-Hodgkin's lymphoma and that its combination with G-CSF can improve the results of the therapy and relieve adverse reactions.     

Changes in neutrophil counts and functions after the administration of recombinant human granulocyte colony-stimulating factor in a patient with chronic idiopathic neutropenia]

The cause of chronic idiopathic neutropenia (CIN) is unknown. Recently recombinant human granulocyte colony-stimulating factor (rhG-CSF) has been purified. Many studies of effects of rhG-CSF on the patients with neutropenia have been undertaken. We examined changes in neutrophil counts and functions after the administration of rhG-CSF in a patient with CIN. Six hours after the intravenous administration of 40 micrograms of rhG-CSF, neutrophil counts were raised from 90 to 1570/microliters, and the increased neutrophils functioned normally; chemotaxis, phagocytosis and O2(-) generation. It is suggested that rhG-CSF is beneficial for the treatment of infection in patients with CIN.     

Hematological effect of 14 days treatment of recombinant human granulocyte colony-stimulating factor for neutropenia in myelodysplastic syndromes]

Nineteen patients with myelodysplastic syndromes (MDS) were treated with a glycosylated recombinant granulocyte colony-stimulating factor (rG-CSF) for improvement of neutropenia. rG-CSF was administrated intravenously at a dose of 5 micrograms/kg/day for 14 consecutive days. Most of patients responded to rG-CSF and an approximately 10 fold increase of the peak neutrophil counts was observed. The neutrophil counts were maintained at high level during the treatment period and returned to pretreatment levels several days after stopping rG-CSF. Consistent with the recovery of neutrophil, infectious complications improved in many cases. Effects of rG-CSF were confined to neutrophils, sparing blast cells and other blood cells. Eruption was observed in one patient as toxicity. We conclude that rG-CSF therapy is effective in improving neutropenia with MDS patients.     

Treatment of severe neutropenia due to Felty's syndrome or systemic lupus erythematosus with granulocyte colony-stimulating factor.

OBJECTIVES: To examine the efficacy and safety of recombinant human granulocyte colony-stimulating factor (rhG-CSF) and recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) for the treatment of severe neutropenia due to Felty's syndrome (FS) or systemic lupus erythematosus (SLE). METHODS: Eight patients with absolute neutrophil counts (ANC) below 1,000/microL attributable to FS (n = 4) or SLE (n = 4) were treated with rhG-CSF. The hematologic and clinical response as well as side effects were recorded. In addition, reports on the use of rhG-CSF/rhGM-CSF in FS and SLE retrieved from the English language literature were analyzed. RESULTS: RhG-CSF effectively corrected neutropenia due to FS and SLE in seven of the current eight patients. In 54 of 55 FS and SLE patients retrieved from the literature, G-CSF or GM-CSF, respectively, proved to be effective at elevating the neutrophil count, which was often associated with improvement of infectious complications. The neutrophil count often declined again when growth factor treatment was stopped but generally stabilized at a level that exceeded the pretreatment count. Side effects included rare cases of thrombocytopenia, arthralgias, and development of cutaneous leukocytoclastic vasculitis. Side effects were dose dependent and resolved when treatment was discontinued. One of our own patients and 17 previously reported patients continued to benefit from long-term administration of rhG-CSF over periods of more than 40 months. CONCLUSIONS: RhG-CSF is an effective and generally well-tolerated treatment for neutropenia due to FS or SLE. Exacerbation of the underlying rheumatic condition due to G-CSF appears to be rare if G-CSF is administered at the lowest dose effective at elevating the ANC above 1,000/microL.     

In vivo stimulation of granulopoiesis by recombinant human granulocyte colony-stimulating factor.

Osmotic pumps containing Escherichia coli-derived recombinant human granulocyte colony-stimulating factor (rhG-CSF) were attached to indwelling jugular vein catheters and implanted subcutaneously into Golden Syrian hamsters. Within 3 days, peripheral granulocyte counts had increased greater than 10-fold with a concomitant 4-fold increase in total leukocytes. Microscopic examination of Wright-Giemsa-stained blood smears from rhG-CSF hamsters showed that only the neutrophil subpopulation of granulocytes had increased. No significant changes in lymphocyte or monocyte counts were observed during the course of continuous rhG-CSF treatment. After subcutaneous injection at rhG-CSF doses of up to 10 micrograms X kg-1 X day-1 only granulocyte counts were affected. However, at higher dose levels, a transient thrombocytopenia was noted. Erythrocyte had lymphocyte/monocyte counts remained unaffected by rhG-CSF over the entire dose range (0.3-300 micrograms X kg-1 X day-1) studied. Total leukocyte counts increased 3-fold within 12 hr after a single s.c. injection of rhG-CSF. This early effect was associated with an increase in the total number of colony-forming cells and the percent of active cycling cells in the marrow. A sustained elevation of peripheral leukocyte and marrow progenitor counts was observed following seven daily s.c. injections of rhG-CSF. The ability of rhG-CSF to increase the production and release of granulocytes from the marrow may underlie the beneficial effect it produced on the restoration of peripheral leukocyte counts in hamsters made leukopenic by treatment with 5-fluorouracil.     

Treatment of idiopathic neutropenia in the elderly with recombinant human granulocyte colony-stimulating factor.

We administered recombinant human granulocyte colony-stimulating factor (rhG-CSF) intravenously for 2 weeks to 2 elderly patients with severe neutropenia. The absolute neutrophil count (ANC) recovered promptly after the initiation of rhG-CSF therapy and reached a peak (greater than 10 x 10(9)/l) on the 13th day. The ANC fell rapidly after rhG-CSF was discontinued, but it remained within the normal range after therapy. There were no side effects during the entire course of treatment. Therefore, rhG-CSF seems to be a most beneficial treatment in elderly patients with severe neutropenia.