Pharmacokinetic and pharmacodynamic studies of subcutaneously administered recombinant human interleukin-3 following chemotherapy for non-Hodgkin's lymphoma

Summary. The pharmacokinetics and the pharmacodynamic profile of subcutaneously administered recombinant human non-glycosylated interleukin-3 (rhIL-3) was studied in lymphoma patients after standard CHOP chemotherapy. 30 patients received 0.5, 1.0, 5.0, 7.5 and 10/ig/kg (six patients at each dose level) of rhIL-3 for 14 d. Serum rhIL-3 samples were obtained regularly during the treatment and serially over a 24 h period on the first (cycle day 2) and the last (cycle day 15) day of rhIL-3 treatment for pharmacokinetic evaluation. Following s.c. injection on cycle day 2, the maximum rhIL-3 serum concentration ranged from 289pg/ml (0-5/ig/kg) to 4690pg/ml (10/xg/kg). Both the maximum serum concentration ( R = 0.90, P < 0.0001) and the area under the serum concentration-time curve ( R = 0.95, P < 0.0001) were related to dose.
The elimination half-life T_1/2β was 160 min for 0.5 μg/kg and 134 min for 10μg/kg, with no apparent dose relationship. The systemic clearance of 3.0–6.0ml/min/kg was comparable at all dose levels. No significant difference was noted between pharmacokinetic parameters on the first day of rhIL-3 and the last day of treatment, and no accumulation of the drug was noted throughout the study. The pharmacokinetic parameters correlated poorly to the clinical response of the growth factor, where dose in μg/kg seemed to be the most important single factor.     

Synergism of interleukin-12 and interleukin-3 on development of hematopoietic progenitors

Abstract: The recently cloned cytotoxic lymphocyte maturation factor [CLMF] also called NK cell stimulatory factor [NKSF] or interleukin-12 [IL-12] has been described as a growth factor for mature lymphoid cells. The present study investigated whether purified recombinant human IL-12 could stimulate CFU colony growth. Source of progenitor cells were peripheral blood cells depleted of adherent, CD2- and CD56-positive cells. RhIL-12 was investigated either alone or in combination with rhIL-3, rhIL-6 and rhGM-CSF. RhIL-12 alone did not support colony formation of myeloid or erythroid progenitors. RhIL-12 in combination with rhIL-3 increased the numbers of BFU-E and CFU-GM. No synergism or additive effect was seen with the combination of rhIL-12 and rhGM-CSF or rhIL-12 and rhIL-6. An additive increase in the number of granulocytic colonies was observed when rhIL-3, rhIL-6 and rhGM-CSF were used together with rhIL-12. Our result therefore suggest that, in addition to being a potent lymphopoietic stimulator, IL-12 acts synergistically with IL-3 in enhancing the sensitivity of hemopoietic progenitors to IL-3.     

Pharmacokinetics and effects of recombinant human erythropoietin after intravenous and subcutaneous injections in healthy volunteers

A double-blind, placebo-controlled study of the pharmacokinetics and safety of multiple doses of recombinant human erythropoietin [rHuEPO 150 or 300 U/kg either by intravenous (IV) bolus or subcutaneously (SC)] in normal male subjects demonstrated that rHuEPO had a dose-related effect on the hematocrit independent of the route of administration and that multiple doses of rHuEPO had no direct pressor effects. When rHuEPO was injected IV, a monoexponential decrease in serum EPO level was evident for 18 to 24 hours postdose. Absorption of SC injected rHuEPO occurred more slowly, with relatively low serum EPO levels being maintained for 48 hours. All rHuEPO antibody titer determinations were negative. With the exception of significant increases in hemoglobin and hematocrit, no clinically significant changes occurred. No hypertensive, convulsive, or thrombotic events were observed. Of the adverse experiences observed in 10 subjects, none was considered clinically significant, and none of the subjects dropped out because of adverse experiences.     

Recombinant human interleukin-3 and granulocyte-macrophage colony- stimulating factor show common biological effects and binding characteristics on human monocytes

Two human hemopoietic growth factors involved in monocytopoiesis, interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were studied for their ability to stimulate blood monocytes and to bind to the monocyte membrane. Both cytokines maintained monocyte/macrophage numbers during long-term culture and increased cell size as compared with controls. Effects on cell numbers were present at low cytokine concentrations (6 to 20 pmol/L), whereas enhanced 3H-thymidine incorporation was observed only at higher concentrations (greater than or equal to 60 pmol/L). Autoradiographic studies showed only 1% to 3% of stimulated monocytes with nuclear grains. These results suggest that the primary mechanism for IL-3 and GM-CSF-induced maintenance of monocyte/macrophage numbers in humans is through an effect on cell survival. Surface receptors for both IL-3 and GM-CSF were studied by using 125I-labeled recombinant human (rh) cytokines and performing Scatchard analyses. Both cytokines showed curvilinear Scatchard plots, and computer analyses favored a two-site binding model. High-affinity binding data for 125I rhIL-3 (Kd 7.7 to 38.2 pmol/L; receptor number/cell 95 to 580) and for 125I rhGM-CSF (Kd 4.7 to 38.9 pmol/L; receptor number/cell 8 to 67) show similar binding affinities for the two cytokines but a lower receptor number/cell for 125I rhGM-CSF. Low-affinity binding characteristics for 125I rhIL-3 (Kd 513 to 939 pmol/L; receptor number/cell 179 to 5,274) and for 125I rhGM- CSF (Kd 576 to 1,120 pmol/L; receptor number/cell 130 to 657) show a similar pattern for the two cytokines. Specificity of 125I rhIL-3 and 125I rhGM-CSF binding to monocytes was established by the ability of the homologous cytokine to inhibit binding and the inability of a range of other cytokines to compete at 100-fold excess molar concentration. It is important, however, that binding of 125I rhIL-3 was partially inhibited by rhGM-CSF and that rhIL-3 partially inhibited binding of 125I rhGM-CSF to the monocyte membrane under conditions shown to prevent receptor internalization. The degree of inhibition varied between 25% and 80% in different experiments, and quantitative inhibition experiments showed that 1,000-fold excess concentrations of competitor failed to inhibit binding of the heterologous ligand completely. These results demonstrate that human IL-3 and GM-CSF have similar effects on growth and survival of human monocytes in vitro and suggest that these and other common biological effects may be mediated either through a common receptor or through distinct receptors associated on the monocyte membrane.     

Insulin pharmacokinetics following continuous infusion and bolus injection of regular porcine and human insulin in healthy man

To determine the pharmacokinetics of insulin administered by intravenous (IV) and subcutaneous (SC) pump treatment as well as by the conventional subcutaneous route, six insulin preparations of either porcine or human amino acid sequence were investigated intraindividually following IV or SC insulin infusion at two different rates (Study I) and three preparations were investigated after SC bolus injection (Study II) in healthy men. Insulin release was suppressed in Study I by IV administration of somatostatin (500 μg/hr) to avoid interference by endogenous insulin with the measurement of exogenous insulin. Hypoglycemia was prevented by IV administration of glucose. The data obtained demonstrated (1) greater serum concentrations of immunoreactive insulin (IRI) during continuous IV insulin infusion (141 ± 10 (SEM) pmole/liter) than during SC insulin infusion (54 ± 3 pmole/liter; P < 0.0005) (0.8 U/hr); (2) return of serum IRI to baseline values following a 17-minute square wave insulin infusion (12.8 U/hr; time: 0 to 17 minutes) within 40 minutes after IV insulin infusion but not before 180 minutes after the end of SC insulin infusion; (3) peak serum IRI at 60 to 90 minutes after conventional SC insulin injection returning to baseline values at 300 minutes; and (4) identity of the pharmacokinetics of pumped human and porcine insulin within a given group as well as of the accompanying metabolic dynamics of blood glucose and nonesterified fatty acids, but heterogeneity of serum insulin after its SC bolus injection. We conclude that (1) the pharmacokinetic behavior of regular insulin depends primarily on its route of administration; (2) continuous IV infusion of an insulin dose causes significantly higher serum insulin levels than the SC administration of the identical insulin dose, and (3) hyperinsulinemia caused by a square wave insulin infusion (12.8 U/hr; time: 0 to 17 minutes) requires more than four times longer to return to baseline levels following SC administration than after IV administration of the insulin. These differences in the pharmacokinetic behavior of insulin cause a reduced bioavailability of SC administered insulin and have to be taken into account when instituting insulin treatment by various routes.     

Continuous subcutaneous insulin infusion: comparison of plasma insulin profiles after infusion or bolus injection of the mealtime dose

To help optimize meal-time blood glucose control in diabetic patients by continuous subcutaneous insulin infusion we have studied plasma insulin profiles in six normal subjects, suppressing endogenous insulin secretion with somatostatin. Insulin was administered subcutaneously either as a bolus or by high-rate infusion. Mean infusion profiles were similar on the two occasions, with peak levels at 75 and 90 min respectively, and a linear decline to 34% and 36% of peak concentrations at 5 h. Bolus injection resulted in a faster rise in insulin concentration, more consistent with physiological requirements. It is concluded that bolus delivery would be similar in effect while mechanically simpler to achieve than infusion, when part of a dual rate subcutaneous infusion system. The dose should be given 30 min before meals, if peak insulin concentrations are to be coincident with those found physiologically. Insulin concentrations remain high in the post-absorptive phase.     

The tolerability of continuous intravenous infusion of interleukin-3 after DHAP chemotherapy in patients with relapsed malignant lymphoma

Summary The objective of this phase-I study was to establish the maximum tolerable dose of recombinant human interleukin-3 (rhIL-3) after salvage chemotherapy in patients with malignant lymphoma. Twenty-one patients with relapsed Hodgkin's disease or intermediate/high-grade non-Hodgkin's lymphoma received rhIL-3 after the second cycle of DHAP chemotherapy (cisplatin, cytosine-arabinoside, dexamethasone). Cycles 1 and 3 were given without rhIL-3. The rhIL-3 was administered as a continuous intravenous infusion for 10 days starting 48 h after chemotherapy in cycle 2. Five different dose levels of rhIL-3 (0.25, 1.0, 2.5, 5.0, and 10.0g/kg/day) were sequentially tested. At the three lowest dose levels one double-blinded placebo was included for every four patients per dose level. Low-grade fever occurred in 15/21 patients, unrelated to the dose of rhIL-3. Nausea and vomiting (grade 1–2) occurred in seven patients. Headache was dose related, with 3/4 patients at a dose of 10g/kg/day experiencing troublesome grade-2 headache precluding further dose escalation. Facial flushing developed in 3/8 patients at the highest dose levels of rhIL-3. There was a significant increase in eosinophil count during rhIL-3 (p=0.03 cycle 2 vs cycle 1 andp=0.002 cycle 2 vs cycle 3) without accompanying clinical signs or symptoms. No increase in basophil count was observed. There were no increased plasma levels of interleukin-6 or macrophage colony-stimulating factor (M-CSF) during rhIL-3. We conclude that rhIL-3 can be safely administered as a continuous intravenous infusion for 10 days after DHAP chemotherapy. Dose-limiting side effects, especially headache, occur at a dose of 10g/kg/day.This study was supported by Sandoz Pharma, Basel, Switzerland     

Verapamil disposition and cardiovascular effects in elderly patients after single intravenous and oral doses

Summary Pharmacokinetics and pharmacodynamics of verapamil were studied in 11 elderly subjects (age=79.67±4.74 years) and in 11 middle-aged subjects (age=45±11.37 years) following intravenous (IV), single oral, and long-term oral administration.Plasma verapamil concentrations were determined using high-pressure liquid chromatography (HPLC). Twenty-four hour dynamic Holter electrocardiographic (ECG) recordings were employed to study heart rate (HR) and P-R interval.No difference in plasma half-life, distribution volume, body clearance, and area under the curve (AUC) was observed between the two groups after IV and oral verapamil administration.Blood pressure (BP) and HR were significantly reduced after verapamil IV administration in the elderly group only (p<0.05, p<0.01, respectively). After single and long-term oral administration, variable HR and BP responses were observed in both groups.The P-R prolongation following both IV and single oral doses exhibited a delay with respect to the peak plasma concentration, inducing a definite hysteresis loop. The slope of P-R variations (using a linear pharmacodynamic model) was greater in the elderly both after IV and single oral verapamil administration, but statistical significance was obtained only after the single oral dose (p<0.05). In the elderly group, after long-term oral administration, there was a significant prolongation of the P-R interval (p<0.0001) with respect to the corresponding time point of the 24-hour predrug period. Such variations in pharmacodynamic parameters in the elderly did not, however, cause any clinical problem.In conclusion, verapamil seems to be well tolerated in the elderly as well as in younger patients at similar dosages. However, its use in the elderly requires careful clinical evaluation.     

Pharmacokinetics and linear exposure of AFRESA™ compared with the subcutaneous injection of regular human insulin

Aim:  AFRESA™ [Technosphere^® Insulin (TI); MannKind Corporation, Valencia, CA], a dry powder preparation of regular human insulin (RHI), utilizes a novel and versatile drug carrier platform that enables pulmonary administration of medications typically administered by injection. The aim of this study was to compare the pharmacokinetic (PK) and pharmacodynamic (PD) parameters of three different inhaled doses of TI with those of subcutaneous (s.c.) RHI.
Methods:  This randomized, open-label, four-way crossover study of 11 healthy, non-smoking volunteers evaluated PK and PD profiles following single inhalations of 25, 50 or 100 U TI and 10 IU RHI administered subcutaneously using a euglycaemic clamp technique.
Results:  Following inhalation of TI, peak insulin concentrations ( C _max) were achieved approximately 2 h earlier than with RHI (12–17 min for TI vs. 134 min for RHI). Area under the insulin concentration–time curve (AUC) and insulin C _max values increased with increasing TI dose. Insulin exposure, as measured by AUC, was found to be linear over the dose range studied. Compared with s.c. RHI, TI at doses of 25, 50 and 100 U showed a relative bioavailability of 25, 23 and 21%, respectively. The maximum bioeffect, as measured by the glucose infusion rate, occurred approximately 2 h earlier for all three TI doses (42, 50 and 58 min, respectively) than for s.c. RHI (171 min). No treatment-related adverse events were reported with TI.
Conclusion:  TI is an inhaled insulin with a more rapid absorption and a more rapid elimination than subcutaneously administered RHI, resulting in a quick onset and short duration of action. Insulin exposure following TI administration was found to be linear over the dose range of 25–100 U.     

Basal rate subcutaneous insulin infusion: absorption kinetics and relation to local blood flow

Twenty diabetic patients received a constant subcutaneous infusion of 125I-labelled short-acting insulin (1.12 U/h) into the anterior abdominal wall. Measurement of the size of the insulin depot at the infusion site was performed by measuring the radioactivity and by using a calibration bolus to transform count rate to units of insulin in the depot. By the 133Xenon technique, local subcutaneous blood flow rate was measured on the contralateral side of the anterior abdominal wall. From the start of the infusion the SC depot built up slowly, but did not reach steady-state by 6 h. After 24 h of infusion, the size of the depot ranged between 2.7 and 10.9 U (5.2 +/- 0.5 U, mean +/- SE). The size of this steady-state depot was inversely correlated with SC blood flow. After stopping the infusion, insulin disappeared according to first order kinetics without any lag period. The insulin disappearance rate from the depot was positively correlated with the blood flow in a curvilinear fashion. The results suggest that the relationship between blood flow and the size of the insulin depot is best explained by a predominantly blood flow limited removal of insulin at low rates of blood flow, with increasing limitation by diffusion at higher rates.     

Effects of recombinant human granulocyte colony-stimulating factor (CSF), human granulocyte macrophage-CSF, and gibbon interleukin-3 on hematopoiesis in human long-term bone marrow culture.

We have studied the effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF), hG macrophage-CSF (hGM-CSF), and gibbon interleukin-3 (gIL-3) on cell proliferation and differentiation in human long-term bone marrow culture (LTBMC). hG-CSF induced a maximal increase of 2.3-fold in both total nonadherent cells and GM cluster-forming cells, but only an increase of 1.7-fold in GM-colony-forming cell (GM-CFC) numbers, influencing mainly neutrophil differentiation. Cultures treated with hGM-CSF demonstrated a peak of 12.8-, 21- and 3.2-fold elevations in total nonadherent cells, cluster, and GM-CFC, respectively, and influenced differentiation of neutrophils, monocytes, eosinophils, and lymphocytes. Cultures treated with gIL-3 demonstrated the largest expansion in the GM-CFC population, reaching a maximum of 5.3-fold in relation to that of unstimulated controls. IL-3 treatment also increased the numbers of GM clusters and mature cells (including all myeloid cells and lymphocytes) 7.8- and 4.8-fold, respectively. Similar quantitative and qualitative changes were induced by G-CSF, GM-CSF, and IL-3 in LTBMCs of patients in remission after treatment for acute lymphoblastic leukemia or Hodgkin's lymphoma. Overall, the expansion of GM progenitor cells in cultures treated with growth factors was larger in the adherent cell layer than in the nonadherent cell fraction. In addition, hGM-CSF, gIL-3, and hG-CSF to a less extent, increased the cycling rates of GM-CFC progenitors located in the adherent layer. These results indicate that hG-CSF is a much less potent stimulus of hematopoiesis in LTBMC than the other CSFs assayed, and that the increases in cell production after treatment with G-CSF, GM-CSF, or IL-3 may be achieved by primary expansion of different cell populations within the hierarchy of the hematopoietic system. The effects of the growth factors were transient and the longevity of hematopoiesis in the cultures was not altered, suggesting that treatment with IL-3, GM-CSF, or G-CSF had not compromised the ability of primitive cells to give rise to mature cells. This indicates that the stromal microenvironment in LTBMC can override potential differentiation-inducing activities of the CSFs.     

Recombinant human gamma-interferon in patients with chronic active hepatitis B: pharmacokinetics, tolerance and biological effects

Pharmacokinetics, tolerance and biological effects of human recombinant gamma-interferon were studied in 12 patients with chronic active hepatitis B. Serum concentrations of gamma-interferon were measured by radioimmunoassay in four patients after a subcutaneous injection of 10 million U (0.5 mg); the peak serum concentration of gamma-interferon (29 +/- 7 U/ml) was reached after 5 to 8 hr and gamma-interferon remained detectable for 24 to 36 hr. Twelve patients received recombinant gamma-interferon, 2.5 to 10 million U daily, for 4 mo. All suffered from a dose-dependent, flulike syndrome similar to that induced by alpha-interferon. Recombinant gamma-interferon induced a marked increase of serum ALT and a significant decrease of serum hepatitis B virus-DNA. Serum hepatitis B virus-DNA disappeared in one patient during administration of recombinant gamma-interferon. Serum hepatitis B virus-DNA disappeared in four additional patients, and HBeAg disappeared in two patients during the 12 mo after administration of recombinant gamma-interferon. These results indicate that subcutaneous injection is suitable for administration of recombinant gamma-interferon and that recombinant gamma-interferon has an antiviral effect in patients with chronic active hepatitis B.     

Interferon-γ and granulocyte colony-stimulating factor in bronchoalveolar lavage fluid after oesophagectomy

BACKGROUND: Activated polymorphonuclear leucocytes play a pivotal role in pulmonary complications after oesophagectomy. A lot of inflammatory mediators including interferon-gamma and granulocyte colony-stimulating factor are reported to modify the life span of polymorphonuclear leucocytes. AIMS: In this study we investigated whether interferon-gamma and granulocyte colony-stimulating factor are associated with pulmonary complications after oesophagectomy. PATIENTS AND METHODS: We measured interferon-gamma and granulocyte colony-stimulating factor concentrations in bronchoalveolar lavage fluid of 37 patients who had undergone oesophagectomy and examined the relationship between these mediators and pulmonary complications. RESULTS: Pulmonary complications occurred in nine patients (24%, Pneum(+)). There was no significant difference in age, gender, preoperative comorbid conditions, tumour stage, operation method, operating time or blood loss between the Pneum(+) group and another 28 patients(Pneum(-)). Days until extubation were significantly increased in the Pneum(+) group than in the Pneum(-) group. Interferon-gamma (on postoperative day 2) and granulocyte colony-stimulating factor (on postoperative days 1-3) in bronchoalveolar lavage fluid were significantly increased in the Pneum(+) group than in the Pneum(-) group and granulocyte colony-stimulating factor was significantly correlated with days until extubation. CONCLUSIONS: Our results indicate that bronchoalveolar lavage fluid granulocyte colony-stimulating factor is associated with respiratory conditions after oesophagectomy and assaying it can be useful for predicting pulmonary complications.     

Recombinant human interleukin-3 and recombinant human granulocyte-macrophage colony-stimulating factor administered in vivo after high-dose cyclophosphamide cancer chemotherapy: effect on hematopoiesis and microenvironment in human bone marrow.

The effects on bone marrow (BM) cell proliferation and differentiation of recombinant human interleukin-3 (rhIL-3) and recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) administered after high-dose (7 g/m2/d) cyclophosphamide (HD-CTX) chemotherapy were studied in nine patients with malignancies without BM involvement and in three control patients. rhIL-3 at a dose of 1 to 5 micrograms/kg/day was administered for 14 to 18 days by continuous intravenous (i.v.) infusion and rhGM-CSF was administered at a dose of 5.5 micrograms/kg/day for 14 days. Changes induced by cytokine treatment were assessed by morphoimmunohistochemical analysis of BM biopsies. Comparison was made in the cytokine-treated groups and with control patients who received HD-CTX alone. BM cellularity and the myeloid/erythroid (ME) ratio were lower in rhIL-3-treated than in rhGM-CSF-treated patients, but in both groups it was significantly higher than in the controls. The proportion of BM cells stained by PC10, a monoclonal antibody (MoAb) recognizing a proliferation-associated nuclear protein (PCNA), increased from 6.78% to 21.18% (P less than .02) after rhIL-3, and from 5% to 35.33% (P less than .001) after rhGM-CSF; no increase was observed in the control group. The frequency of CD34+ BM cells was unchanged after rhIL-3 (P = NS) and decreased after rhGM-CSF (P less than .001). In both groups, most of the PC10+ cells were represented by promyelocytes and myelocytes with no increase in blast cell numbers. rhIL-3-treated BM showed an increased number of megakaryocytes and increased proliferative activity of erythroid cells as compared with rhGM-CSF cases. BM stroma changes observed in both treated groups included endothelial cell proliferation, increased BM macrophage concentration, and increase in BM fibroblasts as detected with an anti-nerve growth factor receptor antibody. In most rhIL-3-treated cases, BM fibrosis developed after treatment. The same effect was not observed in rhGM-CSF patients.     

Effect of interleukin-3 pretreatment on granulocyte/macrophage colony-stimulating factor induced mobilization of circulating haemopoietic progenitor cells

Summary. Recombinant human colony stimulating factors (CSFs) as single agents are increasingly used for mobilizing peripheral blood progenitor cells (PBPCs) for stem cell transplantation. We have shown in rhesus monkeys that interleukin-3 (IL-3) pretreatment markedly potentiated the increase in PBPC numbers of subsequent administration of granulocyte/macrophage-CSF (GM-CSF). Here we studied the effect of IL-3 pretreatment on GM-CSF-induced mobilization of PB progenitors in patients who were potential candidates for autologous stem cell transplantation (n=16). Patients were treated with GM-CSF at a dose of 5 μ g/kg/d for 5 d and after a treatment free interval received another cycle of GM-CSF immediately following pretreatment with IL-3 at different doses and duration: 2.5 μg/kg/d (n = 4), 5μg/kg/d (n = 3) and 10μg/kg/d (n = 3) for 3d, 5μg/kg/d for 7d (n = 4) and 5μg/kg/d for 14 d (n = 2), respectively. Only 7d pretreatment with IL-3 showed consistent effects. Although IL-3 did not mobilize by itself, pretreatment with 5μg/kg/d of IL-3 for 7d significantly potentiated GM-CSF-induced mobilization of PB CFU-GM numbers, leading to a mean increase in PB CFU-GM numbers over baseline by 18.5 +5.2 (SEM) fold by IL-3/ GM-CSF as compared to a 4.7 + 1.7-fold increase by GM-CSF alone. A significant enhancement by the 7d IL-3 pretreatment was also observed for erythroid (BFU-E) and multi-potential progenitor cells (CFU-mix) which were 3.3 + 1.3-and 3.4 + 0.9-fold, respectively, mobilized by GM-CSF alone, as compared to 8.5 + 2.3- and 19.2 + 3.4-fold, respectively, by the IL-3/GM-CSF combination. Our results suggest that 7 d pretreatment with IL-3 may be a useful mean to augment mobilization of circulating progenitors by more lineage-restricted CSFs. These findings may be important for the design of mobilization strategies that use growth factors without preceding chemotherapy.     

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 μg/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 t_1/2β values ranged from 3.68 ± 0.86 to 22.4 ± 12.0 hr. ANC was correlated with log CL_T (r = 0.72, P < 0.05), and inversely with log dose-adjusted AUC (r = −0.75, P < 0.05) and log dose-adjusted C_max (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 μg/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 suitable alternative route of administration in this patient population. Am. J. Hematol. 54:124–130, 1997 © 1997 Wiley-Liss, Inc.     

Common binding structure for granulocyte macrophage colony-stimulating factor and interleukin-3 on human acute myeloid leukemia cells and monocytes

Granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) control the proliferation of human acute myeloid leukemia (AML) cells in vitro. Previously, we have shown that receptors for GM-CSF and IL-3 are often coexpressed on AML cells. Here we present experiments with purified AML blasts, normal monocytes, and granulocytes that were conducted to analyze the properties of GM-CSF and IL-3 binding proteins in more detail. On AML cells from eight cases we demonstrate two types of GM-CSF receptors: one with low affinity (dissociation constant [kd] 5.1 to 24.8 nmol/L) and one with a high affinity (kd 31 to 104 pmol/L). These AML cells also expressed high affinity receptors for IL-3 (kd 24 to 104 pmol/L). Cross-competition experiments showed that an excess concentration of nonlabeled IL-3 completely prevented the high affinity binding of radiolabled GM-CSF. This competition occurred at 37 degrees C as well as 4 degrees C. Low affinity GM-CSF binding was not affected by IL-3. Binding of radiolabeled IL-3 could be prevented by nonlabeled GM-CSF. In certain cases, this competition was complete, whereas in others only partial (49% to 77%) reduction of the radiolabeled IL-3 binding was seen. On the basis of these ligand binding features, we propose the existence of three receptor types on AML cells: (1) low affinity GM-CSF receptors that do not bind IL-3, (2) dual high affinity GM-CSF/IL-3 receptors, and (3) high affinity IL-3 receptors that do not bind GM-CSF. We could also demonstrate these receptor types on normal monocytes. In addition, a fourth type of receptor was apparent on normal granulocytes (4), incapable of binding IL-3 and with an intermediate affinity for GM-CSF (approximately 400 pmol/L). Chemical crosslinking showed that GM-CSF and IL-3 both bind to proteins with molecular weight values of 130, 105, and 75, which provides additional evidence for the existence of a common GM-CSF/IL-3 receptor complex.     

Recombinant human interleukin-3 in refractory severe aplastic anaemia: a phase I/II trial

Summary. In a 2.5-month-old infant with β-thalassaemia major, DNA analysis of the gamma-beta region revealed homozygosity for two large deletions removing the entire β and β regions including their 5' promoter regions but leaving the delta gene intact. The downstream deletion was predicted to be 7.6 kb in length extending from a point 1.5 kb on the 3' side of the δ-globin gene to about 1.8 kb on the 3' side of the β-globin gene. The upstream deletion, which was also about 7.6 kb, extended from a point 1.5 kb on the 5' side of the β-globin gene to about 4.5 kb on the 3' of the β gene. The δ-giobin gene was intact. From the phenotypic expression of the disease it is concluded that removal of the β gene probably prevents derepression of the γ gene that has previously been observed in the absence of the promoter region of the β gene and the switch mechanism from gamma to beta gene expression may take place earlier than expected.     

Effect of recombinant human interleukin-3 on haematological recovery from chemotherapy-induced myelosuppression

Summary. Patients with non-small-cell lung cancer (NSCLC) were treated with ICE chemotherapy (ifosfamide 2000 mg/m², days 1-3; carboplatin 300 mg/m², day 1; etoposide 75 mg/m², days 1-3) intravenously (i.v.) during the first 3d of a maximum of four 28 d treatment cycles. Interleukin-3 (IL-3) was administered in cycles 2 and 4 as a daily subcutaneous (s.c.) injection on days 5-18. Cohorts of three patients were treated at dosage levels of 0.5, 1.25, 2.5, 5.0, 10.0 and 15.0 μg/kg/d. At 15.0 μg/kg/d a 'flu-like' syndrome of myalgias, arthralgias and fatigue was considered dose-limiting. Other toxicities were headache, fever, urticaria, arrhythmia, chills and flushing. Subsequently, nine patients were added to the group receiving 10 μg/kg/d. 27 patients received IL-3 after their second course of ICE. At 10 and 15 μg/kg/d, IL-3 in cycle 2 was associated with enhanced haematological recovery. Depth of neutrophil nadir and days of neutropenia (ANC < 0.5 × 10⁹/1) were reduced in 9/13 patients and in 8/11 patients, respectively. No effect was seen on platelet nadir or days of thrombocytopenia. IL-3 was well tolerated up to 10 μg/kg/d when given as a daily s.c. injection. Results suggest IL-3 as a potential adjunct to chemotherapy, and further studies to explore administration of IL-3 in combination with other cytokines in this setting are warranted.     

The effect of mixing human soluble and human crystalline zinc-suspension insulin: plasma insulin and blood glucose profiles after subcutaneous injection

The effect of mixing human soluble insulin with two newly developed formulations of human crystalline zinc-suspension insulin was studied in two groups of 8 normal and 6 diabetic subjects. Mixing Human Actrapid with Human Ultratard and Humulin-S with Humulin-Zn, for 60 s before subcutaneous injection, significantly blunted the rise in free insulin levels (p less than 0.05) and the onset of action of the short-acting insulins (p less than 0.01). The loss of solubility that occurs on mixing these insulins, with the consequent loss of the rapid acting component, may diminish their therapeutic usefulness in the control of post-prandial blood glucose.