Erythropoietin

Drugs affecting the hematologic system of the performance horse

Pharmacologic alterations in the hematologic and rheologic properties of blood may have an important effect on transport and delivery of oxygen to working muscle during exercise. This article briefly reviews erythropoiesis, hematologic and rheologic responses to training and exercise, and the influence of these alterations on exercise performance. The hemorrheologic and performance effects of hematinics, hematopoietic stimulants, and alterations in blood rheology are discussed. The effects of exercise on blood coagulation, fibrinolysis and platelet function, and the effects of drugs that alter platelet function are briefly described.

Pure red cell aplasia of pregnancy: a distinct clinical entity

We describe a 31-year-old patient with pure red cell aplasia of pregnancy, successfully managed with regular blood transfusions. In vitro studies showed specific inhibition of day 14 erythroid colonies (BFU-E) using serum and purified immunoglobulin G (IgG) obtained from the patient at diagnosis (before blood transfusion). The inhibition of BFU-E disappeared when haematological remission occurred 3 weeks after delivery and she remains clinically well with a normal haemoglobin 4 years later.

Recombinant erythropoietin overdose

Deliberate self-administration of recombinant human erythropoietin (rHuEpo) in a patient without anemia has never been documented. The case of a 62-year-old man who worked in an allied health care field and surreptitiously injected the drug, causing his hematocrit to increase to a dangerously high level is presented. Resultant complications of the misuse of erythropoietin in this patient included worsening hypertension, exacerbation of chronic lung disease and development of new onset angina. Medical management consisted of endotracheal intubation with mechanical ventilation, intravenous hydration, and serial phlebotomy. The unusual possibility of erythropoietin abuse must be added to the differential diagnosis with a patient with unexplained polycythemia. This case highlights the potential abuse of biological growth factors that may mask medical conditions.

Evidence for a multifactorial control of serum erythropoietin concentration in liver disease

We measured serum erythropoietin (EPO) immunoenzymatically in 245 subjects (151 male, 94 female) to investigate the pathophysiology of its liberation in patients with liver disease. Twelve patients had acute hepatitis, 60 mild chronic liver disease (CLD), 50 cirrhosis (CIR), 43 hepatocellular carcinoma (HCC), 16 malignant extrahepatic disease, 32 benign extrahepatic disease (BEN); 32 subjects served as healthy controls. Higher EPO levels were found in all groups of patients as compared with controls (Bonferroni's test, P < 0.01); CIR and HCC had higher values than CLD and BEN (P < 0.01). By multiple regression analysis, EPO correlated with haematocrit, cholinesterase and C-reactive protein (F = 18.63, P < 0.0001). Thus, circulating EPO increases in patients with liver disease, particularly in its more advanced forms. Besides anaemia, both impairment of liver function (possibly via decreased EPO metabolism) and inflammation seem to play contributory roles in elevating serum EPO.

Effects of clozapine on hematopoiesis and the cytokine system

Using a bioassay for hematopoietic progenitor cells we looked for mechanisms causing clozapine induced neutropenia and agranulocytosis. Micro-agar-cultures of normal peripheral blood mononuclear cells (MNC) of eight patients currently treated with clozapine and of eight probands not receiving any kind of pharmacological treatment were incubated with increasing concentrations of clozapine (0, 7.5, 15, 30 micrograms/ml). Erythropoiesis and megakaryopoiesis were totally unaffected by clozapine. A biologically relevant suppression of granulopoiesis (CFU-GM) could only be shown in cultures incubated with 30 micrograms/ml clozapine. Cytokine analysis presented a strictly dose-dependent suppression of GM-CSF and neopterin release in all cultures. There was no difference between patients and controls at any clozapine concentration. The data support a possible role for cytokines as one mediator of the agranulocytosis producing effects of clozapine.

Medicare payment policy and recombinant erythropoietin prescribing for dialysis patients

The Medicare payment policy for recombinant human erythropoietin (rHuEPO) treatment for dialysis patients changed in January 1991 from a relatively fixed payment per treatment (allowed charge of $40 per < or = 10,000 units injected) to a more variable payment based on the amount of rHuEPO administered with each treatment (allowed charge of $11 per 1,000 units injected). This change provided an opportunity to examine how payment policy can effect the use, cost, and health outcome of a biotechnology product used in the dialysis population. In cross-sectional (n = 71,880 Medicare-entitled dialysis patients) and longitudinal (n = 29,088 Medicare-entitled dialysis patients) study designs, we used Medicare end-stage renal disease program and claims data in bivariate and multivariate analyses to examine the effect of the change in payment policy for rHuEPO on access to the biotechnology, dosing, costs, and hematocrit, including the prescribing patterns at for-profit versus not-for-profit providers. The observation period included several months before (July 1989 to December 1990) and 6 months after (January to June 1991) the change in Medicare payment policy. The mean dose per treatment during the initial and fourth month of therapy was low (2,742 [95% confidence interval, 2,703 to 2,781] units and 2,632 [95% confidence interval, 2,598 to 2,667] units, respectively, in June 1990) and increased 3.4% and 5.0%, respectively, in the next 6 months prior to the change in Medicare payment policy compared with 14.6% and 14.8%, respectively, in the 6 months following the change in payment policy. The average monthly allowed charge for rHuEPO per dialysis patient receiving rHuEPO decreased from $455 before the policy change to $349 immediately following the policy change, because the allowed charge per unit of rHuEPO was lower when payment became more dependent on the amount of rHuEPO administered with each treatment than when the payment was fixed at $40 per treatment. The average monthly allowed charge for rHuEPO increased to $375 in the sixth month following the change in payment policy as a result of the increase in dose and the new variable payment. The unadjusted and adjusted changes in mean hematocrit 6 months after the payment change were positive but clinically very small (0.3 and 0.2 percentage points, respectively).(ABSTRACT TRUNCATED AT 400 WORDS)

Erythropoietin in cardiac surgery

Erythropoietin is the primary growth factor for red blood cells. A glycoprotein hormone synthesized by the kidneys, erythropoietin serves to increase red blood cell production in response to tissue hypoxia. It exerts its effect by increasing the numbers of erythroid progenitor cells in the bone marrow, and by increasing the rate at which their development is accomplished. With the introduction of recombinant erythropoietin in 1987, an important pharmacological agent became available for the manipulation of erythropoiesis. While used primarily for the treatment of the anemia of renal failure, recombinant erythropoietin has also shown usefulness in treating other types of anemias in which the endogenous erythropoietin response is insufficient. Perioperative use of the drug grew as a natural extension of this, and erythropoietin has been applied to correct preoperative anemia, augment autologous blood donation, and improve postoperative red cell recovery. Analysis of these perioperative clinical studies reveals success in these areas, but it also reveals that closer attention to the physiology of the natural response, and to the pharmacology of the recombinant product, might significantly improve results. Such an improvement in efficacy is both desirable and necessary when use of the drug is viewed in the setting of today's changing health care environment. By optimizing dosing schedules and targeting the drug to those most at risk for red cell transfusion, recombinant erythropoietin will likely become an important tool in efforts to achieve the elusive goal of bloodless cardiac surgery.

Serum stem cell factor concentration in patients with myelodysplastic syndromes

Stem cell factor (SCF) is characterized by its capacity to synergize dramatically with other haemopoietic growth factors in in vitro erythroid, myeloid, and lymphoid progenitor culture systems. We have measured serum SCF concentrations by enzyme immunoassay in 85 patients with myelodysplasia (MDS). Serum samples were taken in 1988-89 and in 1991-92 and stored at -20 degrees C. Mean serum SCF concentration in the MDS patients was 2.81 ng/ml (range 0.6-8.0). This was significantly lower (P = 0.0001) than the values for 234 normal subjects; mean 3.30 ng/ml (range 1.3-8.0). No significant relationship between SCF concentration and peripheral blood counts, bone marrow parameters, red cell transfusion status, survival or FAB subtype was found, although a trend of decreasing SCF concentration from refractory anaemia through sideroblastic anaemia and chronic myelomonocytic leukaemia to refractory anaemia with excess blasts was seen. The reduced SCF serum concentration in some patients with myelodysplasia suggests a rationale for therapy with recombinant SCF in these patients.

High doses of intravenous recombinant erythropoietin for the treatment of anaemia in myelodysplastic syndrome

We studied the efficacy of high doses (100,000 IU intravenously (IV)/twice a week) of human recombinant erythropoietin (rHuEpo) in patients with transfusion dependent myelodysplastic syndromes (MDS). Rationale for such dose of IV Epo was the poor in vitro response of MDS erythroid progenitors (CFU-E) to physiological concentrations of Epo, and the usual high endogenous serum Epo levels of MDS patients. Seventeen patients (nine males, eight females) were included, five refractory anaemia (RA), six RA with blasts excess (RAEB), five RA with ringed sideroblasts (RARS). Tolerance was good, except in three patients who experienced severe flu-like syndrome after Epo injection. None of the patients showed hypertension or developed anti rHuEpo antibodies. Three patients (17.6%) with RAEB had 35-60% reduction of transfusion requirements. No progression of disease occurred. Percentage of erythroblasts, endogenous baseline Epo level and in vitro cultures of erythroid progenitors did not correlate with response to Epo treatment. This study shows that very high IV doses induce only seldom and partial improvement in the status of transfusion dependent MDS. This rate of response, not higher than described with lower dosage, probably represents the maximum expectable response to rHuEpo in this category of patients.

Iron deficiency anemia after successful renal transplantation

In patients with chronic renal failure, renal transplantation improves anemia and the production of erythropoietin. In patients undergoing hemodialysis the administration of recombinant human erythropoietin improves anemia with a decrease in bodily iron stores. Therefore, one would expect a similar decrease after kidney transplantation. We followed the ferric parameters to determine the incidence of iron deficiency anemia in 24 consecutive renal transplant patients for an interval long enough to achieve steady state values of hemoglobin (5.1 +/- 0.8 months). Hematological parameters and serum levels of iron, ferritin and erythropoietin were measured. The patients were divided into 2 groups according to the decrease in serum ferritin: group 1--16 with a decrease in respect to basal values (114 +/- 56 ng./ml.) and group 2--those without modifications (720 +/- 320 ng./ml.). Except for the similar values, group 1 showed greater improvement in anemia (red blood cells 4.3 x 10(6) +/- 1.1 x 10(6) versus 3.7 x 10(6) +/- 1.5 x 10(6)/ml., p < 0.01) and hematocrit index (38.5 +/- 5.2 versus 33.0 +/- 5.1%, p < 0.05). Four patients had microcythemia (mean corpuscular volume 76.6 +/- 1.4 fluid) with lower hemoglobin values than the other patients in group 1 (10.77 +/- 0.42 versus 12.79 +/- 0.42 gm./dl., p < 0.05). Among the 16 patients in group 1, 7 of 8 whose basal serum ferritin was less than 150 ng./ml. achieved ferritin levels of less than 30 ng./ml. In conclusion, our data support that renal transplantation produces a rapid decrease in iron stores and in some cases induces iron deficiency anemia. This fact should be evaluated and treated properly.

Clinical validation of an RIA for natural and recombinant erythropoietin in serum and plasma

A sensitive radioimmunoassay (RIA) for the detection of erythropoietin (EPO) was developed using antibody directed against EPO from human urine. With 100 microL of sample, the assay is sensitive to 7 U/L, well below the mean EPO level in normal males (15.1 +/- 3.5 U/L) or females (15.4 +/- 4.8 U/L). Dilutions of a variety of human serum samples show a parallel relationship with the standard EPO. Clinical validation of the RIA was confirmed by appropriate increases or decreases of EPO levels in various types of anemia and polycythemia. Serum EPO levels were also measured in volunteers participating in an autologous blood donation study. The RIA proved to be quite sensitive, detecting small increases even after a single unit phlebotomy. This RIA of human EPO meets all the requirements of a routine clinical assay in terms of specificity and clinical sensitivity and can be easily conducted in routine clinical laboratories.

The Use of Erythropoietin in the Treatment of Post-bone Marrow Transplatation Anemia

The issue of the role of erythropoietin (Epo) in the erythroid reconstitution after bone marrow transplantation (BMT) has been addressed in several recent studies. A defective Epo production in response to anemia has been shown to occur in patients undergoing allogeneic BMT unlike in most of those subjected to an autologous rescue. The factors involved in the inadeguate Epo production in BMT are discussed, with particular attention to the role of the immunosuppressive drug cyclosporin-A, which has been shown to inhibit Epo production in both in vivo and in vitro models. The observation of defective Epo production eventually led to the development of clinical trials of recombinant human Epo (rhEpo) administration in BMT patients; the aims of these studies were to stimulate erythroid engraftment, hence reducing blood transfusion exposure. Although the number of patients studied up to now is relatively small, a benefit from rhEpo administration in terms of accelerated erythroid engraftment seems very likely, and it may also be associated with decreased transfusional needs in most treated patients. However, further studies are needed to better define indications, dosages and schedules of rhEpo in BMT patients.

Early dosing practices and effectiveness of recombinant human erythropoietin

In a national longitudinal-cohort study of 59,462 end-stage renal disease (ESRD) patients, we examined dosing and effectiveness of erythropoietin (EPO) during the first year of its use in clinical practice (July 1989 through June 1990). In unadjusted and multivariate analyses of Medicare claims data, the mean dose of EPO prescribed was: relatively small and similar for initial and maintenance therapy, 2752 (95% confidence interval 2740 to 2764) and 2668 (95% confidence interval 2654 to 2682) units, respectively; lower when initial therapy was started later (591 units lower in September 1989 and 760 units lower in November 1989 vs. July 1989, P < 0.0001); lower by 135 units during initial therapy and by 116 units during maintenance therapy for females (who weigh less) compared to males (P < 0.001); and lower by 400 units for patients treated in for-profit versus not-for-profit centers. In multivariate analysis: hematocrit response was less and mean maintenance dose was 298 units and 621 units greater for patients whose ESRD was due to multiple myeloma and sickle cell disease, respectively, compared to those with hypertension-related ESRD (P < 0.01); and hematocrit response was logarithmically related to dose [hematocrit = 0.97 ln (dose), P < 0.0001]. Forty-four percent of patients had a hematocrit > or = 30 after four months of therapy. The percent of patients transfused during three month periods before and after therapy decreased from 20% to 5%, respectively (P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical and biological effects of erythropoietin treatment of myelodysplastic syndrome

To evaluate its clinical efficacy as well as its biologic safety, human recombinant Erythropoietin (rh-Epo) was given to 19 patients with myelodysplastic syndromes (MDS) in an open non-randomized study. Among the seventeen evaluable patients only two showed an apparent hematologic response to rh-Epo treatment. In these patients hemoglobin levels increased from a mean pretreatment value of 8.5 and 8.4 g/dl up to 11.7 and 11.3 g/dl respectively and remained relatively stable for several weeks. In one of these patients the transfusion requirement decreased from 4 to 1.5 units per month whereas the other had no transfusion requirement during the whole period of rh-Epo treatment. Interestingly, when the responding patients, after a "wash-out" period of at least ten weeks, received an additional course of rh-Epo results were less impressive. Before treatment the serum level of endogenous Epo was 18 and 110 mU/ml in the two responding patients, whereas a mean value of 532 mU/ml (range 17-2797 mU/ml) was observed in non responders. The treatment of MDS patients with rh-Epo was clinically well tolerated since no relevant side effects were registered. Moreover, no evidence of harmful cytogenetic changes nor activation of myeloid growth factor genes, as determined by Northern blot analysis of GM-CSF and G-CSF gene expression, could be related to rh-Epo treatment. Overall, it appears that administration of rh-Epo is well tolerated but the therapeutic effects appear to be restricted to a minority of patients and a limited period of time.

A serial study of the erythropoietic response to thermal injury

OBJECTIVE

Since controversy exists over whether erythropoietin levels are increased or decreased after thermal injury, a prospective study was performed to answer this question as well as to characterize the erythropoietic response to thermal injury.

SUMMARY BACKGROUND DATA

The concept of using erythropoietin to reduce the need for blood transfusions after thermal injury is attractive. However, since the etiology of burn anemia is both unclear and multifocal, prior to initiating a trial of erythropoietin therapy, it will be necessary to better define the erythropoietic response to thermal injury.

METHODS

Twenty-four burn patients with a mean burn size of 31 +/- 18% had serial measurements of serum iron, total iron binding capacity (TIBC), ferritin, erythropoietin, transferrin saturation, hemoglobin, and reticulocyte counts performed on burn days 1, 3, 5, 7, 10, 14, and then weekly.

RESULTS

The erythropoietic response was characterized by a decrease in hemoglobin levels as well as serum iron, TIBC, and transferrin saturation (p < 0.05). Ferritin and erythropoietin levels increased as did the reticulocyte count. The erythropoietin response to anemia appeared to be at least grossly intact, since there was an appropriate inverse relationship between the degree of anemia and the magnitude of the erythropoietin response (r2 = .61, p < 0.00001).

CONCLUSIONS

Since the erythropoietin levels of these anemic burn victims reached supranormal levels and they manifested a moderate reticulocytosis, the role of replacement erythropoietin therapy after thermal injury requires further study.

Effect of serum parathyroid hormone and bone marrow fibrosis on the response to erythropoietin in uremia

BACKGROUND AND METHODS

Anemia is common in patients with chronic renal insufficiency and secondary hyperparathyroidism. Erythropoietin therapy is effective, but the dose required varies greatly. One possible determinant of the efficacy of erythropoietin therapy is the extent of marrow fibrosis caused by hyperparathyroidism. We examined the relation between the erythropoietic response to erythropoietin and hyperparathyroidism in a cross-sectional study of 18 patients undergoing hemodialysis who had received erythropoietin therapy for one to three years. In 7 patients (the poor-response group), the dose of intravenous erythropoietin needed to maintain a mean (+/- SD) target hematocrit of 35 +/- 3 percent was > 100 units per kilogram of body weight three times a week, and in 11 patients (the good-response group) it was < or = 100 units per kilogram. In all patients, indexes of the adequacy of dialysis and the extent of hyperparathyroidism and aluminum toxicity were determined monthly, and bone histomorphometry was performed.

RESULTS

The mean (+/- SD) dose of erythropoietin required to maintain the target hematocrit was 174 +/- 33 units per kilogram three times a week in the poor-response group and 56 +/- 18 units per kilogram in the good-response group. The mean ages, duration and adequacy of dialysis, increment in hematocrit, iron requirements, and serum concentrations of calcium, phosphate, and aluminum were similar in the two groups. The percentages of osteoid volume and surface, the osteoid thickness, and the stainable aluminum content of bone were similar in the two groups. In contrast, the mean serum parathyroid hormone concentration, the percentages of osteoclastic and eroded bone surfaces, and the degree of marrow fibrosis were greater in the poor-response group than in the good-response group (P = 0.03, P = 0.04, P = 0.009, and P = 0.009, respectively).

CONCLUSIONS

In patients with uremia, the dose of erythropoietin needed to achieve an adequate hematocrit response may depend on the severity of secondary hyperparathyroidism and the extent of bone marrow fibrosis.

Augmentation by erythropoietin of the fetal-hemoglobin response to hydroxyurea in sickle cell disease

BACKGROUND

Hydroxyurea increases the production of fetal hemoglobin in patients with sickle cell anemia, inhibiting the polymerization of hemoglobin S and potentially improving vaso-occlusive manifestations and hemolysis. Recombinant erythropoietin increases the number of reticulocytes containing fetal hemoglobin in laboratory animals and in humans. We studied whether hydroxyurea and erythropoietin might have a potentiating effect on the production of fetal hemoglobin in patients with sickle cell disease.

METHODS

We treated four patients who were receiving hydroxyurea for sickle cell disease (three who were homozygous for sickle cell anemia and one with sickle beta zero-thalassemia) with escalating doses of intravenous erythropoietin for seven weeks, along with oral iron sulfate. Doses of hydroxyurea on four consecutive days were alternated with doses of erythropoietin on three consecutive days.

RESULTS

There was a 28 percent increase in the number of reticulocytes containing fetal hemoglobin and a 48 percent increase in the percentage of fetal hemoglobin, as compared with the maximal values obtained with hydroxyurea alone. The percentage of erythrocytes containing fetal hemoglobin (F cells) increased from 64 to 78 percent. As compared with hydroxyurea alone, treatment with hydroxyurea and erythropoietin decreased the mean (+/- SD) serum indirect bilirubin level from 0.8 +/- 0.2 to 0.5 +/- 0.1 mg per deciliter (13.3 +/- 2.9 to 8.9 +/- 2.2 mumol per liter) (P = 0.02), suggesting a further decrease in hemolysis. Red-cell filterability improved.

CONCLUSIONS

Intravenous recombinant erythropoietin with iron supplementation alternating with hydroxyurea elevates fetal-hemoglobin and F-cell levels more than hydroxyurea alone. Such increases decrease intracellular polymerization of hemoglobin S and improve the overall rheologic characteristics of erythrocytes. A reduced dosage of hydroxyurea alternating with erythropoietin may prove less myelotoxic than hydroxyurea given daily or in pulsed-dose regimens. It may also increase levels of fetal hemoglobin in patients with sickle cell disease who have not been helped by hydroxyurea alone.

Cisplatin-associated anaemia treated with subcutaneous erythropoietin. A pilot study

In 20 patients with cisplatin-associated anaemia (haemoglobin less than 90 gl-1), recombinant human erythropoietin was administered subcutaneously three times a week on an outpatient basis. The initial dose was 50 Units Kg-1 of body weight. If response was not achieved within 3 weeks, dose was increased to 75 Units Kg-1. Using the same criteria further escalation to 100 Units Kg-1 was performed. If there was no response erythropoietin was terminated. Fifteen patients obtained an increase in haemoglobin to above 100 gl-1 which was considered as a clinical response in this study, with a dose of 50 Units Kg-1; one patient needed an erythropoietin dose of 75 Units Kg-1 and one a dose of 100 Units Kg-1. Only three patients required haemotransfusions and were considered non responders. Haemoglobin increases occurred despite continuation of cisplatin chemotherapy. In conclusion subcutaneous low dose of erythropoietin seems to be effective and safe in the treatment of cisplatin-induced anaemia.

Benefits and costs of recombinant human erythropoietin for end-stage renal failure: a review. Benefits and costs of erythropoietin

Recombinant human erythropoietin is an efficacious therapy in treatment of the anemia of end-stage renal failure. However, the scale of impact on quality of life and medical care resources remains uncertain. By reviewing the literature we evaluate cost-effectiveness of recombinant human erythropoietin and show how previous studies may have implicitly overestimated cost-effectiveness.

Therapeutic effect of heme arginate in myelodysplastic syndromes

In order to investigate, whether heme would induce a response in myelodysplastic syndromes (MDS), 14 symptomatic patients (4 RA, 3 RARS and 7 RAEB) were treated with infusions of heme arginate 3 mg/kg body weight on 4 consecutive days, mostly for six cycles at 2-week intervals. Three of 14 patients (21%) showed an improvement in anemia (97-152, 79-120 and 92-114 g/l) within a few weeks, and 1 showed a milder increase in hemoglobin level (102-118 g/l). Of the 2 responders with marked thrombocytopenia, 1 showed an improvement in the platelet count (7-37 x 10(9)/l) and her regular need for red cell and platelet transfusions ceased. Some regression in bone marrow (BM) cytology was seen in all 3 responders. One of the responders is still in remission 41 months after cessation of the treatment, while in the other 2 the response lasted for 26 and 5 months. Four patients progressed during the treatment: 1 RA to RAEB, 1 RAEB to RAEBt and 2 RAEB, both with very complex chromosomal abnormalities at the beginning of the therapy, to acute erythroleukemia (AML-M6). Pretreatment delta-aminolevulinic acid synthase and heme synthase activities were generally low. Five patients had mild thrombophlebitis, but not after the infusion procedure was changed. No other side-effects common to growth factors occurred. In conclusion, it is likely that heme arginate has a therapeutic effect on some MDS patients, obviously by stimulating erythropoiesis. The response may be long-lasting.

Serum immunoreactive erythropoietin in patients with idiopathic aplastic and Fanconi's anaemias

In patients with idiopathic aplastic anaemia (n = 34) and Fanconi's anaemia (n = 8), sampled once or on several occasions, serum erythropoietin (Epo) increased with increasing severity of anaemia with apparently similar rates of increase in each group. However, after adjustment for Hb, log Epo values for the Fanconi's anaemics tended to be greater than those for the idiopathic aplastic anaemics (P < 0.01). Erythropoietin concentrations in serum samples from patients with Fanconi's and idiopathic aplastic anaemias tended to be greater than in samples from patients with anaemias from protein energy malnutrition, myelodysplasia and iron deficiency. The results suggest that there is no deficiency of erythropoietin in Fanconi's and idiopathic aplastic anaemias and that if exogenous erythropoietin is of any benefit it would need to be administered in doses large enough to induce a significant increase in log Epo. Results of the study illustrate the need to take account of the assumptions which underlie interpretation of the statistical analysis. Use of erythropoietin values in place of log Epo gives misleading conclusions demonstrable as invalid as the conditions for normality of distribution of the data and homogeneity of variances were not satisfied.

Recombinant human erythropoietin in the treatment of infants with anaemia of prematurity

Recombinant human erythropoietin (rHuEPO) was administered subcutaneously three times a week to 18 infants with the anaemia of prematurity at doses of 75, 150, 300, or 600 units/kg per week for 4 weeks, starting at 3-4 weeks of postnatal age. A significant and dose-dependent increase in reticulocyte count was observed from a mean baseline value of 71 x 10(9)/l to 200 x 10(9)/l after 3 weeks of therapy, compared with a change from 69 to 97 x 10(9)/l in 66 historical controls. The haematocrit value remained unchanged during rHuEPO treatment, whereas it steadily declined until 9 weeks of postnatal age in the controls. These effects were accompanied by a marked reduction in serum iron concentration and transferrin saturation in patients receiving standard-dose iron supplements, but not in those given larger doses. Only 3 of 18 patients required a red blood cell transfusion. These infants were among the most anaemic at entry into the study and 2 of them were unable to complete rHuEPO therapy, while the third developed iron deficiency anaemia. These data indicate that rHuEPO with appropriate iron supplementation may accelerate the recovery from anaemia of prematurity. Larger scale placebo-controlled studies are now needed to confirm these findings and verify their impact on transfusion requirements of premature infants.

Innovative therapies in hematology and oncology

As one can see, there are a number of new and exciting advances in the prevention, detection, and treatment of various malignancies. We anxiously await the future to see the exact integration of the tremendous advances taking place in the cellular and molecular biopsy of disease and its application to the therapy of patients.

Erythropoietin therapy obviates the need for recurrent transfusions in a patient with severe hemolysis due to prosthetic valves

Erythropoietin has been proved extremely effective in ameliorating the anemia of chronic renal failure and is currently under intensive investigation. We describe a patient with severe anemia and secondary hemochromatosis due to prosthetic valves, who has been successfully treated with erythropoietin. During 12 months' follow-up, an acceptable hemoglobin level was maintained without any need for blood transfusions; in addition, there was evidence indicating regression of hemochromatosis. This patient illustrates that erythropoietin therapy might prove beneficial for similar cases.

Use of blood transfusion in management of anemia

Transfusion of red blood cells is useful in restoring oxygen-carrying capacity in patients with symptomatic anemia. In general, physicians should avoid transfusing blood based on hemoglobin concentration alone. Instead, they should focus on the impact of anemia on the patient's symptoms and level of activity. The concern for HIV infection and viral hepatitis has only served to highlight the potential risks associated with homologous transfusion therapy. These concerns should be carefully considered, along with possible alternatives, before a decision is made to transfuse. It is important to define the cause of anemia and to institute appropriate corrective therapy. The availability of recombinant human erythropoietin offers an option in selected patients to reduce or eliminate the need for red blood cell transfusion.

Anemia of renal failure. Use of erythropoietin

Chronic renal failure is almost invariably accompanied by symptomatic anemia. It has been demonstrated that the primary cause of this anemia is inadequate production of erythropoietin by the diseased kidneys. The isolation of erythropoietin, followed by the cloning and expression of the human erythropoietin gene, made possible clinical trials of rHuEPO in uremic patients. rHuEPO produced dramatic increases in the hematocrit in almost all patients treated and also ameliorated many symptoms, such as lethargy, dizziness, and poor appetite, that had long been attributed to the effect of uremic toxins. Adverse effects of treatment with rHuEPO noted in the early clinical trials included hypertension, seizures, arteriovenous fistula or shunt thrombosis, and hyperkalemia. Further study of rHuEPO has shown that many of these side effects may be no more frequent in patients receiving rHuEPO than in other uremic patients not receiving rHuEPO. Reduction of the rHuEPO dosage and subcutaneous administration produce less rapid increases in the hematocrit and may lessen the incidence and severity of these side effects. rHuEPO therapy places great demands on both the body's iron stores and the capacity to rapidly transfer iron from storage sites to the erythroid progenitor cells. Thus, almost all patients treated with rHuEPO become iron deficient and require oral or parenteral iron replacement. Response to rHuEPO in uremic patients is diminished if the anemia is complicated by iron deficiency, inflammatory disorders, aluminum overload, or deficiency of folate or vitamin B12. rHuEPO therapy is safe and effective in the treatment of the anemia of chronic renal failure. The use of rHuEPO leads to enhanced quality of life and eliminates the need for red cell transfusions. In addition to hemodialysis patients, predialysis patients and those on CAPD benefit from and are candidates for rHuEPO therapy.

Recombinant human erythropoietin is effective in correcting erythropoietin-deficient anaemia after allogeneic bone marrow transplantation

Two children affected by severe aplastic anaemia (SAA) underwent allogeneic bone marrow transplantation (BMT) using partially matched family donors. In both cases there was a successful engraftment of donor haemopoietic stem cells. However, after an initial erythropoietic recovery, 5 months following BMT both children became severely anaemic. Although multiple factors were responsible for anaemia, in both cases there was a markedly impaired erythropoietin response to anaemia, as indicated by the inappropriately low levels of serum erythropoietin (EPO). Treatment with recombinant human erythropoietin (rHuEPO) induced a sustained erythropoietic response with complete correction of anaemia. This pilot study suggests that rHuEPO can be effective in correcting long-lasting anaemia after marrow transplantation, characterized by inadequate erythropoietin production.

Testicular steroidogenesis and androgen use and abuse

The possibility of widespread use of androgens in the normal male population for the promotion of growth, sexual dysfunction, contraception, osteoporosis and ageing and large scale abuse by athletes have propelled androgen replacement out of the narrow confines of male hypogonadism and highlighted the many gaps in our knowledge. There is now a new appreciation of the much wider aetiological, therapeutic, preventative and public health implications surrounding the clinical use of androgens. To realize the many potential health benefits through manipulations of the androgen milieu of normal men, basic and clinical investigations into a number of key unresolved issues are urgently required. There is a need to understand the molecular mechanisms underlying the differential roles of testosterone, DHT and oestradiol in various androgen-responsive target tissues especially with reference to the pathogenesis of prostatic hyperplasia or carcinoma. It is also necessary to define the dose-response relationships of the action of androgens on spermatogenesis (and basis for inter-ethnic differences), sexual and aggressive behaviour and bone mineral turnover over a wide dose range. Clinically, it is important to systematically assess whether there is any increased risk for cardiovascular and prostatic diseases in androgen replacement and the risk-benefit issues concerning androgen therapy in aged men. Development of androgens with high therapeutic indices, long half-lives, zero-order release kinetics and perhaps selective target tissue specificity through modification to the steroid structure can further optimize future modalities of androgen therapy.

Recombinant human erythropoietin for autologous blood donation: effects on perioperative red-blood-cell and serum erythropoietin production

To speed collection of blood for autologous transfusion during elective surgery, patients may be given recombinant human erythropoietin (r-HuEPO). In a controlled trial, we evaluated the effects of r-HuEPO on perioperative red-blood-cell and serum erythropoietin (s-EPO) production in patients donating blood before elective orthopaedic surgery. Patients were assigned randomly to receive no r-HuEPO (12 patients), or 3000 U (4), 6000 U (5), or 9000 U (4) of r-HuEPO intravenously twice a week from the time of the first blood donation. All patients received iron sulphate. 1200 ml blood was collected from each patient in three weekly donations of 400 ml. The 3000, 6000, and 9000 U treatment groups produced 284, 350, and 383 ml, respectively, of red cells during donation, and the untreated controls produced 211 ml. s-EPO concentrations were within the normal range during donation. After surgery, s-EPO concentrations peaked on postoperative day 1 in untreated patients and on day 7 in treated patients; therefore, r-HuEPO may suppress endogenous erythropoietin secretion. Although administration of r-HuEPO increases production of red blood cells, the preoperative anaemia induced by repeated phlebotomy without r-HuEPO may accelerate the postoperative secretion of endogenous erythropoietin.

Polycythemia vera

Polycythemia vera (PV) is one of the myeloproliferative diseases, and, as such, is an example of clonal hematopoiesis. The progeny of a single, abnormal, hematopoietic stem cell gain a growth advantage over their normal counterparts resulting in overproduction of red cells generally accompanied by overproduction of granulocytes and platelets as well. There are a variety of nonspecific symptoms at onset related to the increased red cell mass and hematocrit accompanied by the more specific manifestations of pruritus, erythromelalgia, and hepatic, portal, and mesenteric vein thrombosis. Splenomegaly and hypertension are common. The laboratory hallmark is an increased red cell mass. There is also often an increase in white cell count, platelet count, and leukocyte alkaline phosphatase along with other findings reflecting the increased rate of turnover of hematopoietic cells. The bone marrow biopsy generally displays hypercellularity involving all three cell lines and absent iron stores. The diagnosis of PV depends on excluding spurious polycythemia in which there is a high hematocrit but a normal red cell mass and secondary polycythemia in which there is an increased red cell mass in response to tissue hypoxia or the inappropriate production of erythropoietin, generally by a tumor. In addition, one should try to establish the diagnosis in a positive fashion by a combination of studies of the blood and bone marrow. Phlebotomy and occasionally plateletpheresis should be used as acute therapy. Chronic therapy is guided by the knowledge that patients treated with phlebotomy alone have an increased rate of thrombotic complications particularly in older patients and those with previous thrombotic disease. Myelosuppressive therapy can reduce the incidence of these complications, but is commonly associated with an increased incidence of second malignancies, particularly acute leukemia. At present, hydroxyurea is the myelosuppressive agent of choice. Antiplatelet agents have a limited role except in the palliation of the syndrome of erythromelalgia. Median survival is approximately 10 years. As implied above, the causes of morbidity and mortality vary with the mode of chronic therapy which has been employed, leukemia being more common after myelosuppressive therapy and thrombotic complications being more common after therapy with phlebotomy alone. Ten percent to 50% of patients move into a spent phase followed by postpolycythemic myeloid metaplasia, irrespective of previous therapy employed. Eventually, the major problems may be cytopenias and massive splenomegaly.

Monokines inhibiting erythropoietin production in human hepatoma cultures and in isolated perfused rat kidneys

The blood level of erythropoietin (Epo) is often anomalously low in anemic patients with inflammatory or malignant diseases. Therefore, we studied effects of pure recombinant immunomodulatory peptides on Epo formation in cultures of the human hepatoma cell line, HepG2. Interleukin (IL)-1 beta, IL-1 alpha, and tumor necrosis factor alpha lowered Epo production with half-maximal inhibition at 2, 5, and 20 U/ml, respectively. IL-6, transforming growth factor beta 2 and interferon gamma did not inhibit. Furthermore, IL-1 beta (10 U/ml) proved to block Epo formation in isolated serum-free perfused rat kidneys. Proposedly, monokines play a role in the pathogenesis of Epo deficiency in various diseases.