The treatment of anaemia in the myelodysplastic syndromes with recombinant human erythropoietin

Review of therapeutic options and the management of patients with myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a poorly understood group of disorders caused by one or more genetic aberrations in the bone marrow-derived cell line responsible for hematopoiesis. Recent advances in genetic medicine have offered new insights into the epigenesis as well as the prognosis of MDS, but have not resulted in new or improved curative treatment options. Bone marrow transplantation, introduced before the advent of genetic medicine, is still the only potential cure. Advances in other medical and pharmaceutical areas have broadened the scope of supportive care and disease-modifying therapies, and treating physicians now have a broad range of disease management options depending on a patient's likely prognosis. There is now clear evidence that appropriate supportive care and therapeutic intervention can improve progression-free and overall survival of MDS patients.

Amelioration of anemia in the ICGN mouse, a renal anemia model, with a subcutaneous bolus injection of erythropoietin adsorbed to hydroxyapatite matrix

The recombinant human erythropoietin (rhEPO) is used for the treatment of patients with renal anemia. However, rhEPO should be administered subcutaneously or intravenously three times a week. The repetitive injections of rhEPO result in burdens to patients. To resolve this problem, we investigated the sustaining release methods using an rhEPO-hydroxyapatite (HAp) made by spray-drying technique as the drug delivery system. Two types of rhEPO-HAp formulations were prepared; zinc (Zn) formulation and Zn and poly-L-lactic acid (PLA) formulation. These formulations were examined in genetically anemic model, ICGN (ICR-derived glomerulonephritis) mice. According to in vivo release test of rhEPO from HAp in ICGN mice, elevated plasma concentration of rhEPO could be maintained for more than 7 days. These mice showed the amelioration of anemia for more than 3 weeks post-administration without causing any side effect. In conclusion, Zn or Zn/PLA formulation of HAp was considered to be one of the useful carriers of rhEPO for long-term improvement of anemia.

Sustained efficacy of erythropoietin with a hydroxyapatite carrier administered in mice

For chronic kidney disease patients with renal anemia, recombinant human erythropoietin (rHuEPO) is a very effective drug; however, the treatment regime is troublesome, requiring multiple administrations each week. In the present study, we examined the efficiency of hydroxyapatite (HAp) as a drug delivery carrier for the sustained release of erythropoietin (EPO) to reduce the frequency of administration. Spray-dried HAp microparticles, formed from zinc-containing HAp (Zn-HAp) and Zn-HAp calcined at 400 degrees C, were used as carriers of EPO, and five Zn-HAp formulation samples incorporating EPO were prepared; no formulation, poly-L-lactic acid (PLA) formulation, zinc (Zn) formulation, Zn/PLA formulation, and calcined/Zn/PLA formulation. ICR mice were administered these samples or commercial rHuEPO (Epogin) as a control from dorsal neck subcutaneous, and hematological and histopathological analyses, including enzyme-linked immunosorbent assay for plasma EPO concentration, were performed. An increase in the blood EPO level was detected on days 3 and 8 post-administration. Peak hematopoiesis was delayed and higher hematological values were obtained on day 14 post-administration with no serious adverse reactions compared with the control. The Zn/PLA formulation sample was found to be most effective in reducing the initial peak while sustaining the delayed release of EPO. In conclusion, the Zn-HAp formulation samples were considered to be useful carriers for the sustained release of EPO, and the Zn/PLA formulation appears to be the most effective of five Zn-HAp formulation samples in sustaining EPO release.

l-arginine import via cationic amino acid transporter CAT1 is essential for both differentiation and proliferation of erythrocytes

In the present study, we examined the role in hematopoiesis of cationic amino acid transporter 1 (CAT1), which transports l-arginine, l-lysine, l-ornithine, and l-histidine. The expression level of human CAT1 (hCAT1) mRNA in mononuclear cells (MNCs) fractionated according to lineage-selective markers was examined by reverse transcriptase-polymerase chain reaction. The expression of CAT1 in glycophorin A-positive erythroid cells was 8 times higher than in nonfractionated MNC (control) cells. Characteristics of l-arginine uptake by K562 cells, an established leukemic cell line used as an erythroid model, were similar to those of CAT1 in regards to saturation kinetics, sodium independence, and substantial inhibition of l-arginine uptake by N-ethylmaleimide, which is a specific inhibitor of system y+ amino acid transporter. Removal of l-arginine from the culture medium prevented both proliferation and differentiation of K562 cells, while removal of l-lysine or l-histidine had little effect on differentiation, though proliferation was blocked. Hematopoietic stem cells obtained from human cord blood failed to develop into erythroid cells in the absence of l-arginine in the culture medium. These findings indicate that hCAT1 is involved in erythroid hematopoiesis through its role in importing l-arginine, which appears to be essential for the differentiation of red blood cells.

The Role of Erythropoietin in the Anemia of Myelodysplastic Syndrome

Although erythropoietin (EPO) deficiency is not responsible for the anemia of myelodysplasia, pharmacologic doses of recombinant human EPO (rHuEPO, epoetin alfa) and epoetin beta have been studied extensively as treatment of anemia in myelodysplastic syndrome (MDS). When an epoetin is used as a single growth factor in patients with MDS, clinically meaningful responses occur in only a small minority of patients (16%). Patients who are transfusion-dependent are less likely to respond than patients who are transfusion-independent. Serum EPO level has a weak association with response rate and cannot be used to select or exclude patients from empirical trials of epoetins. The dose schedule commonly used as initial treatment 40,000 U/week, is consistent with clinical observations, but an optimal dose schedule has not been determined. The combination of an epoetin and granulocyte colony-stimulating factor (G-CSF) produces a higher erythroid response rate (36%) than the regimen of epoetin alone, but we have found no randomized trial data to support this point. However, the design of the clinical trials, which included adding G-CSF after epoetin alone had failed, supports the hypothesis that combined use of growth factors, rather than just higher doses of epoetin, is responsible for the high response rate observed with the combination of epoetin and G-CSF. Unfortunately, as in the case of epoetin alone, patients who are transfusion-dependent (> or =2 U red blood cells/month) are less likely to respond to combined growth factor therapy. Although the ability of patients with MDS to show an erythroid response to epoetin is of biologic interest, because of high costs and the limited response rate in transfusion-dependent patients, epoetin therapy, with or without G-CSF, cannot be regarded as a definitive therapy for the anemia of MDS.

Serum erythropoietin (EPO) levels correlate with survival and independently predict response to EPO treatment in patients with myelodysplastic syndromes

Treatment with recombinant erythropoietin (EPO) can alleviate anaemia in patients with myelodysplastic syndromes (MDS). The present study, based on a long-term follow-up of 68 MDS patients (26RA, 16 RAS, 26 RAEB) treated with EPO alone, pinpoints pre-treatment variables associated with response induction, response duration and overall survival. Response, defined as an increase in haemoglobin >15gL1 or eliminated erythrocyte transfusion requirements, was observed in 22 of 66 (33%) evaluable patients. The median response duration was 15 (range 3-64+) months. Using univariate logistic regression models, responders displayed significantly lower baseline serum EPO levels (S-EPO), more often normal bone marrow blast cell content (RA/RAS vs. RAEB), normal cytogenetics and no need for erythrocyte transfusion. In a multiple logistic regression model, S-EPO (P=0.009), marrow blast content (P=0.031) and erythrocyte transfusion need (P=0.024) remained associated with response induction. The probability of response for a patient with S-EPO >50UL1, RA/RAS and no transfusion need was 0.79 (0.53-0.93, 95% CI). The median overall survival time from start of EPO treatment was 26 months, significantly longer for responders than for non-responders (49 vs. 18 months, P=0.018). Survival was also predicted by baseline S-EPO; patients with S-EPO >50UL1 (n=50) had a median survival of 17 months, as compared to 65 months for those with S-EPO >50UL1 (n=14, P=0.024). The international prognostic scoring system (IPSS) for MDS predicted survival (P=0.003) and progression to acute leukemia (P<0.001) but not response to EPO treatment. Furthermore, in a logistic regression model with S-EPO and IPSS, S-EPO (but not IPSS) was again a significant predictor for response (P=0.007). Our data facilitate the optimal selection of MDS patients suitable for EPO treatment and pinpoint S-EPO as a powerful predictor of response and overall survival in MDS.

Apoptosis and prognostic factors in myelodysplastic syndromes

The myelodysplastic syndromes (MDS) are a group of disorders characterized by peripheral pancytopenia despite normo- or hyper-cellular bone marrow. This is thought to be due to apoptosis of hematopoietic bone marrow cells, resulting in ineffective hematopoiesis. Several studies have confirmed the presence of a high apoptotic rate and proliferative state in the bone marrow of MDS. However, MDS is a heterogeneous disease from the point of view of prognosis. Some patients develop only anemia and show long survival with or without maintenance therapy, while others develop fatal pancytopenia or leukemic changes and therefore show a poor prognosis. This review focuses on the relationship between prognosis and apoptotic or proliferative processes affecting hematopoietic cells in the bone marrow of patients with MDS.

Erythropoietin receptor in myelodysplastic syndrome and leukemia

Erythropoietin (Epo) is one of the main regulators of growth and differentiation of hematopoietic cells. In normal bone marrow cells, the amount of erythropoietin receptor (EpoR) was highest in the CD34+ CD38- subset, and decreased on lineage committed progenitor cells expressing CD38 antigens. Among the erythroid cells expressing GpA antigens, CD34-positive fractions expressed more EpoR than CD34-negative fractions. Although the amounts of EpoR of bone marrow cells from patients with refractory anemia (RA) were less than those of normal bone marrow cells in all phenotypes examined, there was no statistical significant difference. EpoR was detected on leukemia cells from 60% of acute myeloblastic leukemia (AML) cases and 29% of acute lymphoblastic leukemia (ALL) cases, and distributed widely among all FAB-subtypes. In spite of the presence of EpoR, in vitro proliferative response to Epo was not observed in a large proportion of AML. And there was no correlation between the amount of EpoR and the in vitro response to EPO. Patients with both EpoR expression and in vitro response to Epo had shorter remission duration than those without EpoR.

Pilot study of low-dose interleukin-11 in patients with bone marrow failure

PURPOSE

Interleukin-11 (IL-11) is a thrombopoietic cytokine that attenuates postchemotherapy thrombocytopenia at doses of 50 microg/kg/d subcutaneously. Very little is known about the activity of IL-11 in patients with bone marrow failure states.

PATIENTS AND METHODS

Our preliminary experience with IL-11 at doses of 50 microg/kg/d suggested that patients with bone marrow failure developed significant peripheral and pulmonary edema after the prolonged dosing necessary for treating these conditions. We, therefore, initiated a study of low-dose IL-11 (starting dose, 10 microg/kg/d).

RESULTS

Sixteen patients were assessable for response. Six patients had diploid cytogenetics; the others had a variety of chromosomal abnormalities. Six (38%) of 16 patients showed a platelet response to IL-11, and two had a multilineage response (to IL-11 alone, n = 1; to IL-11 plus G-CSF and erythropoietin, n = 1). The median increase in peak platelet counts was 95 x 10(9)/L above baseline in the responders (range, increase of 55 x 10(9)/L to 130 x 10(9)/L above baseline). Responders included five of 11 patients with myelodysplasia and one of four patients with aplastic anemia. Response durations were 12, 13, 14+, 25, 30, and 30+ weeks. Side effects of IL-11 were mild (peripheral edema, n = 7; conjunctival injection, n = 7; myalgia, n = 1; all grade 1). Seven patients had no side effects.

CONCLUSION

Our pilot study suggests that administration of low-dose IL-11 (10 microg/kg/d) can raise platelet counts without significant toxicity in selected thrombocytopenic patients with bone marrow failure.

Decreased amount of mpl and reduced expression of glycoprotein IIb/IIIa and glycoprotein Ib on platelets from patients with refractory anemia: analysis by a non-isotopic quantitative ligand binding assay and immunofluorescence

Using a non-isotopic ligand binding assay and immunofluorescence, we examined the amount of mpl, glycoprotein IIb/IIIa (gpIIb/IIIa) and glycoprotein Ib (gpIb) on platelets from healthy volunteers and patients with refractory anemia (RA). For the analysis of mpl expression, we applied both a non-isotopic ligand binding assay and immunofluorescence using anti-mpl monoclonal antibody, and compared the results from both methods. The non-isotopic ligand binding assay has been developed in our laboratory and is suitable for the quantitative analysis of a small amount of cytokine receptors such as mpl on platelets. In platelets from patients with RA, the amount of mpl expressed by the D value was 0.05+/-0.03 (mean+/-standard deviation), and was significantly lower than that in healthy volunteers (0.15+/-0.05, p<0.0001). The mean fluorescence intensities (MFI) of gpIIb/IIIa and gpIb on platelets from RA patients were 28.8+/-8.8 and 20.8+/-7.7, respectively, and were significantly lower than those on normal subjects (93.2+/-22.6 and 67.4+/-9.1, p<0.0001 and p<0.0001, respectively). There was a good correlation between the amount of mpl and the MFI of gpIIb/IIIa (p=0.794, p<0.0001) or gpIb (p=0.774, p<0.0001), and between those of gpIIb/IIIa and gpIb (p=0.728, p<0.0001). We demonstrated a decreased amount of mpl as well as a reduced expression of gpIIb/IIIa and gpIb on platelets from RA patients.

Long-term follow-up of 18 patients with myelodysplastic syndromes responding to recombinant erythropoietin treatment

The outcome of continued EPO therapy was studied in 18 responding MDS patients. The EPO dose was reduced in a stepwise fashion to find the lowest possible maintenance dose. Relapses of anemia were associated with either progressive disease or reduction of the administered EPO dose. In the latter group second responses to renewed EPO therapy were readily achieved. Long-term responses were seen in about a third of the patients. Thus, it seems safe to reduce the EPO dose among responding patients. This approach may have advantages both from a medical and a socio-economic perspective.

Evaluation of apoptosis as a prognostic factor in myelodysplastic syndromes

The myelodysplastic syndromes (MDS) are a group of disorders characterized by peripheral pancytopenia despite normo- or hypercellular bone marrow. This is thought to be as a result of the apoptosis of haematopoietic bone marrow cells resulting in ineffective haematopoiesis. To clarify the relationship between prognosis and apoptosis and/or cell proliferation in the bone marrow, we studied 51 cases with MDS. Bone marrow biopsies were stained immunohistochemically for MIB-1 (marker for proliferating cells) and CD34 (marker for stem cells). Apoptosis was visualized by detection of DNA fragmentation using TdT incorporation of nucleotides on 3' ends of DNA (TUNEL technique) and expressed as the apoptotic rate. MDS patients included 32 with refractory anaemia (RA), one RA with ringed sideroblasts (RARS) patient, seven RA with excess of blasts (RAEB) patients, eight patients with RAEB in transformation (RAEB-t) and three patients with chronic myelomonocytic leukaemia (CMMoL). In addition, we also studied six cases with acute myeloid leukaemia (AML) arising from MDS (AML-MDS) and ten control subjects. Fatal pancytopenia was the cause of death in 19 out of 51 patients. The apoptotic rate was higher in MDS patients (5.5%) than in control subjects (0.6%) and AML-MDS patients (0.4%). The percentage of MIB-1 positive cells was higher in MDS and AML-MDS than in control. The percentage of CD34-positive cells was higher in AML-MDS, RAEB, RAEB-t and CMMoL patients than control subjects and RA patients. Our findings indicate the activation of both the proliferative and apoptotic rates in MDS. Poor prognosis correlated significantly with higher apoptotic rates, but not with percentages of MIB-1 and CD34-positive cells. Our results suggest that apoptosis might be a useful prognostic factor and inhibition of apoptotic mechanisms may induce leukaemic transformation in MDS.

Amifostine cytotoxicity and induction of apoptosis in a human myelodysplastic cell line

Amifostine (AMF), a phosphorylated aminothiol, has been used to treat myelodysplastic syndrome (MDS), where it produces a stimulatory effect on hematopoiesis in bone marrow. To determine if AMF also produced a direct effect on human MDS cells, we planned a study to evaluate the effect of a continuous exposure to AMF on a human MDS cell line. AMF was shown to have a growth-inhibitory effect on MDS cells, with an IC(50) of 14 microM after a 5 day exposure. Cell cycle analysis revealed that a 5 day exposure to 20 microM AMF increased the percentage of cells in G0/G1 and this was accompanied by a decrease in the percentage of cells in S phase. Cytoflorometric and agarose-gel electrophoretic analysis revealed that this effect correlated with cell membrane alterations and DNA fragmentation consistent with an induction of apoptosis without affecting the expression of p53 protein or inducing any lymphoid or myeloid differentiation in the MDS cell line. We conclude that the continuous exposure of a human MDS cell line to AMF is cytotoxic and associated with an induction of apoptosis independent of alterations in p53 expression.

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.

Quantitative expression of erythropoietin receptor (EPO-R) on acute leukaemia cells: relationships between the amount of EPO-R and CD phenotypes, in vitro proliferative response, the amount of other cytokine receptors and clinical prognosis. Japan Adult Leukaemia Study Group

Expression of erythropoietin (EPO) receptor (EPO-R) was analysed in leukaemia cells from 150 patients with acute myeloid leukaemia (AML) or acute lymphoblastic leukaemia (ALL). EPO-R was expressed in 81 (60%) out of 136 AML, and in vitro treatment with EPO led to proliferation of leukaemia cells in 13 (16%) out of 81 AML examined. EPO-R expression and in vitro response to EPO were observed in all subtypes of AML according to the French-American-British (FAB) classification. All eight patients with FAB-M6 expressed EPO-R, and one out of four showed an in vitro response to EPO. Although there was no significant correlation (r = 0.2522) between the amount of EPO-R and the in vitro response to EPO, all of the AML patients who showed in vitro response expressed EPO-R. Stem cell factor significantly enhanced both EPO-R expression and in vitro response to EPO. Interleukin-3 tended to increase in vitro response to EPO. CD phenotypes, the amount of granulocyte colony-stimulating factor (G-CSF) receptors and the amount of TPO receptors had no significant relationship with the amount of EPO-R. Patients with both EPO-R expression and in vitro response to EPO had shorter duration of complete remission than those without EPO-R (P = 0.0053). EPO-R was expressed in four (29%) out of 14 ALL, and none out of five ALL showed in vitro response to EPO.

Meta-analyses of the effectiveness of erythropoietin for end-stage renal disease and cancer

Anemia, a decreased oxygen-carrying capacity of the blood, develops frequently in patients with end-stage renal disease (ESRD) or cancer. Given the wide variation in clinical response to erythropoietin in the treatment of anemia associated with these diseases, 2 meta-analyses of its effectiveness were undertaken. Databases (MEDLINE and International Pharmaceutical Abstracts) were searched to identify relevant articles. Search terms included erythropoietin, anemia, end-stage renal disease, cancer, multiple myeloma, and myelodysplastic syndrome. Searches were limited to human subjects and the English language. Reference lists of identified articles were reviewed for further articles of interest. The primary author (W.A.M.) selected the articles, and 2 researchers, working independently, extracted the necessary data. Articles had to meet the following criteria to be included in the meta-analyses: (1) Articles must have dealt with treatment of subjects with documented anemia. (2) Studies must have been original research with sample size > or =10. (3) Abstracts could be included if the full research manuscript was unavailable. (4) Patients could not be concurrently receiving other growth factors. (5) The quality of the selected articles must have been assessed by 2 independent researchers. A clinical response to erythropoietin was defined as a 0.06 increase in hematocrit or a 20 g/L increase in hemoglobin. Thirty-nine of the 76 identified articles were included in the meta-analyses. The effectiveness of erythropoietin was calculated at 87% for ESRD, 79% for multiple myeloma, 40% for solid tumor cancer, and 13% for myelodysplastic syndrome. Both subgroup and sensitivity analyses were performed.

Limited erythropoietic response to combined treatment with recombinant human interleukin 3 and erythropoietin in myelodysplastic syndrome

Twenty-two patients with myelodysplastic syndrome were treated with combined recombinant human erythropoietin and recombinant human interleukin 3 (rHuIL-3). All 22 patients were evaluable for toxicity and 21/22 for response. Thirteen patients (62%) required rHuIL-3 dose reduction because of toxicity. Nineteen experienced a 50% or greater rise in neutrophil count. Of seven patients with initial platelet counts of > 100,000, three experienced increases of > 15,000/ml while an equal number had a comparable decline. Five patients (21%) experienced a significant rise in reticulocyte count, and two transfusion-dependent patients experienced a significant decrease in transfusions. Erythroid burst-forming units were increased by > or = 50% in nine of 11 patients after combined therapy. Similar changes were seen in multipotential colony-forming units. Clinical responses were comparable to results obtained with epo alone while toxicities due to IL-3 were significant.

A randomized double-blind placebo-controlled study with subcutaneous recombinant human erythropoietin in patients with low-risk myelodysplastic syndromes

To evaluate the effect of recombinant human erythropoietin (rHuEpo) on the haemoglobin level and transfusion requirement in low-risk myelodysplastic syndromes (MDS), 87 patients were enrolled in a randomized double-blind placebo-controlled study, 44 patients were assigned to epoetin alpha (150 U/kg/d s.c. for 8 weeks) and 43 to placebo arms. MDS types were homogenous in both groups: refractory anaemia (RA) 47.7-48.8%. refractory anaemia with ringed sideroblasts (RAS) 20.5-25.6%, refractory anaemia with excess of blasts (RAEB) (blasts < 10%) 31.8-25.6%, 14/38 evaluable patients responded to epoetin alpha versus 4/37 to placebo (P=0.007). 50% of RA responded to epoetin alpha versus 5.9% to placebo (P=0.0072), RAS 37.5% v 18.2% (P=0.6) and RAEB 16.7% v 11.1% (P=1.00). 60% of non-pretransfused patients responded to epoetin alpha (Hb 8.35< or = 0.73 to 10.07+/-1.87 g/dl), whereas a slight decrease was observed in the placebo group (8.4+/-0.66 to 8.19+/-0.92 g/dl) (P=0.0004). Percentage of transfused patients was similar in both arms. Basal erythropoietin (Epo) serum levels > 200 mU/l predicted for a non-response. At week 4 sTfR levels were increased > 50% in responders (P=0.013), whereas an increase < 18% predicted for non-response (P=0.006). Leucocyte and platelet counts were not influenced by epoetin alpha treatment. Adverse events occurred in 31.8% of the rHuEpo-treated versus 42.99%) of the placebo-treated patients (P=0.2), and seven patients did not complete the course. In conclusion, rHuEpo was effective in the treatment of low-risk MDS. RA subtype, no transfusions prior to rHuEpo therapy, and low basal Epo levels were associated with higher probability of response. Soluble transferrin receptor level at the fourth week was an early predictor of response.

A pilot trial of 13-cis-retinoic acid and alpha-tocopherol with recombinant human erythropoietin in myelodysplastic syndrome patients with progressive or transfusion-dependent anemias. The Central Pennsylvania Oncology Group

A pilot study was performed to determine the efficacy of 13-cis-retinoic acid (CRA) and alpha-tocopherol (AT) with increasing doses of recombinant human erythropoietin (rHuEPO) in anemic patients with primary myelodysplastic syndrome (MDS), to determine response rate and to determine the dose requirement and long-term effects of rHuEPO therapy on the transition to acute non-lymphocytic anemia and survival of these patients. Twenty-four consecutive MDS patients were entered into the study. Patients were stratified according to their FAB classification at study entry. Therapy consisted of a 6 month trial of CRA (100 mg m(-2) day(-1) and AT (800 mg day(-1)) with rHuEPO (150 units kg(-1) body weight subcutaneously three times a week). The rHuEPO dose was escalated to daily doses at 2 months, and 300 U kg(-1) body weight given three times a week for another 2 months and continuing therapy after 6 months in responsive patients. Response was measured by elimination of transfusions requirement (partial response, PR) and normal hemoglobin level and complete blood counts (complete response, CR). Observed responses for the 23 evaluable patients were 2 CR and 6 PR (34.8%). Odds ratio analysis showed that patients with anemia alone were 14 times more likely to respond than patients with pancytopenia (p = 0.06). In our study, two patients (8%) transformed to acute leukemia in CRA + AT + rHuEPO-treated patients. Median survival of 34 months with a median follow-up of 17 months (range 3-70 months) was observed. The response rates with the addition of rHuEPO to CRA and AT was similar but occurs earlier at 2 months compared to 6-10 months with CRA and AT alone and did not alter survival. There was no increase in the risk for leukemia in the group treated with rHuEPO. Response to either therapy appeared to be limited to patients in the early stages of MDS.

Hematopoietic growth factors for the treatment of myelodysplastic syndromes

Administration of recombinant human granulocyte colony-stimulating factor (rhG-CSF), rh granulocyte-macrophage colony-stimulating factor (rhGM-CSF) or rh interleukin-3 (rhIL-3) effectively stimulate and expand marrow myelopoiesis resulting in a dose-dependent increment of peripheral blood neutrophils in most patients with myelodysplasias (MDS). Clinical outcome with fewer infections have been reported in a few studies using rhG-CSF or rhGM-CSF, including a large randomized, controlled trial with rhGM-CSF. Clinical effective stimulation of megakaryopoiesis and erythropoiesis are however infrequent. Recently, rh erythropoietin (rhEpo) has been used to overcome the ineffective erythropoiesis in MDS to reduce transfusions needed. However, the efficiency has been low in most studies with marked differences in response rates. The most impressive clinical results were obtained in patients with milder forms of MDS combined with low prestudy endogenous S-Epo levels. The possible synergistic effect of combining rhEpo with rhG-CSF or rhGM-CSF has been studied with erythropoietic response rates of about 40%. The safety of the cytokine administration seems acceptable with no significant stimulation of leukemic myelopoiesis and subsequent progression into overt acute myeloid leukemia. In conclusion, combinations of hematopoietic growth factors may be of clinical benefit in some patients with MDS. However, due to the cost and unpredictable clinical outcome there is a need for extended laboratory research to understand the functional defects of MDS stem cells and progenitors.

Clinical use of hematopoietic growth factors in the myelodysplastic syndromes

Recent advances in the molecular genetics of myelodysplastic syndromes (MDS) have shed new light on the pathogenesis of MDS allowing a better understanding of the defects of differentiation of the transformed clone and suppression of normal hematopoiesis. The clinical hematologist, however, continues to be challenged with the treatment of patients with MDS. Pancytopenia and defective function of neutrophils and platelets lead to a high risk of infectious and hemorrhagic complications. The progression to acute myeloid leukemia adds to morbidity and mortality. Supportive care including red blood cell and platelet transfusions are still the cornerstone of therapeutic management. While prophylactic administration of G-CSF or GM-CSF cannot be recommended, treatment of febrile neutropenia might benefit from administration of G-CSF in addition to antibiotics. Administration of high-dose erythropoietin will improve erythropoiesis in around 20% of the patients, mainly in those with rather preserved erythroid function and no or low transfusion need. Coadministration of erythropoietin with either G-CSF or GM-CSF could increase the response rate. Allogeneic stem cell transplantation still is the only curative treatment and prolongs survival. Intensive chemotherapy for advanced MDS is possible with an acceptably low rate of early death and a complete remission rate between 45% to 60%, while initial results of autologous transplantation are promising.

Myelodysplastic syndromes in the elderly: the role of growth factors in management

Myelodysplastic syndrome (MDS) comprises a group of heterogeneous clonal bone marrow disorders leading to peripheral cytopenia(s) and hypercellular marrow in the majority of the patients. The morphology of the cell lines is characterized by dysplastic features in some or all cell lines. The FAB classification has divided MDS in five subgroups, namely (1) RA (refractory anemia); (2) RARS (refractory anemia with ring sideroblasts); (3) CMML (chronic myelomonocytic leukemia); (4) RAEB (refractory anemia with excess blasts); and (5) RAEB-T (refractory anemia with excess blasts in transformation). Myelodysplastic syndrome remains primarily a disease of the elderly. With a reported median age of 74.4 years, patients have a chronic relentless course with complication of cytopenias, and a significant number of MDS patients, especially from the RAEB and RAEB-T categories, end up in acute myeloid leukemic transformation. Cytogenetic abnormalities are present in 40-58% of the cases and can provide not only help in diagnosis, but also understanding regarding the clinical course and prognostic aspect. Management of MDS is quite pragmatic and at this stage far from satisfactory. Various modalities have included use of differentiating agents, aggressive chemotherapy, bone marrow transplant and, more recently, significant interest has been generated in the use of hematopoietic growth factors. Differentiating agent trials have been unrewarding so far; chemotherapy trials have resulted in less benefit and more early toxic deaths, especially in the elderly MDS patients where the disease predominates. Bone marrow transplant appears suitable for some patients who are at a younger age. Salvation from this disease is being searched in the proper usage of hematopoietic growth factors and cytokines. There has been concern, however, that usage of growth factors has led to early and enhanced transformation of these patients to frank acute leukemic states. This concept appears to be somewhat refuted by newer controlled trials with GM-CSF and G-CSF, emphasizing that the acute leukemic transformation is the natural course of the disease and is not hastened by growth factor use. Preliminary studies are also suggesting that a combination of growth factors, especially G-CSF and erythropoietin as compared to chemotherapies, could be more beneficial in prolonging the survival of MDS patients who have progressed to the acute leukemic phase. More studies are needed for the understanding of the pathogenetic mechanism(s) in order to facilitate a more suitable and appropriate management strategy for MDS.

A good response rate to recombinant erythropoietin alone may be expected in selected myelodysplastic patients. A preliminary clinical study

The use of recombinant erythropoietin for treatment of anemia in myelodysplastic patients has so far produced poorer results than expected. Most clinical studies have been conducted without any selection of patients. In the present study we report our experience with the use of rhEPO in a population of selected MDS subjects. Only patients affected by refractory anemia according to FAB criteria, without significant WBC and platelets reduction, with normal LDH and short history of disease were eligible for the study and were treated with rhEPO at a dosage of 150 mg/kg three times a week for 2 months. Among the 12 so treated patients, 7 (58.3%) achieved complete remission, 2 partial remission and 3 failed to respond. This high response rate makes more than acceptable the cost/benefit ratio for rhEPO in RA patients and may identify a subgroup of patients that can be treated successfully with rhEPO alone.

Responsiveness to stem cell factor (SCF) of peripheral blood colony-forming cells from patients with myelodysplastic syndromes (MDS)

We have previously reported that serum stem factor (SCF) levels are significantly lower in patients with myelodysplastic syndrome (MDS) than normal controls. We have now studied the effects of adding SCF to cultures of blood mononuclear cells from patients with MDS and normal subjects. Three of 17 patients with MDS showed marked increases in erythroid colony numbers with SCF + erythropoietin compared to interleukin-3 + erythropoietin. In two cases (1RA and 1ISA) the erythroid colony numbers became normal. The same RA patient also showed a marked increase in myeloid colony numbers, which were undetectable with granulocyte-macrophage colony-stimulating factor alone, but within the normal range when SCF was added. A fourth patient (ISA) showed a 4.7-fold increase in myeloid colonies with SCF, but no erythroid response. The normal subjects showed a trend towards increased numbers of myeloid colonies with SCF; erythroid colonies did not increase. A correlation was found between the MDS patients' haemoglobin levels and erythroid colony numbers with and without SCF, but there was no correlation between erythroid or myeloid colonies in the presence of SCF and their serum SCF level.

What is ineffective erythropoiesis in myelodysplastic syndromes?

The anaemia of MDS is multifactorial with intramedullary ineffective erythropoiesis resulting from an imbalance between erythroid proliferation, differentiation and apoptosis in favour of initial hypercellularity with high cell death through to a lower cellularity, lower death state with the eventual evolution of the leukaemic clone in many patients. The fundamental molecular abnormality(ies) in MDS, which produce the milieu for the heterogeneous molecular insults described (e.g., oncogene mutations) remains elusive. Many questions such as why MDS red cells are macrocytic and what are the precise cellular and molecular mechanisms of ineffective erythropoiesis remain unanswered but future study of the erythroid lineage should provide molecular clues to the earliest abnormalities in the pathogenesis of MDS.

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 micrograms/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.

Sequential administration of recombinant human granulocyte-macrophage colony-stimulating factor and human erythropoietin for treatment of myelodysplastic syndromes

Treatment of myelodysplastic syndromes (MDS) with recombinant human erythropoietin (Epo) is successful in only 10% to 25% of patients. We performed a pilot study in 10 anaemic patients with MDS to examine whether sequentially applied recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) and Epo improves haemoglobin levels and/or reduces red blood cell transfusion requirements. Morphological diagnoses of patients were refractory anaemia (RA) in 3 cases, RA with ring sideroblasts in 3 cases and RA with excess blasts in 4 cases. GM-CSF was given subcutaneously at a dose of 150 micrograms/m2/d during the initial 10 days. From day 11, Epo was administered by subcutaneous injections for 8 weeks at a dose of 100 U/kg/d and subsequently at an escalated dose of 200 U/kg/d in 3 patients. Changes in reticulocyte counts, haemoglobin levels, RBC support and ferrokinetic parameters were compared with pretreatment values. Two out of 8 evaluable patients showed a rise in haemoglobin levels at week 8 and 10, respectively, and lost their transfusion dependency for a period of 13 and 27 weeks. In 1 patient, haemoglobin level increased only after dose escalation of Epo (200 U/kg/d). Leukocyte counts remained uneffected by treatment with Epo, while 1 patient showed a 4-fold increase in platelet numbers. Toxicity was mild. Two patients died of pneumonia and global heart failure, respectively, unrelated to growth factor therapy. Based on this pilot study, we conclude that sequential treatment with GM-CSF and Epo does not increase erythroid responses in anaemic patients with MDS. Because of the delayed increase in haemoglobin in both responders, we surmise that the beneficial effects were induced by Epo alone.

Trilineage recovery by combination therapy with recombinant human granulocyte colony-stimulating factor and erythropoietin in patients with aplastic anemia and refractory anemia

Ten patients with aplastic anemia (AA) and seven patients with refractory anemia (RA) were treated with recombinant human granulocyte colony-stimulating factor (rhG-CSF) and erythropoietin (rhEpo) in combination. rhG-CSF (5-20 micrograms/kg) and rhEpo (120-720 U/kg) were administered by s.c. injection three times a week for at least six months, and the administration was continued as maintenance therapy for as long as possible when hematological responses were observed. Six (60%) of the ten AA patients and four (58%) of the seven RA patients showed multilineage responses. Of these responders, six patients achieved trilineage recovery. While all of the responders were dependent on red blood cell transfusions and eight of them required platelet transfusions before treatment, they now no longer need transfusions of either red blood cells or platelets. A median treatment duration of 9 (range 1 to 28) months was required to achieve multilineage recovery. The responders showed an ability to maintain the multilineage recovery for 9+ to 47+ months and to tolerate long-term treatment. These results indicate that the long-term treatment with rhG-CSF and rhEpo may benefit a substantial percentage of patients with AA and RA and provide an optional therapy for these patients.

Hematopoietic growth factors and the treatment of tumor-associated anemias

Erythropoietin, alone or in combination with colony-stimulating factors, is a promising agent in the treatment of patients with cancer-related 'anemia of chronic disorders', chemo/radiotherapy-induced anemia, or anemia due to myelodysplastic or myeloproliferative syndromes. In the first two groups, at least half of the patients can be expected to respond to erythropoietin alone, with an average response delay of about 4 weeks and maximal responses at weekly doses of approximately 1000 U/kg. In myelodysplastic syndromes, only 10-20% of patients respond to conventional doses of erythropoietin, but doses exceeding 1000 U/kg weekly in combination with granulocyte colony-stimulating factor yield response rates of about 40%. Although these results show that hematopoietic growth factors can be used successfully to treat cancer-related anemias, economic constraints preclude their use at the present time.

Therapy with recombinant human erythropoietin in patients with myelodysplastic syndromes

We conducted a Phase I-II trial of recombinant human erythropoietin-beta (rhEPO) in patients with myelodysplastic syndrome (MDS). Patients with anemia and pathologically confirmed MDS were eligible for the study. Treatment consisted of rhEPO by subcutaneous injection thrice weekly for 6 weeks at one of three dose levels (100 U/kg (three patients), 200 U/kg (three patients) and 400 U/kg (14 patients)). Ferrous sulfate (325 mg po tid) was also administered if the transferrin saturation was below 30% (two patients). Patients were monitored with weekly CBC, white cell differential, and reticulocyte counts. Bone marrow examinations were performed at the conclusion of the treatment period and after a 2 week washout period. Patients who responded to therapy were continued on rhEPO at the same dose for 6 additional months. Response criteria included: 50% reduction in transfusion requirements compared with the 6 week pre-study period; doubling of reticulocyte count that was maintained on two determinations at least 1 week apart; or an increase in hemoglobin by at least 1.2 gm/dl without transfusions. Pre-treatment factors potentially predictive of response were analyzed by univariate analysis and in a multivariate fashion by classification and regression trees. Seven of the twenty patients sustained an untransfused rise in serum hemoglobin > or = 1.2 gm/dl. Four of the sixteen patients (including three of seven patients experiencing a rise in serum hemoglobin) who were transfusion-dependent prior to the study achieved a reduction or elimination of their transfusion requirements. Five of thirteen patients who received rhEPO during the extension phase had a continued response. A low baseline erythropoietin level (< 50 mU/ml) was the best predictor of hemoglobin response when controlling for other variables. rhEPO has a role in the treatment of certain patients with MDS, particularly in those whose endogenous serum erythropoietin levels are not markedly elevated.

Recombinant human erythropoietin in the treatment of myelodysplastic syndromes--response patterns

Different response patterns to recombinant human erythropoietin (rHuEpo) administration to anemic patients with myelodysplastic syndromes (MDS) are described. The biology of rHuEpo effect on erythropoiesis in patients with MDS has not been elucidated. However, until more biological information is obtained, it could be prudent to consider these response patterns as guidelines in the treatment of MDS. In the small but interesting series of nine patients with MDS only one responded to rHuEpo within the treatment period of eight weeks. Two additional patients continued the treatment on their own, and after 16 weeks a response was noted for the first time. A third patient was treated for only six weeks and a delayed response was recorded while off treatment for ten weeks. This response was also recorded 16 weeks from treatment initiation-as in the other two patients. A fourth patient with MDS developed transfusion related hemosiderosis and during iron chelation therapy the RBC transfusion rate dropped to a rate lower than the rate needed before the rHuEpo treatment. It is emphasized that in non responders, non-routine approaches should be considered.

Factor IX gene haplotypes in Brazilian blacks and characterization of unusual DdeI alleles

Analysis of factor IX gene polymorphisms is considered the best approach for prenatal diagnosis and carrier detection of haemophilia B when the identification of the gene mutation is not possible. Studies involving factor IX gene polymorphisms in Black populations are scarce and essentially restricted to the North-American Black population whose composition is substantially different from that of the Brazilian and presumably other Black populations of South America. In this paper we report the analysis of eight factor IX gene polymorphisms in Brazilian Blacks: 5' BamHI, DdeI, intron 2 BamHI, XmnI, TaqI, TaqI, MspI, MnlI and HhaI. Characterization of the VNTR-like DdeI polymorphism revealed six different alleles: B, AB, A2B, A2B2, A3B and A5B, the last being described here for the first time. The 5' BamHI, DdeI, MspI and HhaI polymorphisms showed the highest heterozygosities (0.40-0.50) and are in linkage equilibrium with one another. 19 complete haplotypes could be identified in this population. Based on the results we propose a systematic strategy for carrier detection and prenatal diagnosis of haemophilia B in this population. The combined analysis of four polymorphisms (5' BamHI, HhaI, MspI and DdeI) provided an informative genetic marker in 85% of the females. The use of all eight polymorphisms allows information in 95% of females. Additionally, differences in gene frequencies and haplotype distribution suggest dissimilarities in factor IX gene polymorphisms between the Brazilian and the North-American Black populations.

Inadequate erythropoietin response to anemia: definition and clinical relevance

The development of a specific and sensitive immunoassay for the measurement of serum erythropoietin (s-Epo) allows to improve our understanding of the model of in vivo regulation of erythropoiesis. In most anemias, circulating hemoglobin level determines Epo production which in turn stimulates erythropoietic activity. The disruption of the expected feedback mechanism of Epo production leads to an inadequately low s-Epo. The definition of inadequate Epo response to anemia relies on the documentation of a downregulated dependence of s-Epo on Hb with respect to the same dependence in patients with a physiologically regulated erythropoiesis. Literature reports a wide range of so called adequate s-Epo response to anemia and a number of criteria for judging on the adequateness of s-Epo at a certain degree of anemia. The O/P (observed/predicted) ratio allows categorization of each individual patient. The clinical syndromes in which an inadequate Epo response has been reported are numerous and the mechanisms of defective Epo production are different. A number of evidences clearly point to a relation between responsiveness to r-Hu-Epo and inadequate Epo response. This inequivocabily confirms the role inadequate Epo response plays in the pathogenesis of anemia.

New treatment approaches for myelodysplastic syndrome and secondary leukaemias

Allogeneic BMT is the treatment of choice for patients with MDS or sAML, offering a good chance of long-term disease-free survival if the transplant is performed in an early stage of disease or if the patient receives the transplant in complete remission after polychemotherapy. The transplant is limited to a minority of relatively young patients (aged below 55 years) with an HLA-identical sibling. Allogeneic BMT may also be considered when a closely- or fully-matched unrelated donor has been identified for a young and fit patient. All patients, including those without an excess of blasts, should be conditioned with bone marrow ablative therapy rather than an immune suppressive regime, such as cyclophosphamide alone. For the majority of patients there is no standard therapy other than appropriate supportive care. Relatively young patients below the age of 60 years with poor risk features can be considered for treatment with combination chemotherapy. Maintaining remission after remission-induction chemotherapy is a difficult issue. Patients not eligible for allogeneic BMT could be treated with post-remission chemotherapy or autologous BMT in the framework of prospective studies. Older patients can be considered for treatment with haematopoietic growth factors alone or in combination with differentiating agents such as low-dose Ara-C. This treatment should be delivered within the context of carefully designed and conducted trials.

Low-dose ara-C in myelodysplastic syndromes (MDS) and acute leukemia following MDS: proposal for a predictive model

Patients with myelodysplastic syndromes (MDS) comprise an extremely heterogeneous group. There is a need for decision models both for predicting the natural course of the disease and the outcomes of different treatment alternatives. In 102 consecutive patients with MDS or acute myelogenous leukemia (AML) following MDS, pre-treatment variables were studied in relation to the response to treatment with low-dose ara-C. Thirty patients (29%) responded with either a complete remission or a significant rise in the hemoglobin level. For the remaining 71%, the treatment was ineffective and in some cases hazardous. The factors associated with a poor response to treatment could be divided into two groups: one included low platelet counts and the presence of chromosomal aberrations, both signs of progressive MDS with a short survival, and the other comprised morphological findings, indicating ineffective hemopoiesis. Patients with platelet counts > 150 x 10(9)/l had a response rate of 55%, compared to 24% in patients with subnormal platelet counts. Logistic regression identified low bone marrow cellularity, absence of ring sideroblasts and < 2 chromosomal aberrations as predictors of a favourable response in patients with platelet counts < 150 x 10(9)/l. These factors and the platelet count were combined in a predictive model which divided patients into three groups with different probabilities of response: one favourable (38% of the patients), with a response rate of > 50%; a second, intermediate group (33% of the patients), with a response rate of 24%; and a third, unfavourable group (29% of the patients) with only 3% responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of recombinant human erythropoietin in the treatment of refractory anemias without excess of blasts in myelodysplastic syndromes

To determine the efficacy of recombinant human erythropoietin at pharmacological doses in myelodysplastic syndromes (MDS) without excess of blasts, 20 patients with refractory anemias (RA) or refractory anemias with ring sideroblasts (RARS) were treated in an open study with escalating doses from 40 U/kg to 300 U/kg three times a week subcutaneously during a period of 3 months. Maintenance therapy at the lowest effective dose was continued in responders. A dose response of CFU-E and BFU-E to Epo was analysed at the entry. Bone marrow examination with an in vitro study of hematopoietic progenitors was performed before and after the first three months. Seven of 20 patients responded: a total recovery was observed in 3 patients; one became transfusion independent and a reduction of 50% of the transfusion requirement was achieved in 3 others. 3 patients are still receiving treatment for 2, 3 and 4 years. No significant correlation was found between the in vitro and clinical response. A non parametric analysis of responders and non responders emphasised the importance of a long delay between the diagnosis and the treatment, (p = 0.024) and an endogenous Epo level less than 100 mU/ml (p = 0.025) in order to predict the efficacy of rhEpo. This study offers evidence that patients with refractory anemias without excess of blasts in the bone marrow respond to rhEpo at pharmacological doses. Larger studies are required in order to define the patients who may respond and to elucidate the mechanism of the positive effect of rhEpo.