Responsiveness of bone marrow erythroid progenitors (CFU-E and BFU-E) to recombinant human erythropoietin (rh-Ep) in vitro in multiple myeloma

The Implications of Anemia in Multiple Myeloma

Multiple myeloma (MM) is commonly associated with anemia. Several causes have been implicated, but anemia of chronic disease with inadequate erythropoietin (EPO) production related to the inflammatory cytokines appears to be of utmost importance. Interleukin-1 and tumor necrosis factor are capable of suppressing erythropoiesis. Anemia has broad implications. First, the low hemoglobin and hematocrit are associated with poor quality of life and performance and affect daily activity. Second, anemia has an impact on the cardiovascular system. Considering that most MM patients are elderly, this may be even more important. Anemia has been shown to induce or aggravate hypoxia and ischemic complications. Third, anemia has been shown to be a poor prognostic factor in MM. Traditionally, patients with symptomatic anemia were treated with red blood cell transfusions as needed. The introduction of epoetin alfa and epoetin beta into clinical practice opened new avenues to these patients. The administration of epoetins to patients with MM and anemia have been shown to be very useful. Several studies in more than 1000 patients have demonstrated a high response rate (range, 25%-85%; mean, 60%). This response is characterized by a significant increase of hemoglobin, hematocrit, and the number of red blood cells together with a reduction in the blood transfusion requirements. This is also associated with an improved quality of life. Although there is no complete agreement about the role of pretreatment serum EPO levels, many investigators believe that relatively low levels may help in predicting response, thereby limiting the number of potential candidates to receive this expensive therapy. The epoetins are safe and well tolerated with minimal toxicity; however, some concern has been recently raised regarding several dozen patients who developed pure red cell aplasia while on epoetin therapy. However, this adverse effect appears to be extremely rare. Recent data suggest that EPO has additional biologic effects, such as longer-than-expected survival in patients with MM. This observation is further supported by animal studies, demonstrating an antimyeloma effect of EPO in mice models. This effect has been shown to be immune mediated. If these exciting data are confirmed in future clinical trials, this may have significant implications on the treatment of MM.

Serum erythropoietin levels in ovarian cancer patients receiving chemotherapy

OBJECTIVE

To investigate the effects of repeated cis-dichlorodiamine-platinum (CDDP) exposure on serum erythropoietin (Epo) levels.

STUDY DESIGN

In seven patients with ovarian cancer, Epo and haemoglobin concentration (c(Hb)) were measured before, 24h and 7 days after administration of the first three courses of chemotherapy. In seven control patients undergoing gynaecological surgery for non-malignant reasons, Epo and c(Hb) were measured before, 24h and 7 days after the operation.

RESULTS

Following Epo increased, independent of concomitant anaemia, especially after the third course: 51mU/ml (S.D. 46) versus 122mU/ml (S.D. 83) (P=0.02). In the control patients, Epo was lower although the decrease of c(Hb) was significantly higher.

CONCLUSION

Cis-platinum chemotherapy induces an increase in erythropoietin levels independent of anaemia. The underlying mechanism remains to be investigated.

Relation between S-phase fraction of myeloma cells and anemia in patients with multiple myeloma

In an attempt to define the relation among anemia, tumor mass, and proliferative activity of tumor cells in vivo, we measured the proportion and cell cycle distribution of erythropoietic cells and myeloma cells in the bone marrow of patients with multiple myeloma using four-parameter flow cytometry. Forty-three bone marrow samples from 33 patients with stage II or III disease and normal renal function at diagnosis (n = 9), in partial remission (n = 9), and in progression or relapse after chemotherapy (n = 25) were evaluated. Early and late erythropoietic cells were discriminated based on published light scatter properties in combination with CD71 expression. Myeloma cells were detected by exploiting their strong CD38 positivity and light scatter characteristics. Cell cycle distribution of the three cell populations was determined by propidium iodine staining. In the whole group of patients, hemoglobin (Hb) concentration was inversely correlated with beta2-microglob-ulin (p = 0.03), percentage of marrow CD38++ cells (p = 0.008), and percentage of CD38(++) cells in S phase (S-CD38++; p < 0.001). Partial correlation analysis revealed S-CD38++ to be the only independent predictor of Hb concentration (p < 0.001). No correlation was found between Hb concentration and the S-phase fraction of erythropoietic cells. In the subgroup of patients with moderate to severe anemia, defined as Hb concentration <11 g/dL, Hb level correlated negatively only with S-CD38++ (p < 0.001) but not with beta2-microglobulin and percentage of marrow CD38++ cells. In addition, Hb and the S-phase proportion of early erythropoietic cells correlated positively (p = 0.029). The strong inverse correlation between Hb concentration and percentage of myeloma cells in S phase suggests that in multiple myeloma, tumor proliferative activity may have a more important impact on the development of anemia than tumor mass. The S-phase fraction of tumor cells appears to be the most important pathogenic factor, especially in anemic patients. In these patients, the positive relation between Hb concentration and the S-phase fraction of erythropoietic progenitors indicates that development of anemia is associated with inhibition of erythropoiesis.

Measurement of the cell proliferation rate of bone marrow erythroid precursors by flow cytometry: initial applications to multiple myeloma

To investigate the pathophysiology of anemia, a two-color flow cytometric method was developed that measures the proliferative rate of the marrow erythroid cells (EPR). The method uses a monoclonal antibody, RC17.2, to identify erythroid precursors and propidium iodide to determine the %S-phase. This technique was then used to test the hypothesis that a decrease in the proliferative rate of the marrow erythroid precursors contributes to the anemia of multiple myeloma. The EPR was determined on the marrow aspirate from 56 patients and the mean EPR was 31.2% (median, 31: range, 14-55). Patients with anemia (n = 36) had a median EPR of 27% compared to 35% for those patients with a normal Hgb (p = < 0.001); however, there was no difference in the % marrow erythroid precursors (p = 0.96) or % marrow plasma cells (p = 0.08) between the two groups. These results suggest that one possible cause for the anemia of myeloma is a decrease in the EPR. This flow cytometric technique may also be useful in studying other anemias.

The role of recombinant erythropoietin for the treatment of anemia in multiple myeloma

The key role of a blunted production of endogenous erythropoietin (EPO) in determining anemia of patients with multiple myeloma (MM) has been definitively established. Thus, several clinical trials have investigated the effects of recombinant EPO (r-EPO) in anemic MM patients. The results of these studies have demonstrated that r-EPO is a safe and effective drug, which results in an increase in Hb levels in the majority of treated patients. However, several factors, such as serum levels of endogenous EPO, severity of anemia, presence of normal erythroid progenitors, serum levels of some cytokines with inhibitory activity on erythroid function and previous treatments, may significantly affect the possibility of response, thereby suggesting the need for careful selection of MM patients for treatment with r-EPO.

The effect of clenbuterol and recombinant erythropoietin on tumor growth and the anemia caused by the Walker 256 carcinosarcoma

In patients with advanced cancer, anemia is a common complication indicative of a poor prognosis. Attempts to alleviate this have met with mixed success and interventions including erythropoietin often fail to elicit an appropriate response. We have used rats implanted with the Walker 256 carcinosarcoma as a model of non-responsive anemia. This study demonstrates that the provision of recombinant erythropoietin in the presence of clenbuterol, a beta2 agonist, attenuates both the cancer induced anemia and the growth of the tumor in this model. We hypothesize that this treatment relieves the tumor induced inhibition of hematopoiesis, which allows for not only an increase in hematocrit but an increased immunosurveillance resulting in tumor suppression.

Clinical results of recombinant erythropoietin in transfusion-dependent patients with refractory multiple myeloma: role of cytokines and monitoring of erythropoiesis

Recombinant erythropoietin (r-EPO) was administered to 37 patients with advanced, transfusion-dependent and chemo-resistant multiple myeloma (MM), at the fixed dose of 10,000/U s.c., 3 times a week, for 2 months. Thirteen patients (35.1%) achieved a significant response in terms of complete abolition of red cell transfusions. Factors significantly predictive of response were: a) inappropriate production of endogenous EPO, as expressed by a reduced observed/predicted ratio; b) presence of a consistent number of circulating erythroid precursors BFU-E; c) low serum levels of tumor necrosis factor (TNF) and interleukin-1 (IL-1), cytokines with inhibitory activity on erythropoiesis; d) a single line of previously received chemotherapy. Renal failure, bone marrow plasma cell infiltration, serum levels of IL-6 and other main clinical and laboratory parameters did not affect significantly the response to r-EPO. High fluorescence reticulocytes (HFR) and soluble transferrin receptor (sTfR) values were useful to detect an early stimulation of erythropoiesis in responders, while a high percentage of circulating hypochromic erythrocytes (HE), as assessed by an automated counter, identified those patients developing functional iron deficiency during r-EPO treatment. We conclude that about one-third of severely anemic patients with advanced MM, unresponsive to chemotherapy, may benefit by r-EPO therapy. The clinical management of these patients can be accomplished using non-invasive parameters, such as sTfR, HFR and HE.

Does erythropoietin accelerate malignant transformation in multiple myeloma?

Growth factors or humoral agents can support haemopoiesis in various bone marrow disorders. They have the ability to act on multiple cell lineages and in myeloid cells, and the potential to act on the neoplastic equivalent of normal cells. Anaemia is a common feature of multiple myeloma seen in at least two-thirds of patients at presentation. Erythropoietin is increasingly being used with variable effect for the treatment of this anaemia, especially in cases associated with renal failure and in patients in whom blood transfusion may be undesirable or contraindicated. We describe a patient treated with recombinant erythropoietin who developed fulminating malignant transformation. The demonstration of erythropoietin receptors on a human myeloma cell line and the occurrence of the rare complication of plasma cell leukaemia in our patient stresses the need for caution and invites detailed clinical and laboratory studies before its general use.

Recombinant human erythropoietin for the correction of cancer associated anemia with and without concomitant cytotoxic chemotherapy

BACKGROUND

Chronic anemia is a common complication in patients with cancer, especially in those with advanced disease or who are under intensive chemotherapy. Because homologous blood transfusions involve some hazards, the safety and efficacy of recombinant human erythropoietin (r-HuEPO) in the treatment of anemic patients with cancer with and without concomitant chemotherapy were studied.

METHODS

One-hundred two cancer patients with hemoglobin less than 11 g/dl, ferritin greater than 30 micrograms/l, and creatinine < 220 mumol/l were enrolled in the study, 94 were eligible for efficacy evaluation. Sixty-eight patients received chemotherapy (CT group) and 26 had no cytotoxic cancer treatment (NT group). Recombinant human erythropoietin was administered subcutaneously at a dose of 150 U/kg three times per week for 6 weeks; in nonresponders the dose was doubled for the subsequent 6 weeks. Response was defined as the achievement of a hemoglobin increase of 2g/dl. Clinical and laboratory parameters, including serum erythropoietin (EPO) levels, performance status, and quality of life, were investigated at baseline and monitored at regular intervals thereafter.

RESULTS

Response was achieved by 52% and 62% of CT and NT patients, respectively. The highest response rates were observed in patients with lung cancer or with a histology of squamous cell carcinoma (both 80%). In responding patients, the symptoms of anemia subsided. They no longer needed blood transfusions after 4 weeks of therapy; and both their performance status and quality of life improved significantly. The NT patients achieved slightly more favorable results on lower weekly doses: 450 U/kg/week in NT versus 570 U/kg/week in CT patients. Serum EPO levels were higher in nonresponders at baseline and further increased during the course of treatment. Recombinant human erythropoietin was well tolerated by all patients.

CONCLUSION

This multicenter study in a large patient collective shows that r-HuEPO treatment represents a safe and effective means to increase the red cell mass and eliminate the need for blood transfusions in approximately 50% of the patients with chronic anemia of cancer. Responding patients not only have increased levels of hemoglobin, but their performance status also improves significantly, and they enjoy a significantly enhanced quality of life.

Erythropoiesis and erythropoietin in multiple myeloma

In this review, the pathophysiology and treatment of the anemia of multiple myeloma will be examined. While the anemia of cancer has multiple causes, an important component is labeled the "anemia of chronic disease" which is characterized by the combination of a shortened erythrocyte survival with failure of the bone marrow to increase red cell production in compensation. Depressed erythropoiesis is itself related to a combination of factors, including impaired availability of storage iron, inadequate erythropoietin response to anemia, and overproduction of cytokines which are capable of inhibiting erythropoiesis. These cytokines are involved in the retention of iron in the reticuloendothelial system, gastrointestinal tract and hepatocytes, may interfere with erythropoietin production by the kidney, and may exert direct inhibitory effects on erythroid precursors. While overproduction of several such cytokines, including IL-6, IL-1 and TNF-alpha, has been definitely demonstrated in multiple myeloma patients, it is still unclear whether they are directly involved in the pathogenesis of the anemia which develops. Although several mechanisms, such as hemodilution, bleeding, and decreased red cell survival operate, the anemia is mostly caused by defective erythropoietic activity. This in turn is partly explained by inadequate erythropoietin (Epo) production even in some patients without renal impairment. Based on measurements of serum erythropoietin and transferrin receptor, the distinction between marrow unresponsiveness to normal Epo stimulation and deficient Epo production is important for the treatment of the anemia of multiple myeloma with recombinant human Epo. Higher doses would probably be necessary if adequate Epo production is present, whereas only replacement therapy with lower doses may be sufficient when Epo production has been shown to be inappropriate.

Recombinant human erythropoietin for the treatment of chronic anemia in multiple myeloma and squamous cell carcinoma

Recombinant human erythropoietin (rHuEPO) improves chronic anemia of cancer, but the proportion of patients who respond favorably to the treatment varies depending on the type of neoplasia. Preliminary data of the two malignancies with the highest response rates, namely, multiple myeloma and squamous cell carcinoma, are reported. Twenty patients with multiple myeloma and 14 with squamous cell carcinoma, who had presented with hemoglobin levels < 11 g/dl, were treated with rHuEPO, 150 U/kg, three times/week. Response, defined as an increase of at least 2 g/dl hemoglobin within 12 weeks, was achieved by 15 myeloma patients (75%) and 11 patients with squamous cell carcinoma (79%). Tolerance of the treatment was excellent. The WHO performance status and quality of life improved in responders. The remarkably low levels of endogenous EPO in our patients with squamous cell carcinoma, most of whom had been treated with cisplatin-or carboplatin-containing regimens, suggest that anemia in these cases had been at least partly chemotherapy induced. In myeloma patients, the blunted EPO response to the anemic condition may have been partly caused by subclinical tubular insufficiency induced by toxic paraproteins. Future studies should aim to elucidate factors which are responsible for the inability of some patients to respond to rHuEPO treatment, even though in multiple myeloma and squamous cell carcinoma these non-responders are a small minority.