Treatment of acquired severe aplastic anemia: bone marrow transplantation compared with immunosuppressive therapy--The European Group for Blood and Marrow Transplantation experience

Treatment of severe aplastic anemia by immunosuppressor anti-lymphocyte globulin/anti-thymus globulin as the chief medicine in combination with Chinese drugs

OBJECTIVE

To study the therapeutic effect of combined therapy with Chinese drugs and immuno-suppressors, mainly anti-lymphocyte globulin/anti-thymus globulin (ALG/ATG), for the treatment of severe aplastic anemia (SAA), the efficacy associated factors and adverse effects as well.

METHODS

A retrospective analysis was conducted on 65 patients with SAA treated by combined therapy which was supplemented with cyclosporin A, androgen, hematopoietic growth factor, etc.

RESULTS

Of the 57 patients followed-up, 26 (45.6%) were basically cured, 15 (26.3%) remitted, and 8 (14.0%) improved markedly, the total effective rate being 85.9%. By separately comparing with a single item of clinical data, it was shown that the therapeutic effectiveness was correlated, to a certain extent, with age, illness duration, neutrophil count, and bone marrow proliferation in patients before treatment, as well as with infection that occurred in the follow-up period. It was obviously higher in patients with peripheral neutrophil count > 0.5 x 10 10(9)/L (P<0.05). Various degrees of serum sickness-like reactions occurred in the treatment of 36 patients, including fever in 36 (63.2%), skin rash in 8 (14.0%), and musculoskeletal pain in 5 (8.8%).

CONCLUSIONS

The therapeutic effect of combined therapy with Chinese drugs and ALG/ATG in treating SAA could be affirmed, showing some superiority as compared with Western medicine alone. The patients' age, duration of illness, neutrophil count, and bone marrow proliferation before treatment, and degree of infection that occurred could affect the therapeutic efficacy to a certain extent. Adverse reactions resulting from the combined therapy are less, showing the toxicity reducing and effect enhancing action of Chinese drugs.

Fludarabine, cyclophosphamide, anti-thymocyteglobulin, and low-dose total body irradiation conditioning enables 1-HLA-locus-mismatched hematopoietic stem cell transplantation for very severe aplastic anemia without affecting ovarian function

Allogeneic hematopoietic stem cell transplantation for severe aplastic anemia from an alternative donor is associated with higher risks of graft rejection and severe graft-versus-host disease. We developed a conditioning regimen consisting of rabbit anti-thymocyte globulin, fludarabine, cyclophosphamide, and low-dose total body irradiation. Two adult female patients with transfusion-dependent very severe aplastic anemia underwent 1-locus mismatched transplantation using this regimen. Both patients achieved stable engraftment and the clinical course thereafter was uneventful with persistently normal ovarian function. This novel conditioning regimen may be suitable for alternative donor transplantation for severe aplastic anemia, especially in young female patients.

Antibodies to glycosylphosphatidyl-inositol anchored proteins (GPI-AP) in antithymocyte and antilymphocyte globulin: possible role for the expansion of GPI-AP deficient cells in aplastic anemia

Antithymocyte globulin (ATG) and antilymphocyte globulin (ALG) are currently used successfully for immunosuppressive treatment of aplastic anemia. In this study we have investigated whether commercial ATG/ALG preparations contain antibodies against glycosylphosphatidyl-inositol anchored proteins (GPI-AP), which could be responsible for emergence of GPI-deficient populations in aplastic anemia after ATG/ALG therapy. We analyzed four commercial ATG/ALG preparations by competitive binding assays using flow cytometry. Quantification was achieved by calculating the concentration of ATG/ALG required to give 50% inhibition of binding the specific fluorochrome-labeled monoclonal antibody (EC50). High concentrations of antibodies against the GPI-anchored protein CD52 were found in all preparations (Lymphoglobulin Genzyme, Thymoglobulin Genzyme, ATGAM. Pharmacia & Upjohn, and ATG-Fresenius S Fresenius). Antibodies against the GPI-anchored protein CD48 are present in significant concentrations except in the preparation ATGAM. CD16 antibodies were found in lower concentrations. We could not detect significant concentrations of antibodies against the GPI-anchored proteins CD157 and CD14. Campath-1H, a monoclonal antibody against the GPI-anchored protein CD52, has been used as immunosuppressive tool for T-cell depletion. CD52 antibodies in ATG/ALG preparations might contribute in the same way to the immunosuppressive effects in treatment of aplastic anemia. It is known that in a substantial proportion of patients with aplastic anemia GPI-deficient cells are present in a low level at diagnosis or emerge after immunosuppressive therapy. GPI-anchored antibodies in ATG/ALG preparations might lead to a relative advantage for pre-existing GPI-deficient cells caused by an escape from the antibody-mediated attack.

Allogeneic stem cell transplantation for severe aplastic anemia: graft rejection remains a problem

We reviewed the outcome in 15 consecutive patients with severe aplastic anemia with a median age of 23 years who received matched sibling peripheral blood stem cell transplantation. Conditioning regimen was cyclophosphamide (Cy)+anti-thymocyte globulin (ATG). Cumulative incidence of transplant related mortality, graft failure, acute and chronic GVHD were 20%, 33%, 25%, and 8.3%, respectively. Conditioning with Cy only, resulted in higher rejection rate compared to Cy plus ATG (75% versus 12.5%, p=0.03). Eighty percent of patients are alive with a median follow-up of 19.5 (4.6-35.6) months. Two of the three patients who were re-transplanted with fludarabine had sustained donor chimerism.

Treatment strategies for patients with severe aplastic anemia

Treatment strategies for patients with severe aplastic anemia (SAA), depend on the severity of the disease, the age of the patient and the availability of a family donor. Progress in the past has included the early use of combined immunosuppressive therapy (IST) and better matching strategies to select unrelated donors. Currently, the actuarial 10-year survival in 2479 patients registered within the European Group for Blood and Marrow Transplantation (EBMT), is 73 and 68% for patients receiving first-line BMT or IST. The outcome of BMT has significantly improved since 1996, and this is true for both matched sibling donor BMT as well as for alternative donor BMT. Survival is significantly better in children (<16 years) as compared with adults (79 vs 68%, P<0.0001). In contrast, there has been no significant improvement over time for patients receiving IST. Again, results were significantly better in children compared with adults (81 versus 70%, P=0.001), especially in very severe aplasia (83 versus 62%, P=0.0002). This report outlines some of these results as a basis for treatment strategies in SAA.

Antithymocyte globulin and cyclosporin in children with acquired aplastic anemia

OBJECTIVE

To assess the responses to ATG and cyclosporin combination in patients of aplastic anemia.

METHODS

Twenty three (17M: 6F) patients of aplastic anemia (11 very severe aplastic anemia (VSAA) and 12 severe aplastic anemia (SAA), were administered antithymocyte globulin and cyclosporin.

RESULTS

The median age of patents was 8 years (range 6-12 years). Three patients died within 2 months of therapy. Twenty children (11 SAA and 9 VSAA) were finally analysed. Six months after the start of treatment, 8/20 (40%) patients responded-2 complete (CR) and 6 partial responses (PR). At the end of 1 year; 2 patients maintained CR and seven patients continued PR (overall responders 45%). The response was better in SAA (54.5%) with 2 CR and 4 PR; than in VSAA (33%) with 3 PR . Eleven (55%) children were alive without response. One patient developed AML 13 months later.

CONCLUSION

We conclude that antithymocyte globulin and cyclosporin combination is an effective treatment for aplastic anemia patients who are ineligible for bone marrow transplantation.

Outcome of children with aplastic anemia treated with immunosuppressive therapy

BACKGROUND

Immunosuppressive therapy (IST) is the alternative treatment in children with aplastic anemia (AA) who do not have an HLA-matched sibling. The aim of this study is to evaluate the outcome of children with AA treated with IST.

METHODS

We retrospectively reviewed the hospital records of children with AA from 1984 to 2004, treated at our institution with antithymocyte globulin (ATG), cyclosporine (CS), and short course of prednisone.

RESULT

Forty-two patients were treated with IST (24 boys, 18 girls); of whom 26% received G-CSF. The median age at diagnosis was 8.5 years. Sixty-nine, 19, and 12% were diagnosed with severe, very severe, and moderate AA, respectively. Twenty-one percent had hepatitis-associated AA. Median follow-up time was 53.3 months. Sixty-two percent had complete response; 19% had partial response. Two patients relapsed and received a second course of ATG; both had a partial response. The actuarial 5 years survival rate was 67.5%. Two patients developed myelodysplastic syndrome (MDS); both received long-term G-CSF and had partial response after two courses of IST. Fifteen percent of survivors had significant hypertension which persisted after CS was discontinued.

CONCLUSIONS

This study shows promising response in children with AA treated with IST; however, the outcome was inferior to our institutional results with hematopoietic stem cell transplantation from a sibling donor. Hypertension and MDS are late complications. Longer follow-up, larger cohorts, and prospective studies are warranted to evaluate late complications and risk factors.

Prospective multicenter trial comparing repeated immunosuppressive therapy with stem-cell transplantation from an alternative donor as second-line treatment for children with severe and very severe aplastic anemia

We conducted a prospective multicenter study to compare the efficacy of repeated immunosuppressive therapy (IST) with stem-cell transplantation (SCT) from an alternative donor in children with acquired aplastic anemia (AA) who failed to respond to an initial course of IST. Patients with severe (n = 86) and very severe disease (n = 119) received initial IST consisting of antithymocyte globulin (ATG) and cyclosporine. Sixty patients failed to respond to IST after 6 months from the initial IST and were eligible for second-line treatment. Among them, 21 patients lacking suitable donors received a second course of IST. Three patients developed an anaphylactoid reaction to ATG and could not complete the second IST. A trilineage response was seen in only 2 of 18 (11%) evaluable patients after 6 months. Thirty-one patients received SCT from an alternative donor. At 5 years from the initiation of second-line therapy, the estimated failure-free survival (FFS), defined as survival with response, was 83.9% (+/- 16.1%, SD) in the SCT group compared with 9.5% (+/- 9.0%) in the IST group (P = .001). These results suggest that SCT from an alternative donor offers a better chance of FFS than a second IST in patients not responding to an initial IST.

Recent improvement in outcome of unrelated donor transplantation for aplastic anemia

The aim was to determine whether outcome of unrelated donor transplantation for severe aplastic anemia has improved in recent years and whether this is due to patient selection or better transplant technology. We analyzed 498 patients transplanted during 1990-2005. By running univariate regression models dichotomizing year of transplantation we defined 1998 as the year of the most significant change in survival. Five-year survival increased from 32+/-8% before 1998 to 57+/-8% after 1998 (P<0.0001). When comparing the cohort before (n=149) and after 1998 (n=349), there were no differences except for older age, and more frequent use of PBSCs, after 1998. High-resolution HLA typing data were unavailable. After 1998, there was less graft failure (11 vs 26%, P<0.0001), less acute GvHD (cumulative incidence 28 vs 37%, P=0.02) and less chronic GvHD (22 vs 38%, P=0.004). In multivariate analyses adjusting for differences in age, HLA-mismatch, performance score and time to transplantation, there was no change in the year of transplant effect (relative risk of death in transplants after 1998: 0.44 (95% confidence interval 0.33-0.59)). There is no evidence for patient selection to explain significantly improved survival in patients transplanted after 1998. We speculate that this is due to better donor matching.

Treatment of acquired severe aplastic anemia with antilymphocyte globulin, cyclosporin A, methyprednisolone, and granulocyte colony-stimulating factor

Fifty-six adult patients with newly diagnosed acquired severe aplastic anemia (SAA) received horse antilymphocyte globulin (ALG), cyclosporin A (CyA), methylprednisolone (Mpred), granulocyte colony-stimulating factor (G-CSF) as first-line therapy. The median age was 34 (range, 17-72) and median neutrophil count 0.280 x 10(9)/L. Trilineage hematologic recovery (at a median interval of 105 days from treatment) was seen in 46 patients (37 complete, 9 partial) after one (n = 38) or two (n = 8) courses of ALG. Cytogenetic abnormalities were observed in three unresponders, clonal hematologic disease in three complete responders, and relapse of marrow aplasia in four complete responders. Median follow up for surviving patients was 1,668 days (range, 237-4,012). The actuarial survival at 5 years was 82%, falling to 77.1% at 7 years and was stationary at 7 and 8 years. Survival was not influenced by the neutrophil count (72% vs. 87%, for neutrophils less than vs. greater than 0.2 x 10(9)/L; P = 0.54). Immunosuppressive treatment of SAA with the 4-drug combination appears to be effective. The significant prognostic effect of an enduring increase of the white blood cell (WBC) count during G-CSF treatment may suggest complete and partial response to therapy. In nonresponders, the WBC count either did not change or elevated values gradually returned to nearly their initial levels while the patients were still under G-CSF treatment. In patients not responsive to treatment but living under CyA and G-CSF, the possibility of developing cytogenetic abnormalities does not seem to be low, despite the absence of findings attributable to manifest myelodysplastic syndrome.

Hematopoietic Growth Factors in the Treatment of Acquired Bone Marrow Failure States

In severe aplastic anemia (SAA), the use of hematopoietic growth factors (HGFs) to support blood counts is of limited value, as predicted by in vitro studies and measurement of endogenous serum levels of hematopoietic growth factors (HGF), which are markedly elevated. Benefit is usually only seen in those with less severe disease who are unlikely to require HGFs in practice. HGFs administered alone play no role in the treatment of SAA. The main indication for using HGFs, most often granulocyte colony-stimulating factor (G-CSF), in SAA has been to determine whether they increase the response rate to immunosuppressive therapy (IST) and improve survival. While earlier neutrophil recovery occurs when G-CSF is administered with IST, studies to date show no significant advantage in hematologic response or overall survival. Conflicting results have been reported concerning whether G-CSF increases the known risk of myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML) after IST; follow-up of at least 10 years is required, lacking in many clinical studies reported to date. In MDS, HGFs have been used to counteract the intramedullary apoptosis, which leads to ineffective hematopoiesis. In several uncontrolled and controlled studies, especially in low-risk MDS, high-dose erythropoietin (EPO) or its glycosylated derivative darbepoetin (DPO), alone or in combination with G-CSF, increased hemoglobin levels and diminished the need for red blood cell transfusions, in selected patients with prior transfusion frequency of less than 2 units per month and EPO levels below 500 IU/L. Quality-of-life measures were claimed to have improved, but the cost-effectiveness of this approach is debated, as is safety with regard to the risk of progression. G-CSF is used in supportive care of MDS to improve neutropenia during infectious complications, but to date there is no compelling evidence for a survival benefit or alteration of the course of the disease through the use of HGFs in MDS.

Allogeneic stem cell transplantation for aplastic anemia

Aplastic anemia encompasses a heterogeneous group of diseases with distinct pathophysiologies and a common clinical endpoint of marrow failure. Patients with severe aplastic anemia can be treated with immunosuppressive therapy (IST) or hematopoietic stem cell transplantation (HSCT). Over the last 30 years, advances in both treatment modalities have significantly improved the prognosis for this disease; yet this evolution complicates the central therapeutic question in aplastic anemia: which patients should receive IST and which ones should receive HSCT as front-line therapy? In this review, we describe the major improvements that have occurred in transplantation for aplastic anemia in the last 3 decades. We then outline a framework for deciding which patients should be considered for upfront transplantation.

Worse outcome and more chronic GVHD with peripheral blood progenitor cells than bone marrow in HLA-matched sibling donor transplants for young patients with severe acquired aplastic anemia

We analyzed the outcome of 692 patients with severe aplastic anemia (SAA) receiving transplants from HLA-matched siblings. A total of 134 grafts were peripheral blood progenitor cell (PBPC) grafts, and 558 were bone marrow (BM) grafts. Rates of hematopoietic recovery and grades 2 to 4 chronic graft-versus-host disease (GVHD) were similar after PBPC and BM transplantations regardless of age at transplantation. In patients older than 20 years, chronic GVHD and overall mortality rates were similar after PBPC and BM transplantations. In patients younger than 20 years, rates of chronic GVHD (relative risk [RR] 2.82; P = .002) and overall mortality (RR 2.04; P = .024) were higher after transplantation of PBPCs than after transplantation of BM. In younger patients, the 5-year probabilities of overall survival were 73% and 85% after PBPC and BM transplantations, respectively. Corresponding probabilities for older patients were 52% and 64%. These data indicate that BM grafts are preferred to PBPC grafts in young patients undergoing HLA-matched sibling donor transplantation for SAA.

Fludarabine and cyclophosphamide based reduced intensity conditioning (RIC) regimens reduce rejection and improve outcome in Indian patients undergoing allogeneic stem cell transplantation for severe aplastic anemia

Thirty-five patients (25 men and 10 women) with a median age of 20 years with severe aplastic anaemia (SAA) underwent HLA identical stem cell transplantation (HSCT) using a combination of fludarabine and cyclophosphamide +/- anti-thymocyte globulin between 2004 and 2006. Cyclosporine and mini methotrexate were used as GVHD prophylaxis. Graft source included peripheral blood stem cells (28) or G-CSF stimulated bone marrow (7). Two patients expired < 7 days post-HSCT while 32 (91.5%) patients engrafted with a median neutrophil and platelet engraftment time of 12 days each. Three patients (8.5%) developed veno-occlusive disease while acute GVHD occurred in 29% of evaluable patients, with chronic GVHD in 32%. At a mean follow-up of 22 months, 29 (82.8%) are alive and well. When compared with 26 patients previously transplanted using Cy200/antilymphocyte globulin, there was faster neutrophil engraftment (12 vs 16 days; P = 0.002) with significantly lower rejection rates (2.9 vs 30.7%; P = 0.003) and a superior event-free (82.8 vs 38.4%; P = 0.001) and overall survival (82.8 vs 46.1%; P = 0.005). A combination of fludarabine with cyclophosphamide +/- anti-thymocyte globulin reduces rejection and improves overall and event-free survival in Indian patients undergoing HSCT for severe aplastic anaemia.

Aplastic anemia: pathogenesis and treatment

This review highlights some of the contributions that have appeared in the literature in the past decade on the pathogenesis and treatment of aplastic anemia (AA). This summary is brief because the field is vast, spaning from stem cell biology to stem cell disorders, from autoimmunity to transplantation, from graft-versus-host disease to late effects. The immune pathogenesis of AA is now based on several lines of evidence and will be discussed. Immunosuppressive therapy (IST) remains an important option for AA patients who are not candidates for transplantation. Favorable prognostic indicators for IST are young age and a short interval from diagnosis; the neutrophil count seems to have lost its predictive value with current antithymocyte globulin-cyclsoporin combination therapy. The outcome of allogeneic bone marrow transplantations has significantly improved in the past decade, particularly in the unrelated donor setting, to such an extent that treatment strategies may be affected. A short interval between diagnosis and treatment will also improve results for bone marrow transplantation; these rare patients should be referred to an experienced center immediately.

The influence of cyclosporin alone, or cyclosporin and methotrexate, on the incidence of mixed haematopoietic chimaerism following allogeneic sibling bone marrow transplantation for severe aplastic anaemia

We previously reported a randomized trial comparing Cyclosporin-A (CsA) and short-term methotrexate versus CsA alone for graft-versus-host disease (GvHD) prophylaxis in 71 patients undergoing allogeneic haematopoietic stem cell transplantation (HSCT) from a human leucocyte antigen-identical sibling for severe aplastic anaemia (SAA). We found a better survival in the group receiving the two-drug prophylaxis regimen with no significant difference in the probability of developing GvHD between the two groups. The present study details chimaeric analysis and its influence on survival and GvHD occurrence in 45 of the original 71 patients in whom serial samples were available. Analysis was carried out in a blinded prospective manner. Seventy-two per cent achieved complete donor chimaerism (DC), 11% stable mixed chimaerism (SMC) and 17% progressive mixed chimaerism (PMC). The overall 5-year survival probability was 82% (+/-11%) with a significant survival advantage (P = 0.0009) in DC or SMC compared to those with PMC. Chronic GvHD was more frequent in DC patients, whereas no patient with SMC developed chronic GvHD. Graft failure occurred in 50% of the PMC group. This study demonstrates the relevance of chimaerism analysis in patients receiving HSCT for SAA and confirms the occurrence of mixed chimaerism in a significant proportion of recipients.

Acute myeloid leukemia with severe aplastic anemia following immunosuppressive therapy

Severe aplastic anemia (AA) is a life-threatening condition wherein bone marrow transplantation (BMT) is the therapy of choice in a young patient who has a matched sibling donor. Here, we report an 11-year-old boy with severe AA who was referred for BMT late in its course when he had developed acute myeloid leukemia following two courses of immunosuppressive therapy with antithymocyte globulin and cyclosporin. He was then treated with induction therapy using cytosine arabinoside and daunomycin for acute myeloid leukemia, but he succumbed due to infection and refractory leukemia. We discuss the relevance of early referral for BMT in severe AA.

Current concepts in the pathophysiology and treatment of aplastic anemia

Aplastic anemia, an unusual hematologic disease, is the paradigm of the human bone marrow failure syndromes. Almost universally fatal just a few decades ago, aplastic anemia can now be cured or ameliorated by stem-cell transplantation or immunosuppressive drug therapy. The pathophysiology is immune mediated in most cases, with activated type 1 cytotoxic T cells implicated. The molecular basis of the aberrant immune response and deficiencies in hematopoietic cells is now being defined genetically; examples are telomere repair gene mutations in the target cells and dysregulated T-cell activation pathways. Immunosuppression with antithymocyte globulins and cyclosporine is effective at restoring blood-cell production in the majority of patients, but relapse and especially evolution of clonal hematologic diseases remain problematic. Allogeneic stem-cell transplant from histocompatible sibling donors is curative in the great majority of young patients with severe aplastic anemia; the major challenges are extending the benefits of transplantation to patients who are older or who lack family donors. Recent results with alternative sources of stem cells and a variety of conditioning regimens to achieve their engraftment have been promising, with survival in small pediatric case series rivaling conventional transplantation results.

Bone marrow transplants from mismatched related and unrelated donors for severe aplastic anemia

For patients with acquired severe aplastic anemia without a matched sibling donor and not responding to immunosuppressive treatment, bone marrow transplantation from a suitable alternative donor is often attempted. We examined risks of graft failure, graft-versus-host disease and overall survival after 318 alternative donor transplants between 1988 and 1998. Sixty-six patients received allografts from 1-antigen and 20 from >1-antigen mismatched related donors; 181 from matched and 51 from mismatched unrelated donors. Most patients were young, had had multiple red blood cell transfusions and poor performance score at transplantation. We did not observe differences in risks of graft failure and overall mortality by donor type. The probabilities of graft failure at 100 days after 1-antigen mismatched related donor, >1-antigen mismatched related donor, matched unrelated donor and mismatched unrelated donor transplants were 21, 25, 15 and 18%, respectively. Corresponding probabilities of overall survival at 5 years were 49, 30, 39 and 36%, respectively. Although alternative donor transplantation results in long-term survival, mortality rates are high. Poor performance score and older age adversely affect outcomes after transplantation. Therefore, early referral for transplantation should be encouraged for patients who fail immunosuppressive therapy and have a suitable alternative donor.

Fludarabine, cyclophosphamide and anti-thymocyte globulin for alternative donor transplants in acquired severe aplastic anemia: a report from the EBMT-SAA Working Party

We have developed a reduced-intensity conditioning regimen for patients with severe aplastic anemia (SAA) undergoing alternative donor transplants, which includes fludarabine (120 mg/m(2)), cyclophosphamide (1,200 mg/m(2)) and antithymocyte globulin (7.5 mg/kg). Graft-versus-host disease (GvHD) prophylaxis consisted of cyclosporine and methotrexate. We have enrolled 38 SAA patients in this trial: median age of 14 (3-37) years, transplanted from unrelated (n=33) or family mismatched (n=5) donors, with unmanipulated marrow (n=36) or peripheral blood (n=2). Seven patients (18%) had evidence of graft failure, 11% developed grade II-III acute GvHD and 27% developed chronic GvHD. The actuarial 2-year survival is 73%, with a median follow-up of 621 days. Younger patients (<or=14 years) had a lower risk of rejection (5%) and improved actuarial survival (84%). Causes of death were infections (n=3), graft failure (n=2), Epstein-Barr virus lymphoma (n=2) and hemorrhage (n=2). In conclusion, the actuarial 2-year survival is encouraging in young SAA patients receiving a radiation-free conditioning regimen. The significant risk of graft failure in patients 15 years or older may require modification of the conditioning regimen in adults.

Low dose antithymocyte globulin for the treatment of older patients with aplastic anaemia

We report 14 older patients with aplastic anaemia (AA) who were treated with 'low dose' antithymocyte globulin (ATG). The aims of the study were to assess the efficacy and safety of reduced dose ATG in patients over the age of 60 years. Median age was 71 years (range 62-74 years). At the study endpoint (response to treatment at 6 months) 12 patients were evaluable. All patients received lymphoglobuline (horse ATG; Genzyme) at a dose of 0.5vials/10kg/day for 5 days (5mg/kg/day, equivalent to one-third of the standard dose). There were no deaths attributed to ATG. Two patients died during follow-up, from sepsis and anaphylaxis following platelet transfusion, respectively. Only one of the 12 evaluable patients responded to treatment and remains transfusion independent at 14 months after ATG. These results suggest that this lower dose of ATG, though well tolerated, had low efficacy in the treatment of AA.

Allografting in patients with severe, refractory aplastic anemia using peripheral blood stem cells and a fludarabine-based conditioning regimen: the Mexican experience

We studied the effectiveness of a fludarabine/cyclophosphamide-based conditioning regimen without anti-thymocyte globulin in 23 aplastic anemia patients who had no response to previous conventional pharmacologic treatment. Patients received oral busulphan 4 mg/kg/day/2 days, IV cyclophosphamide 350 mg/m(2)/day/3 days, and fludarabine 30 mg/m(2)/day/3 days. For GVHD prophylaxis, patients received MTX 5 mg/m(2) days +1, +3, +6, and +11 and oral cyclosporin A (CyA) 5 mg/kg/day, starting on day -1. Peripheral blood stem cell products were used with a median dose of 5.5 x 10(6) CD34(+)/kg. The patients were followed for an average of 25 months. By a median of day +11, an ANC > 0.5 x 10(9)/L was reached; and by day +12, the platelet count had reached >20,000 x 10(9)/L. Acute grade I-II GVHD occurred in 4 patients, whereas limited chronic GVHD presented in 6 cases. Twenty-one patients (91.3%) achieved engraftment. Two patients failed to engraft, and 4 developed late rejection; 2 of these individuals died, 2 have survived with high transfusion requirements, whereas 2 received a second peripheral blood stem cell infusion and achieved sustained engraftment. Currently 21 (91%) of the 23 patients are alive, whereas 19 of 21 (90%) remain in complete remission. The average cost was about USD 15,000 for this kind of reduced-intensity allotransplant. Reduced-intensity stem cell transplantation represents an affordable alternative to traditional more cytotoxic conditioning for severe aplastic anemia (SAA) patients. Long-term effects however, remain to be evaluated.

Alemtuzumab, fludarabine and melphalan as a conditioning therapy in severe aplastic anemia and hypoplastic myelodysplastic syndrome--single center experience

BACKGROUND

Allogeneic hematopoietic stem cell transplantation is the treatment of choice in young patients with severe aplastic anemia. The main causes of failure after this procedure are graft versus host disease, infections and graft failure, often exacerbated by large numbers of transfusions and prolonged disease duration before transplant.

METHODS

We report the results of allografting following conditioning with fludarabine, alemtuzumab and melphalan in: five patients with severe aplastic anemia and one with hypoplastic myelodysplastic syndrome. All patients had matched sibling donors. Source of hematopoietic stem cell was: bone marrow-2, blood-3, bone marrow and blood-1. The age of recipients was 18-26 years. Four patients received their graft as the first line therapy and two after failure of cyclosporine and antithymocyte globulin treatment. Number of transfused units including red blood cells and platelets before transplantation was 8-100 (median: 22) and 10-32 (median: 11), respectively. All donors and recipients were CMV-seropositive. Conditioning consisted of: alemtuzumab 30 mg/d (day -7 to -5), fludarabine 30 mg/m(2) (days -7 to -3) and melphalan 140 mg/m(2) at the day -2.

RESULTS

The time to granulocytes and platelets recovery was 15 and 25 days, respectively. All patients achieved full donor chimerism on day +60. Only two patients needed ganciclovir as preemptive therapy. Recurrent parvovirus B19 infection with pure red cell aplasia and acute viral B hepatitis was observed in one case. Pure red cell aplasia was successfully treated with immunoglobulins and cyclosporine discontinuation. With a follow-up of 16-39 (median: 29) months all patients are alive, and neither graft failure nor graft versus host disease, or any no other severe complications, was observed.

CONCLUSIONS

Our study suggests that transplantation of hematopoietic stem cell using alemtuzumab, fludarabine and melphalan as a conditioning therapy is safe, inexpensive and effective treatment for patients with severe aplastic anemia, including multi-transfused adults having their disease for a long time.

Making therapeutic decisions in adults with aplastic anemia

The management of adults presenting with aplastic anemia (AA) requires careful exclusion of other causes of bone marrow failure. Late-onset inherited forms of AA may present in adulthood with subclinical disease. Recent long-term studies of HLA identical sibling donor BMT show excellent survival for patients under the age of 40 years, but chronic graft-versus-host disease (GVHD) is still a major problem, impacting on quality of life. Recent improvements in outcome after matched unrelated donor BMT may reflect better donor matching and use of reduced intensity conditioning regimens. For patients treated with immunosuppressive therapy (IST), antithymocyte globulin (ATG) and cyclosporin (CSA) remain the standard regimen with excellent overall survival but less impressive failure-free survival due to nonresponse, relapse and later clonal disorders. The benefit of adding granulocyte colony-stimulating factor (G-CSF) to ATG and CSA is unclear and being assessed in a further prospective European study. Patients who are refractory to conventional IST and currently ineligible for BMT represent difficult management problems. For these patients, new approaches to transplantation are being evaluated, such as fludarabine-based conditioning regimens and the potential use of double umbilical cord blood transplants, but there is a need for new immunosuppressive agents. Improved supportive care is likely to be a major factor in improved outcome of all AA patients whether treated with IST or BMT. Robust predictive factors for response to IST are needed to help in decision making at diagnosis and to help justify exploring novel approaches to therapy.

Outcome of bone marrow transplantation in acquired and inherited aplastic anaemia in the Republic of Ireland

BACKGROUND

Severe Aplastic Anaemia (SAA) and Fanconi Anaemia (FA) are rare haematological disorders characterised by pancytopenia and bone marrow hypoplasia.

AIMS

We performed a retrospective study of all patients who underwent BMT for SAA and FA at St James's Hospital, Dublin, and at OLHSC, Crumlin, between 1985 and 2002.

METHODS

The medical records of 63 patients, 50 with acquired SAA and 13 with FA, were reviewed.

RESULTS

The median age at the time of transplant was 14 years (range 3-43 years). The actuarial survival (OS) (n = 63) was 76% at 17 years. The transplant related mortality (TRM) was 22% (n = 14). The most common cause of death was infection (46%). The survival was significantly better in patients receiving their transplant after 1995 (p = 0.002). Outcome was superior in those receiving less than 20 red cell transfusions prior to transplant: OS 91% (< 20 Units) versus 62% (> or = 20 Units).

CONCLUSIONS

These national results are comparable to those of published international series and support the use of BMT in the treatment of SAA and FA. The known adverse effect of prior transfusion was confirmed.

Haematopoietic stem cell transplantation to treat aplastic anaemia

Aplastic anaemia (AA) consists of pancytopenia and empty bone marrow. Its incidence varies worldwide but predominates in developing countries. Diverse aetiologies are involved, with autoimmunity at the centre of the picture. For the 70% of patients with the severe and very severe forms of AA and who lack a human leukocyte antigen (HLA)-matched sibling, immunosuppressive therapy (IST) is key in treating the disease, with a remission rate close to 70%, an 80-90% 5-year survival rate in responding patients and a relapse rate close to 10%. For the 30% with a sibling donor available, haematopoietic stem cell transplant (HSCT) from bone marrow or peripheral blood has up to a 90% chance of cure, with a 5-10% graft rejection/failure rate. Patients who fail IST (25-30%) and lack a sibling donor can benefit from CD34(+)-enriched, partially T cell-depleted unrelated stem cell transplants, with a general survival rate up to 37%, the newest source of stem cells for this modality being cord blood. Non-myeloablative, irradiation-free conditioning regimens offer appreciable benefits, and new immunosuppressive agents, such as fludarabine and alemtuzumab, have been incorporated with promising preliminary results. Graft-versus-host disease, graft failure and infections remain significant challenges in HSCT for which innovative treatment strategies are being developed at present.

Diagnosis and treatment of children with aplastic anemia

BACKGROUND

Long-term survival rates among children diagnosed with severe aplastic anemia (SAA) are excellent due to the success of human leukocyte antigen (HLA)-identical related hematopoietic stem cell transplantation (HSCT), concurrent advances in immunosuppressive treatment (IST), and improved supportive care. The challenge in making treatment recommendations for children with SAA, therefore, is to balance the apparent chronicity and morbidity following IST, with the potential up-front toxicity and complications of HSCT.

METHODS

This review provides an update on the diagnosis and a risk-based treatment algorithm for children with acquired SAA. Recent experience using alternative donor HSCT and efforts to extend HSCT eligibility through advances in donor matching, de-escalation of conditioning regimens, and potential marrow graft engineering are highlighted. We discuss IST response rates, risks of relapse, and complications including clonal evolution.

CONCLUSIONS

While good treatment options exist for a majority of children diagnosed with SAA, novel non-transplantation treatments for unresponsive and relapsed patients without suitable transplant donors are needed. Further improvements in outcome will ultimately require a more complete understanding of the pathophysiology of aplastic anemia (AA).

The polymorphisms -318C>T in the promoter and 49A>G in exon 1 of CTLA4 and the risk of aplastic anemia in a Caucasian population

Aplastic anemia (AA) is a rare disease with a major autoimmune pathogenetic component. CTLA4 is a T-lymphocyte surface molecule involved in the maintenance of immune tolerance. Some polymorphisms associated with a reduced expression of CTLA4, and thus presumably with increased tendency to autoimmunity, have been associated with various autoimmune diseases. In this study, we evaluated the distribution of the low expression polymorphisms -318C > T and 49A > G of CTLA4 in a population of 67 patients with acquired AA and in 100 normal controls. There was no difference in the distribution of the tested polymorphism between patients and controls and, within the patient group, between those who responded to immunosuppression vs those who did not respond. This study indicates that the polymorphisms -318C > T and 49A > G of CTLA4 do not affect the risk of developing AA and do not influence the response to immunosuppression.

Management of acquired aplastic anaemia

Outcome of patients with aplastic anaemia (AA), whether treated with allogeneic BMT or immunosuppressive therapy has steadily increased over the last three decades. However, there is a difference in quality of outcome between these two therapeutic modalities. There is no plateau for survival after ATG as patients are at later risk of transformation to myelodysplasia (MDS) or acute myeloid leukaemia (AML), paroxysmal nocturnal haemoglobinuria and relapse of their aplasia. In contrast, AA patients are not at risk of these later complications if they have undergone successful bone marrow transplantation. Long term survival after HLA identical sibling BMT is 80-90%, but GVHD and graft rejection remain to be addressed. The results of unrelated donor BMT for AA have shown considerable improvement over the last five years. Difficulties remain for those patients who fail immunosuppressive therapy and in whom BMT is not possible, since alternative immunosuppressive agents have so far proven to be somewhat disappointing.

Flow cytometric evaluation of circulating CD34 + cell counts and apoptotic rate in children with acquired aplastic anemia and myelodysplasia

OBJECTIVE

Identification of a rapid and noninvasive test for the follow-up of aplastic anemia (AA) patients during immunosuppressive therapy (IST) to evaluate its functional effect on hematopoietic progenitors (HPC) and for early detection of progression to myelodysplasia or relapse.

MATERIALS AND METHODS

Absolute count and apoptotic rate (AR) of peripheral blood (PB) CD34+ cells were evaluated by three-color flow cytometry for CD45, CD34, and annexin V in cord blood (CB), normal children, and adults, as well as in pediatric patients with AA at diagnosis and during IST, Fanconi anemia (FA), chronic immune cytopenia, and refractory anemia with excess blasts (RAEB).

RESULTS

In normal subjects, the AR of PB CD34+ cells showed a progressive increase (p < 0.05), while their counts decreased (p < 0.05) from birth to adulthood. In very severe AA (vSAA) and severe AA (SAA) at diagnosis, the AR was 91.6% +/- 2.8%, higher than controls (p < 0.05), and PB CD34+ cell count was 2.6 +/- 2.4/microL. In FA patients, the PB CD34+ AR was again significantly increased (54.2% +/- 13.7%) with an absolute count of 3.7 +/- 1.2/microL. Conversely, in RAEB the AR was 11.7% +/- 3.5% and the absolute count 85.1 +/- 48.2/microL (p < 0.05). Chronic immune cytopenias did not significantly differ from controls.

CONCLUSIONS

Flow cytometry evaluation of PB CD34+ AR and counts is a noninvasive and feasible first-step method for the differentiation of AA and myelodysplasia (MDS), and it might be useful for monitoring AA during IST to secure the early detection of relapse or transformation to MDS.

Successful non-T-cell-depleted nonmyeloablative hematopoietic stem cell transplantation (NST) from an HLA-haploidentical 2-loci-mismatched sibling in a heavily transfused patient with severe aplastic anemia based on the fetomaternal microchimerism

A 37-year-old Japanese man with systemic hemochromatosis due to multiple transfusions was referred to us for the treatment of severe aplastic anemia (SAA), from which he had been suffering for 24 years. The patient had diabetes arising from the hemochromatosis, chronic anal fissures, and a kidney abscess due to neutropenia. He was treated with a nonmyeloablative preconditioning regimen followed by non-T-cell-depleted (non-TCD) allogeneic peripheral blood stem cell transplantation (PBSCT) from his human leukocyte antigen (HLA)-haploidentical 2-loci-mismatched sibling. Prompt engraftment of granulocytes and platelets was observed, and graft-versus-host disease was easy to control. Noninherited maternal antigens in the donor were confirmed prior to PBSCT, and they were also detected in small quantities in the recipient. This report describes the first successful nonmyeloablative hematopoietic stem cell transplant in a heavily transfused SAA patient from an HLA-haploidentical 2-loci-mismatched sibling donor. The result suggests that a long-term fetomaternal microchimerism-positive sibling can be a second-line donor if an alternative HLA-identical donor is not available.

Aplastic Anemia: Management of Adult Patients

The primary therapeutic approach to acquired aplastic anemia (AA) in older adults differs from the primary approach used in children and younger adults because in the former group, the results of allogeneic bone marrow transplantation (BMT) are less favorable. With increasing age of the patients, immunosuppressive therapy with antithymocyte globulin (ATG) and cyclosporine (CsA) constitutes the primary treatment option and may be better than BMT. There are very few clinical clues as to the selection of patients likely to respond to immunosuppression. Repeated ATG/CsA cycles are often used as salvage regimens, but in refractory patients BMT may be the best treatment option, as the prognosis for non-responders is poor without definitive treatment. Conservative therapy such as intense immunosuppression is associated with a high relapse rate but does not impact the survival and overall prognosis. The inability to eliminate autoimmune T cell clones using current therapeutic strategies suggests that prolonged immunosuppressive maintenance therapy may be needed for a substantial proportion of patients. Late clonal complications of conservatively treated patients include evolution to myelodysplasia and paroxysmal nocturnal hemoglobinuria and may develop in 20% of the patients. However, BMT also has several sequelae including an increased frequency of solid tumors. Novel immunosuppressive and immunomodulatory agents and constantly improving results of allogeneic BMT will further improve the survival rate of adult patients with AA.

Favorable effect on acute and chronic graft-versus-host disease with cyclophosphamide and in vivo anti-CD52 monoclonal antibodies for marrow transplantation from HLA-identical sibling donors for acquired aplastic anemia

Between August 1989 and November 2003, 33 patients at our center with acquired aplastic anemia underwent bone marrow transplantation (BMT) from HLA-identical sibling donors with cyclophosphamide and in vivo anti-CD52 monoclonal antibodies (MoAb) for conditioning. The median age at BMT was 17 years (range, 4-46 years). Before BMT, 58% were heavily transfused (>50 transfusions), and 42% had previously experienced treatment failure with antithymocyte globulin-based immunosuppressive therapy. Unmanipulated bone marrow was used as the source of stem cells in all patients except 1. Graft-versus-host disease (GVHD) prophylaxis was with cyclosporine alone in 19 (58%) patients; 14 received anti-CD52 MoAb in addition to cyclosporine. The conditioning regimen was well tolerated without significant acute toxicity. Graft failure was seen in 8 patients (primary, n = 4; secondary, n = 4). Of those whose grafts failed, 4 survived long-term (complete autologous recovery, n = 2; rescue with previously stored marrow, n = 1; second allograft, n = 1). The cumulative incidence of graft failure and grade II to IV acute and chronic GVHD was 24%, 14%, and 4%, respectively. None developed extensive chronic GVHD. With a median follow-up of 59 months, the 5-year survival was 81% (95% confidence interval, 68%-96%). No unexpected early or late infectious or noninfectious complications were observed. We conclude that the conditioning regimen containing cyclophosphamide and anti-CD52 MoAb is well tolerated and effective for acquired aplastic anemia with HLA-matched sibling donors. The favorable effect on the incidence and severity of GVHD is noteworthy in this study and warrants further investigation.

Management of patients receiving antithymocyte globulin for aplastic anemia and myelodysplastic syndrome

Antithymocyte globulin (ATG) is used commonly in patients with severe aplastic anemia and those undergoing renal transplant. Its utility also is being explored in the treatment of myelodysplastic syndrome, conditioning regimens for hematopoietic stem cell transplant, and prophylaxis of graft-versus-host disease. As indications for ATG expand, knowledge regarding its administration and management of associated toxicities is needed. These toxicities range from life-threatening anaphylaxis associated with the infusion to flu-like symptoms that occur one to two weeks after the infusion. Adverse effects are classified according to the severity and system impacted. Mild toxicities respond to comfort measures and include fever, chills, urticarial rash, and vomiting. Moderate toxicities require acute interventions and include fluid-responsive hypotension, nonischemic chest pain, and reversible oxygen desaturation. Severe toxicities require intensive support and include those refractory to earlier intervention. Management of these toxicities usually is limited to fluid resuscitation and noninvasive monitoring. Occurrence of infusion-related toxicities may require premature discontinuation of therapy. Therefore, an educated healthcare team and interdisciplinary clinical management guidelines are important to ensure the safe administration and complete course of ATG.

Clinical relevance of serial quantitative analysis of hematopoietic chimerism after allogeneic stem cell transplantation in children for severe aplastic anemia

Allogeneic stem cell transplantation (allo-SCT) is a well-established treatment modality for children with severe aplastic anemia (SAA). Treatment failures are rare and mostly caused by graft rejection. Increasing mixed chimerism represents a stage at the very beginning of graft rejection, where immunological intervention might be an effective prophylactic approach. To substantiate this, we: (1) monitored peripheral blood cells from children with SAA after allo-SCT and performed pre-emptive immunotherapy in patients with increasing MC. In all, 23/34 courses of 32 children with SAA after allo-SCT showed a complete chimerism (CC) throughout and 10/34 developed different types of mixed chimerism (MC). Altogether, 4/10 with MC spontaneously developed decreasing MC, 2/10 courses persisted with low proportions of autologous cells below 30% (stable-MC), 4/10 developed increasing MC and one patient showed an autologous recovery. All patients with CC, decreasing MC or stable MC remained in continuous complete remission (CCR). In all, 2/4 patients with increasing MC developed graft rejection. Based on these observations, 2/4 new patients with increasing MC received low-dose DLIs prophylactically, and remained in CCR without any GVHD. These results substantiate that low-dose DLI in children with SAA and increasing MC can prevent graft rejection with a calculable risk to induce severe GVHD.

Long-term outcome after bone marrow transplantation for severe aplastic anemia

From January 1978 to December 2001, 133 patients with severe aplastic anemia (SAA) underwent non-T cell-depleted allogeneic bone marrow transplantation from an HLA-identical sibling donor, at the Hospital Saint Louis using either the combination of cyclophosphamide (Cy) and thoracoabdominal irradiation (TAI; n = 100) or Cy and antithymocyte globulin (ATG; n = 33), as a conditioning regimen. With 13.6 years of follow-up, the 10-year survival estimate was 64%. Four factors were associated with lower survival: older age, use of Cy-TAI, any form of treatment prior to transplantation (either androgens or immunosuppressive therapy, [IST]), and grade II to IV acute graft-versus-host disease (GvHD). TAI was the sole factor associated with the occurrence of acute GvHD. The risk of cancers (15-year cumulative incidence, 10.9%) was associated with older age and with the use of cyclosporine as IST before transplantation. Cumulative incidences and risk factors of nonmalignant late effect including avascular osteonecrosis and late bacterial, viral, and fungal infection were also analyzed. Improved results using Cy-ATG as conditioning can lead to more than 90% chance of cure in patients with SAA. Even if, in our experience, the role of Cy-ATG versus that of Cy-TAI remained inextricably related to the year of transplantation, the major detrimental role of the GvHD disease in the long-term outcome and its relation to TAI supports avoidance of irradiation in the conditioning regimen. Furthermore, avoidance of any IST before transplantation in patients with a sibling donor is a prerequisite for attaining such excellent results.

Drug-induced myelosuppression : diagnosis and management

Myelosuppression is a common and anticipated adverse effect of cytotoxic chemotherapy. It is a potential but rare idiosyncratic effect with any other drug, but there is a recognised association with a number of higher-risk agents which justify additional vigilance. Genetic risk factors are being identified which may predispose individuals to this reaction with particular drugs. As marker tests become available, dose adjustment or alternative treatment choices may help to avoid more severe reactions. Myelosuppression is potentially life threatening because of the infection and bleeding complications of neutropenia and thrombocytopenia. Strategies for monitoring, early detection, diagnostic confirmation and appropriate supportive care are well developed for cytotoxic therapy. Developments in antimicrobial chemotherapy, blood product transfusion support and growth factor therapy have improved outcomes. These advances are largely applicable to idiosyncratic drug-induced myelosuppression, reinforcing the importance of early recognition and referral to appropriate expertise. Many reactions will resolve on drug withdrawal with appropriate supportive care during the period of cytopenia. Prolonged marrow failure may require more specific treatment with intensive immunosuppression or consideration of bone marrow transplantation.

Addition of low-dose busulfan to cyclophosphamide in aplastic anemia patients prior to allogeneic bone marrow transplantation to reduce rejection

Busulfan was added at the dose of 4 mg/kg to 200 mg/kg cyclophosphamide in 81 patients (3-53 years, median 24) with aplastic anemia to reduce graft rejection. Graft-versus-host disease (GVHD) prophylaxis comprised cyclosporine-methotrexate. The number of prior transfusions was 0-276 (median 26), and 48% had received prior immunosuppressive therapy. Two patients experienced primary graft failure, and 10 secondary rejection at 28-1001 days (median 317 days). The cumulative incidence of rejection was 22%; for heavily transfused patients (>/=50 U) it was 43% compared to 16% for the rest (P=0.06). Overall survival rate at 8 years was 56%; patients who received </=15 and >15 transfusions was 78 and 50%, respectively (P=0.01), whereas it was 67 and 28% for </=50 and >50 transfusions, respectively (P=0.002). In multivariate analysis, higher number of prior transfusions, shorter period of immunosuppression with cyclosporine and GVHD were associated with inferior survival; moreover, a higher risk of graft rejection were associated with a higher number of prior transfusions and a trend was observed for a shorter cyclosporine administration. Low-dose busulfan is feasible and may be helpful in patients exposed to <50 transfusions. However, rejection remains a significant problem, mainly in heavily transfused patients.

Hematopoietic stem cell transplantation for severe aplastic anemia--experience of an institute in Taiwan

Hematopoietic stem cell transplantation (HSCT) is an accepted treatment strategy for patients with severe aplastic anemia (SAA). We report our experience in a general hospital in Taiwan. From March 1985 to July 2001, 79 consecutive SAA patients, 46 male and 33 female, with a median age of 22 (4–43) years, received 80 courses of transplantation. Cyclophosphamide and total body radiation were used for the conditioning regimen, and cyclosporine-A and methotrexate for graft-versus-host disease (GVHD) prevention. Patients were followed for a median of 39 months (from 8 days to 194 months). Myeloid and platelet engraftment occurred in a median of 15 (8–27) days and 18 (8–77) days, respectively. Three patients had primary and three patients secondary graft failure. Five patients (6.8%) had grade II–IV acute GVHD in 73 evaluable patients. Chronic GVHD occurred in 23 (34.8%) patients, with extensive stage in six. Only two patients had CMV disease. The projected 3- and 5-year overall survival rates estimated by the Kaplan-Meier method were 76.08 and 74.13%, respectively. Age at transplant, non-sibling donor, mononuclear cell dose, grade II–IV acute GVHD, interval from diagnosis to transplant, and red blood cell and platelet transfusion before transplant were poor prognostic factors for overall survival by univariate analysis. Grade II–IV acute GVHD was the only prognostic factor affecting overall survival after multivariate Cox regression analysis (P=0.040). In conclusion, SAA patients receiving HSCT have good long-term survival. The low incidence of acute GVHD in our patients may be related to ethnicity.