Making therapeutic decisions in adults with aplastic anemia

Hematopoietic Stem-Cell Transplantation versus Immunosuppressive Therapy in Patients with Adult Acquired Severe Aplastic Anemia: A Cost-Effectiveness Analysis

Objective

Controversy remains regarding which therapy to initially select for severe aplastic anemia (SAA) patients aged 35–50. This cost-effectiveness analysis aimed to use the Markov model to compare immunosuppressive therapy (IST) with hematopoietic stem-cell transplantation (HSCT) in age-stratified patients with SAA.

Methods

A cost-effectiveness analysis using a Markov model compared IST with HSCT in age-stratified patients with SAA. Baseline data were derived from a systematic literature review and collected from Huashan Hospital, Fudan University. The primary outcome was an incremental cost-effectiveness ratio (ICER).

Results

The HSCT strategy dominated in patients aged 18–35 even though it was $146,970 more expensive than IST, and the ICER of HSCT to IST was $14,054.19/quality-adjusted life-year (QALY), which was less than the willingness-to-pay value of $25,397.57/QALY. The IST strategy dominated in patients aged 35–50, because it was $72,009 less expensive than HSCT and yielded 3.24 QALYs more than HSCT. The model was vigorous in the sensitivity analyses of the key variables tested through the plausible ranges that were acquired from costing sources and previously published literature.

Conclusion

The preferred induction strategy for patients aged 18–35 with SAA appears to be HSCT, and the preferred strategy for patients aged 35–50 is IST, which minimizes costs while maximizing QALYs.

Idiopathic Aplastic Anemia in Children and Adults: Diagnosis, Treatments, and Management - A Review

Aplastic Anemia (AA) is also known as idiopathic aplastic anemia (IAA) and the production of new blood cells ceases in AA, which leads to an abnormal hematological syndrome such as pancytopenia and suppression of hypo-cellular bone marrow. The pathophysiology of AA in most cases is immune-mediated and is stimulated by type 1 cytotoxic T cells. Reliable early diagnostic tests of IAA are not yet available, therefore most of the cases are identified in advanced stages. Recently, abnormal immune response and hematopoietic cell deficiencies are defined genetically, such as in target cells of telomere repair gene mutations and by the dysregulation of T-cell activation pathways. Importantly, anti-thymocyte globulins and cyclosporine-associated immunosuppression are successful treatments for restoring blood cell production in most of the cases, however, clonal hematologic diseases remain challenging. In the current review, we have discussed the common practices in the treatment, pathophysiology, diagnosis, and management of AA.

Unexpected unrelated umbilical cord blood stem cell engraft in two patients with severe aplastic anemia that received immunosuppressive treatment: A case report and literature review

Severe aplastic anemia (SAA) is a life-threatening bone marrow disorder. Bone marrow transplantation is the primary therapy for SAA; however, its efficacy is limited by numerous factors, including lack of histocompatible sibling donor, patient age and graft-versus-host-disease (GVHD) following transplantation. Immunosuppressive treatment (IST) is the first procedure developed for patients without a sibling donor. Our previous study reported that patients administered enhanced IST, in addition to a regime of unrelated umbilical cord blood (UCB) transfusion, exhibited higher efficiency and a reduced rate of relapse. Therefore, the present study reported the cases of 2 patients that received enhanced IST plus unrelated UCB transfusion. These patients exhibited complete hematological recovery with an increased rate of mixed chimerism and demonstrated no signs of GVHD or relapse during the 2-year follow-up period. Thus, enhanced immunosuppressive treatment (low-dose cyclophosphamide and antithymocyte globulin) combined with UCB transfusion may be an effective treatment for patients with SAA.

Allogeneic hematopoietic stem cell transplantation as the first-line treatment option in a patient with severe aplastic anemia without a matched related donor: A case report

The outcomes of matched unrelated donor (MUD) hematopoietic stem cell transplantation (HSCT) and immunosuppressive therapy (IST) in patients with severe aplastic anemia (SAA) remain controversial. The clinical outcome in patients that undergo transplantation following failed IST is typically poorer when compared with patients that initially underwent transplantation. Clinical treatment algorithms have been proposed to determine the management of such patients, and account for individual conditions, personal preferences and prognostic risk factors. The present study reports the promising outcome of a 22-year-old patient exhibiting SAA. The patient underwent peripheral blood stem cell transplantation (PBSCT) from an MUD using a fludarabine-based conditioning regimen and low-dose total body irradiation as an alternative method to first-line IST. The patient achieved rapid bone marrow reconstitution and has been in complete remission for 32 months. The aim of the fludarabine-based conditioning regimen with PBSCT was to improve the patient’s therapeutic outcome and provide a convenient treatment strategy. Furthermore, this regimen extends the application of HSCT to patients who are older or those that are without a matched related donor.

Alternative immunosuppression in patients failing immunosuppression with ATG who are not transplant candidates: Campath (Alemtuzumab)

Antithymocyte globulin (ATG)-based immunosuppression remains the standard immunosuppressive therapy (IST) for aplastic anemia (AA) patients lacking a sibling donor; however, treatment failures are relatively frequent, including about one-quarter to one-third of patients who do not show any response to initial IST, and about half of the initial responders who may experience subsequent relapses or require continuous maintenance IST. For these patients, there is the option of further IST, which may include additional courses of ATG-based IST, or attempts with alternative IST regimens. Alemtuzumab is a monoclonal anti-CD52 Ab, which has been recently investigated as novel IS agent for the treatment of AA patients. Recent data from different groups have clearly demonstrated the biological efficacy of Alemtuzumab in AA patients, ruling out the initial concerns about possible unacceptable infectious risks secondary to its extremely powerful lympholytic effect. Preliminary data demonstrate a remarkable efficacy, especially in the context of relapsed and, to less extent, refractory patients, whereas data in naïve patients are still limited. On the basis of these results, Alemtuzumab-based immunosuppression is a worthy option for AA and other marrow failure patients requiring a second-line IST. Here we describe a consensus regimen that the European Group for Blood and Marrow Transplantation Severe Aplastic Anemia Working Party suggests for AA patients failing initial IST who are not indicated for SCT.

Aplastic anemia: immunosuppressive therapy in 2010

Acquired aplastic anemia (AA) is the typical bone marrow failure syndrome characterized by an empty bone marrow; an immune-mediated pathophysiology has been demonstrated by experimental works as well as by clinical observations. Immunusuppressive therapy (IST) is a key treatment strategy for aplastic anemia; since 20 years the standard IST for AA patients has been anti-thymocyte globuline (ATG) plus cyclosporine A (CyA), which results in response rates ranging between 50% and 70%, and even higher overall survival. However, primary and secondary failures after IST remain frequent, and to date all attempts aiming to overcome this problem have been unfruitful. Here we review the state of the art of IST for AA in 2010, focusing on possible strategies to improve current treatments. We also discuss very recent data which question the equality of different ATG preparations, leading to a possible reconsideration of the current standards of care for AA patients.

A randomized controlled study in patients with newly diagnosed severe aplastic anemia receiving antithymocyte globulin (ATG), cyclosporine, with or without G-CSF: a study of the SAA Working Party of the European Group for Blood and Marrow Transplantation

We evaluated the role of granulocyte colony-stimulating factor (G-CSF) in patients with severe aplastic anemia (SAA) treated with antithymocyte globulin (ATG) and cyclosporine (CSA). Between January 2002 and July 2008, 192 patients with newly diagnosed SAA not eligible for transplantation were entered into this multicenter, randomized study to receive ATG/CSA with or without G-CSF. Overall survival (OS) at 6 years was 76% ± 4%, and event-free survival (EFS) was 42% ± 4%. No difference in OS/EFS was seen between patients randomly assigned to receive or not to receive G-CSF, neither for the entire cohort nor in subgroups stratified by age and disease severity. Patients treated with G-CSF had fewer infectious episodes (24%) and hospitalization days (82%) compared with patients without G-CSF (36%; P = .006; 87%; P = .0003). In a post hoc analysis of patients receiving G-CSF, the lack of a neutrophil response by day 30 was associated with significantly lower response rate (56% vs 81%; P = .048) and survival (65% vs 87%; P = .031). G-CSF added to standard ATG and CSA reduces the rate of early infectious episodes and days of hospitalization in very SAA patients and might allow early identification of nonresponders but has no effect on OS, EFS, remission, relapse rates, and mortality. This study was registered at www.clinicaltrials.gov as NCT01163942.

First-line matched related donor hematopoietic stem cell transplantation compared to immunosuppressive therapy in acquired severe aplastic anemia

Introduction

Acquired severe aplastic anemia (SAA) is a rare and progressive disease characterized by an immune-mediated functional impairment of hematopoietic stem cells. Transplantation of these cells is a first-line treatment option if HLA-matched related donors are available. First-line immunosuppressive therapy may be offered as alternative. The aim was to compare the outcome of these patients in controlled trials.

Methods

A systematic search was performed in the bibliographic databases MEDLINE, EMBASE, and The Cochrane Library. To show an overview of various outcomes by treatment group we conducted a meta-analysis on overall survival. We evaluated whether studies reported statistically significant factors for improved survival.

Results

26 non-randomized controlled trials (7,955 patients enrolled from 1970 to 2001) were identified. We did not identify any RCTs. Risk of bias was high except in 4 studies. Young age and recent year of treatment were identified as factors for improved survival in the HSCT group. Advanced age, SAA without very severe aplastic anemia, and combination of anti-lymphocyte globulin with cyclosporine A were factors for improved survival in the IST group. In 19 studies (4,855 patients), summary statistics were sufficient to be included in meta-analysis. Considerable heterogeneity did not justify a pooled estimate. Adverse events were inconsistently reported and varied significantly across studies.

Conclusions

Young age and recent year of treatment were identified as factors for improved survival in the transplant group. Advanced age, SAA without very severe aplastic anemia, and combination of anti-lymphocyte globulin with cyclosporine A were factors for improved survival in the immunosuppressive group. Considerable heterogeneity of non-randomized controlled studies did not justify a pooled estimate. Adverse events were inconsistently reported and varied significantly across studies.

Kaposi's sarcoma developed after allogeneic hematopoietic stem cell transplantation

A 33-year-old Chinese male patient with severe aplastic anemia received matched sibling allogeneic hematopoietic stem cell transplantation using antithymocyte globulin containing conditioning regimen after 4 months of unsuccessful treatment with cyclosporine A. Following transplantation, the patient was immunosuppressed demonstrated by intermittent infections, including a varicella 3 months after transplantation. Although DNA-STR results on day +30 confirmed complete donor engraftment, repeat DNA-STR analysis performed more than 3 months after transplantation showed a mosaic phenotype. Cyclosporine tapering commenced early, but the last DNA-STR result confirmed complete graft rejection. On day +198, the patient presented with fever, skin boil in the right temporal region, severe pancytopenia, intrabodominal lymphadenopathy and hepatosplenomegaly. Within 1 month, superficial lymphadenopathy and right exophthalmos developed. Excisional lymph node biopsy pathology confirmed Kaposi's sarcoma (KS). The patient succumbed due to intracranial bleeding as a result of thrombocytopenia. This is the first study of KS that developed following stem cell transplantation for severe aplastic anemia. The precipitating factors underlying KS development in this case and its differentiation from post-transplant lymphoproliferative disorders are analyzed.

Successful sustained engraftment after reduced-intensity umbilical cord blood transplantation for adult patients with severe aplastic anemia

We retrospectively analyzed 12 consecutive adult severe aplastic anemia patients who received unrelated umbilical cord blood transplantation after a reduced-intensity conditioning regimen (RI-UCBT). The conditioning regimen consisted of 125 mg/m² fludarabine, 80 mg/m² melphalan, and 4 Gy of total body irradiation. The median infused total nucleated cell number and CD34(+) cell number were 2.50 × 10⁷/kg and 0.76 × 10⁵/kg, respectively. Eleven of the 12 patients achieved primary neutrophil and platelet engraftment. All patients who achieved engraftment had complete hematologic recovery with complete donor chimerism, except for one patient who developed late graft failure 3 years after RI-UCBT. Two of the 12 patients died of idiopathic pneumonia syndrome, and the remaining 10 patients are alive, having survived for a median of 36 months. Our encouraging results indicate that RI-UCBT may become a viable therapeutic option for adult severe aplastic anemia patients who lack suitable human leukocyte antigen-matched donors and fail immunosuppressive therapy.

Immunosuppressive therapies in the management of immune-mediated marrow failures in adults: where we stand and where we are going

Immunosuppression is a key treatment strategy for aplastic anaemia (AA) and the related immune-mediated bone marrow failure syndromes (BMFS). For the last 20 years the standard immunosuppressive regimen for AA patients has been anti-thymocyte globulin (ATG) plus ciclosporin A (CyA), which results in response rates ranging between 50% and 70%, and even higher overall survival. However, primary and secondary failures after immunosuppressive therapy remain frequent, and to date all attempts aiming to overcome this problem have been unfruitful. This article reviews the state of the art of current immunosuppressive therapies for AA, focusing on open questions linked to standard immunosuppressive treatment, and on experimental immunosuppressive strategies which could lead to future improvement of current treatments. Specific immunosuppressive strategies employed for other BMFS, such as lineage-restricted marrow failures, myelodysplastic syndromes and large granular lymphocyte leukaemia-associated cytopenias, are also briefly discussed.

Predictors of response to immunosuppressive therapy with antithymocyte globulin and cyclosporine and prognostic factors for survival in patients with severe aplastic anemia

BACKGROUND

Immunosuppressive therapy (IST) with antithymocyte globulin (ATG) plus cyclosporine (CSA) is standard therapy in patients with severe aplastic anemia (SAA) who do not have an available HLA-matched sibling donor.

METHODS AND PATIENTS

The current study aimed to determine the predictive factors for response to IST in patients with SAA and to identify prognostic factors following IST. A total of 62 patients diagnosed with SAA who received IST with either rabbit ATG (n = 33) or horse ATG (n = 29) plus CSA between October 1994 and December 2007 were included.

RESULTS

With a median follow-up duration of 60.5 months, complete response and overall response were estimated to be 31% and 53%, respectively. The 4 yr overall survival rate was 75 + or - 6%. In terms of predicting the response to IST, neutrophil counts above 0.3 x 10(9)/L prior to IST were the only significant predictive factor (P = 0.02). Survival following IST was significantly different in favor of both the group showing high absolute reticulocyte counts (ARC) above 10.9 x 10(9)/L prior to IST (P = 0.004) and the group achieving any response following IST (P = 0.002).

CONCLUSIONS

Pre-IST neutrophil counts might predict the response to IST, while absolute ARCs prior to IST and response status after IST could be prognostic factors following IST.

Single-Center Experience: immunosuppressive therapy as frontline treatment for 33 children with acquired severe aplastic anemia

The authors retrospectively analyzed the records of 33 children with acquired severe aplastic anemia (SAA) diagnosed from July 1998 to October 2007 and first treated by immunosuppressive therapy (IST). Serial hematologic parameters, complications, transfusion requirements, and time to response were assessed. Allogeneic hematopoietic stem cell transplantation (HSCT) was attempted in 7 patients after failure of IST (n = 6) or relapse following an initial response to IST (n = 1). One child died of post-transplant lymphoproliferative disorder. Thirty of the 33 patients are alive and well after a median follow-up of 45 months (range, 7-116 months). Overall (transfusion-independent) response to IST was 73% (24/33). The actuarial 5 years survival rate was 89.4%. In this study, all patients with SAA received IST as standard front-line therapy. Approximately three-fourths of patients with SAA have durable recovery and excellent overall survival.

Subcutaneous alemtuzumab plus cyclosporine for the treatment of aplastic anemia

Aplastic anemia (AA) is most frequently due to autoimmune attack on its own stem cells. Alemtuzumab is a monoclonal antibody which recognizes the CD52 antigen on the surface of T and B cells. It has proved useful in autoimmune diseases, lymphoproliferative conditions, and graft versus host disease. Based on its immunosuppressive properties, we treated 14 AA patients with alemtuzumab. Median age was 23 years. Ten milligrams of alemtuzumab were injected subcutaneously each day for five consecutive days. Cyclosporine A was also administered orally at a dose of 2 mg/kg every 12 h for 3 months, and then gradually tapered. Response to alemtuzumab was followed for a median of 20 months. There were eight responses (57.1%), two complete and six partial. Whereas six (42.8%) patients were non-responders. Median complete blood count values on alemtuzumab responders were Hb 13.1 mg/dL, absolute neutrophil count 2.4 x 10(9)/L, and platelets 97.5 x 10(9)/L. A good response was produced in 57% of AA patients with the administration of alemtuzumab, who lacked a stem cell donor.

Unrelated donor stem cell transplantation in acquired severe aplastic anemia: a systematic review

Acquired severe aplastic anemia is a rare disease characterized by an immune-mediated functional impairment of hematopoietic stem cells. Transplantation of these cells from unrelated donors is a treatment option frequently offered to patients after failed immunosuppressive therapy. The aim was to investigate the outcome of these patients treated with unrelated donor transplants. Systematic literature searches were performed in MEDLINE, EMBASE, and The Cochrane Library. All databases were searched from inception to June 2009. Only full-text publications and studies including at least 10 patients were considered. The primary outcome was 5-year overall survival from the day of transplantation and the secondary outcomes were graft failure and graft-versus-host disease. A meta-analysis of survival estimates was conducted and heterogeneity was investigated. A total of 18 studies, one controlled trial and 17 case series were identified. The overall survival at five years and the corresponding confidence interval was stated in 8 studies and ranged from 28% to 94%. A meta-analysis revealed considerable heterogeneity between the studies that could not be explained and was also present in subgroups of the studies. The proportion of acute graft failure was 45% in one study using only umbilical cord blood, and it was reported to be 0-26% in 15 studies using mainly bone marrow as stem cell source after different follow-up periods. Acute GVHD grade II-IV was reported for 8-86% and extensive chronic GVHD for 0-38% of the evaluated patients in 16 studies. Recipient age, human leukocyte antigen match, performance status, year of transplantation, and conditioning with serotherapy were identified as significant factors for improved survival. Unrelated donor hematopoietic stem cell transplantation in patients with acquired severe aplastic anemia after failure to immunosuppressive therapy is a treatment option. A stable physical condition of the patients before receiving the transplant (for example, performance and age) may be associated with a better survival. Detailed HLA-matching facilitated by DNA-based typing, among other factors, may have contributed to recent improvements on survival after unrelated donor HSCT as a second-line treatment.

Phase II study of rabbit anti-thymocyte globulin, cyclosporine and granulocyte colony-stimulating factor in patients with aplastic anemia and myelodysplastic syndrome

We investigated efficacy and safety of rabbit anti-thymocyte globulin (rATG), cyclosporine and granulocyte colony-stimulating factor (G-CSF) as first-line therapy for patients with aplastic anemia (AA) and low or intermediate-1 or hypoplastic myelodysplastic syndrome (MDS). rATG 3.5 mg/kg (or 2.5 mg/kg per day for patients >or=55 years with MDS) was given for 5 days. Cyclosporine (5 mg/kg) and G-CSF (5 microg/kg) were given daily and continued for up to 6 months or longer. Responses were assessed about 3 and 6 months after therapy. Thirty-six patients have been enrolled on study and 32 patients treated; 25 were evaluable for a response (13 with AA, 12 with MDS); the rest are too early. The median age was 62 years (range, 20-83) for patients with AA and 63 (range, 42-80) for patients with MDS. Of 13 patients, 12 (92%) patients with AA responded (5 complete response (CR), 7 partial response (PR)), whereas of 12 patients, 4 (33%) patients with MDS responded (1 CR, 3 PR). For patients with AA, the median time to response (TTR) was 93 days (range, 79-623), whereas in the MDS group the median TTR was 111 days (range, 77-139). Grade III/IV toxicities were mainly cytopenias and neutropenic fever. Combination of rATG, cyclosporine and G-CSF is safe and effective as first-line treatment of AA and has significant activity in low-risk MDS.

Myelodysplasia and acute leukemia as late complications of marrow failure: future prospects for leukemia prevention

Patients who have acquired and inherited bone marrow failure syndromes are at risk for the development of clonal neoplasms including acute myeloid leukemia, myelodysplastic syndrome, and paroxysmal nocturnal hemoglobinuria. This article reviews the evidence supporting a model of clonal selection, a paradigm that provides a reasonable expectation that these often fatal complications might be prevented in the future.

Hematopoietic growth factors in aplastic anemia patients treated with immunosuppressive therapy-systematic review and meta-analysis

Immunosuppressive therapy is the treatment for aplastic anemia patients ineligible for transplantation. The role of hematopoietic growth factors as adjunct to treatment in these patients is unclear. We conducted a systematic review and meta-analysis of randomized controlled trials comparing treatment with immunosuppressive therapy and hematopoietic growth factors to immunosuppressive therapy alone in patients with aplastic anemia. Two reviewers appraised the quality of trials and extracted data. For each trial, results were expressed as relative risks with 95% confidence intervals (CI) for dichotomous data. The addition of hematopoietic growth factors yielded no difference in overall mortality at 100 days, one year and five years [relative risks 1.33 (95% CI 0.56-3.18), relative risks 0.90 (95% CI 0.50-1.63) and relative risks 0.89 (95% CI 0.55-1.46), respectively]. There was no difference in overall hematologic response and in the occurrence of infections. HGF significantly decreased the risk for relapse, relative risks 0.45 (95% CI 0.30-0.68, 3 trials). Hematopoietic growth factors were not associated with higher occurrence of myelodysplastic syndrome and acute myeloid leukemia or paroxysmal nocturnal hemoglobinuria. The addition of hematopoietic growth factors does not affect mortality, response rate or infections occurrence. Therefore, it should not be recommended routinely as an adjunct to the immunosuppressive therapy for patients with aplastic anemia.

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.

Bone marrow failure as a risk factor for clonal evolution: prospects for leukemia prevention

Patients with bone marrow failure syndromes are at risk for the development of clonal neoplasms, including paroxysmal nocturnal hemoglobinuria (PNH), myelodysplasia (MDS), and acute myelogenous leukemia (AML). Approximately 10% to 20% of those who survive acquired aplastic anemia will develop a clonal disease within the decade following their diagnosis. The relative risk of clonal neoplasms is very significantly increased in children and adults with inherited bone marrow failure syndromes as well. Until recently, the mechanisms underlying clonal evolution have been opaque, but a sufficient amount of evidence has now accumulated to support a model in which cells resistant to extracellular apoptotic cues are selected from the stem cell pool. Indeed, in the past two years this paradigm has been validated in preclinical models that are robust enough to reconsider new therapeutic objectives in aplastic states and to support the planning and development of rationally designed leukemia prevention trials.