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

Idiopathic Aplastic anemia: Indian Perspective

Aplastic anemia (AA) is a rare immunologically mediated bone marrow failure syndrome, characterized by progressive loss of hematopoietic stem cells resulting in peripheral pancytopenia. Elaborative investigation including molecular tests is required to exclude inherited bone marrow failure syndrome (IMBFS) as the treatment and prognosis vary dramatically between them. Haematopoietic stem cell transplant with a fully matched sibling donor (MSD-HSCT) is still the only curative treatment. Management of AA is a real-time challenge in India, because of the delay in the diagnosis, lack of proper supportive care, limited availability of the expertise centre, and the patient's affordability. Recently, results with intensified immunosuppressive therapy that includes anti-thymocyte globulin with cyclosporine-A (CsA) and eltrombopag, are enough encouraging to consider it as treatment of choice in patients lacking MSD or who are not fit for HSCT. However, limitations in resource constraints settings including the cost of therapy limit its full utilization. Relapse of the disease or evolution to myelodysplasia or paroxysmal nocturnal haemoglobinuria (PNH) in a proportion of patients is another challenge with immunosuppressants. The majority of the AA patients still receive CsA with or without androgens in India, mostly because of increased cost and limited availability of HSCT and ATG. The use of the unrelated or alternative donor is still upcoming in India, with unavailable data in terms of response and survival. Therefore, there is an utmost need for novel agents for the better management of AA having a balanced efficacy and toxicity profile to improve the survival and quality of life.

Hematopoietic Stem Cell Transplantation in Nepal: international partnership, implementation steps and clinical outcomes

Blood & Marrow Transplantation (BMT) is rarely available in many low-middle-income countries (LMIC). In 2012, Civil Service Hospital, a government hospital in Kathmandu (Nepal) partnered with the University of Illinois at Chicago (USA) to consult on the establishment of BMT in their hospital, train staff and promote educational activities. The implementation of BMT occurred in 3 phases over 4 years and included: regular on-site visits, training of personnel in Chicago, continuous remote communication, co-organization of educational events in Kathmandu. The Nepalese government funded the construction of a state-of-the art BMT unit and stem cell lab inside Civil Hospital. Autologous hematopoietic stem cell transplant (HSCT) was started in 2016 and allogeneic HSCT from matched related (MRD) or haploidentical (Haplo) donors in 2017. Transplant cost was $5,200 for autologous, $10,000 for MRD and $13,300 for Haplo HSCT. The major socio-economic determinants reported by Nepalese BMT providers were: cost of transplant, loss revenue of the patient or caregiver and cost of transportation. All patients (n=66) received peripheral blood stem cell grafts and all allogeneic HSCT received post-transplant cyclophosphamide (PTCy) as graft versus host disease (GVHD) prophylaxis. In autologous HSCT (n=30), with a median follow-up of 1029 days (range:130-1653) 87% were alive, and transplant-related mortality (TRM) was 10%. In allogeneic HSCT (n=36), all patients engrafted and with a median follow-up of 204 days (range: 12-1131) 75% of them were alive (MRD: 71%, Haplo: 83%), with a TRM of 19%. Only 3 of 36 patients developed acute GVHD ≥ grade 2. Median overall survival (OS) in autologous HSCT was 1610 days, whereas it was not reached in allogeneic HSCT. The long-lasting partnership of UIC helped building capacity and allowed Civil Service Hospital team to establish a BMT program in Nepal that has high quality standards at affordable cost for the majority of the patients.

Full Dose Cyclophosphamide with the Addition of Fludarabine for Matched Sibling Transplants in Severe Aplastic Anemia

The recommended therapy for severe aplastic anemia (SAA) in younger patients with a matched sibling donor (MSD) is allogeneic hematopoietic cell transplantation (allo-HCT). A number of conditioning regimens and protocols have been used for these patients. Here we report a homogeneous cohort of SAA patients receiving a uniform transplantation protocol. This study is a retrospective analysis of 82 consecutive patients with SAA who underwent MSD allo-HCT at a single center. The median duration of follow-up for survivors was 100 months, the 10-year overall survival (OS) was 87.5%, and the 10-year event-free survival was 75.3%. The OS was 97.4% for "mobilized" bone marrow (BM) graft recipients and 78.9% for "nonmobilized" BM graft recipients (P = .01. The cumulative incidence of acute graft-versus-host disease (GVHD) was 25.6%, that of chronic GVHD was 27.16%, and that of graft failure was 16.2%. Recipient age ≥30 years and transplantation at >6 months after SAA diagnosis were associated with a increased risk of events. In the presence of a fully matched sibling donor, allo-HCT with a mobilized BM graft and fludarabine-cyclophosphamide conditioning is an efficacious and safe approach. Early transplantation is associated with a better outcome, emphasizing the importance of not delaying transplantation in these patients. Prospective trials are needed to determine the optimal regimen.

Special issues related to the diagnosis and management of acquired aplastic anemia in countries with restricted resources, a report on behalf of the Eastern Mediterranean blood and marrow transplantation (EMBMT) group and severe aplastic anemia working party of the European Society for blood and marrow transplantation (SAAWP of EBMT)

Aplastic anemia is a relatively rare but potentially fatal disorder, with a reported higher incidence in developing countries in comparison to the West. There are significant variations in epidemiological as well as etiological factors of bone marrow failure syndromes in the developing countries in comparison to the developed world. Furthermore, the management of bone marrow failure syndromes in resource constraint settings has significant challenges including delayed diagnosis and referral, limited accessibility to healthcare facilities, treatment modalities as well as limitations related to patients who require allogeneic stem cell transplantation. Here we will provide a review of the available evidence related to specific issues of aplastic anemia in the developing countries and we summarize suggested recommendations from the Eastern Mediterranean blood and bone marrow transplantation (EMBMT) group and the severe aplastic anemia working party of the European Society of blood and marrow transplantation (SAAWP of EBMT) related to the diagnosis and therapeutic options in countries with restricted resources.

An Antithymocyte Globulin-Free Conditioning Regimen Using Fludarabine and Cyclophosphamide Is Associated with Good Outcomes in Patients Undergoing Matched Related Family Donor Transplantation for Aplastic Anemia

Allogeneic hematopoietic stem cell transplantation (HSCT) using fludarabine (Flu)-based conditioning regimens are being increasingly being used in patients with aplastic anemia (AA). We describe an antithymocyte globulin (ATG)-free conditioning regimen consisting of Flu and cyclophosphamide (Cy) in patients undergoing matched related donor (MRD) HSCT for AA. Between 2004 and 2019, 212 patients underwent MRD HSCT using Flu (30 mg/m²/day for 6 days) and Cy (60 mg/kg/day for 2 days) for conditioning. The graft source was peripheral blood stem cells in all patients. Graft-versus-host disease (GVHD) prophylaxis consisted mainly of cyclosporine and methotrexate, although 41 patients received post-transplantation Cy as part of a study. Engraftment occurred in 91% of patients at a median of 16 days, whereas 4 patients (1.8%) experienced primary graft failure and 15 (7.1%) died before achieving engraftment. Toxicity was minimal. The incidence of grade II-IV acute GVHD (aGVHD) was 27.9%, and that of grade III-IV aGVHD was 11.3%. Chronic GVHD occurred in 41.6%. 80% were free of immunosuppression at 60 months and long-term complications were seen in 8.4%. At a median of 46 months, 158 patients were alive and well, with a 5-year overall survival (OS) of 75.3 ± 3.0%. The 5-year OS was 80.6 ± 4.1% for patients age <20 years (n = 93), 74.5 ± 4.6% for those age 20 to 40 years (n = 91), and 59.7 ± 9.5% for those age >40 years (n = 28) (P = .11). Patients classified as low risk had better OS compared with those at high risk (93.2 ± 2.9% versus 65.7 ± 4.1%; P = .000). Factors affecting OS on multivariate analysis included aGVHD (P = .02) and graft failure (P = .000). This large series using Flu/Cy for conditioning before MRD HSCT confirms good outcomes in patients with AA, with excellent outcomes in low-risk patients. Suitable modifications are needed to improve outcomes in high-risk patients.

Similar outcomes of alemtuzumab-based hematopoietic cell transplantation for SAA patients older or younger than 50 years

Survival after allogeneic hematopoietic cell transplantation (HSCT) for severe aplastic anemia (SAA) among older patients remains poor and associated with increased risk for graft-versus-host disease (GVHD). In this retrospective study of 65 consecutive patients with acquired SAA who were transplanted using fludarabine, low-dose cyclophosphamide, and alemtuzumab (FCC), outcomes of 27 patients aged at least 50 years were compared with those of 38 patients younger than 50 years. The median age of the older cohort was 61 years (range, 51-71 years); 21 (78%) patients were transplanted from unrelated donors (3 of 21 from HLA 9/10 mismatch donors) and 6 from matched sibling donors. One-year GVHD-free, relapse-free survival (GRFS) was comparable to that of patients younger than 50 years (84% vs 94%, respectively; P = .23). Both groups showed low rates of acute (5% vs 4%) and chronic (18% vs 14%) GVHD, with no cases of severe GVHD among matched donor transplants, and similar 1-year transplant-related mortality (14% vs 5.4%, older vs younger; P = .23). HSCT comorbidity index (HTC-CI) scores were similar between the groups, but overall survival with an HCT-CI of at least 3 was lower compared with a score less than 3 (76% vs 98%; P = .005). Median donor T-cell chimerism among older patients was 64% and 60% at 1 and 3 years, respectively, and was similar to that of younger patients. Increased B regulatory cells potentially contributed to low alloreactivity and mutual donor-recipient tolerance in older patients. Effect of comorbidities rather than age alone may be a more important determinant of suitability for FCC HSCT in older patients.

Comparison of Conventional Cyclophosphamide versus Fludarabine-Based Conditioning in High-Risk Aplastic Anemia Patients Undergoing Matched-Related Donor Transplantation

Allogeneic stem cell transplant for high-risk aplastic anemia (AA) yields inferior results using conventional cyclophosphamide (CY)-based conditioning. The use of fludarabine (Flu)-based regimens has resulted in improved outcomes in high-risk patients. Limited data are available comparing these two conditioning regimens in such patients. We retrospectively analyzed 192 high-risk patients undergoing matched-related donor transplantation from July 2001 to December 2018. The median age was 19.5 (2–52) years. Patients were divided into 2 groups, Cy²⁰⁰ anti-thymocyte globulin (ATG)²⁰ (Gp1 n = 79) or Flu^120–150 Cy^120–160 ATG²⁰ (Gp2 n = 113). The risk of graft failure was significantly higher in Gp1, and the majority occurred in patients with >2 risk factors (p = 0.02). The incidence of grade II-IV acute graft versus host disease (GVHD) and chronic GVHD was not significantly different between the two groups. The overall survival (OS) of the study cohort was 81.3 %, disease-free survival (DFS) 76.6 % and GVHD-free relapse-free survival (GRFS) was 64.1%. DFS and GRFS were significantly higher in Gp2 as compared to Gp1: DFS 84.1% versus 68.4 % (p = 0.02), GRFS 77.9% versus 54.4% (p = 0.01), respectively. We conclude that Flu-based conditioning is associated with superior OS, DFS and GRFS as compared to the conventional Cy-based regimen in high-risk AA.

Modified diagnostic criteria, grading classification and newly elucidated pathophysiology of hepatic SOS/VOD after haematopoietic cell transplantation

Sinusoidal obstruction syndrome (SOS), previously known as hepatic veno-occlusive disease (VOD), remains a multi-organ system complication following haematopoietic cell transplantation (HCT). When SOS/VOD is accompanied by multi-organ dysfunction, overall mortality rates remain >80%. However, the definitions related to the diagnosis and grading of SOS/VOD after HCT are almost 25 years old and require new and contemporary modifications. Importantly, the pathophysiology of SOS/VOD, including the contribution of dysregulated inflammatory and coagulation cascades as well as the critical importance of liver and vascular derived endothelial dysfunction, have been elucidated. Here we summarise new information on pathogenesis of SOS/VOD; identify modifiable and unmodifiable risk factors for disease development; propose novel, contemporary and panel opinion-based diagnostic criteria and an innovative organ-based method of SOS/VOD grading classification; and review current approaches for prophylaxis and treatment of SOS/VOD. This review will hopefully illuminate pathways responsible for drug-induced liver injury and manifestations of disease, sharpen awareness of risk for disease development and enhance the timely and correct diagnosis of SOS/VOD post-HCT.

Alternative donor transplants for severe aplastic anemia

Allogeneic hematopoietic stem-cell transplantation remains the only curative treatment for patients with acquired severe aplastic anemia (SAA). When a matched sibling is not available, one can search for a matched unrelated donor or a cord blood unit (CB) in the international registries or, more recently, for an HLA haploidentical (HAPLO) family member. International guidelines call for a course of antithymocyte globulin (ATG) and cyclosporine before a patient with SAA receives a transplant from a donor other than an HLA identical sibling, but whether this is necessary for patients age <20 years is less clear. Here I will examine the rapid increase in HAPLO transplantations for SAA, showing encouraging early results both in children and young adults. Graft-versus-host disease prophylaxis remains of primary importance in patients with SAA, and in vivo T-cell depletion with either ATG or alemtuzumab offers a significant survival advantage. Finally, I will discuss the strong age effect, which is particularly evident at >40 and 50 years of age for reasons not entirely clear and which should be taken into account when designing a treatment strategy for a given patient.

Allogeneic Matched Related Donor Bone Marrow Transplantation for Pediatric Patients With Severe Aplastic Anemia Using "Low-dose" Cyclophosphamide, ATG Plus Fludarabine

BACKGROUND

The combination of cyclophosphamide (CY) and antithymocyte globulin (ATG) has been used as a standard conditioning regimen for matched related donor transplantation in patients with severe aplastic anemia.

PROCEDURE

To decrease the regimen-related toxicity while maintaining appropriate engraftment and survival rates, fludarabine (FLU) was added to the regimen. Four pediatric patients received matched related donor bone marrow transplantation with CY (50 mg/kg×2) (instead of the 50 mg/kg×4 standard dosing), equine ATG (30 mg/kg×3), with the addition of FLU (30 mg/m×4). Graft versus host disease (GvHD) prophylaxis included a calcineurin inhibitor and methotrexate.

RESULTS

No grade 4 acute toxicities occurred during the first 30 days after transplant. All patients engrafted with normalization of peripheral blood counts and transfusion independence. One patient developed grade 1 to 2 acute GvHD, followed by chronic GvHD that resolved. With a median follow-up of 41.7 months, all 4 patients are alive and transfusion free, with complete donor chimerism. This combination of a low-dose CY/ATG+FLU regimen was overall very well tolerated and contributed toward a successful outcome including engraftment, chimerism, and survival.

CONCLUSION

This small pilot study shows that this cytoreductive regimen could be considered as the standard of care for transplantation of pediatric patients with aplastic anemia from HLA-matched siblings.

Clinical evaluation of haploidentical hematopoietic combined with human umbilical cord-derived mesenchymal stem cells in severe aplastic anemia

BACKGROUND

This study not only evaluated the clinical effects of treatment using haploidentical hematopoietic stem cells (haplo-HSCs) combined with human umbilical cord mesenchymal stem cells (UC-MSCs) in patients with severe aplastic anemia (SAA), but also investigated the factors related to graft versus host disease (GVHD).

METHODS

Cotransplantation of haplo-HSCs and UC-MSCs was performed in 24 SAA patients. The conditioning regimens consisted of rabbit anti-human T-lymphocyte immunoglobulin (ATG), cyclophosphamide, and fludarabine with or without busulfan. GVHD was prevented using cyclosporine A, ATG, anti-CD25 monoclonal antibody, and mycophenolate material.

RESULTS

The incidence of acute GVHD was 50%. The incidence of severe acute GVHD was not related to gender, age, donor-recipient relations, and patient/donor pair, while patient/donor pair (r = 0.541, P = 0.022) was significantly correlated with incidence of chronic GVHD. Upon follow-up for a median of 13 months, 5 of the 24 patients (20.8%) were dead. The survival rates at 3 and 6 months in all patients were 87.5% (21/24) and 83.3% (20/24), respectively.

CONCLUSION

Cotransplantation of haplo-HSCs combined with UC-MSCs was an effective and safe approach for the treatment of patients with SAA. The appropriate conditioning regimen and early treatment for infection also played a critical role in the success of HSCT.

Hematopoietic cell transplantation for aplastic anemia

PURPOSE OF REVIEW

Improvements in allogeneic hematopoietic cell transplantation (HCT) with better donor selection, conditioning regimens and graft vs. host disease prophylaxis make it reasonable to move HCT earlier in the algorithm for management of severe aplastic anemia (SAA). Recent progress in transplantation is reviewed whereas issues related to developing countries are also addressed.

RECENT FINDINGS

Multiple research centers are reporting on clonality, mutations and telomere disorders in SAA, which may help to choose the most appropriate therapy upfront. Eltrombopag, in combination with immunosuppressive therapy (IST), has shown remarkable improvement over historical IST, and long-term follow-up is awaited. In younger patients and in experienced centers, matched unrelated-donor (MUD) and related haploidentical transplants (haplo-HCT) are being reported with survival approaching that seen with sibling transplants. Literature from resource-limited countries highlight the need to modify guidelines to make them affordable and cost-effective. Bone marrow remains the graft source of choice; peripheral blood stem cells may be acceptable in special circumstances in resource-constrained countries.

SUMMARY

The potential of novel research findings and new therapeutic trials should be maximized by validation in different centers, countries and patient populations to provide personalized care to patients with aplastic anemia.

Post-Transplant Cyclophosphamide as Sole Graft-versus-Host Disease Prophylaxis Is Feasible in Patients Undergoing Peripheral Blood Stem Cell Transplantation for Severe Aplastic Anemia Using Matched Sibling Donors

High-dose cyclophosphamide (PTCY) after allogeneic hematopoietic cell transplantation (HSCT) has been shown to be effective in preventing graft-versus-host disease (GVHD) after HLA-matched bone marrow transplantation. We performed a phase II study of PTCY given at 50 mg/kg i.v. on days 3 and 4 as the sole GVHD prophylaxis after HSCT for severe aplastic anemia (SAA) in patients receiving granulocyte colony-stimulating factor-mobilized peripheral blood stem cell (PBSC) grafts from HLA-matched related donors after conditioning with fludarabine, CY, and single-dose total body irradiation. Thirty patients with a median age of 29 years (range, 16 to 49) were enrolled in this study. Engraftment was seen in 27 patients (90%) at a median of 16 days (range, 12 to 21) post-HSCT. None of the patients developed veno-occlusive disease of the liver or hemorrhagic cystitis. Grades II to IV acute GVHD was seen in 22% of patients with grades III to IV GVHD in 11.1%. The 2-year cumulative incidence of chronic GVHD was 22.7%. Fourteen patients (46.6%) did not require any further immunosuppression after receiving PTCY. Comparing with 2 historical cohorts of 30 patients each who received cyclosporine and methotrexate (MTX; at 15 mg/m² [MTX15] and 10 mg/m² [MTX10]), the incidence of grades II to IV acute GVHD was lower, albeit not significantly, with the use of PTCY (PTCY, 22.2%, vs MTX15, 37.1%, vs MTX10, 53.8%; P = .056), whereas rates of chronic GVHD were significantly reduced (PTCY, 22.7%, vs MTX15, 63.6%, vs MTX10, 76.2%; P = .013). Viral infections including cytomegalovirus were significantly higher with the use of PTCY (60%) compared with cyclosporine and MTX (MTX15, 23.3%, vs MTX10, 33.3%; P = .008). Overall survival was similar between the 3 groups. We conclude that PTCY as the sole GVHD prophylaxis is associated with low rates of acute and chronic GVHD in patients undergoing PBSC transplant for SAA using HLA-matched donors. This trial is registered at CTRI/2010/091/001480.

Population pharmacokinetics of fludarabine in patients with aplastic anemia and Fanconi anemia undergoing allogeneic hematopoietic stem cell transplantation

Although hematopoietic stem cell transplantation (HSCT) with a conditioning regimen consisting of fludarabine (F-araA) and cyclophosphamide (Cy) is associated with improved outcome in young patients with aplastic anemia (AA) and Fanconi anemia (FA), several factors limit the success of the procedure. We evaluated the population pharmacokinetics (POPPK) of F-araA and its influence on HSCT outcome in patients (n=53) with AA and FA undergoing HSCT. Patients carrying a 5′-UTR polymorphism in NT5E gene (rs2295890 G>C) exhibited significantly lower plasma F-araA clearance compared to those with wild-type genotype (7.12 vs 5.03 L/h/m² (29%) P<0.05). F-araA clearance was significantly higher in patients with AA compared to FA (2.46 ×, P<1e−6). Of all the outcome parameters evaluated (engraftment, rejection/graft failure, GvHD, TRM, OS), high F-araA AUC (>29.4 μm*h) was the only significant factor associated with the development of aGvHD by both univariate and multivariate analysis (P=0.02). The influence of plasma F-araA levels need to be evaluated in a larger cohort of patients to propose the need for therapeutic drug monitoring.

Comparing Outcomes with Bone Marrow or Peripheral Blood Stem Cells as Graft Source for Matched Sibling Transplants in Severe Aplastic Anemia across Different Economic Regions

Bone marrow (BM) is the preferred graft source for hematopoietic stem cell transplantation (HSCT) in severe aplastic anemia (SAA) compared with mobilized peripheral blood stem cells (PBSCs). We hypothesized that this recommendation may not apply to those regions where patients present later in their disease course, with heavier transfusion load and with higher graft failure rates. Patients with SAA who received HSCT from an HLA-matched sibling donor from 1995 to 2009 and reported to the Center for International Blood and Marrow Transplant Research or the Japan Society for Hematopoietic Cell Transplantation were analyzed. The study population was categorized by gross national income per capita and region/countries into 4 groups. Groups analyzed were high-income countries (HIC), which were further divided into United States-Canada (n = 486) and other HIC (n = 1264); upper middle income (UMIC) (n = 482); and combined lower-middle, low-income countries (LM-LIC) (n = 142). In multivariate analysis, overall survival (OS) was highest with BM as graft source in HIC compared with PBSCs in all countries or BM in UMIC or LM-LIC (P < .001). There was no significant difference in OS between BM and PBSCs in UMIC (P = .32) or LM-LIC (P = .23). In LM-LIC the 28-day neutrophil engraftment was higher with PBSCs compared with BM (97% versus 77%, P = .002). Chronic graft-versus-host disease was significantly higher with PBSCs in all groups. Whereas BM should definitely be the preferred graft source for HLA-matched sibling HSCT in SAA, PBSCs may be an acceptable alternative in countries with limited resources when treating patients at high risk of graft failure and infective complications.

Alternative donor transplants for severe aplastic anemia: current experience

Patients with acquired severe aplastic anemia (SAA), who lack a human leukocyte antigen (HLA) identical sibling donor (SIB), have two therapeutic options: immunosuppressive therapy with anti-thymocyte globulin (ATG) and cyclosporine (CsA), or a transplant from an alternative donor. In these patients, the current guidelines of the European Group for Blood and Marrow Transplantation (EBMT) call for a course of ATG + CsA first and transplantation in case of no response. The alternative donor source can be an unrelated donor (UD), a cord blood (CB) unit, or a family mismatched member, in most instances genetically HLA haplo-mismatched (HAPLO). In the present review, we will discuss recent results of transplants from matched UD and SIB donors, with significantly improved outcome, especially with UD in the past decade. We will also be looking at CB transplants, and the problems of limited stem cell dose. Finally HAPLO grafts have been explored in patients lacking or having rejected an unrelated or CB graft: early results seem encouraging, though the procedure should still be considered experimental.

Matched related donor hematopoietic stem cell transplantation results in a long-term follow-up of a pediatric acquired severe aplastic anemia subset: A stem cell source perspective

HSCT has substantially improved pediatric acquired SAA patients' outcomes. Retrospectively, we attempted to assess the outcome of MRD HSCT in 65 pediatric patients referred to a single center from 1992 to 2012. We were particularly interested to find out whether source of SC (PB, n = 40 and BM, n = 25) significantly impacts EFS and GVHD incidence. With a median follow-up of 45 months, total EFS was 87.7%; EFS for PB and BM groups was 87.5% and 88%, respectively. Acute GVHD (grades 3-4) occurred in 13 patients (PB, n = 10 [25%] and BM, n = 3 [12%]), acute GVHD (grades 2-4) occurred in 24 (PB, n = 16 [40%] and BM, n = 8 [32%]). Extensive chronic GVHD occurred in five patients (PB, n = 3 [7.5%] and BM, n = 2 [8%]). Cox regression revealed that elapsed time of <10 months between diagnosis and HSCT is associated with improved survival (hazard ratio, 95% CI = 1.204, 1.010-1.434, p = 0.038). SC source did not significantly affect EFS, incidence of acute GVHD (grades 3-4), or extensive chronic GVHD (p = 0.938, 0.121, and 0.487, respectively). Based on our findings, pediatric acquired SAA patients are benefitted most if MRD-HSCT is carried out early in disease process and SC source does not affect outcome of MRD-HSCT in these patients.

Improving Outcome of Aplastic Anaemia with HLA-Matched Sibling Donor Hematopoietic Stem Cell Transplantation: An Experience of Gujarat Cancer and Research Institute (GCRI)

Fifteen patients, with a median age of 19 years having severe aplastic anaemia (SAA) underwent human leucocyte antigen (HLA) identical sibling donor hematopoietic stem cell transplantation (HSCT) using conditioning regimens containing cyclophosphamide with antithymocyte globulin (ATG) or a combination of fludarabine and cyclophosphamide with or without ATG during December 2007 to May 2013. Cyclosporine and mini methotrexate were used as graft versus host disease (GVHD) prophylaxis. Graft source included peripheral blood stem cells in 11, bone marrow in 3 and both in 1. One patient had primary graft failure while 14 patients were engrafted with a median neutrophil and platelet engraftment time of 13.5 days. One patient had secondary graft rejection. Acute GVHD occurred in 3 patients and chronic GVHD in 4. One year death rate in engrafted patients was 14.28 %. At a mean follow-up of 21.2 months, 12 (80 %) are alive and well. One of the donors was a patient of haemophilia but the disease did not occur in the recipient. The graft was successful and the recipient is alive till date.

A combination of fludarabine, half-dose cyclophosphamide, and anti-thymocyte globulin is an effective conditioning regimen before allogeneic stem cell transplantation for aplastic anemia

Conditioning regimens consisting of reduced-dose cyclophosphamide (CY) and fludarabine (FDR) have been investigated for use in allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with aplastic anemia to reduce the toxicities associated with CY. However, the ideal dose of CY has not been identified. In addition, little information is available regarding donor cell chimerism after allo-HSCT with these regimens. Therefore, we retrospectively analyzed 13 patients who underwent allo-HSCT with half-dose CY (100 mg/kg in total), FDR, and anti-thymocyte globulin at total doses of 2.5-10 mg/kg at our center. All the patients except one, who died due to encephalopathy on day 20, achieved neutrophil engraftment a median of 18.5 days after HSCT with complete donor-type chimerism. Two patients who received a graft from an HLA-matched donor subsequently developed mixed chimerism (MC) associated with transfusion-dependent cytopenia. One became transfusion-independent after donor lymphocyte infusion, but continues to exhibit MC. The other regained complete donor-type chimerism after the cessation of cyclosporine, but remains transfusion-dependent. These findings suggest that a conditioning regimen with half-dose CY and FDR is effective for achieving neutrophil engraftment and complete donor-type chimerism. However, subsequent MC may be observed, especially after HLA-matched HSCT.

Management of adult patients older than 40 years refractory to at least one immunosuppressive course: HLA-identical sibling HSCT using fludarabine-based conditioning

Allogeneic hematopoietic SCT (HSCT) from an HLA-identical sibling donor is the recommended upfront therapeutic option for young patients with SAA. The outcome of allogeneic sibling HSCT has remarkably improved during the last decade as a function of improvement in transplantation supportive care. However, there is still much debate concerning the upper age limit for sibling HSCT in SAA, particularly in patients who are refractory to at least one immunosuppressive course. Recent studies suggest that fludarabine-based conditioning may improve HSCT outcome in older patients with SAA. This review discusses available data about the use of fludarabine-based conditioning in transplantation of older patients with SAA. More definitive conclusions are needed from larger studies before the wide adoption of fludarabine-based conditioning as an alternative to the standard CY and ATG-based conditioning.

Successful bone marrow transplantation for children with aplastic anemia based on a best-available evidence strategy

  A best-available evidence strategy, i.e., the best-available donors, conditioning regimens and GVHD prophylaxis were chosen at the time of BMT for AA, was analyzed retrospectively. The outcomes for 18 children with AA who underwent allogeneic BMT were analyzed. The median age was 11 yr (range 4-16), and nine were men. As conditioning regimens, seven had low-dose irradiation + CY, six had ATG + CY + Flu, and five had ATG + CY. Donors were HLA-matched siblings in 10, HLA-mismatched family in one, HLA-matched unrelated in three, and HLA-mismatched unrelated in four. As GVHD prophylaxis, three received CsA alone, nine received CsA + MTX, and six received tacrolimus + MTX. All 18 patients showed engraftment. The median number of days until the neutrophil count exceeded 500/μL was 16 (range 11-21) post-transplant. Five developed more than grade 2 acute GVHD, and three developed extensive cGVHD. One patient died because of interstitial pneumonia complicated with cGVHD. Five-yr OS was 94% (95% CI: 83-105). These results suggest that a strategy of treating patients based on the best-available evidence is acceptable.

Impact of age on outcomes after bone marrow transplantation for acquired aplastic anemia using HLA-matched sibling donors

BACKGROUND

Transplantation from an HLA-matched sibling is the treatment of choice for young patients with acquired severe aplastic anemia. For older patients, the acceptable upper age limit for transplantation as first-line treatment varies. The current analysis, therefore, sought to identify age or ages at transplantation at which survival differed.

DESIGN AND METHODS

We studied the effect of patients' age, adjusting for other significant factors affecting outcomes, in 1307 patients with severe aplastic anemia after HLA-matched sibling transplantation using logistic and Cox regression analysis. Age categories (<20 years, 20-40 years, >40 years) were determined using Martingale residual plots for overall survival and categories based on differences in survival.

RESULTS

Patients aged over 40 years old were more likely to have had immunosuppressive therapy, a poor performance score and a longer interval between diagnosis and transplantation. Neutrophil recovery was similar in all age groups but patients aged over 40 years had a lower likelihood of platelet recovery compared to patients aged less than 20 years (OR 0.45, P=0.01) but not compared to those aged 20-40 years (OR 0.60, P=0.10). Compared to the risk of mortality in patients aged less than 20 years, mortality risks were higher in patients over 40 years old (RR 2.70, P<0.0001) and in those aged 20-40 years (RR 1.69, P<0.0001). The mortality risk was also higher in patients aged over 40 years than in those 20-40 years old (RR 1.60, P=0.008).

CONCLUSIONS

Mortality risks increased with age. Risks were also higher in patients with a poor performance score and when the interval between diagnosis and transplantation was longer than 3 months, implying earlier referral would be appropriate when this treatment option is being considered.

Fludarabine-based conditioning chemotherapy for allogeneic hematopoietic stem cell transplantation in acquired severe aplastic anemia

Thirty-eight patients who met the diagnostic criteria for severe aplastic anemia underwent allogeneic hematopoietic stem cell transplantation (HSCT). The median patient age was 20 years (range, 14-36 years). Twenty-four patients were treatment-naïve, 11 had failed one or more previous courses of immunosuppressive therapy, and 3 had failed a previous HSCT. The conditioning regimen included fludarabine 30 mg/m(2)/day for 3 days (days -9, -8, and -7) and cyclophosphamide 50 mg/kg/day for 4 days (days -5, -4, -3, and -2). Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and short-course methotrexate. All patients underwent transplantation with unmanipulated bone marrow as the stem cell source. The median total nucleated cell (TNC) dose was 2.43 × 10(8)/kg (range, 0.60-6.7 × 10(8)/ kg). The conditioning regimen was well tolerated, with minimal treatment-related mortality. Engraftment was observed in all patients after transplantation; the median time to engraftment of neutrophils and platelets was 18 and 23 days, respectively. Twenty-five of the 27 patients with available chimeric studies at day 180 maintained donor chimerism. Acute GVHD grade ≥II was diagnosed in 4 patients (11%). Extensive chronic GVHD was observed in 8 patients (25%) who survived beyond day +100, at a median observation time of 43 months. Graft rejection with relapse of aplais was observed in one patient. The overall survival (OS) for the whole group was 79%. A trend toward improved OS was observed in the treatment-naïve patients (83% vs 71%), but this was statistically insignificant (P = .384). The fludarabine-based conditioning regimen used in this study with relatively young cohort of patients was well tolerated, with a low rate of rejection and treatment outcomes comparable to those seen in other, more intense and potentially more toxic conditioning regimens. Our results await validation in a larger study, optimally in a randomized controlled manner.

Fludarabine, cyclophosphamide, antithymocyte globulin, with or without low dose total body irradiation, for alternative donor transplants, in acquired severe aplastic anemia: a retrospective study from the EBMT-SAA Working Party

BACKGROUND

We analyzed the outcome of 100 patients with acquired severe aplastic anemia undergoing an alternative donor transplant, after immune suppressive therapy had failed.

DESIGN AND METHODS

As a conditioning regimen, patients received either a combination of fludarabine, cyclophosphamide, and antithymocyte globulin (n=52, median age 13 years) or this combination with the addition of low dose (2 Gy) total body irradiation (n=48, median age 27 years).

RESULTS

With a median follow-up of 1665 and 765 days, the actuarial 5-year survival was 73% for the group that received fludarabine, cyclophosphamide, and antithymocyte globulin and 79% for the group given the conditioning regimen including total body irradiation. Acute graft-versus-host disease grade III-IV was seen in 18% and 7% of the groups, respectively. Graft failure was seen in 17 patients with an overall cumulative incidence of 17% in patients receiving conditioning with or without total body irradiation: 9 of these 17 patients survive in the long-term. The most significant predictor of survival was the interval between diagnosis and transplantation, with 5-year survival rates of 87% and 55% for patients grafted within 2 years of diagnosis and more than 2 years after diagnosis, respectively (P=0.0004). Major causes of death were graft failure (n=7), post-transplant-lymphoproliferative-disease (n=4) and graft-versus-host disease (n=4).

CONCLUSIONS

This study confirms positive results of alternative donor transplants in patients with severe aplastic anemia, the best outcomes being achieved in patients grafted within 2 years of diagnosis. Prevention of rejection and Epstein-Barr virus reactivation may further improve these results.

Improved outcome of patients older than 30 years receiving HLA-identical sibling hematopoietic stem cell transplantation for severe acquired aplastic anemia using fludarabine-based conditioning: a comparison with conventional conditioning regimen

Older age is a limitation for HLA-identical sibling hematopoietic stem cell transplantation (HSCT) as first-line therapy for severe acquired idiopathic aplastic anemia (SAA). Fludarabine (Flu)-based conditioning might improve outcome in older patients. We analyzed retrospectively 30 patients older than 30 years receiving such reduced-intensity conditioning HSCT according to recommendations of the European Group for Blood and Marrow Transplantation (EBMT) and compared their outcome to a control group receiving the standard regimen (cyclophosphamide+/-antithymocyte globulin) over the same study period (1998-2007). Patients conditioned with Flu had a higher probability of overall survival than the control group (p=0.04) when adjusting for recipient's age. This might be related to a trend towards a reduced incidence of graft failure in patients receiving Flu (0% vs. 11%, p=0.09), while no difference was observed regarding graft-versus-host disease incidence. Flu-based conditioning regimen may reduce the negative impact of age in older patients with SAA receiving an HLA-identical sibling HSCT.

Aplastic anemia: pathophysiology and treatment

An immune basis for most patients with aplastic anemia (AA) provides a rationale for immunosuppressive therapy (IST), using antithmyocyte globulin and cyclosporine as one therapeutic modality; hematologic response is observed in up to 75% of patients. Recent advances in understanding the pathogenesis of AA have identified defective telomere maintenance as an important explanation for the onset of marrow failure, relapse and clonal evolution after IST, in some patients with AA. The finding of inherited mutations in the telomerase gene complex in patients with apparent acquired AA has important implications for clinical management. Hematopoietic stem cell transplantation (HSCT) for acquired AA, whether from an HLA identical sibling or an unrelated donor, provides an excellent chance of long term cure. Current issues with HSCT include graft rejection, chronic GVHD and poor outcome in older patients. The lack of a suitable bone marrow donor for all patients who need a transplant, illustrates the need for novel transplant procedures, such as cord blood transplantation.

Allogeneic hematopoietic stem cell transplantation for acquired aplastic anemia using cyclophosphamide and antithymocyte globulin: a single center experience

Between February 1998 and October 2007, 97 (69 male, 28 female) patients with acquired aplastic anemia and a median age of 18 years (range, 2-39) received related allogeneic hematopoietic stem cell transplantation. Ninety-five patients received bone marrow grafts and two patients G-CSF primed peripheral blood stem cell transplantation. The donors were genotypically HLA-identical siblings in 94 cases, HLA-matched parents in 2 cases and a syngeneic twin in 1 case. Median time from diagnosis to transplantation was 2 months (range, 1-15). Conditioning regimen consisted of cyclophosphamide combined with antithymocyte globulin in all patients. For graft versus host disease (GVHD) prophylaxis, all patients received methotrexate and cyclosporine. Eighty-six patients showed evidence of hematopoietic engraftment. Eight patients died before engraftment. Rejection rate was 14.8% with three primary graft failures and eight secondary graft rejections occurring between 2 and 27 months post transplantation. Of the 11 rejecting patients, 3 died from infection and 8 proceeded to a second transplantation. Among the eight patients re-transplanted, seven are alive with successful second engraftments and one died from acute grade III GVHD. Acute GVHD occurred in 15.5% and extensive chronic GVHD in only 5.3% of patients. The 4-year overall probability of survival was 76.8%. Infection was the cause of 81.1% of deaths. The major factor affecting survival was onset of infection before transplantation. Major ABO donor-recipient incompatibility, disease severity and acute GVHD had also negative impact on survival. These results could be improved by reducing the time to transplant and by a more efficient supportive care policy.Bone Marrow Transplantation advance online publication, 27 July 2009; doi:10.1038/bmt.2009.175.

Diagnosis and treatment of acquired aplastic anemia

Acquired severe aplastic anemia can be treated successfully with either immunosuppressive therapy or bone marrow transplantation. Although immunosuppressive therapy can be readily administered to all patients, it is not a curative approach and is associated with a higher risk of clonal evolution than is transplantation, which yields rapid and long-lasting hematologic remission. This article reviews the key diagnostic and prognostic factors that influence the choice of therapy in patients with acquired aplastic anemia.

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.

Graft-versus-host disease following marrow transplantation for aplastic anemia: different impact of two GVHD prevention strategies

Prevention of GVHD is one of the most desirable goals of BMT in aplastic anemia (AA). We reviewed the medical records of 24 consecutive patients treated with BMT for acquired AA using two different GVHD prevention strategies. Ten patients were given alemtuzumab-based GVHD prophylaxis (50-60 mg in three divided doses on days -8, -7 and -6), and 14 patients were given conventional GVHD prophylaxis with calcineurin inhibitors plus MTX before the introduction of the alemtuzumab-based protocols. The incidence of acute, chronic and 'serious GVHD' was significantly reduced in alemtuzumab-treated patients compared to conventionally treated patients [11 vs 64% (P=0.03), 0 vs 78% (P=0.002) and 0 vs 57% (P=0.007), respectively]. Engraftment time and rates of graft failure appeared similar in the two groups. A significantly higher proportion of alemtuzumab-treated patients developed CMV reactivation compared to control patients (83 vs 12%; P=0.03); none developed CMV disease. The rates of other infectious complications did not appear significantly different. Our data suggest that 50-60 mg of alemtuzumab given according to the current schedule significantly reduces the risk of GVHD without increasing the risk of graft failure or serious infections.

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.