French multicenter 22-year experience in stem cell transplantation for beta-thalassemia major: lessons and future directions

Finding a balance in reduced toxicity hematopoietic stem cell transplantation for thalassemia: role of infused CD3+ cell count and immunosuppression

We performed a retrospective analysis on 124 patients with transfusion-dependent thalassemia who were registered in the German pediatric registry for stem cell transplantation. All patients underwent first allogeneic hematopoietic stem cell transplantation (HSCT) between 2011 and 2020 and belonged mainly to Pesaro risk class 1-2. Four-year overall (OS) and thalassemia-free survival (TFS) were 94.5% ± 2.9% and 88.0% ± 3.4% after treosulfan-fludarabine-thiotepa- and 96.9% ± 3.1% (P = 0.763) and 96.9% ± 3.1% (P = 0.155) after busulfan-fludarabine-based conditioning. Mixed chimerism below 75% occurred predominantly in treosulfan-based regimens (27.5% versus 6.2%). OS and TFS did not differ significantly between matched sibling, other matched family and matched unrelated donor (UD) HSCTs (OS: 100.0%, 100.0%, 96.3% ± 3.6%; TFS: 96.5% ± 2.4%, 90.0% ± 9.5%, 88.9% ± 6.0%). However, mismatched UD-HSCTs performed less favorable (OS: 84.7% ± 7.3% (P = 0.029); TFS: 79.9% ± 7.4% (P = 0.082)). We generated a scoring system reflecting the risk to develop mixed chimerism in our cohort. The main risk-reducing factors were a high CD3+ cell count (≥6 × 107/kg) in the graft, busulfan-conditioning, pre-conditioning therapy and low-targeted ciclosporin A trough levels. Acute GvHD grade III-IV in treosulfan-based concepts predominantly occurred in patients with UD and reduced GvHD prophylaxis but not in the context of high CD3+ cell doses. Taken together, this information might be used to develop more risk-adapted HSCT regimens for thalassemia patients.

Survival and late effects of hematopoietic cell transplantation in patients with thalassemia major

In this retrospective study, we evaluated long-term survival and late effects in 137 patients affected by thalassemia major (TM) who received an allogeneic hematopoietic cell transplantation (HCT). Median age at HCT was 10.1 years. After a median follow-up of 30 years, 114 (83.2%) patients are living and 108 (78.8%) are cured. The cumulative incidence of nonrelapse mortality and thalassemia recurrence was 9.5% at 1 year and 10.2% at 39 years respectively. The 39-years cumulative incidence of overall survival and disease-free survival were 81.4% and 74.5%. One hundred twenty-three patients who survived more than 2 years after HCT were evaluated for late effects concerning hematological disorders, iron burden, growth, obesity, diabetes mellitus, thyroid and gonadal function, eye, heart, liver, lung, kidney, gastrointestinal, neurologic and psychiatric system, osteoarticular system, secondary solid cancer (SSC), performance status, and Covid-19 infection. Fertility was preserved in 21 males whose partners delivered 34 neonates and 25 females who delivered 26 neonates. Fifteen cases of SSC were diagnosed for a 39-year cumulative incidence of 16.4%. HCT represents a definitive cure for the majority of TM patients at the price, however, of a non-negligible early and late mortality which in the long run affects survival and disease-free survival.

Thalassemia-free and graft-versus-host-free survival: outcomes of hematopoietic stem cell transplantation for thalassemia major, Turkish experience

We report the national data on the outcomes of hematopoietic stem cell transplantation (HSCT) for thalassemia major (TM) patients in Turkey on behalf of the Turkish Pediatric Stem Cell Transplantation Group. We retrospectively enrolled 1469 patients with TM who underwent their first HSCT between 1988 and 2020 in 25 pediatric centers in Turkey. The median follow-up duration and transplant ages were 62 months and 7 years, respectively; 113 patients had chronic graft versus host disease (cGVHD) and the cGVHD rate was 8.3% in surviving patients. Upon the last visit, 30 patients still had cGvHD (2.2%). The 5-year overall survival (OS), thalassemia-free survival (TFS) and thalassemia-GVHD-free survival (TGFS) rates were 92.3%, 82.1%, and 80.8%, respectively. cGVHD incidence was significantly lower in the mixed chimerism (MC) group compared to the complete chimerism (CC) group (p < 0.001). In survival analysis, OS, TFS, and TGFS rates were significantly higher for transplants after 2010. TFS and TGFS rates were better for patients under 7 years and at centers that had performed over 100 thalassemia transplants. Transplants from matched unrelated donors had significantly higher TFS rates. We recommend HSCT before 7 years old in thalassemia patients who have a matched donor for improved outcomes.

Economic evaluation of betibeglogene autotemcel (Beti-cel) gene addition therapy in transfusion-dependent β-thalassemia

Background: Standard of care (SoC) for transfusion-dependent β-thalassemia (TDT) requires lifelong, regular blood transfusions as well as chelation to reduce iron accumulation. Objective: This study investigates the cost-effectiveness of betibeglogene autotemcel ('beti-cel'; LentiGlobin for β-thalassemia) one-time, gene addition therapy compared to lifelong SoC for TDT. Study design: Microsimulation model simulated the lifetime course of TDT based on a causal sequence in which transfusion requirements determine tissue iron levels, which in turn determine risk of iron overload complications that increase mortality. Clinical trial data informed beti-cel clinical parameters; effects of SoC on iron levels came from real-world studies; iron overload complication rates and mortality were based on published literature. Setting: USA; commercial payer perspective Participants: TDT patients age 2-50 Interventions: Beti-cel is compared to SoC. Main outcome measure: Incremental cost-effectiveness ratio (ICER) utilizing quality-adjusted life-years (QALYs) Results: The model predicts beti-cel adds 3.8 discounted life years (LYs) or 6.9 QALYs versus SoC. Discounted lifetime costs were $2.28 M for beti-cel ($572,107 if excluding beti-cel cost) and $2.04 M for SoC, with a resulting ICER of $34,833 per QALY gained. Conclusion: Beti-cel is cost-effective for TDT patients compared to SoC. This is due to longer survival and cost offset of lifelong SoC.

Hematopoietic stem cell transplantation for people with β-thalassaemia

BACKGROUND

Thalassaemia is an autosomal recessive blood disorder, caused by mutations in globin genes or their regulatory regions, resulting in a reduced rate of synthesis of one of the globin chains that make up haemoglobin. In β-thalassaemia there is an underproduction of β-globin chains combined with excess of free α-globin chains. The excess free α-globin chains precipitate in red blood cells, leading to their increased destruction (haemolysis) and ineffective erythropoiesis. The conventional treatment is based on the correction of haemoglobin through regular red blood cell transfusions and treating the iron overload that develops subsequently with iron chelation therapy. Although, early detection and initiations of such supportive treatment has improved the quality of life for people with transfusion-dependent thalassaemia, allogeneic hematopoietic stem cell transplantation is the only widely available therapy with a curative potential. Gene therapy for β-thalassaemia has recently received conditional authorisation for marketing in Europe, and may soon become widely available as another alternative therapy with curative potential for people with transfusion-dependent thalassaemia. This is an update of a previously published Cochrane Review.

OBJECTIVES

To evaluate the effectiveness and safety of different types of hematopoietic stem cell transplantation, in people with transfusion-dependent β-thalassaemia.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also searched online trial registries. Date of the most recent search: 07 April 2021.

SELECTION CRITERIA

Randomised controlled trials and quasi-randomised controlled trials comparing hematopoietic stem cell transplantation with each other or with standard therapy (regular transfusion and chelation regimen).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened trials and had planned to extract data and assess risk of bias using standard Cochrane methodologies and assess the quality using GRADE approach, but no trials were identified for inclusion in the current review.

MAIN RESULTS

No relevant trials were retrieved after a comprehensive search of the literature.

AUTHORS' CONCLUSIONS

We were unable to identify any randomised controlled trials or quasi-randomised controlled trials on the effectiveness and safety of different types of hematopoietic stem cell transplantation in people with transfusion-dependent β-thalassaemia. The absence of high-level evidence for the effectiveness of these interventions emphasises the need for well-designed, adequately-powered, randomised controlled clinical trials.

Hematopoietic Stem Cell Transplantation in Thalassemia Patients: a Jordanian Single Centre Experience

Introduction:

Beta thalassemia major is the commonest inherited hematological disorder worldwide which needs lifelong sufficient supportive management. Hematopoietic stem Cell transplantation (HSCT) is the only curative treatment available till now.

Aim:

To evaluate the outcome of children who underwent allogenic hematopoietic stem Cell transplantation as a curative approach for Thalassemia Major, treated at Queen Rania AL- Abdullah children Hospital (QRCH)

Methods:

A retrospective review of the medical files was conducted for all children (< 15 years) who had thalassemia major and received HSCT between January, 2010 and January, 2019. The following variables were studied for all patients: age , gender, Pesaro classifications, the count of infused raw bone marrow stem cell (CD34), engraftment time, outcome and complications.

Results:

A total of 34 children were transplanted for thalassemia major, at an average of 4 cases per year. All underwent allogenic raw bone marrow transplantation from matched related donors. Thirteen patients (38.2%) were males and twenty one (61.2%) were females. The age ranged between 2 and 15 years, with a median age of 6.5 years. According to Pesaro classification, 31 patients were class 2 (91.2%) and 3 patients were class 3 (8.8%) while no single case met the criteria for class 1 Pesaro classification. The median CD34 count was 3.5 million/Kg of recipient weight (range, 1.5*10⁶-7*10⁶ /kg). The median time for neutrophil engraftment was 15.5 days. At a median follow up of 5 years (range 1- 9.5), 33 patients were alive. One patient died before 100 days post transplantation due to grade IV acute gastrointestinal Graft Versus Host Disease (GVHD). Three patients had secondary graft failure (8.8%). Six patients (17.5 %) developed mild grade 1-2 skin GVHD while another patient developed hemorrhagic cystitis due to BK virus and cytomegalovirus (CMV) which reactivated simultaneously, and was successfully managed.

Conclusion:

The outlook for Thalassemia major has dramatically changed after HSCT, with a considerable success in Jordan and results comparable to international data.

Systematic Literature Review of the Burden of Disease and Treatment for Transfusion-dependent β-Thalassemia

PURPOSE

β-Thalassemia is an inherited blood disorder characterized by reduced or no production of adult hemoglobin. Systematic identification of the burden of β-thalassemia with contemporary treatments is lacking in published literature. Thus, a gap exists in understanding the baseline burden on which to assess future treatments. Therefore, a systematic literature review (SLR) was performed to assess management and outcomes in patients with transfusion-dependent β-thalassemia (TDT) who received long-term transfusion regimens.

METHODS

Searches of MEDLINE, EMBASE, and 5 conference websites were conducted to identify clinical-practice studies in Italy, France, Germany, Greece, the United States, and the United Kingdom, published since January 2007. The review found 135 articles meeting the SLR criteria.

FINDINGS

Among patients carrying 2 β-thalassemia mutations, 64%-89% underwent regular transfusions at intervals of between 2 and 4 weeks. Transfusion-associated complications that were reported included iron overload, transfusion reactions, alloimmunization, and infections. Analyses of 42, 25, and 73 studies reporting liver iron concentration (median, 8.5 mg/g of dry weight [dw]; interquartile range [IQR], 4.5-11.0 mg/g dw), cardiac _T2* magnetic resonance imaging (median, 27.4 ms; IQR, 26.0-30.2 ms), and serum ferritin (median, 1465.0 ng/mL; IQR, 1238.2-1797.0 ng/mL), respectively, showed wide ranges in iron levels and a general trend toward improved iron control in recent years. Adverse transfusion reactions and alloimmunization were reported in ~50% and 10%-20% in patients, respectively. Rates of transfusion-transmitted infections were highly variable by study but were lower in more recent cohorts. Complications stemming from iron overload and underlying disease captured in this SLR included cardiac disease, liver disease, and endocrine and musculoskeletal disorders. Approximately 10% of patients were diagnosed with heart failure, with rates ranging from 2.9% to 20.9% across 6 studies. Other significant complications reported with β-thalassemia included pain (25%-69%), psychiatric disorders (25%-30%), and reduced health-related quality of life. Despite substantial improvements in survival, patients with TDT remained at an increased risk for early mortality.

IMPLICATIONS

Consistent with improvements in transfusion practices and iron monitoring and management, outcomes in patients with TDT have improved. However, iron overload and disease-associated complications remain a challenge in this population. This review supports the burden of disease affecting patients with β-thalassemia and provides a baseline health status against which to assess future improvements in care.

Major Issues of Care in Thalassemia Major Children Refugees

Beta thalassemia major (βTM) is the most common inherited hemoglobinopathy. Management essentially focuses on preventing and treating complications. Conventional treatment is based on a regular blood transfusion program, and chelation therapy. Management essentially focuses on preventing and treating complications. Severe complications of βTM are very rarely seen in children in Europe. In the context of the migrant crisis, pediatricians will be confronted with the challenge of managing severe complicated βTM. We report the case of 2 Syrian 10-year-old twin girls who arrived to France with numerous and severe complications of βTM: hemochromatosis, alloimmunization, hypopituitarism, osteopenia… Their clinical management, which led to successful vital and functional improvement, is reported in this article.

Allogenic Hematopoietic Cell Transplantation in Thalassemia Major: A Single-center Retrospective Analysis From India

Thalassemia is a major public health problem in developing countries. Sibling matched hematopoietic stem cell transplantation (HCT) is the recommended treatment for thalassemia major (TM). We retrospectively analyzed our data of thalassemia major patients who underwent HCT at a tertiary care center in Northern India from January 2008 to September 2017. The primary end points were overall survival (OS) and thalassemia-free survival (TFS), and secondary end points were complications post HCT (graft-versus-host-disease [GVHD], hemorrhagic cystitis [HC], and sinusoidal obstruction syndrome [SOS]). Data of 203 transplants for 200 patients (3 s transplants) were evaluated. Median follow-up period was 29.1 months (range, 0.3 to 116.7 mo). The overall survival (OS) was 88.5% and TFS was 82%. Class risk analysis showed a significantly higher OS and TFS in class I and class II compared to class III high risk group (OS: P=0.0017; TFS: P=0.0005) and (OS: P=0.0134; TFS: P=0.0027) respectively. Acute and chronic GVHD was seen in 59 (29.5%) and 18 (9%) patients, respectively, and SOS and HC were seen in 23 (11.5%) and 11 (5.5%) patients, respectively. This study reconfirms that allogenic HCT is feasible in developing world with the overall survival and TFS comparable to that reported in Western literature and should be considered early in all TM patients with available matched sibling donors.

Innovative Curative Treatment of Beta Thalassemia: Cost-Efficacy Analysis of Gene Therapy Versus Allogenic Hematopoietic Stem-Cell Transplantation

Seventy-five percent of patients with beta thalassemia (β-thalassemia) do not have human leukocyte antigen-matched siblings and until recently had no access to a curative treatment. Gene therapy is a promising treatment that can be proposed to these patients. This study estimates its cost and efficacy. In a monocentric retrospective study and cost-efficacy analysis, this study compared the two-year outcomes and costs of patients with β-thalassemia treated by gene therapy and hematopoietic stem-cell transplantation (HSCT). Grade III and grade IV complications, hospitalizations, and length of stay were extracted from the hospital discharge data. Costs were estimated from hospital accounting information and national cost studies. A total of seven patients with β-thalassemia treated between 2009 and 2016 were included, of whom four received gene therapy. Patients treated by gene therapy were older and had fewer complications and hospital admissions. Infectious complications were three times more frequent for patients treated with HSCT than for gene therapy. Average costs were €608,086 for patients treated by gene therapy and €215,571 for HSCT. The total cost of the vector was 48% of the total cost of gene therapy. Gene therapy as a curative alternative for patients lacking human leukocyte antigen-matched donors was costlier but resulted in fewer complications than HSCT.

Indications for haematopoietic stem cell transplantation for haematological diseases, solid tumours and immune disorders: current practice in Europe, 2019

This is the seventh special EBMT report on the indications for haematopoietic stem cell transplantation for haematological diseases, solid tumours and immune disorders. Our aim is to provide general guidance on transplant indications according to prevailing clinical practice in EBMT countries and centres. In order to inform patient decisions, these recommendations must be considered together with the risk of the disease, the risk of the transplant procedure and the results of non-transplant strategies. In over two decades since the first report, the EBMT indications manuscripts have incorporated changes in transplant practice coming from scientific and technical developments in the field. In this same period, the establishment of JACIE accreditation has promoted high quality and led to improved outcomes of patient and donor care and laboratory performance in transplantation and cellular therapy. An updated report with operating definitions, revised indications and an additional set of data with overall survival at 1 year and non-relapse mortality at day 100 after transplant in the commonest standard-of-care indications is presented. Additional efforts are currently underway to enable EBMT member centres to benchmark their risk-adapted outcomes as part of the Registry upgrade Project 2020 against national and/or international outcome data.

Comparable Outcomes of Allogeneic Peripheral Blood versus Bone Marrow Hematopoietic Stem Cell Transplantation in Major Thalassemia: A Multivariate Long-Term Cohort Analysis

Allogeneic hematopoietic stem cell transplantation (HSCT) currently is the only available curative option for transfusion-dependent thalassemia. Peripheral blood is a more convenient source for HSCT in comparison with bone marrow. Information about the relative success of transplantation with these 2 graft sources would help physicians and patients choose between them. The aim of this study was to evaluate the pros and cons of using peripheral blood instead of bone marrow as the graft source in thalassemia transplantation. We analyzed the transplant results of 567 transfusion-dependent thalassemia patients who received a transplant between 1998 and 2015 considering their stem cell source as a comparative variable. In multivariate Cox analysis the survival advantage for bone marrow compared with peripheral blood was not significant after adjusting for sex, age, and hepatic fibrosis presence. Rejection incidence was significantly lower in patients who used peripheral blood as their graft source. Acute and chronic graft-versus-host disease were more frequent in peripheral blood transplants, but the difference was not statistically significant. This study shows that peripheral blood could be an alternative stem cell source in patients undergoing allogeneic HSCT for thalassemia.

Unrelated Donor Transplantation in Children with Thalassemia using Reduced-Intensity Conditioning: The URTH Trial

Allogeneic hematopoietic stem cell transplantation (HSCT) can cure transfusion-dependent thalassemia (TDT). In a multicenter trial we investigated the efficacy of reduced-intensity conditioning (RIC) before unrelated donor (URD) HSCT in children with TDT. Thirty-three children, ages 1 to 17 years, received bone marrow (BM) or umbilical cord blood (UCB) allografts. Median time to neutrophil engraftment was 13 days (range, 10 to 25) and 24 days (range, 18 to 49) and platelet engraftment 23 days (range, 12 to 46) and 50 days (range, 31 to 234) after BM and UCB allografts, respectively. With a median follow-up of 58 months (range, 7 to 79), overall and thalassemia-free survival was 82% (95% CI, .64% to .92%) and 79% (95% CI, .6% to .9%), respectively. The cumulative incidence of grades II to IV acute graft-versus-host disease (GVHD) after BM and UCB allografts was 24% and 44%; the 2-year cumulative incidence of chronic extensive GVHD was 29% and 21%, respectively; 71% of BM and 91% of UCB recipients discontinued systemic immunosuppression by 2 years. Six patients who had Pesaro risk class 2 (n = 5) and class 3 (n = 1) died of GVHD (n = 3), viral pneumonitis (n = 2) and pulmonary hemorrhage (n = 1). Outcomes after this RIC compared favorably with URD HSCT outcomes for TDT and supported engraftment in 32 of 33 patients. Efforts to reduce GVHD and infectious complications are being pursued further.

Late effects after hematopoietic stem cell transplantation for β-thalassemia major: the French national experience

In this retrospective study, we evaluate long-term complications in nearly all β-thalassemia-major patients who successfully received allogeneic hematopoietic stem cell transplantation in France. Ninety-nine patients were analyzed with a median age of 5.9 years at transplantation. The median duration of clinical follow up was 12 years. All conditioning regimens were myeloablative, most were based on busulfan combined with cyclophosphamide, and more than 90% of patients underwent a transplant from a matched sibling donor. After transplantation, 11% of patients developed thyroid dysfunction, 5% diabetes, and 2% heart failure. Hypogonadism was present in 56% of females and 14% of males. Female patients who went on to normal puberty after transplant were significantly younger at transplantation than those who experienced delayed puberty (median age 2.5 vs. 8.7 years). Fertility was preserved in 9 of 27 females aged 20 years or older and 2 other patients became pregnant following oocyte donation. In addition to patient’s age and higher serum ferritin levels at transplantation, time elapsed since transplant was significantly associated with decreased height growth in multivariate analysis. Weight growth increased after transplantation particularly in females, 36% of adults being overweight at last evaluation. A comprehensive long-term monitoring, especially of endocrine late effects, is required after hematopoietic stem cell transplantation for thalassemia.

Hematopoietic stem cell transplantation for children with β-thalassemia major: multicenter experience in China

BACKGROUND

β-Thalassemia major (β-TM) has become a public health problem in mainland China. Hematopoietic stem cell transplantation (HSCT) has remained the only cure for β-TM in mainland China since 1998.

METHODS

This multicenter retrospective study provides a comprehensive review of the outcomes of 50 pediatric patients with β-TM who received HSCT between 1998 and 2009 at five centers in mainland China. Both related (n = 35) and unrelated donors (n = 15) with complete human leukocyte antigen matches were included. The stem cell sources included bone marrow (BM), peripheral blood stem cells, umbilical cord blood (UCB) and a combination of BM and UCB or a combination of BM and peripheral blood stem cells from a single sibling donor.

RESULTS

The probabilities of 5-year overall survival (OS) and thalassemia-free survival (TFS) after the first HSCT were 83.1 and 67.3%, respectively. Graft failure (GF) occurred in 17 patients. Univariate analyses showed that umbilical cord blood transplantation (UCBT) was one of the potential risk factors for decreased OS (P = 0.051), and that UCBT (P = 0.002) was potentially related to TFS. GF incidence was distinct between the UCBT and non-UCBT groups (P = 0.004). Four cases of UCB-BM combined transplantation led to decreased risks of mortality and recurrence. In the UCBT group, related donor transplantation produced more favorable results than unrelated donor transplantation in OS (P = 0.009) but not in TFS (P = 0.217).

CONCLUSIONS

GF was the primary cause of UCBT failure. Though UCBT from related donors was not favorable, the combined transplantation of UCB and BM could improve the prognosis of UCBT.

Long-term survival of beta thalassemia major patients treated with hematopoietic stem cell transplantation compared with survival with conventional treatment

Allogeneic hematopoietic stem cell transplantation (HSCT) in thalassemia remains a challenge. We reported a single-centre case-control study of a large cohort of 516 children and adult patients treated with HSCT or blood transfusion support and iron chelation therapy; 258 patients (median age 12, range 1-45) underwent sibling (67%) or unrelated (33%) HSCT; 97 patients were adults (age ≥ 16 years). The median follow-up after HSCT was 11 years (range 1-30). The conditioning regimen was busulfan (80.6%) or treosulfan-based (19.4%). A cohort of 258 age-sex matched conventionally treated (CT) patients was randomly selected. In transplanted patients the 30-year overall survival (OS) and thalassemia-free survival (TFS) were 82.6 ± 2.7% and 77.8 ± 2.9%, compared to the OS of 85.3 ± 2.7% in CT patients (P = NS); The incidence of grade II-IV acute and chronic graft versus host disease (GvHD) was 23.6% and 12.9% respectively. The probability of rejection was 6.9%. Transplant-related mortality (TRM) (13.8%) was similar to the probability of dying of cardiovascular events in CT patients (12.2%). High-risk Pesaro score (class 3) was associated with lower OS (OR = 1.99, 95% C.I.=1.31-3.03) and TFS (OR = 1.54, 95% C.I.=1.12-2.12). In adult patients, the 23-years OS and TFS after HSCT were 70 ± 5% and 67.3 ± 5%, compared to 71.2 ± 5% of OS in CT (P = NS). Finally, treosulfan was associated with lower risk of acute GvHD (P = .004; OR = 0.28, 95% C.I.=0.12-0.67). In conclusion, the 30-year survival rate of ex-thalassemia patients after HSCT was similar to that expected in CT thalassemia patients, with the vast majority of HSCT survivors cured from thalassemia.

A Multicenter Retrospective Analysis Stressing the Importance of Long-Term Follow-Up after Hematopoietic Cell Transplantation for β-Thalassemia

Allogeneic hematopoietic cell transplantation (HCT) is curative in patients with β-thalassemia major. However, most reports on HCT outcomes lack long-term follow-up data with the exception of single-center reports. An international multicenter retrospective data collection and analysis was conducted in 176 β-thalassemia patients who were 1 year or beyond after first HCT to evaluate follow-up methods and outcomes at 7 centers. Median age at HCT was 5.5 years (range, .6 to 18.5), and median follow-up was 7 years (range, 1 to 20). HCT was predominantly from HLA-matched related donors (91%) with bone marrow as stem cell source (91%) and myeloablative conditioning regimens (88%). Late mortality or persistent chronic graft-versus-host disease (GVHD) was rare (<2%). Graft rejection was reported in 23% (24% of these occurred beyond 1 year) post-HCT. Of 119 patients with donor chimerism results available for ≥4 years post-HCT, 50% had >95%, 22% had 50% to 95%, 7% had 20% to 50% and 25 (21%) had <20% donor chimerism. Organ dysfunction was identified in 10% pre-HCT and in 20% post-HCT even without complete clinical details on all patients. Hypogonadism and elevated creatinine for age were most commonly reported and significantly higher in recipients ≥ 7 years at the time of HCT (P = .007) and in those with pre-existing morbidity before HCT (P = .02). Outcomes were unaffected by pre-HCT ferritin or GVHD. Mean z scores for height and weight were low at baseline and remained low post-HCT (79%), confirming that growth impairment from disease lacked recovery post-HCT during this follow-up period. HCT for β-thalassemia has a high rate of cure and low mortality, especially in the young and from HLA-matched related donors. Half of the number of recipients live with mixed chimerism that requires continued follow-up because of a risk of late graft rejection (14%). Organ function after HCT when <7 years of age was generally preserved. Hypogonadism, renal dysfunction, and growth impairment that failed to correct were late complications identified most frequently in older transplant recipients. Systematic follow-up of individual organs such as lung and heart were inadequate but important. These data support the development of simple measures of uniformly tracking long-term HCT outcomes and organ functions in children and adolescents who undergo HCT for thalassemia, allowing for systematic identification and implementation of standardized surveillance strategies and interventions.

ATG vs thiotepa with busulfan and cyclophosphamide in matched-related bone marrow transplantation for thalassemia

Matched-related bone marrow transplantation (BMT) may cure >80% of low-risk children with severe thalassemia (ST). Very long-term follow-up studies have shown how the standard busulfan-cyclophosphamide (BuCy) regimen may be associated with normalization of health-related quality of life, no second malignancies in the absence of chronic graft-versus-host disease, and fertility preservation in many patients. However, because BuCy may be associated with high rejection rates, some centers incorporate thiotepa (Tt) in busulfan- or treosulfan-based regimens, a combination that may increase the risk of permanent infertility. This study retrospectively compares matched-related BMT outcomes in 2 groups of low-risk ST patients conditioned with either Tt or anti-thymocyte globulin (ATG) in addition to BuCy. A total of 81 consecutive first BMTs were performed in 5 collaborating startup BMT centers in the Indian subcontinent between January 2009 and January 2016; 30 patients were transplanted after conditioning with Tt-BuCy between January 2009 and July 2013, whereas between August 2013 and January 2016, 51 patients received ATG-BuCy. All patients were <15 years and had no hepatomegaly (liver ≤2 cm from costal margin). Actuarial overall survival in the Tt-BuCy and ATG-BuCy groups was 87% and 94% and thalassemia-free survival was 80% and 85% at a median follow-up of 37 and 17 months, respectively, with no significant differences by log-rank statistics. Substituting Tt with ATG in the standard BuCy context seems safe and effective and may decrease transplant-related mortality. Higher fertility rates are expected for patients who received ATG-BuCy.

Hematopoietic stem cell transplantation for people with ß-thalassaemia major

BACKGROUND

Thalassemia is an inherited autosomal recessive blood disorder, caused by mutations in globin genes or their regulatory regions. This results in a reduced rate of synthesis of one of the globin chains that make up haemoglobin. In ß-thalassaemia major there is an underproduction of ß-globin chains combined with excess of free α-globin chains. The excess free α-globin chains precipitate in red blood cells, leading to their destruction (haemolysis) and ineffective erythropoiesis. The conventional approach to treatment is based on the correction of haemoglobin status through regular blood transfusions and iron chelation therapy for iron overload. Although conventional treatment has the capacity to improve the quality of life of people with ß-thalassaemia major, allogeneic hematopoietic stem cell transplantation is the only currently available procedure which has the curative potential. This is an update of a previously published Cochrane Review.

OBJECTIVES

To evaluate the effectiveness and safety of different types of allogeneic hematopoietic stem cell transplantation, in people with severe transfusion-dependant ß-thalassaemia major, ß-thalassaemia intermedia or ß0/+- thalassaemia variants requiring chronic blood transfusion.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Date of the most recent search: 18 August 2016.

SELECTION CRITERIA

Randomised controlled trials and quasi-randomised controlled trials comparing allogeneic hematopoietic stem cell transplantation with each other or with standard therapy (regular transfusion and chelation regimen).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened studies and had planned to extract data and assess risk of bias using standard Cochrane methodologies but no studies were identified for inclusion.

MAIN RESULTS

No relevant studies were retrieved after a comprehensive search of the literature.

AUTHORS' CONCLUSIONS

We were unable to identify any randomised controlled trials or quasi-randomised controlled trials on the effectiveness and safety of different types of allogeneic stem cell transplantation in people with severe transfusion-dependant ß-thalassaemia major or ß0/+- thalassaemia variants requiring chronic blood transfusion. The absence of high-level evidence for the effectiveness of these interventions emphasises the need for well-designed, adequately-powered, randomised controlled clinical trials.

Current and future alternative therapies for beta-thalassemia major

Beta-thalassemia is a group of frequent genetic disorders resulting in the synthesis of little or no β-globin chains. Novel approaches are being developed to correct the resulting α/β-globin chain imbalance, in an effort to move beyond the palliative management of this disease and the complications of its treatment (e.g. life-long red blood cell transfusion, iron chelation, splenectomy), which impose high costs on healthcare systems. Three approaches are envisaged: fetal globin gene reactivation by pharmacological compounds injected into patients throughout their lives, allogeneic hematopoietic stem cell transplantation (HSCT), and gene therapy. HSCT is currently the only treatment shown to provide an effective, definitive cure for β-thalassemia. However, this procedure remains risky and histocompatible donors are identified for only a small fraction of patients. New pharmacological compounds are being tested, but none has yet made it into common clinical practice for the treatment of beta-thalassemia major. Gene therapy is in the experimental phase. It is emerging as a powerful approach without the immunological complications of HSCT, but with other possible drawbacks. Rapid progress is being made in this field, and long-term efficacy and safety studies are underway.

Successful matched sibling donor marrow transplantation following reduced intensity conditioning in children with hemoglobinopathies

Fifty-two children with symptomatic sickle cell disease sickle cell disease (SCD) (N = 43) or transfusion-dependent thalassemia (N = 9) received matched sibling donor marrow (46), marrow and cord product (5), or cord blood (1) allografts following reduced intensity conditioning (RIC) with alemtuzumab, fludarabine, and melphalan between March 2003 and May 2014*. The Kaplan-Meier probabilities of overall and event-free survival at a median of 3.42 (range, 0.75-11.83) years were 94.2% and 92.3% for the group, 93% and 90.7% for SCD, and 100% and 100% for thalassemia, respectively. Treatment-related mortality (all related to graft versus host disease, GVHD) was noted in three (5.7%) recipients, all 17-18 years of age. Acute and chronic GVHD was noted in 23% and 13%, respectively, with 81% of recipients off immunosuppression by 1 year. Graft rejection was limited to the single umbilical cord blood recipient who had prompt autologous hematopoietic recovery. Fourteen (27%) had mixed chimerism at 1 year and beyond; all had discontinued immunosuppression between 4 and 12 months from transplant with no subsequent consequence on GVHD or rejection. Infectious complications included predominantly bacteremia (48% were staphylococcus) and CMV reactivation (43%) necessitating preemptive therapy. Lymphocyte recovery beyond 6 months was associated with subsidence of infectious complications. All patients who engrafted were transfusion independent; no strokes or pulmonary complications of SCD were noted, and pain symptoms subsided within 6 months posttransplant. These findings support using RIC for patients with hemoglobinopathy undergoing matched sibling marrow transplantation (*www.Clinical Trials.gov: NCT00920972, NCT01050855, NCT02435901).

Should busulfan therapeutic range be narrowed in pediatrics? Experience from a large cohort of hematopoietic stem cell transplant children

Busulfan, the corner stone of hematopoietic stem cell transplantation regimens, has a narrow therapeutic window. Therapeutic drug monitoring (TDM)-guided dosing to reach the conventional area under the concentration-time curve (AUC) target range of 900-1500 μmol min/L is associated with better outcomes. We report our experience with busulfan TDM in a large cohort of children. The aims were to investigate the relevance of using a more restricted therapeutic range and investigate the association between busulfan therapeutic range and clinical outcome. This study includes 138 children receiving 16 doses of intravenous busulfan, with the first dose assigned based on weight and doses adjusted to a local AUC target range of 980-1250 μmol min/L. Busulfan TDM combined with model-based dose adjustment was associated with an increased probability of AUC target attainment, for both target range: 90.8% versus 74.8% for the conventional target range and 66.2% versus 43.9% for the local target range (P<0.001). The median follow-up was 56.2 months. Event-free survival was 88.5%, overall survival was 91.5% and veno-occlusive disease occurred in 18.3% of patients. No difference was observed for clinical outcomes depending on the selected target range. Pharmacokinetic monitoring and individualization of busulfan dosage regimen are useful in improving target attainment, but using a restricted target range has no impact on clinical outcomes.

Modeling promising nonmyeloablative conditioning regimens in nonhuman primates

Minimal conditioning or even no conditioning would be the preferred preparation for most gene therapy applications for nonmalignant diseases. However, reduced intensity conditioning (RIC) regimens in patients with nonhematologic malignancies have not led to long-term engraftment unless a selective advantage was present for the transplanted donor cells. Similar findings have also been observed in a number of large animal studies. Inadequate myelosuppression levels were thought to be responsible for the outcomes. To address this issue several innovative protocols in small animals have been presented with selective hematopoietic myelosuppression and less systemic toxicity. Such protocols promised to curb the transplant-related morbidity and mortality in myeloablative conditioning and provide effective long-term engraftment, especially in patients with gene-corrected autografts. In the present study we have tested some of these promising RIC regimens in nonhuman primates, a clinically relevant large animal model. Our data suggest that transient myelosuppression induced by anti-c-Kit antibody in conjunction with low-dose irradiation may lead to long-term engraftment, albeit at low levels. The animals with busulfan conditioning with or without anti-c-Kit that received gene-modified autologous transplants with green fluorescent protein expression had similar myelosuppression, but failed long-term engraftment and despite immunosuppressive treatment had all the hallmarks seen previously in similar models without immunosuppression. Our preliminary data expand current knowledge of RIC and emphasize the need to explore whether specific and directed myelosuppression alone is adequate in the absence of microenvironmental modulation, or whether innovative combinations are necessary for safe and effective engraftment.

New directions for rabbit antithymocyte globulin (Thymoglobulin(®)) in solid organ transplants, stem cell transplants and autoimmunity

In the 30 years since the rabbit antithymocyte globulin (rATG) Thymoglobulin^® was first licensed, its use in solid organ transplantation and hematology has expanded progressively. Although the evidence base is incomplete, specific roles for rATG in organ transplant recipients using contemporary dosing strategies are now relatively well-identified. The addition of rATG induction to a standard triple or dual regimen reduces acute cellular rejection, and possibly humoral rejection. It is an appropriate first choice in patients with moderate or high immunological risk, and may be used in low-risk patients receiving a calcineurin inhibitor (CNI)-sparing regimen from time of transplant, or if early steroid withdrawal is planned. Kidney transplant patients at risk of delayed graft function may also benefit from the use of rATG to facilitate delayed CNI introduction. In hematopoietic stem cell transplantation, rATG has become an important component of conventional myeloablative conditioning regimens, following demonstration of reduced acute and chronic graft-versus-host disease. More recently, a role for rATG has also been established in reduced-intensity conditioning regimens. In autoimmunity, rATG contributes to the treatment of severe aplastic anemia, and has been incorporated in autograft projects for the management of conditions such as multiple sclerosis, Crohn’s disease, and systemic sclerosis. Finally, research is underway for the induction of tolerance exploiting the ability of rATG to induce immunosuppresive cells such as regulatory T-cells. Despite its long history, rATG remains a key component of the immunosuppressive armamentarium, and its complex immunological properties indicate that its use will expand to a wider range of disease conditions in the future.

Hematopoietic stem cell transplantation in thalassemia major and sickle cell disease: indications and management recommendations from an international expert panel

Thalassemia major and sickle cell disease are the two most widely disseminated hereditary hemoglobinopathies in the world. The outlook for affected individuals has improved in recent years due to advances in medical management in the prevention and treatment of complications. However, hematopoietic stem cell transplantation is still the only available curative option. The use of hematopoietic stem cell transplantation has been increasing, and outcomes today have substantially improved compared with the past three decades. Current experience world-wide is that more than 90% of patients now survive hematopoietic stem cell transplantation and disease-free survival is around 80%. However, only a few controlled trials have been reported, and decisions on patient selection for hematopoietic stem cell transplantation and transplant management remain principally dependent on data from retrospective analyses and on the clinical experience of the transplant centers. This consensus document from the European Blood and Marrow Transplantation Inborn Error Working Party and the Paediatric Diseases Working Party aims to report new data and provide consensus-based recommendations on indications for hematopoietic stem cell transplantation and transplant management.

Indications for allo- and auto-SCT for haematological diseases, solid tumours and immune disorders: current practice in Europe, 2015

This is the sixth special report that the European Society for Blood and Marrow Transplantation regularly publishes on the current practice and indications for haematopoietic SCT for haematological diseases, solid tumours and immune disorders in Europe. Major changes have occurred in the field of haematopoietic SCT over the last years. Cord blood units as well as haploidentical donors have been increasingly used as stem cell sources for allo-SCT, thus, augmenting the possibility of finding a suitable donor for a patient. Continuous refinement of conditioning strategies has also expanded not only the number of potential indications but also has permitted consideration of older patients or those with co-morbidity for a transplant. There is accumulating evidence of the role of haematopoietic SCT in non-haematological disorders such as autoimmune diseases. On the other hand, the advent of new drugs and very effective targeted therapy has challenged the role of SCT in some instances or at least, modified its position in the treatment armamentarium of a given patient. An updated report with revised tables and operating definitions is presented.

Infectious complications following allogeneic stem cell transplantation by using anti-thymocyte globulin-based myeloablative conditioning regimens in children with hemoglobinopathies

BACKGROUND

Anti-thymocyte globulin (ATG) has been used to prevent graft failure/rejection in the setting of allogeneic stem cell transplantation (allo-SCT) for hemoglobinopathies; however, epidemiology data for transplant-related infections in this population are scarce.

METHOD

We retrospectively analyzed the epidemiology of bacterial, fungal, viral, and parasitic infections in a cohort of 105 children and adolescents with β-thalassemia (n = 100) or sickle cell disease (n = 5) who underwent allo-SCT using human leukocyte antigen (HLA)-identical sibling (n = 96) or HLA-compatible unrelated donors (n = 9) in a single institution. All patients received an ATG-based conditioning regimen.

RESULTS

The cumulative incidence of cytomegalovirus (CMV) viremia was 45.7% (95% confidence interval [CI] 33-55%), developing at a median of 48 (range 12-142) days without evidence of overt CMV disease. Herpes zoster developed in 8 patients at a median of 12 months post transplant, while 10 patients presented with late onset hemorrhagic cystitis at a median of 35 days post transplant. The cumulative incidence of bacteremia was 17.1% (95% CI 10.6-25%), occurring at a median of 74 (range 24-110) days. No patient developed probable or definite invasive fungal infection. Four deaths were recorded; 2 of them were attributed to infections (toxoplasmosis and Pneumocystis jirovecii pneumonia, respectively).

CONCLUSION

The rate of infections after allo-SCT, using an ATG-containing preparative regimen, in our population of pediatric patients with hemoglobinopathies is comparable to that reported elsewhere with the use of non-ATG containing regimens.

Hematopoietic stem cell transplantation for people with ß-thalassaemia major

BACKGROUND

Thalassemia is an inherited blood disorder, caused by mutations in regulatory genes and transmitted as an autosomal recessive disorder, which results in a reduced rate of synthesis of one of the globin chains that make up haemoglobin. In ß-thalassaemia major there is an underproduction of ß-globin chains combined with excess of free α-globin chains. The excess free α-globin chains damage the red blood cell membranes, leading to their destruction and a phenomenon termed ineffective erythropoiesis. The conventional approach to treatment is based on the correction of haemoglobin status through regular blood transfusions and iron chelation therapy for iron overload. Although conventional treatment has the capacity to improve the quality of life of people with ß-thalassaemia major, allogeneic hematopoietic stem cell transplantation is the only currently available procedure which has the potential to definitively cure the disease.

OBJECTIVES

To evaluate the effectiveness and safety of different types of allogeneic hematopoietic stem cell transplantation, in people with severe transfusion-dependant ß-thalassaemia major, ß-thalassaemia intermedia or ß0/+- thalassaemia variants requiring chronic blood transfusion.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Date of the most recent search: 11 November 2013.

SELECTION CRITERIA

Randomised controlled trials and quasi-randomised controlled trials comparing allogeneic hematopoietic stem cell transplantation with each other or with standard therapy (regular transfusion and chelation regimen).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened studies and had planned to extract data and assess risk of bias using standard Cochrane Collaboration methodologies but no studies were identified for inclusion.

MAIN RESULTS

No relevant studies were retrieved after a comprehensive search of the literature.

AUTHORS' CONCLUSIONS

We were unable to identify any randomised controlled trials or quasi-randomised controlled trials on the effectiveness and safety of different types of allogeneic stem cell transplantation in people with severe transfusion-dependant ß-thalassaemia major or ß0/+- thalassaemia variants requiring chronic blood transfusion. The absence of high-level evidence for the effectiveness of these interventions emphasises the need for well-designed, adequately-powered, randomised controlled clinical trials.

Bone marrow transplantation for thalassemia from alternative related donors: improved outcomes with a new approach

Bone marrow transplantation (BMT) performance can be limited by a lack of ideal donors, and the role of alternative donor hematopoietic cell transplantation in thalassemia is not well established. Here we used a new treatment protocol (Pc 26.1) in 16 thalassemia patients to perform BMT using phenotypically HLA-identical or 1-antigen-mismatched relatives (related donors [RDs]). We compared these results with HLA-matched sibling (matched sibling donors [MSDs]) BMT in 66 patients. The entire RD group and 88% of MSD group had sustained engraftment. Rejection incidence was 0% in the RD and 12% (95% confidence interval [95% CI], 6%-21%) in MSD groups (P = .15), with respective thalassemia-free survival probabilities of 94% (95% CI, 63%-99%) and 82% (95% CI, 70%-89%) (P = .24). Transplant-related mortality was 6% (95% CI, 1%-26%) in the RD group and 8% (95% CI, 3%-16%) in the MSD group (P = .83). The intensified new protocol was not associated with increased nonhematologic toxicity. The present data show that the Pc 26.1 preparative regimen allows thalassemia patients to safely undergo BMT from RDs who are not HLA-matched siblings, with transplant outcomes similar to patients with MSD grafts.

Long-term health-related quality of life evaluated more than 20 years after hematopoietic stem cell transplantation for thalassemia

The principal aim of our study was to investigate whether patients transplanted more than 20 years ago for β-thalassemia major had a different health-related quality of life (HRQoL) compared with the general population. The Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and the Functional Assessment of Cancer Therapy-Bone Marrow Transplant (FACT-BMT) were received from 109 ex-thalassemia patients who underwent hematopoietic stem cell transplantation (HSCT) during the 1980s and 1990s. Adjusted comparisons were performed separately for patient age at HSCT and the presence or absence of graft-versus-host disease (GVHD). Sociodemographic and clinical variables were also analyzed. The median age of our cohort at HSCT and the time of the survey was 12 years (range, 1-36) and 34 years (range, 21-48), respectively, with a median follow-up age of 22.8 years (range, 11.7-30.3). Statistical analysis of data collected more than 20 years after HSCT showed that the long-term HRQoL of ex-thalassemia patients was very similar to that of the general population. Clinical meaningful differences were only found for the general health (GH) scale (-8.9; 95% CI, -15.0 to 2.7, P = .005). Mental health, education level, employment status, marital status, living arrangements, and birth rate were compatible with normal living patterns. The development of GVHD and older age at transplantation were important impairing factors. Additional analyses performed to evaluate HRQoL in an age-sex-matched cohort of 124 patients receiving conventional treatment of β-thalassemia revealed poorer outcomes compared with the cohort of transplanted patients.