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

Clinical Outcomes Among Patients With Sickle Cell Disease and Transfusion-Dependent Beta-Thalassemia Treated With Allogeneic Hematopoietic Stem Cell Transplantation: A Systematic Literature Review

Background

The purpose of this study is to synthesize evidence on disease-specific outcomes in patients with sickle cell disease (SCD) or transfusion-dependent beta-thalassemia (TDT) following allogeneic hematopoietic stem cell transplant (allo-HSCT).

Methods

A systematic literature review (SLR) was conducted in MEDLINE and Embase to identify publications up to May 2023, including patients with SCD or TDT treated with allo-HSCT. Occurrence of vaso-occlusive crises (VOCs) including acute pain, acute chest syndrome, priapism, and splenic sequestration in SCD, and red blood cell transfusion (RBCT) requirements in TDT were the main outcomes of interest. Transplant-related outcomes such as graft-versus-host disease (GVHD) and graft failure/rejection were summarized in the studies that reported main outcomes. Proportion of patients experiencing VOCs or RBCTs, GVHD, and graft failure/rejection after allo-HSCT were aggregated and descriptively reported with range across studies.

Results

Thirty-one SCD studies met inclusion criteria. Twenty-nine studies assessed for VOC and pain crisis events after allo-HSCT; 11 studies reported ≥1 VOCs after allo-HSCT in 6.9% of the 2,760 patients. Graft failure was reported in 14.4% (0.9%-18.8%, 14 studies) of patients, graft rejection in 5.5% (1.6%-100.0%, 12 studies) of patients, acute GVHD in 22.4% (1.6%-50.0%, 19 studies) of patients, and chronic GVHD in 20.4% (3.3%-57.1%, 14 studies) of patients. Seventy-eight TDT studies met inclusion criteria. Fifty-six studies reported that 8.8% of the 3,107 patients required RBCTs after allo-HSCT. Graft failure was reported in 5.4% (1.1%-80.0%, 21 studies) of patients, graft rejection in 7.5% (0.5%-42.9%, 50 studies) of patients, acute GVHD in 28.4% (5.2%-100.0%, 57 studies) and chronic GVHD in 15.2% (1.3%-50.0%, 51 studies) of TDT patients.

Conclusion

Based on this SLR, after allo-HSCT, a portion of patients with SCD continue to experience VOCs and a portion of patients with TDT continue to require RBCTs, in addition to experiencing GVHD and graft failure or rejection.

Impact of haematopoietic stem cell transplantation for benign and malignant haematologic and non-haematologic disorders on fertility: a systematic review and meta-analysis

Haematopoietic stem cell transplantation (HSCT) exposes patients to long-term complications like gonadal dysfunction and infertility. The European Society for Blood and Marrow Transplantation advised in 2015 that fertility preservation should be considered for children and adolescents requiring HSCT. This systematic review and meta-analysis is part of the FertiTOX project, which aims to close the data gap regarding the gonadotoxicity of anticancer therapies to provide more accurate advice regarding fertility preservation. This review were conducted in November 2023, covering articles since 2000. In total, 56 studies were included in the meta-analysis, comprising 1853 female malignant, 241 female benign, 1871 male malignant, and 226 male benign cases. The analysis, using a random-effects model, estimated the prevalence and its 95% confidence interval, revealing that overall infertility exceeded 30% in all groups. Female malignant cases had a prevalence of 65% (95% CI: 0.58-0.71), while in females with benign disease, it was 61% (CI: 0.48-0.73). Males with malignant disease had a prevalence of 41% (CI: 0.32-0.51), and those with benign disease had 31% (CI: 0.19-0.46). The > 30% overall prevalence indicates a clinical need for fertility preservation counseling in both genders undergoing HSCT. Further prospective studies are necessary to address HSCT's individual impact on gonadal function. This systematic review is registered with the International Prospective Register of Systematic Reviews (PROSPERO) under CRD42023486928.

Betibeglogene autotemcel gene therapy in patients with transfusion-dependent, severe genotype β-thalassaemia (HGB-212): a non-randomised, multicentre, single-arm, open-label, single-dose, phase 3 trial

BACKGROUND

Transfusion-dependent β-thalassaemia (TDT) is a severe disease, resulting in lifelong blood transfusions, iron overload, and associated complications. Betibeglogene autotemcel (beti-cel) gene therapy uses autologous haematopoietic stem and progenitor cells (HSPCs) transduced with BB305 lentiviral vector to enable transfusion independence.

METHODS

HGB-212 was a non-randomised, multicentre, single-arm, open-label, phase 3 study of beti-cel in patients with TDT conducted at eight centres in France, Germany, Greece, Italy, the UK, and the USA. Patients with β0/β0, β0/β+IVS-I-110, or β+IVS-I-110/β+IVS-I-110 genotypes, clinically stable TDT, and a transfusion history of at least 100 mL/kg per year of packed red blood cells (pRBCs) or at least eight transfusions of pRBCs per year in the 2 years before enrolment were eligible for participation. After undergoing HSPC mobilisation and busulfan-based, pharmacokinetic-adjusted myeloablative conditioning, patients were infused with beti-cel and followed up for 24 months. The primary efficacy outcome was transfusion independence, defined as weighted average haemoglobin level of 9 g/dL or above without pRBC transfusions for 12 or more months. The primary outcome was measured in all patients who received an infusion of beti-cel (transplant population); safety was evaluated in all patients who initiated study treatment (intention-to-treat population). Patients were eligible to enrol in the ongoing 13-year long-term follow-up study (for a total of 15 years), LTF-303 (registered at ClinicalTrials.gov, NCT02633943). This trial, HGB-212, was registered at ClinicalTrials.gov (NCT03207009), and is complete.

FINDINGS

From June 8, 2017, to March 12, 2020, 20 patients were screened for eligibility. One patient was ineligible and one withdrew consent before HSPC mobilisation and myeloablative conditioning. Of the 18 patients who received beti-cel, ten (56%) were male and eight (44%) were female; 13 (72%) were younger than 18 years at the time of informed consent, and five (28%) were older than 18 years. 12 (67%) patients had β0/β0 genotypes, three (17%) had β0/ β+IVS-I-110, and three (17%) had β+IVS-I-110/β+IVS-I-110. As of Jan 30, 2023, all patients enrolled in the long-term follow-up study and the median follow-up was 47·9 months (range 23·8-59·0). All 18 patients were evaluable for transfusion independence, with 16 (89%) of 18 reaching and maintaining transfusion independence to last follow=up (estimated effect size 89·9% [95% CI 65·3-98·6]). All patients had at least one adverse event after beti-cel infusion. There were no serious adverse events considered to be related to beti-cel, and no deaths.

INTERPRETATION

These data demonstrate that beti-cel can allow patients with genotypes that cause severe β-thalassaemia (β0/β0, β0/β+IVS-I-110, or β+IVS-I-110/β+IVS-I-110) to reach transfusion independence. Beti-cel offers the potential to attain near-normal haemoglobin levels for those with severe forms of TDT, and a potentially curative option without the risks and limitations of allogeneic HSPC transplantation. Patients are being followed up for a total of 15 years to assess the durability of transfusion independence and long-term safety profile of beti-cel.

FUNDING

Bluebird Bio, Somerville, MA, USA.

The growth and development of children with β-thalassemia major one year after allogeneic hematopoietic stem cell transplantation

Background

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has proven to be an effective curative intervention for children with β-thalassemia major (β-TM). They are susceptible to growth disorders due various factors. The primary objective of this study was to investigate the growth and development of children with β-TM both before and after undergoing allo-HSCT during a one-year follow-up period.

Methods

According to the international reference standards for child growth established by the World Health Organization in 2006, participants were divided into two groups based on their Z scores: weight-for-age Z scores (WAZ), height-for-age Z scores (HAZ), and body mass index-for-age Z scores (BAZ) before allo-HSCT. The first group included children with normal nutritional levels (-2≤ Z scores ≤2), while the second group consisted of children with malnutrition (Z scores <-2 or >2). Measurements of weight, height, and body mass index (BMI) were recorded at six time points: prior to allo-HSCT (T0), and 1 month (T1), 3 months (T3), 6 months (T6), 9 months (T9), and 12 months (T12) following the procedure.

Results

Among the 56 children diagnosed with β-TM, 25% were malnourished prior to HSCT. In the group with normal nutrition, mean WAZ (P=0.04) and HAZ (P<0.001) values were significantly higher at T12 compared to T0; however, mean BAZ was similar at T12 and T0 (P=0.61). In contrast, in the malnutrition group, no significant differences were observed in mean WAZ (P=0.12), HAZ (P=0.27), or BAZ (P=0.75) values between T12 and T0. Notably, the incidence of increased HAZ was significantly more prevalent in children aged seven years or younger than in those older than seven years (P=0.01).

Conclusions

Children diagnosed with β-TM who had normal nutritional levels at the time of allo-HSCT showed significant growth improvements within one year of follow-up compared to their pre-transplantation state. Additionally, the age at which allo-HSCT was performed may substantially influence post-transplantation growth rates. Regular monitoring of growth and development from the time of diagnosis is crucial to ensure optimal nutritional status at the time of allo-HSCT, thereby enhancing the prognosis for these children after transplantation.

Late effects after allogeneic haematopoietic cell transplantation in children and adolescents with non-malignant disorders: a retrospective cohort study

BACKGROUND

Continued advances in haematopoietic cell transplantation (HCT) for children with non-malignant diseases (NMDs) have led to a growing population of survivors in whom late occurring toxic effects remain a challenge. We investigated the incidence of and risk factors for post-transplant toxicities in a contemporary cohort of children and adolescents undergoing HCT for NMDs.

METHODS

In this retrospective cohort study, we extracted data from the Center for International Blood and Marrow Transplantation Research (CIBMTR) database to analyse timing and incidence of effects and risk factors associated with late effects of HCT for treatment of NMDs at age 21 years or younger. Late effects of interest were avascular necrosis, cataracts, congestive heart failure, myocardial infarction, diabetes, gonadal dysfunction, growth hormone deficiency, hypothyroidism, renal failure requiring dialysis, and neurological events (stroke and seizure). Cumulative incidence of each late effect was calculated at 5 years and 7 years after HCT. Risk factors were evaluated in Cox proportional hazards regression analyses. Main exposures were primary NMD, age, sex, ethnicity and race, insurance, donor and graft type, myoablative conditioning, total-body irradiation exposure, graft-versus-host disease (GVHD), and transplant year. Primary outcomes were rates, cumulative incidence probability (95% CI), and risk-factors for organ-specific late effects.

FINDINGS

Between Jan 1, 2000, and Dec 31, 2017, 7785 patients aged 21 years or younger underwent HCT. 1995 patients were ineligible or did not consent to be included. 5790 patients from 171 centres were included in the analysis. 3505 (60·5%) of 5790 patients were male and 2285 (39·5%) were female. 2106 (36·4%) patients were White, 771 (13·3%) were Hispanic, and 773 (12·7%) were Black. 1790 (30·9%) patients were non-USA residents. Median age at HCT was 5·5 years (range 0·0-21·0). 1127 (19%) of 5790 patients had one late effect, and 381 (7%) had at least two. At 7 years post-HCT, the cumulative incidence probability was 1·9 (95% CI 1·5-2·3) for cataracts, 4·9 (4·3-5·6) for diabetes, 2·6 (2·1-3·1) for gonadal dysfunction, 3·2 (2·7-3·8) for hypothyroidism, 5·0 (4·4-5·7) for growth disturbance, 8·1 (7·4-8·9) for renal failure, 1·6 (1·3-2·0) for avascular necrosis, 0·6 (0·4-0·8) for congestive heart failure, 0·2 (0·1-0·3) for myocardial infarction, and 9·4 (8·6-10·2) for neurological effects. Age 10 years or older at HCT, unrelated donor source, total-body irradiation, and GVHD were identified as risk factors for long-term effects.

INTERPRETATION

The findings highlight the need for, and access to, multidisciplinary and lifelong follow-up for children undergoing HCT for NMDs. As more children undergo treatment with cellular therapies for non-malignant conditions, further analyses of post-transplant data could increasingly guide treatment decisions and subsequent long-term surveillance.

FUNDING

National Cancer Institute, National Heart, Lung and Blood Institute, National Institute of Allergy and Infectious Diseases, Health Resources and Services Administration, and Office of Naval Research.

Iron overload disorders: Growth and gonadal dysfunction in childhood and adolescence

Hemochromatosis (HC) is characterized by the progressive accumulation of iron in the body, resulting in organ damage. Endocrine complications are particularly common, especially when the condition manifests in childhood or adolescence, when HC can adversely affect linear growth or pubertal development, with significant repercussions on quality of life even into adulthood. Therefore, a timely and accurate diagnosis of these disorders is mandatory, but sometimes complex for hematologists without endocrinological support. This is a narrative review focused on puberty and growth disorders during infancy and adolescence aiming to offer guidance for diagnosis, treatment, and proper follow-up. Additionally, it aims to highlight gaps in the existing literature and emphasizes the importance of collaboration among specialists, which is essential in the era of precision medicine.

Guideline for the management of conception and pregnancy in thalassaemia syndromes: A British Society for Haematology Guideline

This comprehensive guideline, developed by a representative group of UK-based medical experts specialising in haemoglobinopathies, addresses the management of conception and pregnancy in patients with thalassaemia. A systematic search of PubMed and EMBASE using specific keywords, formed the basis of the literature review. Key terms included "thalassaemia," "pregnancy," "Cooley's anaemia," "Mediterranean anaemia," and others, covering aspects such as fertility, iron burden and ultrasonography. The guideline underwent rigorous review by prominent organisations, including the Endocrine Society, the Royal College of Obstetricians and Gynaecologists (RCOG), the United Kingdom Thalassaemia Society and the British Society of Haematology (BSH) guideline writing group. Additional feedback was solicited from a sounding board of UK haematologists, ensuring a thorough and collaborative approach. The objective of the guideline is to equip healthcare professionals with precise recommendations for managing conception and pregnancy in patients with thalassaemia.

Long-term endocrine sequelae after hematopoietic stem cell transplantation in children and adolescents

PURPOSE

As the survival rate from pediatric cancers has increased significantly with advances in treatment modalities, long-term endocrine complications have also risen. This study investigated the frequencies and risks of endocrine sequelae in childhood cancer survivors who received hematopoietic stem cell transplantation (HSCT).

METHODS

This study included 200 pediatric patients who underwent HSCT. Clinical and endocrinological findings were collected retrospectively. The median follow-up duration after HSCT was 14 years.

RESULTS

Endocrine complications occurred in 135 patients (67.5%). Children who underwent HSCT at pubertal age (n=100) were at higher risk of endocrine complications than those who received it at prepubertal age (79% vs. 56%, P=0.001). The most common complication was hypogonadism (40%), followed by dyslipidemia (22%). Short stature and diabetes mellitus were more prevalent in the prepubertal group, whereas hypogonadism and osteoporosis were more common in the pubertal group. Being female, pubertal age at HSCT, and glucocorticoid use were predictors of an increased risk for any complication. Radiation exposure increased the risk of short stature and hypothyroidism. Hypogonadism was significantly associated with being female, pubertal age at HSCT, and high-dose radiation. Pubertal age at HSCT also increased the risks of osteoporosis and dyslipidemia.

CONCLUSION

This study demonstrates that long-term endocrine complications are common after HSCT in children and adolescents. Age at HSCT is a critical factor for endocrine complications after HSCT. These findings suggest that surveillance strategies for endocrine complications in childhood cancer survivors should be specified according to age at HSCT.

Busulfan and subsequent malignancy: An evidence-based risk assessment

BACKGROUND

The incidence of secondary malignancies associated with busulfan exposure is considered low, but has been poorly characterized. Because this alkylating agent is increasingly utilized as conditioning prior to gene therapy in nonmalignant hematologic and related disorders, more precise characterization of busulfan's potential contribution to subsequent malignant risk is warranted.

PROCEDURE

We conducted a literature-based assessment of busulfan and subsequent late effects, with emphasis on secondary malignancies, identifying publications via PubMed searches, and selecting those reporting at least 3 years of follow-up.

RESULTS

We identified eight pediatric and 13 adult publications describing long-term follow-up in 570 pediatric and 2076 adult hematopoietic cell transplant (HCT) recipients. Secondary malignancies were reported in 0.5% of pediatric HCT recipients, with no cases of myelodysplastic syndrome (MDS) or acute myelocytic leukemia (AML). Fatal secondary malignancies were reported in 0.8% of 1887 evaluable adult HCT recipients, and an overall incidence of secondary malignancies of 4.8% was reported in a subset of 389 evaluable adult patients. We also reviewed long-term results from eight publications evaluating lentiviral- and human promotor-based HSC-targeted gene therapy in 215 patients with nonmalignant conditions, in which busulfan/treosulfan monotherapy or busulfan/fludarabine was the only conditioning. Two malignancies were reported in patients with sickle cell disease (SCD), one of which was potentially busulfan-related. No additional malignancies were reported in 173 patients with follow-up of 5-12 years.

CONCLUSION

The incidence of busulfan-related secondary malignancies is low, and likely to be substantially less than 1% in pediatric transplant recipients, especially those receiving busulfan monotherapy for nonmalignant conditions other than SCD.

Thyroid and Adrenal Dysfunction in Hemoglobinopathies Before and After Allogeneic Hematopoietic Cell Transplant

Purpose

To determine the rate and clinical characteristics associated with abnormal thyroid and adrenal function in recipients of nonmyeloablative hematopoietic cell transplantation (HCT) for sickle cell disease (SCD) and beta-thalassemia.

Methods

We retrospectively reviewed patients who enrolled in 4 nonmyeloablative HCT regimens with alemtuzumab and total body irradiation (TBI). Baseline and annual post-HCT data were compared, which included age, sex, sickle phenotype, thyroid panel (total T3, free T4, thyroid stimulating hormone, antithyroid antibodies), cortisol level, ACTH stimulation testing, ferritin, medications, and other relevant medical history.

Results

Among 43 patients in haploidentical transplant and 84 patients in the matched related donor protocols with mostly SCD, the rate of any thyroid disorder pre-HCT was 3.1% (all subclinical hypothyroidism) and post-HCT was 29% (10 hypothyroidism, 4 Grave's disease, and 22 subclinical hypothyroidism). Ninety-two (72%) patients had ferritin >1000 ng/dL, of which 33 patients (35.8%) had thyroid dysfunction. Iron overload was noted in 6 of 10 patients with hypothyroidism and 12 of 22 patients with subclinical hypothyroidism.Sixty-one percent were on narcotics for pain control. With respect to adrenal insufficiency (AI) pre-HCT, 2 patients were maintained on corticosteroids for underlying rheumatologic disorder and 8 had AI diagnosed during pre-HCT ACTH stimulation testing (total 10, 7.9%). Post-HCT, an additional 4 (3%) developed AI from corticosteroid use for acute graft vs host disease, Evans syndrome, or hemolytic anemia.

Conclusion

Although iron overload was common in SCD, thyroid dysfunction pre-HCT related to excess iron was less common. Exposure to alemtuzumab or TBI increased the rates of thyroid dysfunction post-HCT. In contrast, AI was more common pre-HCT, but no risk factor was identified. AI post-HCT was infrequent and associated with corticosteroid use for HCT-related complications.

Hematopoietic Stem Cell Transplantation in Thalassemia

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only consolidated, potentially curative treatment for patients with transfusion-dependent thalassemia major. In the past few decades, several new approaches have reduced the toxicity of conditioning regimens and decreased the incidence of graft-versus-host disease, improving patients' outcomes and quality of life. In addition, the progressive availability of alternative stem cell sources from unrelated or haploidentical donors or umbilical cord blood has made HSCT a feasible option for an increasing number of subjects lacking an human leukocyte antigen (HLA)-identical sibling. This review provides an overview of allogeneic hematopoietic stem cell transplantation in thalassemia, reassesses current clinical results, and discusses future perspectives.

Hypothyroidism in children with Hb E/β-thalassemia compared between those who received regular transfusion and those who underwent hematopoietic stem cell transplantation

The studies of hypothyroidism in children with transfusion-dependent hemoglobin E/β-thalassemia (TDT), especially in those who underwent hematopoietic stem cell transplantation (HSCT) are limited. We performed a longitudinal retrospective analysis of thyroid function test (TFT) results among TDT patients aged <25 years who received regular transfusion compared to those who underwent HSCT in Faculty of Medicine Siriraj hospital, Thailand during October 2003 to March 2019. Fifty patients (23 TDT, 27 HSCT) were included. The mean age at the last follow-up was 20.1 ± 2.8 vs. 14.5 ± 4.61 years, respectively. The median age at HSCT was 6 (range: 1.9-13.7) years. The prevalence of hypothyroidism among TDT and post-HSCT was 47.8% and 52.2%, respectively. No study patients showed symptoms or signs of hypothyroidism. Subclinical hypothyroidism was the most common type (63.6% of TDT, and 100% of post-HSCT). We found persistent hypothyroidism in 30.4% of TDT, and in 22.2% of post-HSCT. Thyroxine was given in 1 TDT patient with overt hypothyroidism, and in 3 of 6 post-HSCT patients with persistent subclinical hypothyroidism. The ex-thalassemia patients who underwent HSCT after the age of 10 years had a significantly higher risk of post-HSCT hypothyroidism compared to those who underwent HSCT at the age ≤10 years (hazard ratio: 12.01, 95% confidence interval: 1.65-87.41; p = 0.014). In conclusion, hypothyroidism was found to be common in both TDT and post-HSCT patients. Subclinical hypothyroidism without symptoms and signs was the most common type, and was diagnosed only by TFT screening. Long-term regular surveillance of TFT should be performed in both groups of 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.

Fertility preservation for pediatric patients with hemoglobinopathies: Multidisciplinary counseling needed to optimize outcomes

Hemoglobinopathies are autosomal recessive disorders that occur when genetic mutations negatively impact the function of hemoglobin. Common hemoglobinopathies that are clinically significant include sickle cell disease, alpha thalassemia, and beta thalassemia. Advancements in disease-modifying and curative treatments for the common hemoglobinopathies over the past thirty years have led to improvements in patient quality of life and longevity for those who are affected. However, the diseases, their treatments and cures pose infertility risks, making fertility preservation counseling and treatment an important part of the contemporary comprehensive patient care. Sickle cell disease negatively impacts both male and female infertility, primarily by testicular failure and decreased ovarian reserve, respectively. Fertility in both males and females with beta thalassemia major are negatively impacted by iron deposition due to chronic blood transfusions. Hematopoietic stem cell transplant (HSCT) is currently the only curative treatment for SCD and transfusion dependent beta thalassemia. Many of the conditioning regimens for HSCT contain chemotherapeutic agents with known gonadotoxicity and whole-body radiation. Although most clinical studies on toxicity and impact of HSCT on long-term health do not evaluate fertility, gonadal failure is common. Male fertility preservation modalities that exist prior to gonadotoxic treatment include sperm banking for pubertal males and testicular cryopreservation for pre-pubertal boys. For female patients, fertility preservation options include oocyte cryopreservation and ovarian tissue cryopreservation. Oocyte cryopreservation requires controlled ovarian hyperstimulation (COH) with ten to fourteen days of intensive monitoring and medication administration. This is feasible once the patient has undergone menarche. Follicular growth is monitored via transvaginal or transabdominal ultrasound, and hormone levels are monitored through frequent blood work. Oocytes are then harvested via a minimally invasive approach under anesthesia. Complications of COH are more common in patients with hemoglobinopathies. Ovarian hyperstimulation syndrome creates a greater risk to patients with underlying vascular, pulmonary, and renal injury, as they may be less able to tolerate fluids shifts. Thus, it is critical to monitor patients undergoing COH closely with close collaboration between the hematology team and the reproductive endocrinology team. Counseling patients and families about future fertility must take into consideration the patient's disease, treatment history, and planned treatment, acknowledging current knowledge gaps.

New Entity-Thalassemic Endocrine Disease: Major Beta-Thalassemia and Endocrine Involvement

Beta-thalassemia (BTH), a recessively inherited haemoglobin (Hb) disorder, causes iron overload (IO), extra-medullary haematopoiesis and bone marrow expansion with major clinical impact. The main objective of this review is to address endocrine components (including aspects of reproductive health as fertility potential and pregnancy outcome) in major beta-thalassemia patients, a complex panel known as thalassemic endocrine disease (TED). We included English, full-text articles based on PubMed research (January 2017-June 2022). TED includes hypogonadism (hypoGn), anomalies of GH/IGF1 axes with growth retardation, hypothyroidism (hypoT), hypoparathyroidism (hypoPT), glucose profile anomalies, adrenal insufficiency, reduced bone mineral density (BMD), and deterioration of microarchitecture with increased fracture risk (FR). The prevalence of each ED varies with population, criteria of definition, etc. At least one out of every three to four children below the age of 12 y have one ED. ED correlates with ferritin and poor compliance to therapy, but not all studies agree. Up to 86% of the adult population is affected by an ED. Age is a positive linear predictor for ED. Low IGF1 is found in 95% of the population with GH deficiency (GHD), but also in 93.6% of persons without GHD. HypoT is mostly pituitary-related; it is not clinically manifested in the majority of cases, hence the importance of TSH/FT4 screening. HypoT is found at any age, with the prevalence varying between 8.3% and 30%. Non-compliance to chelation increases the risk of hypoT, yet not all studies confirmed the correlation with chelation history (reversible hypoT under chelation is reported). The pitfalls of TSH interpretation due to hypophyseal IO should be taken into consideration. HypoPT prevalence varies from 6.66% (below the age of 12) to a maximum of 40% (depending on the study). Serum ferritin might act as a stimulator of FGF23. Associated hypocalcaemia transitions from asymptomatic to severe manifestations. HypoPT is mostly found in association with growth retardation and hypoGn. TED-associated adrenal dysfunction is typically mild; an index of suspicion should be considered due to potential life-threatening complications. Periodic check-up by ACTH stimulation test is advised. Adrenal insufficiency/hypocortisolism status is the rarest ED (but some reported a prevalence of up to one third of patients). Significantly, many studies did not routinely perform a dynamic test. Atypical EM sites might be found in adrenals, mimicking an incidentaloma. Between 7.5-10% of children with major BTH have DM; screening starts by the age of 10, and ferritin correlated with glycaemia. Larger studies found DM in up to 34%of cases. Many studies do not take into consideration IGF, IGT, or do not routinely include OGTT. Glucose anomalies are time dependent. Emerging new markers represent promising alternatives, such as insulin secretion-sensitivity index-2. The pitfalls of glucose profile interpretation include the levels of HbA1c and the particular risk of gestational DM. Thalassemia bone disease (TBD) is related to hypoGn-related osteoporosis, renal function anomalies, DM, GHD, malnutrition, chronic hypoxia-induced calcium malabsorption, and transplant-associated protocols. Low BMD was identified in both paediatric and adult population; the prevalence of osteoporosis/TBD in major BTH patients varies; the highest rate is 40-72% depending on age, studied parameters, DXA evaluation and corrections, and screening thoracic-lumbar spine X-ray. Lower TBS and abnormal dynamics of bone turnover markers are reported. The largest cohorts on transfusion-dependent BTH identified the prevalence of hypoGn to be between 44.5% and 82%. Ferritin positively correlates with pubertal delay, and negatively with pituitary volume. Some authors appreciate hypoGn as the most frequent ED below the age of 15. Long-term untreated hypoGn induces a high cardiovascular risk and increased FR. Hormonal replacement therapy is necessary in addition to specific BTH therapy. Infertility underlines TED-related hormonal elements (primary and secondary hypoGn) and IO-induced gonadal toxicity. Males with BTH are at risk of infertility due to germ cell loss. IO induces an excessive amount of free radicals which impair the quality of sperm, iron being a local catalyser of ROS. Adequate chelation might improve fertility issues. Due to the advances in current therapies, the reproductive health of females with major BTH is improving; a low level of statistical significance reflects the pregnancy status in major BTH (limited data on spontaneous pregnancies and growing evidence of the induction of ovulation/assisted reproductive techniques). Pregnancy outcome also depends on TED approach, including factors such as DM control, adequate replacement of hypoT and hypoPT, and vitamin D supplementation for bone health. Asymptomatic TED elements such as subclinical hypothyroidism or IFG/IGT might become overt during pregnancy. Endocrine glands are particularly sensitive to iron deposits, hence TED includes a complicated puzzle of EDs which massively impacts on the overall picture, including the quality of life in major BTH. The BTH prognostic has registered progress in the last decades due to modern therapy, but the medical and social burden remains elevated. Genetic counselling represents a major step in approaching TH individuals, including as part of the pre-conception assessment. A multidisciplinary surveillance team is mandatory.

Late endocrine effects after hematopoietic stem cell transplantation in children with nonmalignant diseases

The number of children undergoing hematopoietic stem cell transplantation (HSCT) for nonmalignant diseases has increased in recent years. Endocrine complications are common after HSCT for malignant diseases, while little is known about long-term prevalence and risk factors in children transplanted for nonmalignant diseases. We retrospectively evaluated gonadal function, near adult height and thyroid function in 197 survivors of pediatric HSCT for hemoglobinopathies (n = 66), inborn errors of immunity/metabolism (n = 74) and bone marrow failure disorders (n = 57); median follow-up was 6.2 years (range 3.0-10.5). Gonadal dysfunction occurred in 55% of (post)pubertal females, was still present at last assessment in 43% and was more common after busulfan- than treosulfan-based conditioning (HR 10.6, CI 2.2-52.7; adjusted for HSCT indication). Gonadal dysfunction occurred in 39% of (post)pubertal males, was still present at last assessment in 32% and was less common in those who were prepubertal compared to (post)pubertal at HSCT (HR 0.11; CI 0.05-0.21). Near adult height was more than 2 SDS below mean parental height in 21% of males and 8% of females. Hypothyroidism occurred in 16% of patients; 4% received thyroxin treatment. In conclusion, endocrine complications, especially gonadal dysfunction, are common after pediatric HSCT for nonmalignant conditions. In females, treosulfan seems less gonadotoxic than busulfan. Careful long-term endocrine follow-up is indicated.

Male-Specific Late Effects in Adult Hematopoietic Cell Transplantation Recipients: A Systematic Review from the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation

Male-specific late effects after hematopoietic cell transplantation (HCT) include genital chronic graft-versus-host disease (GVHD), hypogonadism, sexual dysfunction, infertility, and subsequent malignancies, such as prostate, penile, and testicular cancer. These effects may be closely intertwined and cause prolonged morbidity and decreased quality of life after HCT. Here we provide a systematic review of male-specific late effects in a collaboration among transplantation physicians, endocrinologists, urologists, dermatologists, and sexual health professionals through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. We used a systematic review methodology to summarize incidence, risk factors, screening, prevention, and treatment of these complications and provide consensus evidence-based recommendations for clinical practice and future research. Most of the evidence regarding male GVHD is still based on limited data, precluding strong therapeutic recommendations. Therefore, we recommend systematic screening for male genital GVHD regularly and reporting of cases to large registries to allow for a better understanding. Future research also should address treatment, given the little published evidence currently available. Male-specific endocrine consequences of HCT include hypogonadism, which also may affect bone health. Given the scanty evidence, current recommendations for hormone substitution and/or bone health treatment are based on similar principles as for the general population. Following HCT, sexual health decreases, and this topic should be addressed at regular intervals. Future studies should focus on interventional strategies to address sexual dysfunction. Infertility remains prevalent in patients having undergone myeloablative conditioning, warranting the offer of sperm preservation for all HCT candidates. Most studies on fertility rely on descriptive registry analysis and surveys, underscoring the importance of reporting post-HCT conception data to large registries. Although the quality of evidence is low, the development of cancer in male genital organs does not seem more prevalent in HCT recipients compared with the general population; however, subsequent malignancies in general seem to be more prevalent in males than in females, and special attention should be given to skin and oral mucosa. Male-specific late effects, which likely are more underreported than female-specific complications, should be systematically considered during the regular follow-up visits of male survivors who have undergone HCT. Care of patients with male-specific late effects warrants close collaboration between transplantation physicians and specialists from other involved disciplines. Future research should be directed toward better data collection on male-specific late effects and on studies about the interrelationships among these late effects, to allow the development of evidence-based effective management practices.

Male-specific late effects in adult hematopoietic cell transplantation recipients: a systematic review from the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation

Male-specific late effects after hematopoietic cell transplantation (HCT) include genital chronic graft-versus-host disease (GvHD), hypogonadism, sexual dysfunction, infertility, and subsequent malignancies. They may be closely intertwined and cause prolonged morbidity and decreased quality of life after HCT. We provide a systematic review of male-specific late effects in a collaboration between transplant physicians, endocrinologists, urologists, dermatologists, and sexual health professionals through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research, and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. The systematic review summarizes incidence, risk factors, screening, prevention and treatment of these complications and provides consensus evidence-based recommendations for clinical practice and future research.

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.

Differences in longitudinal growth patterns of children and adolescents with transfusion-dependent hemoglobin E/β-thalassemia and those achieving successful hematopoietic stem-cell transplantation

BACKGROUND

Short stature is a very common endocrinopathy among children with transfusion-dependent (TD) thalassemia. Hematopoietic stem-cell transplantation (HSCT) is the only effective curative treatment for TD thalassemia. This study aimed to identify and compare the longitudinal growth patterns of children with TD hemoglobin E (Hb E)/β-thalassemia against those of children successfully undergoing HSCT.

MATERIALS AND METHODS

We reviewed the medical records of 39 patients with TD Hb E/β-thalassemia receiving regular blood transfusions, and 39 post-HSCT patients. Longitudinal weight and height Z-scores at each year of age were recorded for TD patients, and longitudinal weight and height Z-scores at each year before and after HSCT were obtained for post-HSCT patients.

RESULTS

The mean weight and height Z-scores of TD patients decreased gradually and were lowest at age 13. However, post-HSCT subjects saw significant improvement in their mean weight and height Z-scores 6 and 3 years after HSCT, respectively, relative to pre-HSCT baseline values.

CONCLUSIONS

Longitudinal growth patterns differed between patients successfully undergoing HSCT and children and adolescents with TD Hb E/β-thalassemia. HSCT significantly improved height outcomes of children and adolescents with TD Hb E/β-thalassemia.

A Short Review on Growth and Endocrine Long-term Complications in Children and Adolescents with β-Thalassemia Major: Conventional Treatment versus Hematopoietic Stem Cell Transplantation

The conventional treatment of β-thalassemia (β-TM) patients is based on the correction of anemia through regular blood transfusions and iron chelation therapy. However, allogeneic hematopoietic stem cell transplantation (HSCT) remains the only currently available technique that has curative potential. Variable frequency and severity of long-term growth and endocrine changes after conventional treatment as well as after HSCT have been reported by different centers. The goal of this mini-review is to summarize and update knowledge about long-term growth and endocrine changes after HSCT in patients with β-TM in comparison to those occurring in β-TM patients on conventional treatment. Regular surveillance, early diagnosis, treatment, and follow-up in a multi-disciplinary specialized setting are suggested to optimize the patient's quality of life (www.actabiomedica.it).

Testicular Tissue Banking for Fertility Preservation in Young Boys: Which Patients Should Be Included?

Due to the growing number of young patients at risk of germ cell loss, there is a need to preserve spermatogonial stem cells for patients who are not able to bank spermatozoa. Worldwide, more and more clinics are implementing testicular tissue (TT) banking programs, making it a novel, yet indispensable, discipline in the field of fertility preservation. Previously, TT cryopreservation was predominantly offered to young cancer patients before starting gonadotoxic chemo- or radiotherapy. Nowadays, most centers also bank TT from patients with non-malignant conditions who need gonadotoxic conditioning therapy prior to hematopoietic stem cell (HSCT) or bone marrow transplantation (BMT). Additionally, some centers include patients who suffer from genetic or developmental disorders associated with prepubertal germ cell loss or patients who already had a previous round of chemo- or radiotherapy. It is important to note that the surgical removal of TT is an invasive procedure. Moreover, TT cryopreservation is still considered experimental as restoration methods are not yet clinically available. For this reason, TT banking should preferably only be offered to patients who are at significant risk of becoming infertile. In our view, TT cryopreservation is recommended for young cancer patients in need of high-risk chemo- and/or radiotherapy, regardless of previous low-risk treatment. Likewise, TT banking is advised for patients with non-malignant disorders such as sickle cell disease, beta-thalassemia, and bone marrow failure, who need high-risk conditioning therapy before HSCT/BMT. TT retrieval during orchidopexy is also proposed for patients with bilateral cryptorchidism. Since patients with a medium- to low-risk treatment generally maintain their fertility, TT banking is not advised for this group. Also for Klinefelter patients, TT banking is not recommended as it does not give better outcomes than a testicular sperm extraction later in life.

Curative therapy for hemoglobinopathies: an International Society for Cell & Gene Therapy Stem Cell Engineering Committee review comparing outcomes, accessibility and cost of ex vivo stem cell gene therapy versus allogeneic hematopoietic stem cell transplantation

Thalassemia and sickle cell disease (SCD) are the most common monogenic diseases in the world and represent a growing global health burden. Management is limited by a paucity of disease-modifying therapies; however, allogeneic hematopoietic stem cell transplantation (HSCT) and autologous HSCT after genetic modification offer patients a curative option. Allogeneic HSCT is limited by donor selection, morbidity and mortality from transplant conditioning, graft-versus-host disease and graft rejection, whereas significant concerns regarding long-term safety, efficacy and cost limit the broad applicability of gene therapy. Here the authors review current outcomes in allogeneic and autologous HSCT for transfusion-dependent thalassemia and SCD and provide our perspective on issues surrounding accessibility and costs as barriers to offering curative therapy to patients with hereditary hemoglobinopathies.

HSCT remains the only cure for patients with transfusion-dependent thalassemia until gene therapy strategies are proven to be safe

Patients with β-thalassemia suffer from severe anemia, iron overload and multiple complications, that affect their quality of life and well-being. Allogeneic hematopoietic stem cell transplantation (HSCT) from an HLA-matched sibling donor, performed in childhood, has been the gold standard for thalassemic patients for decades. Unfortunately, siblings are available only for the minority of patients. Fully matched unrelated donors have been the second choice for cure, with equal results as far as overall survival is concerned, having though the cost of frequent and serious complications. On the other hand, haploidentical transplantation is performed more frequently during the last decade, with promising results. Gene therapy represents a novel therapeutic approach, with impressive results from clinical trials, both from gene addition strategies, as well as from the emerging gene editing tools. After reviewing current critical points of HSCT using alternative donors and assessing recently reported safety issues of gene therapy methods, we conclude that, although a breakthrough, the safety of gene therapy remains to be established.

Improving outcomes and quality of life for patients with transfusion-dependent β-thalassemia: recommendations for best clinical practice and the use of novel treatment strategies

INTRODUCTION

β-thalassemia is one of the most common inherited monogenic diseases. Many patients are dependent on a lifetime of red blood cell (RBC) transfusions and iron chelation therapy. Although treatments have a significant impact on quality of life (QoL), life expectancy, and long-term health outcomes have improved in recent decades through safer RBC transfusion practices and better iron chelation strategies. Advances in the understanding of the pathology of β-thalassemia have led to the development of new treatment options that have the potential to reduce the RBC transfusion burden in patients with transfusion-dependent (TD) β-thalassemia and improve QoL.

AREAS COVERED

This review provides an overview of currently available treatments for patients with TD β-thalassemia, highlighting QoL issues, and providing an update on current clinical experience plus important practical points for two new treatments available for TD β-thalassemia: betibeglogene autotemcel (beti-cel) gene therapy and the erythroid maturation agent luspatercept, an activin ligand trap.

EXPERT OPINION

Approved therapies, including curative gene therapies and supportive treatments such as luspatercept, have the potential to reduce RBC transfusion burden, and improve clinical outcomes and QoL in patients with TD β-thalassemia. Cost of treatment is, however, likely to be a significant barrier for payors and patients.

Thalassemia and autoimmune diseases: Absence of evidence or evidence of absence?

The thalassemias are a group of inherited disorders of hemoglobin synthesis that continue to pause a global public health concern. The complex molecular and pathogenetic pathways involved in disease process lead to an array of comorbidities that require lifelong management. The disease and its treatment can also lead to alterations in immune function and a link to various autoimmune diseases has been frequently suggested. However, most data stem from single case reports and small studies that do not allow proper assessment of causal associations. Still, the high morbidity in thalassemia makes patients vulnerable to the added burden of coexisting autoimmune diseases, and special management considerations in this patient population are warranted. In this review, we explore insights and data from the literature on various autoimmune disease that have been observed in patients with thalassemia. The role of the thalassemia carrier state in modifying outcomes of patients with autoimmune diseases is also discussed.

Gene Therapy of the Hemoglobinopathies

Sickle cell disease and the ß-thalassemias are caused by mutations of the ß-globin gene and represent the most frequent single gene disorders worldwide. Even in European countries with a previous low frequency of these conditions the prevalence has substantially increased following large scale migration from Africa and the Middle East to Europe. The hemoglobin diseases severely limit both, life expectancy and quality of life and require either life-long supportive therapy if cure cannot be achieved by allogeneic stem cell transplantation. Strategies for ex vivo gene therapy aiming at either re-establishing normal ß-globin chain synthesis or at re-activating fetal γ-globin chain and HbF expression are currently in clinical development. The European Medicine Agency (EMA) conditionally licensed gene addition therapy based on lentiviral transduction of hematopoietic stem cells in 2019 for a selected group of patients with transfusion dependent non-ß° thalassemia major without a suitable stem cell donor. Gene therapy thus offers a relevant chance to this group of patients for whom cure has previously not been on the horizon. In this review, we discuss the potential and the challenges of gene addition and gene editing strategies for the hemoglobin diseases.

Pubertal outcomes of children transplanted with allogeneic stem cells after myeloablative total body irradiation or busulfan: Influence of age and sex is confirmed, while a role of chronic graft-versus-host disease in delayed puberty onset is revealed

INTRODUCTION

Myeloablative conditioning before allogeneic HSCT during childhood exposes to serious long-term complications, especially gonadal dysfunction. Pubertal issues are less described than other post-HSCT sequelae in childhood.

METHODS

Pubertal development and biological gonadal parameters were assessed in a retrospective monocentric cohort of prepubertal patients who underwent HSCT after myeloablative conditioning with TBI or busulfan between 1981 and 2017.

RESULTS

Seventy-four patients (28 girls and 46 boys) were included. No spontaneous pubertal development was found in 50% of girls and 10% of boys (P < .001), and delayed puberty or no spontaneous pubertal development was found in 57% of girls and 24% of boys (P = .009). HRT was used in 82% of girls and 24% of boys (P < .001). In univariate analysis, TBI conditioning (P = .05), female sex (P < .001), acute GVHD (P = .05), extensive chronic GVHD (P = .021), steroid treatment >6 months (P = .016), and malignant diseases (P = .016) were associated with no spontaneous pubertal development, whereas TBI conditioning (P = .003) and extensive chronic GVHD (P = .005) were associated with delayed puberty. In multivariate analysis, factors independently associated with no spontaneous puberty onset were female sex (P = .001) and age >10 years (P = .033). Factors independently associated with delayed puberty were extensive chronic GVHD (P = .041) and age >10 years (P = .031).

CONCLUSION

This study highlighted the toxicity of MAC in prepubescent children: TBI did worse, but this was especially true for the most susceptible patients (girls, leukemic patients, and patients older than 10 years). It suggests a possible role of GVHD in delayed puberty.

[Research advances in transplantation for thalassemia major]

Thalassemia is an inherited blood disorder caused by disordered globin chain synthesis due to mutations in the regulatory genes for hemoglobin. At present, allogeneic hematopoietic stem cell transplantation (allo-HSCT) is recognized as the only curative method for treatment. Through the revolution of pretransplantation regimens and selection of donor and source of stem cells, patients' survival has been greatly improved. This article reviews the development of transplantation for thalassemia and related research advances, in order to provide suitable treatment options for clinical application.

Saving whom? The ethical challenges of harvesting tissue from savior siblings

PURPOSE OF THE STUDY

To discuss the ethical challenges for the therapeutic team when dealing with a young savior sibling as a potential tissue donor.

BASIC PROCEDURES

Savior siblings are children that are created to serve a sibling as a donor of umbilical cord blood, bone marrow, or peripheral blood from which hematopoietic stem cells are derived. These cells are used for hematopoietic stem cell therapy, which is the only curative treatment for certain hemoglobinopathies. We used a case including a 19-year-old thalassemia patient and his two and a half year old sister from our practice as ethics consultants. Our methodological basis is the principlism approach by Beauchamp and Childress, consisting of four principles: autonomy, non-maleficence, beneficence, and justice.

MAIN FINDINGS

We found that the main conflict arises between the autonomy of the savior sibling as well as the non-maleficence regarding her and the beneficence of the thalassemia patient.

PRINCIPAL CONCLUSIONS

Decision-making is complex when decisions within the family are concerned, especially when non-competent young children are involved. The therapeutic team does not only have to recognize the principal vulnerability of children but also the different scales of vulnerability depending on their age.

Risks associated with fertility preservation for women with sickle cell anemia

OBJECTIVE

To highlight the risk of complications among women with sickle cell anemia (SCA) receiving fertility preservation treatment (FPT) before hematopoietic stem cell transplant (HSCT).

DESIGN

Single-center case series.

SETTING

Academic fertility center.

PATIENT(S)

Women aged 15-32 years with SCA undergoing FPT before HSCT.

INTERVENTION(S)

Retrospective, systematic review.

MAIN OUTCOME MEASURE(S)

FPT modality, SCA complications during FPT.

RESULT(S)

Over an 8-year period (2009-2017), seven women with SCA ages 15-32 years (mean 28.5 years) underwent FPT with embryo cryopreservation (n = 1), oocyte cryopreservation (n = 4), and ovarian tissue cryopreservation (n = 2). The five women subjects who underwent oocyte or embryo cryopreservation were treated with an antagonist controlled ovarian hyperstimulation protocol and individualized gonadotropin dosing. The trigger medications included leuprolide acetate (n = 2), and human chorionic gonadotropin (n = 3). Most patients (n = 5) received a disease-modifying therapy for SCA (hydroxyurea or chronic transfusions) before FPT. Three patients experienced periprocedural SCA complications that included life-threatening respiratory failure, painful crisis requiring interruption of a stimulation cycle, and severe postharvest painful crisis.

CONCLUSION(S)

Women with SCA may choose to undergo diverse FPT strategies before HSCT and are at risk for serious SCA-related complications. Evidence-based strategies to mitigate SCA-related morbidity and to optimize fertility preservation outcomes are needed.

Stem cell transplantation in sickle cell disease: therapeutic potential and challenges faced

INTRODUCTION

Sickle cell disease (SCD) is the most common inherited hemoglobinopathy worldwide, and is a life-limiting disease with limited therapeutic options to reduce disease severity. Despite being a monogenic disorder, the clinical phenotypes of SCD are variable, with few reliable predictors of disease severity easily identifying patients where the benefits of curative therapy outweigh the risks. Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative option, though significant advances in gene therapy raise the promise for additional curative methods. Areas covered: Allogeneic transplantation in SCD has evolved and improved over the last two decades, now offering a standard of care curative option using a human leukocyte antigen (HLA)-matched sibling donor. Many of the seminal transplantation studies are reviewed here, demonstrating how initial failures and successes have influenced and led to current HSCT strategies. Such strategies aim to overcome setbacks and limitations, and focus on conditioning regimens, immune suppression methods, the use alternative donor sources, and gene therapy approaches. Expert commentary: SCD is a curable disease. Each dedicated effort to refine transplantation methods, expand the donor pool, and bring gene therapy models to fruition will make enormous impacts reducing disease burden and improving outcomes and quality of life for patients with SCD.