Outcomes of mismatched and unrelated donor hematopoietic stem cell transplantation in Fanconi anemia conditioned with chemotherapy only

Liver abnormalities are frequent and persistent in patients with Fanconi anemia

ABSTRACT

Liver disease has not been well described in patients with Fanconi anemia (FA). Improvements in outcomes of transplant mean that more individuals with FA are reaching adulthood and new features of the FA phenotype are being discovered. We performed a retrospective review of liver function in a cohort of 97 patients with FA followed-up for at least 10 years at a single center. We identified a high frequency of transaminitis (n = 31, 32%) without elevation of bilirubin and with no evidence of structural hepatic abnormality in patients with FA. Transaminitis was persistent in many cases, sometimes lasting more than a decade without clinical manifestation, although 2 patients with prolonged transaminitis are deceased from liver failure, indicating important long-term clinical consequences. Transaminitis was found in patients who had and had not received transplant but was more frequent in recipients of transplant. Exposure to total body irradiation increased risk (odds ratio, 15.5 [95% confidence interval, 2.44-304.54]; P = .01), whereas treatment with androgens did not. Review of limited numbers of liver biopsies and autopsy material showed a cholestatic pattern of liver injury, with progressive fibrosis, in the majority of patients. Occurrence in cases without transplant as well as cases with transplant argues against a potential diagnosis of atypical liver graft-versus-host disease. Limited data regarding therapy suggest no benefit from treatment with steroids or other immune suppressive medications or ursodeoxycholic acid. Our data show that liver disease is common in patients with FA, and because most children with FA now reach adulthood, end-stage liver disease in young adulthood means systematic testing of potential therapies is urgently needed.

Germline predisposition to myeloid neoplasms: Characteristics and management of high versus variable penetrance disorders

Myeloid neoplasms with germline predisposition have been recognized increasingly over the past decade with numerous newly described disorders. Penetrance, age of onset, phenotypic heterogeneity, and somatic driver events differ widely among these conditions and sometimes even within family members with the same variant, making risk assessment and counseling of these individuals inherently difficult. In this review, we will shed light on high malignant penetrance (e.g., CEBPA, GATA2, SAMD9/SAMD9L, and TP53) versus variable malignant penetrance syndromes (e.g., ANKRD26, DDX41, ETV6, RUNX1, and various bone marrow failure syndromes) and their clinical features, such as variant type and location, course of disease, and prognostic markers. We further discuss the recommended management of these syndromes based on penetrance with an emphasis on somatic aberrations consistent with disease progression/transformation and suggested timing of allogeneic hematopoietic stem cell transplant. This review will thereby provide important data that can help to individualize and improve the management for these patients.

Pediatric Bone Marrow Failure: A Broad Landscape in Need of Personalized Management

Irreversible severe bone marrow failure (BMF) is a life-threatening condition in pediatric patients. Most important causes are inherited bone marrow failure syndromes (IBMFSs) and (pre)malignant diseases, such as myelodysplastic syndrome (MDS) and (idiopathic) aplastic anemia (AA). Timely treatment is essential to prevent infections and bleeding complications and increase overall survival (OS). Allogeneic hematopoietic stem cell transplantation (HSCT) provides a cure for most types of BMF but cannot restore non-hematological defects. When using a matched sibling donor (MSD) or a matched unrelated donor (MUD), the OS after HSCT ranges between 60 and 90%. Due to the introduction of post-transplantation cyclophosphamide (PT-Cy) to prevent graft versus host disease (GVHD), alternative donor HSCT can reach similar survival rates. Although HSCT can restore ineffective hematopoiesis, it is not always used as a first-line therapy due to the severe risks associated with HSCT. Therefore, depending on the underlying cause, other treatment options might be preferred. Finally, for IBMFSs with an identified genetic etiology, gene therapy might provide a novel treatment strategy as it could bypass certain limitations of HSCT. However, gene therapy for most IBMFSs is still in its infancy. This review summarizes current clinical practices for pediatric BMF, including HSCT as well as other disease-specific treatment options.

Unmanipulated haploidentical haematopoietic cell transplantation with radiation-free conditioning in Fanconi anaemia: A retrospective analysis from the Chinese Blood and Marrow Transplantation Registry Group

Haematopoietic cell transplantation (HCT) is the only curative treatment for haematological complications in patients with Fanconi anaemia (FA). Haploidentical (haplo-) HCT is a promising alternative for FA. We aimed to analyse the outcomes of unmanipulated haplo-HCT in patients with FA with radiation-free conditioning. A total of 56 patients from 11 centres between 2013 and 2021 in China were retrospectively analysed. The mean (SD) cumulative incidence was 96.4% (0.08%) for 30-day neutrophil engraftment and 85.5% (0.24%) for 100-day platelet engraftment. With a median (range) follow-up of 2.4 (0.2-5.8) years, favourable mean (SD) overall survival of 80.9% (5.5%) and event-free survival of 79.3% (5.6%) were achieved. The mean (SD) incidences of acute graft-versus-host disease (aGvHD) Grade II-IV and Grade III-IV were 55.4% (0.45%) and 42.9 (0.45%) respectively. The mean (SD) cumulative incidence of 3-year chronic graft-versus-host disease (cGvHD) was 34.7% (0.86%) and that of moderate-to-severe cGvHD was 9.0% (0.19%). Our data demonstrate that in unmanipulated haplo-HCT for patients with FA, radiation-free regimens based on fludarabine and low-dose cyclophosphamide ± busulfan achieved favourable engraftment and survival with relatively high incidences of aGvHD and cGvHD. These results prompt the use of low-intensity conditioning without radiation and intensive GvHD prophylaxis when considering unmanipulated haplo-HCT in patients with FA.

Bone marrow transplant using fludarabine-based reduced intensity conditioning regimen with in vivo T cell depletion in patients with Fanconi anemia

FA is the most common cause of inherited BMF syndromes. The only cure for BMF in FA remains HSCT. Due to DNA instability in FA, RIC has been used to decrease immediate and late complications of HSCT. Most FA conditioning regimens in mismatched and unrelated donor transplants rely on TBI, which increases the risk of secondary malignancies. Most of the non-TBI conditioning regimens use an ex vivo T-cell depletion approach, but this is not feasible at all pediatric stem cell transplant programs. To evaluate the success of HSCT in patients with FA using non-TBI conditioning regimens with in vivo T-cell depletion approach. HSCT using non-TBI based conditioning was performed on two siblings with FA. The first sibling underwent matched unrelated donor transplant with a BM graft using fludarabine, alemtuzumab, busulfan, and cyclophosphamide conditioning and cyclosporine and mycophenolate as GVHD prophylaxis. The second sibling underwent MSD transplant with UCB and BM grafts using similar approach, but without busulfan and mycophenolate. Both siblings had engraftment without signs of acute or chronic GVHD. Acute post-transplant complications included brief viral reactivations. At last follow-up, both siblings continued to have full immune reconstitution with stable chimerism. Conditioning regimens without radiation and inclusion of alemtuzumab can lead to successful engraftment without development of GVHD and reduce risk of developing secondary neoplasms, even with unrelated donor transplants.

Excellent overall and chronic graft-versus-host-disease-free event-free survival in Fanconi anaemia patients undergoing matched related- and unrelated-donor bone marrow transplantation using alemtuzumab-Flu-Cy: the UK experience

Haematopoietic stem cell transplantation (HSCT) remains the only curative option in Fanconi anaemia (FA). We analysed the outcome of children transplanted for FA between 1999 and 2018 in the UK. A total of 94 transplants were performed in 82 patients. Among the donors, 51·2% were matched related donors (MRD) while the remainder were alternative donors. Most patients received a fludarabine-cyclophosphamide (Flu-Cy)-based conditioning regimen (86·6%) and in vivo T-cell depletion with alemtuzumab (69·5%). Five-year overall survival (OS) was 85·4% [70·4-93.2] with MRD, 95·7% [72·9-99.4] with matched unrelated donors (MUD), 44·4% [6·6-78.5] with mismatched unrelated donors (MMUD) and 44·4% [13·6-71.9] with mismatched related donors (MMRD) (P < 0·001). Other factors significantly impacting OS were pre-transplant bone marrow status, source of stem cells, cytomegalovirus (CMV) serostatus, preparation with Flu-Cy, use of total body irradiation (TBI) and alemtuzumab as serotherapy. In multivariate analysis, absence of myelodysplastic syndrome (MDS) or leukaemia, bone marrow as source of stem cells, cytomegalovirus (CMV) other than +/- (Recipient/Donor) and Flu-Cy were protective factors for five-year OS. Five-year chronic graft-versus-host-disease (cGVHD)-free event-free survival was 75·4% with the same risk factors except for CMV serostatus. Five-year non-relapse mortality was 13·8% [7·3-22.3]. Only five patients (6·1%) developed grade II-IV acute GVHD and two patients chronic GVHD. These data confirm the excellent outcome of matched related or unrelated HSCT in children with FA.

Long-term outcome in patients with Fanconi anemia who received hematopoietic stem cell transplantation: a retrospective nationwide analysis

We retrospectively analyzed nationwide records of 163 Fanconi anemia (FA) patients [aplastic anemia (AA), n = 118; myelodysplastic syndrome (MDS), n = 30; acute leukemia, n = 15] who underwent first allogeneic hematopoietic stem cell transplantation (HSCT) between 1987 and 2015 in Japan. An alternative donor was used in 119 (73%) patients, and 160 (98%) patients received a non-T-cell-depleted graft. With an 8.7-year median follow-up, 5-year overall survival (OS) was 81%. The 5-year OS was significantly higher in AA patients than in MDS and acute leukemia patients (89%, 71%, and 44%, respectively). In the MDS/leukemia group, factors associated with poor outcome in univariate analysis were older age at HSCT (≥ 18 years), conditioning regimen without anti-thymocyte or lymphocyte globulin, and grade II-IV acute graft-versus-host disease. After 1 year, of 137 survivors, 15 developed subsequent malignancies, of whom 12 were diagnosed with head and neck (HN)/esophageal cancer. An irradiation regimen and older age were associated with the risk of HN/esophageal cancer. Five of seven deaths were attributed to subsequent malignancies more than 5 years after HSCT. On the basis of the risk factors for HSCT in MDS/leukemia patients and subsequent malignancies, a more effective HSCT approach is required.

Busulfan Pharmacokinetics and Precision Dosing: Are Patients with Fanconi Anemia Different?

It is well known that pharmacokinetics (PK)-guided busulfan (BU) dosing increases engraftment rates and lowers hepatotoxicity in patients undergoing hematopoietic cell transplantation (HCT). However, there are no published PK data in patients with Fanconi anemia (FA), who are known to have baseline DNA repair defect and related inherent sensitivity to chemotherapy. In our prospective, multi-institutional study of alternative donor HCT for FA using chemotherapy-only conditioning, we replaced the single dose of total-body irradiation with BU at initial doses of 0.8 to 1.0 mg/kg and 0.6 to 0.8 mg/kg given i.v. every 12 hours for 4 doses. Patients received the first dose of i.v. busulfan on day -8, and blood levels for PK were obtained. PK samples were drawn following completion of infusion. BU PK levels were collected at 2 hours, 2 hours and 15 minutes, and 4, 5, 6, and 8 hours from the start of infusion. The remaining 3 doses of BU were given on days -7 and -6. Thirty-seven patients with available BU PK data with a median age of 9.2 years (range, 4.3 to 44 years) are included in the final analyses. The overall BU PK profile in patients with FA is similar to non-FA patients after considering their body weight. In our cohort, a strong correlation between BU clearance and weight supports current practice of per kilogram dosing. However, not surprisingly, we show that the disease (ie, host) sensitivity related to FA is the main determinant of total dose of BU that can be safely administered to patients in this high-risk population. On the basis of our results, we propose an optimal BU concentration at steady-state level of ≤350 ng/mL (equivalent to total cumulative exposure of 16.4 mg*h/L for 4 doses over 2 days) for patients with FA undergoing HCT. To our knowledge, this is the first and largest report of prospective BU PK in patients with FA undergoing HCT, providing an optimal BU target cutoff to achieve stable donor engraftment while avoiding excessive toxicity.

Treatment modalities and outcomes of Fanconi anemia patients with head and neck squamous cell carcinoma: Series of 9 cases and review of the literature

BACKGROUND

Fanconi anemia (FA) is associated with an increased risk of developing head and neck squamous cell cancer (HNSCC) and presents a treatment dilemma due to concerns of increased toxicities from chemotherapy and radiation therapy (RT).

METHODS

We reviewed the literature on HNSCC in FA patients and report on our experience treating 9 FA patients with HNSCC.

RESULTS

Surgery was generally well-tolerated and surgery alone resulted in durable local control for 2 patients. Four patients received adjuvant RT that was tolerable in most cases, although 1 patient required a treatment break and early cessation of RT. Three of the irradiated patients received concurrent cetuximab.

CONCLUSIONS

In patients with adverse features, adjuvant radiation with concurrent cetuximab may be feasible with careful monitoring, although local disease control is infrequent. Early detection via screening permitting a surgery-alone approach represents the best opportunity for cure in FA patients with HSNCC.

Principles of alemtuzumab immunoablation in hematopoietic cell transplantation for non-malignant diseases in children: A review

Alemtuzumab is a humanized mAb targeted to CD52. Alemtuzumab is highly immunosuppressive with the ability to deplete T and B cells (in addition to other immune cell lines). A growing understanding of the PKs, dosing, and timing of administration of alemtuzumab has allowed for the study of its use as a conditioning agent for allogeneic HCT. The highly immunosuppressive properties of the drug are particularly appealing in the setting of non-malignant HCT, where GVHD provides no clinical benefit and relapse of malignancy is not applicable. In addition, the degree of immune suppression achieved with alemtuzumab has allowed for a reduction in the intensity of myeloablative cytotoxic agents included in some HCT conditioning regimens, allowing for fewer acute and late toxicities. This review paper will provide a comprehensive summary of the mechanism of action, PKs, dosing, and timing of alemtuzumab, a brief description of its use in various allogeneic HCT protocols for non-malignant conditions and a summary of the data regarding its use for GVHD therapy. The goal of this review was to provide an understanding as to how alemtuzumab might be safely incorporated into HCT conditioning regimens for children with non-malignant disease, allowing for expanded access to curative HCT therapy.

How I manage patients with Fanconi anaemia

Fanconi Anaemia is a rare, genetic heterogeneous multisystem disease that is the most common congenital syndrome of marrow failure. Twenty genes have been reported to cause the disease. Remarkable progress has been made over the last 20 years in the understanding of the genetic and pathophysiological mechanisms. Unfortunately, these advances have not been completely paralleled by advances in medical treatment, where the most important component remains stem cell transplantation. This therapy, although contributing to long-term negative effects, such as increased occurrence of late malignancies, is the only current option capable of prolonging the survival of patients. In spite of relevant recent progress in matched unrelated donor transplants, the largest studies with longer follow-up still show a superiority of matched sibling donor transplants with a success rate, in selected cohorts, of over 90%. This article reviews different aspects of the disease, including genetics, diagnosis and treatment options, with special focus on stem cell transplantation, comprehensive post-diagnosis management, decision-making processes and long-term follow-up.

Radiation-free, alternative-donor HCT for Fanconi anemia patients: results from a prospective multi-institutional study

Fanconi anemia (FA) is an inherited bone marrow failure syndrome characterized by chromosomal fragility, progressive marrow failure, and cancer predisposition. Hematopoietic cell transplantation (HCT) is curative for FA-related marrow failure or leukemia, but both radiation exposure during transplant and graft-versus-host disease (GVHD) may increase risk of later malignancies of the head and neck and anogenital area. In this study, we tested a radiation-free conditioning regimen with a T-cell-depleted graft to eliminate radiation exposure and minimize early and late toxicities of transplant. Forty-five patients (median age, 8.2 years; range 4.3-44) with FA underwent HCT between June 2009 and May 2014. The preparative regimen included busulfan, cyclophosphamide, fludarabine, and rabbit anti-thymocyte globulin. Busulfan levels were monitored to avoid excess toxicity. All grafts were CD34-selected/T-cell-depleted using the CliniMacs CD34 columns (Miltenyi). Thirty-four patients (75.6%) with marrow failure and 11 (24.4%) with myelodysplastic syndrome underwent HCT using matched unrelated (n = 25, 55.5%), mismatched unrelated (n = 14, 31.1%), or mismatched related donors (n = 6, 13.4%). One year probabilities of overall and disease-free survival for the entire cohort, including patients with myeloid malignancy and those receiving mismatched related/haploidentical grafts, were 80% (±6%) and 77.7% (±6.2%), respectively (median follow-up 41 months). All young children (<10 years of age) undergoing HCT for marrow failure using low-dose busulfan-containing regimen survived. No patients developed acute grade 3-4 GVHD. Sequential reduction of busulfan dose was successfully achieved per study design. Our results show excellent outcomes in patients with FA undergoing alternative donor HCT without radiation exposure. The study is registered to www.clinicaltrials.gov as #NCT01082133.

Current Knowledge and Priorities for Future Research in Late Effects after Hematopoietic Cell Transplantation for Inherited Bone Marrow Failure Syndromes: Consensus Statement from the Second Pediatric Blood and Marrow Transplant Consortium International Conference on Late Effects after Pediatric Hematopoietic Cell Transplantation

Fanconi anemia (FA), dyskeratosis congenita (DC), and Diamond Blackfan anemia (DBA) are 3 of the most common inherited bone marrow failure syndromes (IBMFS), in which the hematologic manifestations can be cured with hematopoietic cell transplantation (HCT). Later in life, these patients face a variety of medical conditions, which may be a manifestation of underlying disease or due to pre-HCT therapy, the HCT, or a combination of all these elements. Very limited long-term follow-up data exist in these populations, with FA the only IBMFS that has specific published data. During the international consensus conference sponsored by the Pediatric Blood and Marrow Transplant Consortium entitled "Late Effects Screening and Recommendations following Allogeneic Hematopoietic Cell Transplant (HCT) for Immune Deficiency and Nonmalignant Hematologic Disease" held in Minneapolis, Minnesota in May of 2016, a half-day session was focused specifically on the unmet needs for these patients with IBMFS. A multidisciplinary group of experts discussed what is currently known, outlined an agenda for future research, and laid out long-term follow-up guidelines based on a combination of evidence in the literature as well as expert opinion. This article addresses the state of science in that area as well as consensus regarding the agenda for future research, with specific screening guidelines to follow in the next article from this group.

Hematopoietic cell transplantation in Fanconi anemia: current evidence, challenges and recommendations

INTRODUCTION

Hematopoietic cell transplantation for Fanconi Anemia (FA) has improved dramatically over the past 40 years. With an enhanced understanding of the intrinsic DNA-repair defect and pathophysiology of hematopoietic failure and leukemogenesis, sequential changes to conditioning and graft engineering have significantly improved the expectation of survival after allogeneic hematopoietic cell transplantation (alloHCT) with incidence of graft failure decreased from 35% to <10% and acute graft-versus-host disease (GVHD) from >40% to <10%. Today, five-year overall survival exceeds 90% in younger FA patients with bone marrow failure but remains about 50% in those with hematologic malignancy. Areas covered: We review the evolution of alloHCT contributing to decreased rates of transplant related complications; highlight current challenges including poorer outcomes in cases of clonal hematologic disorders, alloHCT impact on endocrine function and intrinsic FA risk of epithelial malignancies; and describe investigational therapies for prevention and treatment of the hematologic manifestations of FA. Expert commentary: Current methods allow for excellent survival following alloHCT for FA associated BMF irrespective of donor hematopoietic cell source. Alternative curative approaches, such as gene therapy, are being explored to eliminate the risks of GVHD and minimize therapy-related adverse effects.

Four decades of stem cell transplantation for Fanconi anaemia in the Netherlands

This article presents the haematopoietic stem cell transplantation (SCT) results of the complete Dutch Fanconi anaemia (FA) patient cohort. Sixty-eight Dutch FA patients have been transplanted since 1972. In total, 63 (93%) patients engrafted, 54 after first SCT and 9 after second SCT. Fludarabine (FLU)-based conditioning was associated with decreased graft failure (odds ratio 0·21, P = 0·01), decreased early mortality (hazard ratio 0·25, P = 0·01) and improved 5-year overall survival (FLU 87·8% [standard error (SE) 5·1%] versus non-FLU 59·3% [SE 9·5%], P = 0·01). Late mortality was mainly caused by squamous cell carcinoma. Twenty-two patients were treated with the current Dutch FA conditioning regimen (FLU 150 mg/m(2) and cyclophosphamide 30 mg/kg ± anti-thymocyte globulin - no irradiation). Stem cell donors were matched related (n = 8) or alternative donors (n = 14). Stable engraftment after first SCT was achieved in 19 (86%) patients. At a median follow-up of 3·9 years 20 (91%) patients are alive. Our study provides a unique overview of a nation-wide SCT cohort illustrating the major improvements in treatment regimen and patient outcome in recent years. It shows that a non-irradiation and busulfan-free conditioning regimen can be used successfully, also in alternative donor SCT. Furthermore, it underlines the importance of late cancer screening and comprehensive care for this complex disorder.