Hematopoietic cell transplantation and cellular therapies in Switzerland. Evolution over 25 years. A report from the stem cell transplantation and cellular therapies working groups of the SBST 1997-2021.

The Swiss Blood Stem Cell Transplantation and Cellular Therapy Group (SBST) leads a mandatory national registry for all hematopoietic stem cell transplants (HCT) and cellular therapies. After 25 years, information was available for 11,226 patients receiving an HCT (4031 allogeneic and 7195 autologous), including 925 pediatric patients. We compared patient characteristics and outcome by quinquennia 1997-2001, 2002-2006, 2007-2011, 2012-2016, and 2017-2021. There were numerous changes over time. Allogeneic transplant recipients became older (median age 33.7 vs. 54.3) and had more frequently unrelated donors and reduced intensity conditioning in later quinquennia. Similarly, age increased for recipients of autologous HCT (median 48.3 vs. 59.9). We did not see a significant drop in transplant activity during the SARS-CoV-2 pandemic. Analysis of outcome showed overall survival (relative risk (RR) of death 0.664 (0.529-0.832) and progression free survival (RR 0.708 (0.577-0.870) being improved over time comparing the latest to the first quinquennium adjusting for risk factors. Non-relapse mortality decreased in recipients of allogeneic HCT (RR: 0.371 (0.270-0.509)) over time but relapse risks did not. Outcome of autologous HCT improved as well across quinquennia, this improvement was mainly due to decreased relapse risks (RR 0.681 (0.597-0.777)), possibly related to maintenance treatment or rescue treatment for relapse mainly in myeloma patients. Cellular therapies other than allogeneic or autologous HCT, particularly chimeric antigen receptor T-cells (CAR-T) treatment have started to increase after 2019, year of approval of the first commercial CAR-T product in Switzerland. Data on chimeric antigen receptor T-cell treatment are too early for comparative analyses. Detailed analyses of changes over time are presented. This study includes all HCTs, and cellular therapies, data useful for quality assurance programs, health care cost estimation and benchmarking. Between 50% and 60% of patients are long-term survivors after both types of HCT, indicating growing populations of surviving patients requiring long-term care.

Characterization of engraftment dynamics in myelofibrosis after allogeneic hematopoietic cell transplantation including novel conditioning schemes.

Introduction: Myelofibrosis (MF) is a rare hematopoietic stem cell disorder progressing to bone marrow (BM) failure or blast phase. Allogeneic hematopoietic cell transplantation (HCT) represents a potentially curative therapy for a limited subset of patients with advanced MF, who are eligible, but engraftment in MF vs. AML is delayed which promotes complications. As determinants of engraftment in MF are incompletely characterized, we studied engraftment dynamics at our center. Methods: A longitudinal cohort of 71 allogeneic HCT performed 2000-2019 with >50% after 2015 was evaluated. Results: Median time to neutrophil engraftment ≥0.5x109/l was +20 days post-transplant and associated with BM fibrosis, splenomegaly and infused CD34+ cell number. Engraftment dynamics were similar in primary vs. secondary MF and were independent of MF driver mutations in JAK2, CALR and MPL. Neutrophil engraftment occurred later upon haploidentical HCT with thiotepa-busulfan-fludarabine conditioning, post-transplant cyclophosphamide and G-CSF (TBF-PTCy/G-CSF) administered to 9.9% and 15.6% of patients in 2000-2019 and after 2015, respectively. Engraftment of platelets was similarly delayed, while reconstitution of reticulocytes was not affected. Conclusions: Since MF is a rare hematologic malignancy, this data from a large number of HCT for MF is essential to substantiate that later neutrophil and platelet engraftment in MF relates both to host and treatment-related factors. Observations from this longitudinal cohort support that novel conditioning schemes administered also to rare entities such as MF, require detailed evaluation in larger, multi-center cohorts to assess also indicators of long-term graft function and overall outcome in patients with this infrequent hematopoietic neoplasm undergoing allogeneic transplantation.

Case report: mRNA-1273 COVID-19 vaccine-associated myopericarditis: Successful treatment and re-exposure with colchicine.

Introduction: Vaccine-induced myocarditis is a rare complication of messenger RNA (mRNA) COVID-19 vaccines. Case presentation: We report a case of acute myopericarditis in a recipient of allogeneic hematopoietic cells following the first dose of the mRNA-1273 vaccine and the successful administration of a second and third dose while on prophylactic treatment with colchicine to successfully complete the vaccination. Conclusion: Treatment and prevention of mRNA-vaccine-induced myopericarditis represent a clinical challenge. The use of colchicine is feasible and safe to potentially reduce the risk of this rare but severe complication and allows re-exposure to an mRNA vaccine.

Suitability of haematopoietic cell donors: updated consensus recommendations from the WBMT standing committee on donor issues.

The contribution of related donors to the globally rising number of allogeneic haematopoietic stem cell transplantations (HSCT) remains increasingly important, particularly because of the growing use of haploidentical HSCT. Compared with the strict recommendations on the suitability for unrelated donors, criteria for related donors allow for more discretion and vary between centres. In 2015, the donor outcome committee of the Worldwide Network for Blood and Marrow Transplantation (WBMT) proposed consensus recommendations of suitability criteria for paediatric and adult related donors. This Review provides updates and additions to these recommendations from a panel of experts with global representation, including the WBMT, the European Society for Blood and Marrow Transplantation donor outcome committee, the Center for International Blood and Marrow Transplant Research donor health and safety committee, the US National Marrow Donor Program, and the World Marrow Donor Association, after review of the current literature and guidelines. Sections on the suitability of related donors who would not qualify as unrelated donors have been updated. Sections on communicable diseases, clonal haematopoiesis of indeterminate potential, paediatric aspects including psychological issues, and reporting on serious adverse events have been added. The intention of this Review is to support decision making, with the goal of minimising the medical risk to the donor and protecting the recipient from transmissible diseases.

External Validation of the Revised Pretransplant Assessment of Mortality Score in Allogeneic Hematopoietic Cell Transplantation: A Cohort Study.

Pretransplant risk scores such as the revised Pretransplant Assessment of Mortality (rPAM) score help to predict outcome of patients receiving allogeneic hematopoietic cell transplantation (allo-HCT). Since the rPAM has not been validated externally in a heterogeneous patient population with different diseases, we aimed to validate the rPAM score in a real-world cohort of allo-HCT patients. A total of 429 patients were included receiving their first allo-HCT from 2008 to 2015. The predictive capacity of the rPAM score for 4-year overall survival (OS), nonrelapse mortality (NRM), and cumulative incidence of relapse (CIR) after allo-HCT was evaluated. Moreover, we evaluated the impact of the rPAM score for OS and used uni- and multivariable analyses to identify patient- and transplant-related predictors for OS. In rPAM score categories of <17, 17-23, 24-30, and >30, the OS probability at 4 years differed significantly with 61%, 36%, 26%, and 10%, respectively (P < 0.0001). In contrast to CIR, the NRM increased significantly in patients with higher rPAM scores (P < 0.001). Regarding the OS, the rPAM score had an area under the receiver operating characteristics curve of 0.676 (95% confidence interval [CI], 0.625-0.727) at 4 years. In the multivariable analysis, the rPAM score was associated with OS-independently of conditioning regimens (adjusted hazard ratio per 1-unit increase, 1.10; 95% CI, 1.06-1.10; P < 0.001). Additionally, forced expiratory volume in 1 second and the disease risk index were the components of the rPAM significantly associated with outcome. In our large real-world cohort with extended follow-up, the rPAM score was validated as an independent predictor of OS in patients with hematologic disorders undergoing allo-HCT.

Co-Occurring CSF3R W791* Germline and Somatic T618I Driver Mutations Induce Early CNL and Clonal Progression to Mixed Phenotype Acute Leukemia.

Chronic neutrophilic leukemia (CNL) relates to mutational CSF3R activation with membrane proximal CSF3R mutations such as T618I as driver mutations, but the significance of truncating mutations is not clarified. In CNL, concomitant mutations promote disease progression, but insight into longitudinal acquisition is incomplete. In this study, we investigated the role of co-occurring germline and somatic CSF3R mutations in CNL, and assessed the impact of clonal evolution on transformation to acute leukemia. We employed sequential next generation sequencing and SNP array karyotyping to assess clonal evolution in CNL of early manifestation age based on a 33-year-old patient. Germline vs. somatic mutations were differentiated using a sample from the hair follicle. To investigate a potential predisposition for CNL development and progression by germline CSF3R-W791*, allelic localizations were evaluated. We detected a somatic CSF3R-T618I mutation at 46% variant allele frequency (VAF) at the time of CNL diagnosis, which co-occurred with a CSF3R-W791* truncation at 50% VAF in the germline. Evaluation of allelic localization revealed CSF3R-T618I and W791* on the same allele. A concomitant ASXL1 mutation at 39% VAF increased to 48% VAF upon transformation to mixed phenotype acute leukemia (MPAL), which has both myeloid and lymphoid features. Clonal evolution further involved expansion of the CSF3R double-mutant clone to 90% VAF via copy neutral loss of heterozygosity on chromosome 1p and the emergence of a RUNX1 mutant subclone. Allogeneic transplantation induced complete remission. This study highlights that CNL not only transforms to AML but also to MPAL. The molecular evolution is especially interesting with a CSF3R-W791* mutation in the germline and acquisition of CSF3R-T618I on the same allele compatible with increased susceptibility for mutation acquisition facilitating RUNX1-related clonal transformation.

Optimized cyclosporine starting dose may reduce risk of acute GvHD after allogeneic hematopoietic cell transplantation: a single-center cohort study.

Cyclosporine A (CsA) is commonly used for Graft versus Host Disease (GvHD) prophylaxis at a recommended starting dose of 3 mg/kg/d: Evidence for the effect of different CsA starting doses on GvHD risk is limited. We therefore estimated the association of 5 mg/kg/d (CsA5) and 3 mg/kg/d (CsA3) CsA starting doses with GvHD risk in two consecutive cohorts of allogeneic hematopoietic cell transplantation (allo-HCT) patients, exploring potential risk factors for incident acute GvHD, with a focus on CsA starting dose. We analyzed 519 patients within CsA5 (n = 153) and CsA3 (n = 366). The cumulative incidence function of acute GvHD grade ≥2 was higher in the CsA3 compared to the CsA5 group (41% vs. 33%, respectively; p = 0.043), without impacting chronic GvHD. In multivariable analysis, a CsA starting dose of 3 mg/kg/d, no ATG use, unrelated donor and high to very high disease risk index were significantly associated with acute GvHD grade ≥2. A higher CsA starting dose of 5 mg/kg/d was independently associated with lower acute GvHD risk, and higher CsA levels in the early period after allo-HCT were reached.

Low Incidence of hepatic sinusoidal obstruction syndrome/veno-occlusive disease in adults undergoing allogenic stem cell transplantation with prophylactic ursodiol and low-dose heparin.

Hepatic sinusoidal obstruction syndrome (SOS)/veno-occlusive disease (VOD) is a complication after allogenic hematopoietic stem-cell transplantation (allo-HSCT) with high mortality. The purpose of this study was to assess the incidence and outcome of SOS in patients after allo-HSCT with the impact of ursodeoxycholic acid (UDCA) and low-dose heparin as SOS prophylaxis. Out of 1016 patients, 23 developed SOS, with a cumulative incidence of 2.3% (95% CI 1.3-3.3) 6 months after HSCT. Approximately one quarter of these patients (26.1%) had late-onset SOS. A high proportion were very severe SOS cases (74%), and 83% of the patients were treated with defibrotide (DF). In multivariate analysis, advanced disease (p = 0.003), previous HSCT (p = 0.025) and graft versus host disease (GvHD) prophylaxis by post-transplant cyclophosphamide (PTCy) (p = 0.055) were associated with the development of SOS. The 1-year overall survival (OS) was significantly lower in the SOS group compared to patients without SOS (13% versus 70%, p = 0.0001). In conclusion, we found a low incidence of SOS in patients receiving low-dose heparin and UDCA prophylactically, but among SOS patients, a high mortality. Low-dose heparin and UDCA might be a prophylactic approach for SOS.

Frequency, reactivity and evolution of human leukocyte antigen and human platelet antigen antibodies in the setting of hematopoietic cell transplantation.

BACKGROUND AND OBJECTIVES: Antibodies (Ab) against HLA and HPA antigens play an important role in HCT. In this prospective study we evaluated prevalence and kinetics of HLA- and HPA-Ab after HCT, including a possible donor-recipient transfer and their clinical relevance in respect to platelet transfusion refractoriness (PTR). MATERIALS AND METHODS: Patients were consecutively recruited. Ab were determined by microbead assay technique and a mean fluorescence intensity cut-off of 1,000. RESULTS: At baseline, 21 donors (42 %) and 27 patients (54 %) had HLA-Ab with a mean panel reactivity (cPRA) of 34.9 ± 29.4 % and 46.1 ± 36.5 %, respectively. We observed a significant higher number of HLA-Ab specificities in female donors and patients and a predominance of HLA-class I Ab. At day 0 we detected an increase of HLA-Ab (from 526 to 673) and cPRA (55.2 ± 31.9 %). Thirty-six patients (72 %) developed new HLA-Ab, mainly 3 weeks after HCT. In 7 patients an HLA-Ab with the same specificity as detected in the corresponding donor emerged, suggesting a possible transfer from the donor to the recipient. Overall, MFI showed a high variation. Type and number of transfusions were not associated with number and intensity of HLA-Ab (ρ: -0.05 - 0.02). Number of HLA-Ab, cPRA and intensity were not associated with PTR, which occurred in 9 patients (18 %) and none had bleeding WHO > 2. CONCLUSIONS: Although a considerable number of patients have and develop HLA-Ab before and early after HCT, we found no association with PTR and bleeding and management should be individualized.

Transfusions in Aplastic Anemia Patients Cause HLA Alloimmunization: Comparisons of Current and Past Cohorts Demonstrate Progress.

Transfusions are the mainstay of supportive therapy in patients with aplastic anemia (AA) and may lead to anti- HLA alloimmunization, thereby also increasing the risk for donor-specific antibodies in the setting of HLA-mismatched transplantation. Historically, AA patients were thought to be at particularly high risk for HLA alloimmunization. In past decades, blood product manufacturing (leukoreduction) and HLA antibody testing have improved significantly by single antigen bead (SAB) technology. It is currently unknown how those developments have impacted HLA alloimmunization and treatment outcome in patients with AA. We retrospectively investigated 54 AA patients treated by immunosuppressive therapy or allogeneic hematopoietic cell transplantation after the introduction of the SAB assay at our center. We compared the HLA antibody results to a historical AA cohort (n = 26), treated before introduction of leukoreduced blood products from 1975 to 1995. HLA alloimmunization was detected in 43 of 54 (80%) recently treated patients. Past pregnancy, female gender, disease severity, age, and a history of other transfusions were significantly associated with a larger number or higher intensity (mean fluorescence intensity) of HLA antibodies. Treatment outcome including bleeding episodes, response to treatment, engraftment, graft-versus-host disease, and overall survival was not associated with HLA alloimmunization. In the historical cohort a significantly higher number of HLA antibodies (P < .01) with a higher mean fluorescent intensity (P < .01) was observed. HLA alloimmunization remains frequent in AA tested by current techniques, but it has significantly decreased since prior decades and does not affect treatment outcome. © 2021 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Immune cytopenia after allogeneic haematopoietic stem-cell transplantation: challenges, approaches, and future directions.

Immune-mediated cytopenia after allogeneic haematopoietic stem-cell transplantation is rare. The pathophysiology of immune-mediated anaemia, thrombocytopenia, and neutropenia, which occur alone or in combination with other cytopenias, is unclear and most probably a consequence of immune dysregulation. Risk factors for this complication have been identified in retrospective studies but these should be interpreted with caution and should not be generalised to this heterogeneous patient population. Diagnosis is challenging, requires awareness of such complications, and has to be differentiated from a multitude of other, and sometimes overlapping, possible complications. The clinical course of immune-mediated cytopenia is highly variable. Treatment requires an interdisciplinary approach and ranges from observation to symptomatic measures and directed therapies. Intensive immunosuppression is associated with an increased risk of infections and relapse, and current treatments are based on approaches in patients who have not undergone transplantation. Plasma cell-directed therapies, immunomodulation, and receptor-stimulating agents can be used to treat immune-mediated cytopenia.

New-onset Post-transplant Diabetes and Therapy in Long-term Survivors After Allogeneic Hematopoietic Stem Cell Transplantation.

BACKGROUND: Survival after allogeneic hematopoietic stem cell transplantation (allo-HSCT) has increased but so have long-term sequelae. New-onset post-transplant diabetes mellitus (PTDM) occurs frequently following allo-HSCT. PATIENTS AND METHODS: Study endpoints were incidence and risk factors of PDTM. We studied 599 adult patients suffering from either acute myeloid leukemia n=220), acute lymphoblastic leukemia (n=79), chronic myeloid leukemia (n=22), myelodysplastic syndrome/myeloproliferative neoplasm (n=105), chronic lymphocytic leukemia (n=37), lymphoma/myeloma (n=116, or non-malignant disorders (e.g. bone marrow failure, hemoglobinopathies) (n=20) who underwent myeloablative (466; 77.8%) or non-myeloablative (131; 21.9%) allo-HSCT between 2006 and 2016. RESULTS: Altogether, 39 patients (6.5%) developed PTDM. In a competing-risk analysis, time to PTDM was associated with acute grade 2-4 graft-versus-host-disease (p=0.017). Further cardiovascular risk factors were hypertension (n=145; 24.2%), coronary artery disease (n=36, 6%), dyslipidemia (n=139; 23.3%), and stroke (n=12; 2%). CONCLUSION: After allo-HSCT, a significant number of patients developed PTDM and patients with acute graft-versus-host-disease were found to have a higher risk for PTDM. Long-term and continuous follow-up for diabetes and cardiovascular risk factors after HSCT is important in order to be able to provide timely and appropriate treatment.

Adverse event reporting for cellular therapy products: Current status and future directions.

Adverse event (AE) and adverse reaction (AR) reporting are key components of patient safety and surveillance systems. Review and analysis of this data yields opportunities for process improvement, product information and interventions, and can lead to improved patient outcomes and donor safety overall. AE and AR reporting for cellular therapy products is fragmented and not well characterized in a central reference. This review article, authored by experts from various organizations, serves to summarize the current state of reporting and offers opportunities for streamlining and coordination, as well as key reference for professionals in this field.

Routine next generation sequencing of lymphoid malignancies: clinical utility and challenges from a 3-Year practical experience.

Since 2016, a next-generation sequencing (NGS) panel targeting 68 genes frequently mutated in lymphoid malignancies is an accredited part of routine diagnostics at the Institute of Pathology in Basel, Switzerland. Here, we retrospectively evaluate the feasibility and utility of integrating this NGS platform into routine practice on 80 diagnostic cases of lymphoid proliferations. NGS analysis was useful in most instances, yielding a diagnostically, predictively and/or prognostically meaningful result. In 35 out of the 50 cases, in which conventional histopathological evaluation remained indecisive, molecular subtyping with the NGS panel was helpful to either confirm or support the favored diagnosis, enable a differential diagnosis, or seriously question a suspected diagnosis. A total of 61 actionable or potentially actionable mutations in 34 out of 80 cases that might have enabled patient selection for targeted therapies was detected. NGS panel analysis had implications for prognosis in all 15 cases interrogated for risk assessment.

Toxicity associated with PD-1 blockade after allogeneic haematopoietic cell transplantation.

Cancer immunotherapy with immune checkpoint inhibitors (ICIs) such as programmed death ligand-1 (PD-L1) blockers offers pronounced clinical benefit with durable responses and a manageable safety profile. Patients with a high risk of immune-related adverse events are generally excluded from clinical trials testing ICI therapy. Thus, only a little information on the safety and clinical outcome of patients treated with an ICI after allogeneic haematopoietic cell transplantation (HCT) is currently available. Here, we report the characteristics and outcomes of six patients with, respectively, clear cell renal carcinoma, diffuse large cell B-cell lymphoma, Hodgkin lymphoma, a microsatellite instable colorectal cancer and melanoma who were treated with PD-1 blocking antibodies. All patients had previously undergone allogeneic HCT. Severe grade 3–5 immune-related adverse events were observed in three of five patients who received full-dose ICI therapy. One patient received a lower dose of PD-1 blocking antibody. Only one patient had an objective response, whereas all the other patients had progressive disease. The high toxicity of a full- dose anti-PD-1 treatment regimen suggests that other treatment approaches for patients after allogeneic HCT are needed outside of the context of relapsed Hodgkin disease. In cases where ICI therapy is the only treatment option, reduced dosing should be explored.

Reduced dose of post-transplantation cyclophosphamide compared to ATG for graft-versus-host disease prophylaxis in recipients of mismatched unrelated donor hematopoietic cell transplantation: a single-center study.

Post-transplantation cyclophosphamide (PTCy) demonstrated effectiveness to prevent GVHD after haploidentical hematopoietic cell transplantation (HCT). Reducing toxicities with a maximized efficacy is still challenging in HCT. In this retrospective study, we analyzed the safety and efficacy of transplantation from a 1-antigen HLA-mismatched unrelated donor (9/10 MMUD) in 80 patients with hematological disorders between 2010 and 2018; 22 patients received PTCy with a reduced dose of 40 mg/kg, cyclosporine A, and mycophenolate mofetil (MMF); 58 patients received anti-thymocyte globulin (ATG), cyclosporine A, and either methotrexate or MMF for GVHD prophylaxis. Cumulative incidence (CI) of acute GVHD grades II-IV in the PTCy group was significantly lower (15% vs. 50%, p = 0.006); however, CI of chronic GVHD was (not significantly) lower in the PTCy group (26% vs. 35%, p = 0.137). One-year OS was significantly longer (p = 0.008) in the PTCy group with a similar 1-year PFS (p = 0.114) in both groups. Rates of 1-year relapse and non-relapse mortality were similar. Median time to neutrophil engraftment was comparable in both GVHD prophylaxis groups (14 days vs. 16 days, respectively, p = 0.107). Our results show that a lower dose of PTCy-based prophylaxis is an effective and safe strategy to prevent acute GVHD in HCT with 9/10 MMUD compared to ATG.