Safety and long-term survival results of the addition of inotuzumab ozogamicin to the conditioning regimen of allogeneic stem cell transplantation: A single-center phase 1,2 trial

Here we report on the first prospective study evaluating the safety and long-term survival when an escalating dose of inotuzumab ozogamicin (INO) (0.6, 1.2, or 1.8 mg/m2 on day 13) was added to one alkylator-containing conditioning regimen in patients with relapsed CD22 (+) lymphoid malignancies who were candidates for hematopoietic stem cell transplantation (HSCT). Twenty-six patients were enrolled. Six (23%) of these patients entered the phase 1 study: four were treated at an INO dose of 0.6 mg/m2 and two at dose of 1.2 mg/m2. None of these patients experienced dose-limiting toxicities. The remaining 20 (77%) patients entered the phase 2 part of the study at the maximum dose of 1.8 mg/m2. One patient developed VOD; this patient had received nivolumab immediately before HSCT while simultaneously experiencing hyperacute graft-vs-host disease (GVHD). Treatment-related mortality (TRM) at 5 years was 12%. With a median follow-up of 48.7 months, the 5-year overall survival (OS) and progression-free survival (PFS) rates were 84% and 80%, respectively. Compared with a historical cohort who received same conditioning for HSCT but without INO (n = 56), the INO group showed no significant differences in incidence of liver toxicity, engraftment time, TRM, or risk of acute GVHD. Patients with lymphoma who received INO had a trend for a better 5-year OS (93% versus 68%) and PFS (93% versus 58%) than those in the control group. In conclusion, our results showed that INO is safe with no increased risk of VOD when combined with one alkylator-containing regimen of HSCT.

ABT199/venetoclax synergism with thiotepa enhances the cytotoxicity of fludarabine, cladribine and busulfan in AML cells

ABT199/venetoclax, an inhibitor of the pro-survival BCL-2 protein, has improved AML treatment. Its efficacy in hematopoietic stem cell transplantation (HSCT), when combined with other chemotherapeutic drugs, has not been thoroughly investigated. The present study demonstrates the synergistic cytotoxicity of ABT199/venetoclax with the DNA alkylator thiotepa (Thio) in AML cells. Cleavage of Caspase 3, PARP1 and HSP90, as well as increased Annexin V positivity, suggest potent activation of apoptosis by this two-drug combination; increased levels of γ-H2AX, P-CHK1 (S317), P-CHK2 (S19) and P-SMC1 (S957) indicate an enhanced DNA damage response. Likewise, the increased level of P-SAPK/JNK (T183/Y185) and decreased P-PI3Kp85 (Y458) suggest enhanced activation of stress signaling pathways. These molecular readouts were synergistically enhanced when ABT199/venetoclax and Thio were combined with fludarabine, cladribine and busulfan. The five-drug combination decreased the levels of BCL-2, BCL-xL and MCL-1, suggesting its potential clinical relevance in overcoming ABT199/venetoclax resistance. Moreover, this combination is active against P53-negative and FLT3-ITD-positive cell lines. Enhanced activation of apoptosis was observed in leukemia patient-derived cell samples exposed to the five-drug combination, suggesting a clinical relevance. The results provide a rationale for clinical trials using these two- and five-drug combinations as part of a conditioning regimen for AML patients undergoing HSCT.

Incidence and risk factors of early onset VOD/SOS differ in younger vs older adults after stem cell transplantation

ABSTRACT

Veno-occlusive disease (VOD) is a rare but potentially life-threatening complication after allogeneic hematopoietic stem cell transplantation (allo-SCT). Although increasing awareness and modern transplant techniques have mitigated risk, the interaction of historic risk factors in the current era with posttransplant cyclophosphamide (PTCy) is unknown. We performed a retrospective single-center analysis of adult patients aged ≥18 years undergoing allo-SCT (N = 1561) using predominately PTCy as graft-versus-host disease (GVHD) prophylaxis (72%). We found a higher rate of VOD at 16.8% (20 of 119) in those aged ≤25 years compared with 3.8% (55 of 1442) in those aged >25 years, with unique predictors of VOD within each cohort. Multivariate classification and regression tree (CART) analysis confirmed age as the primary independent determinant of the rate of VOD. Among patients aged 18 to 25 years, disease risk index (DRI; 31% with high/very high DRI vs 12% low/intermediate DRI; P = .03) and prior lines of chemotherapy (24% with >1 vs 6% with ≤1; P = .03) were the strongest predictors of VOD. Incidence of VOD in patients aged >25 years of age consistently ranged between 3% and 5% across most risk factors evaluated, with only hepatic factors (baseline elevation of bilirubin, aspartate transferase, alanine aminotransferase) or gemtuzumab exposure associated with increased rates of VOD. There was no significant difference in rates of VOD in those receiving PTCy compared with those receiving alternate GVHD prophylaxis. Our data highlight the differences in incidence and predictors of VOD between younger (≤25) and older (>25) adults undergoing allo-SCT.

Harmonizing definitions for hematopoietic recovery, graft rejection, graft failure, poor graft function, and donor chimerism in allogeneic hematopoietic cell transplantation: a report on behalf of the EBMT, ASTCT, CIBMTR, and APBMT

Despite emergence of novel therapies to treat hematologic malignancies, allogeneic hematopoietic cell transplantation (allo-HCT) remains an essential treatment modality capable of curing these diseases. Allo-HCT has been also shown to be curative in benign hematologic disorders such as aplastic anemia, sickle cell disease, and thalassemia, among others. Recently, the American Society for Transplantation and Cellular Therapy (ASTCT) published standardized definitions for hematopoietic recovery, graft rejection, graft failure, poor graft function, and donor chimerism. To attempt broader international consensus, a panel of adult and pediatric physician transplant experts was assembled from European Society for Blood and Marrow Transplantation (EBMT), ASTCT, the Center for International Blood and Marrow Transplant Research (CIBMTR), and Asia-Pacific Blood and Marrow Transplantation (APBMT). Consensus was defined as ≥70% of voting members strongly agreeing or somewhat agreeing with a definition. With few exceptions, there was a consensus to endorse the prior ASTCT definitions. Importantly, we revised existing EBMT and CIBMTR data collection forms to align with these harmonized definitions that will facilitate research and international collaboration among transplant researchers and across transplant registries.

The Role of Outpatient Physical Medicine and Rehabilitation in a Multidisciplinary Prehabilitation Program for Older Adults before Allogeneic Hematopoietic Stem Cell Transplant

INTRODUCTION

Physical rehabilitation is increasingly incorporated throughout the allogeneic hematopoietic stem cell transplant (allo-HSCT) journey for older adults.

OBJECTIVE

This study aimed to describe physical medicine and rehabilitation (PM&R)-related diagnoses, exercise barriers, and management recommendations for older adults before allo-HSCT.

DESIGN

Fifty PM&R consults as part of the Enhanced Recovery-Stem Cell Transplant (ER-SCT) multidisciplinary prehabilitation program at a comprehensive cancer center were retrospectively reviewed.

RESULTS

Many PM&R-related diagnoses (173), exercise barriers (55), and management recommendations (112) were found. Common diagnoses were musculoskeletal dysfunction (more commonly back, shoulder, then knee) (n = 39, 23%) and fatigue (n = 36, 21%). Common exercise barriers were also musculoskeletal dysfunction (more commonly back, knee, then shoulder) (total n = 20, 36%) and fatigue (n = 20, 36%). Most patients (n = 32, 64%) had 1 or more exercise barriers. Common PM&R management recommendations were personalized exercise counseling (n = 37, 33%), personalized nutrition management (n = 19, 17%), body composition recommendations (n = 17, 15%), medications (n = 15, 13%), and orthotics and durable medical equipment (n = 8, 7%).

CONCLUSION

Routine PM&R referral of older allo-HSCT patients for prehabilitation resulted in the identification of many rehabilitative needs and substantial additional management recommendations. Increased early, collaborative prehabilitation efforts between PM&R and allo-HSCT teams to optimize care for these patients is recommended.

Characteristics and outcomes of children, adolescents and young adults with relapsed/refractory non-hodgkin lymphoma undergoing autologous stem cell transplant

BACKGROUND

There is paucity of data regarding outcomes of children, adolescents and young adults (CAYA) patients with non-Hodgkin lymphoma (NHL) undergoing autologous stem cell transplantation (ASCT).

METHODS

Patients aged 0-39 years undergoing first ASCT for NHL at MD Anderson Cancer Center between 2000 and 2020 were analyzed.

RESULTS

Two hundred twenty-one patients were included in the analysis, 129 (58%) were male and the median age was 32 (range 6-39) years. The most common histological subtypes were diffuse large B cell lymphoma (DLBCL) (44%), T-NHL (19%) and primary mediastinal B-Cell lymphoma (PMBCL) (19%). Younger patients (age ≤ 25) had lower incidence of DLBCL and higher incidence of PMBCL and T-NHL compared to older patients (age > 25) (P = 0.02). None of the younger patients had double hit (DH)/double expressor (DE) DLBCL, compared to 14 patients in the older age group (18%, P = 0.07). Considering the three main aggressive NHL subtypes (DLBCL, PMBCL and T-NHL), younger patients had numerically better 15-year post-transplant progression free survival (PFS) (67% vs. 54%) and overall survival (OS) (71% vs. 62%) compared to older patients, yet these differences did not reach statistical significance (P = 0.19 and P = 0.24, respectively). In multivariate analysis, not achieving a CR prior to ASCT was independently predictive of worse PFS [partial remission (PR) (HR, 3.9); stable disease (SD) (HR, 18.0), P = 0.03] and of worse OS [PR (HR, 4.2), SD (HR, 6.5) and progressive disease (HR, 4.7), P < 0.0001]. DH/DE status was an independent adverse predictor of PFS in multivariate analysis (HR 5.8, p = 0.03). Ten patients (4.5%) (all aged > 25 years) developed second primary malignancies (SPM), at a median of 34.4 (range, 1.0-196.6) months after ASCT, and SPM was the cause of death in five (50%) of them.

CONCLUSIONS

CAYA NHL patients aged ≤ 25 years who received ASCT presented a distinct NHL histology as compared to older CAYA patients, and none in this younger age group had DH/DE DLBCL. We observed a trend towards improved PFS and OS in younger patients. Disease status at ASCT was predictive of both PFS and OS. DH/DE status was an adverse predictor of PFS.

Synergistic cytotoxicity of fludarabine, clofarabine, busulfan, vorinostat and olaparib in AML cells

Combinations of nucleoside analog(s) and DNA alkylating agent(s) are used for cancer treatment as components of pre-transplant regimens used in hematopoietic stem cell transplantation. Their efficacies are enhanced by combining drugs with different mechanisms of action, which also allows a reduction in the individual drug dosages and thus potentially in toxicity to the patient. We hypothesized that addition of SAHA and olaparib, an HDAC- and a PARP-inhibitor, respectively, to the established combination of fludarabine, clofarabine and busulfan would enhance AML cell cytotoxicity. Exposure of the AML cell lines KBM3/Bu2506, MV4-11, MOLM14 and OCI-AML3 to the 5-drug combination resulted in synergistic cytotoxicity with combination indexes < 1. Increased protein acetylation and decreased poly(ADP-ribosyl)ation were observed, as expected. Activation of apoptosis was suggested by cleavage of Caspase 3 and PARP1, DNA fragmentation, increased reactive oxygen species, and decreased mitochondrial membrane potential. The reduction in poly(ADP-ribosyl)ation was independent of caspase activation. Several proteins involved in DNA damage response and repair were downregulated, which may be contributing factors for the observed synergism. The increased phosphorylation of DNAPKcs suggests inhibition of its kinase activity and diminution of its role in DNA repair. A similar synergism was observed in patient-derived cell samples. These findings will be important in designing clinical trials using these drug combinations as pre-transplant conditioning regimens for AML patients.

High-Dose Chemotherapy and Autologous Stem Cell Transplantation for Relapsed or Refractory Primary Mediastinal Large B-Cell Lymphoma

Primary mediastinal large B-cell lymphoma (PMBCL) is an uncommon, aggressive type of non-Hodgkin lymphoma. Rituximab-containing chemoimmunotherapy with or without radiation therapy (RT) is standard first-line treatment. Relapsed or refractory (R/R) disease has long been treated with salvage chemotherapy followed by high-dose chemotherapy (HDC), with autologous stem cell transplantation (ASCT) in appropriate patients. We retrospectively analyzed all patients with R/R PMBCL treated with HDC/ASCT at our center between January 2000 and August 2022. The 60 study patients received either rituximab-BEAM (n = 37) or rituximab-gemcitabine/busulfan/melphalan (R-GemBuMel) with or without vorinostat (n = 23), followed by ASCT. Forty-six patients received mediastinal RT, either as prior consolidation of frontline therapy or following ASCT. At median follow-up of 6 years (range, .3 to 21 years), the 5-year progression-free survival (PFS) and overall survival (OS) rates of the whole group were 58% and 77%, respectively, for the entire cohort, 51% and 65% for the R-BEAM recipients, and 69% and 82% for R-vorinostat/GemBuMel recipients. Multivariable analyses showed that a negative positron emission tomography scan at ASCT (hazard ratio [HR], .28) and involvement of only 1 organ (HR, .33) were independently associated with improved PFS. In addition, receipt of R-vorinostat/GemBuMel (HR, .23) was an independent favorable predictor of OS. Our data indicate that HDC/ASCT is effective in R/R PMBCL, with improved outcomes in patients receiving R-vorinostat/GemBuMel.

The Transplantation Ecosystem: A New Concept to Improve Access and Outcomes for Older Allogeneic Hematopoietic Cell Transplantation Patients

Allogeneic hematopoietic cell transplantation (HCT) is increasingly offered to older adults with hematologic malignancies, even though nonrelapse mortality remains a major concern in older patients owing to more comorbidities and greater frailty compared with their younger counterparts. The importance of patient fitness, a well-matched donor, and disease control to the success of allogeneic HCT have been well documented; however, these factors fail to account for the impact of the complex transplantation ecosystem (TE) that older adult HCT candidates must navigate. We propose a definition of the TE modeled after the social determinants of health. Furthermore, we outline a research agenda aimed at increasing understanding of the roles of individual social determinants of transplantation health in the larger ecosystem and how they may benefit or harm older adult HCT candidates. Herein we define the TE and its individual tenets, the social determinants of transplantation health. We review the available literature while incorporating the expertise of the membership of the American Society for Transplantation and Cellular Therapy (ASTCT) Special Interest Group for Aging. The membership of the ASTCT Special Interest Group for Aging identify knowledge gaps and strategies to address them for each of the described social determinants of transplantation health. The ecosystem is an essential but underappreciated pillar for transplant access and success. We put forth this novel research agenda seeking to gain a better understanding of the complexity of HCT in older adults and develop strategies to improve access to HCT, survival, and quality of life.

Clinical relevance of MYC/BCL2 expression and cell of origin in patients with diffuse large b-cell lymphoma treated with autologous transplant

Dual expression of MYC and BCL2 proteins (double-expressor lymphoma [DEL]) as well as cell of origin (COO) are important prognostic factors in patients with diffuse large B-cell lymphoma (DLBCL) after conventional chemotherapy. We studied the prognostic impact of DEL and COO in patients with relapsed DLBCL treated with autologous stem cell transplant (ASCT). Three-hundred and three patients with stored tissue samples were identified. Classification was successful in 267 patients: 161 (60%) were DEL/non-double hit (DHL), 98 (37%) were non-DEL/non-DHL, and 8 (3%) were DEL/DHL. Compared to non-DEL/non-DHL, DEL/DHL had worse overall survival while DEL/non-DHL did not significantly differ in overall survival. On multivariable analysis, DEL/DHL, age >60 years, and >2 prior therapies, but not COO, were important prognostic factors for overall survival. When we explored the interaction of COO and BCL2 expression, patients with germinal center B-cell (GCB)/BCL2 (+) had inferior progression-free survival (PFS) compared to GCB/BCL2 (-) patients (HR, 4.97; P = 0.027). We conclude that the DEL/non-DHL and non-DEL/non-DHL subtypes of DLBCL have similar survival after ASCT. The negative impact of GCB/BCL2 (+) on PFS warrants future trials targeting BCL2 after ASCT. The inferior outcomes in DEL/DHL need to be verified in a larger number of patients.

Evolving trends and outcomes in older patients with acute myeloid leukemia including allogeneic stem cell transplantation

Outcomes in older patients with acute myeloid leukemia (AML) have historically been poor. Given advances in low-intensity therapy (LIT) and stem cell transplantation (SCT), we performed a retrospective single-center study to evaluate the contemporary outcomes of this population. We reviewed all patients ≥60 years with newly diagnosed AML between 2012 and 2021 and analyzed treatment and SCT-related trends and outcomes. We identified 1073 patients with a median age of 71 years. Adverse clinical and cytomolecular findings were frequent within this cohort. In total, 16% of patients were treated with intensive chemotherapy, 51% with LIT alone, and 32% with LIT plus venetoclax. The composite complete remission rate with LIT plus venetoclax was 72%, which was higher than with LIT alone (48%, p < .0001) and comparable to intensive chemotherapy (74%, p = .6). The median overall survival (OS) with intensive chemotherapy, LIT, and LIT plus venetoclax was 20.1, 8.9, and 12.1 months, respectively. 18% of patients received SCT. SCT rates were 37%, 10%, and 22% in patients treated with intensive chemotherapy, LIT, and LIT plus venetoclax, respectively. The 2-year OS, relapse-free survival (RFS), cumulative incidence (CI) of relapse, and CI of treatment-related mortality with frontline SCT (n = 139) were 59%, 52%, 27%, and 22%, respectively. By landmark analysis, patients undergoing frontline SCT had superior OS (median 39.6 vs. 21.4 months, p < .0001) and RFS (30.9 vs. 12.1 months, p < .0001) compared with responding patients who did not. Outcomes in older patients with AML are improving with more effective LIT. Measures should be pursued to increase access to SCT in older patients.

Impact of type of induction therapy on outcomes in older adults with AML after allogeneic stem cell transplantation

Although venetoclax-based lower-intensity regimens have greatly improved outcomes for older adults with acute myeloid leukemia (AML) who are unfit for intensive chemotherapy, the optimal induction for older patients with newly diagnosed AML who are suitable candidates for hematopoietic stem cell transplant (HSCT) is controversial. We retrospectively analyzed the post HSCT outcomes of 127 patients ≥60 years of age who received induction therapy at our institution with intensive chemotherapy (IC; n = 44), lower-intensity therapy (LIT) without venetoclax (n = 29), or LIT with venetoclax (n = 54) and who underwent allogeneic HSCT in the first remission. The 2-year relapse-free survival (RFS) was 60% with LIT with venetoclax vs 54% with IC, and 41% with LIT without venetoclax; the 2-year overall survival (OS) was 72% LIT with venetoclax vs 58% with IC, and 41% with LIT without venetoclax. The benefit of LIT with venetoclax induction was greatest in patients with adverse-risk AML (2-year OS: 74%, 46%, and 29%, respectively). Induction with LIT, with or without venetoclax, was associated with the lowest rate of nonrelapse mortality (NRM) (2-year NRM: 17% vs 27% with IC; P = .04). Using multivariate analysis, the type of induction therapy did not significantly affect any of the post HSCT outcomes evaluated; hematopoietic cell transplantation-specific comorbidity index was the only factor that independently predicted RFS and OS. LIT plus venetoclax followed by HSCT is a feasible treatment strategy in older, fit, HSCT-eligible patients with newly diagnosed AML and may be particularly beneficial for those with adverse-risk disease.

Harmonizing Definitions for Diagnostic Criteria and Prognostic Assessment of Transplantation-Associated Thrombotic Microangiopathy: A Report on Behalf of the European Society for Blood and Marrow Transplantation, American Society for Transplantation and Cellular Therapy, Asia-Pacific Blood and Marrow Transplantation Group, and Center for International Blood and Marrow Transplant Research

Transplantation-associated thrombotic microangiopathy (TA-TMA) is an increasingly recognized complication of hematopoietic cell transplantation (HCT) associated with significant morbidity and mortality. However, TA-TMA is a clinical diagnosis, and multiple criteria have been proposed without universal application. Although some patients have a self-resolving disease, others progress to multiorgan failure and/or death. Poor prognostic features also are not uniformly accepted. The lack of harmonization of diagnostic and prognostic markers has precluded multi-institutional studies to better understand incidence and outcomes. Even current interventional trials use different criteria, making it challenging to interpret the data. To address this urgent need, the American Society for Transplantation and Cellular Therapy, Center for International Bone Marrow Transplant Research, Asia-Pacific Blood and Marrow Transplantation, and European Society for Blood and Marrow Transplantation nominated representatives for an expert panel tasked with reaching consensus on diagnostic and prognostic criteria. The panel reviewed literature, generated consensus statements regarding diagnostic and prognostic features of TA-TMA using the Delphi method, and identified future directions of investigation. Consensus was reached on 4 key concepts: (1) TA-TMA can be diagnosed using clinical and laboratory criteria or tissue biopsy of kidney or gastrointestinal tissue; however, biopsy is not required; (2) consensus diagnostic criteria are proposed using the modified Jodele criteria with additional definitions of anemia and thrombocytopenia. TA-TMA is diagnosed when ≥4 of the following 7 features occur twice within 14 days: anemia, defined as failure to achieve transfusion independence despite neutrophil engraftment; hemoglobin decline by ≥1 g/dL or new-onset transfusion dependence; thrombocytopenia, defined as failure to achieve platelet engraftment, higher-than-expected transfusion needs, refractory to platelet transfusions, or ≥50% reduction in baseline platelet count after full platelet engraftment; lactate dehydrogenase (LDH) exceeding the upper limit of normal (ULN); schistocytes; hypertension; soluble C5b-9 (sC5b-9) exceeding the ULN; and proteinuria (≥1 mg/mg random urine protein-to-creatinine ratio [rUPCR]); (3) patients with any of the following features are at increased risk of nonrelapse mortality and should be stratified as high-risk TA-TMA: elevated sC5b-9, LDH ≥2 times the ULN, rUPCR ≥1 mg/mg, multiorgan dysfunction, concurrent grade II-IV acute graft-versus-host disease (GVHD), or infection (bacterial or viral); and (4) all allogeneic and pediatric autologous HCT recipients with neuroblastoma should be screened weekly for TA-TMA during the first 100 days post-HCT. Patients diagnosed with TA-TMA should be risk-stratified, and those with high-risk disease should be offered participation in a clinical trial for TA-TMA-directed therapy if available. We propose that these criteria and risk stratification features be used in data registries, prospective studies, and clinical practice across international settings. This harmonization will facilitate the investigation of TA-TMA across populations diverse in race, ethnicity, age, disease indications, and transplantation characteristics. As these criteria are widely used, we expect continued refinement as necessary. Efforts to identify more specific diagnostic and prognostic biomarkers are a top priority of the field. Finally, an investigation of the impact of TA-TMA-directed treatment, particularly in the setting of concurrent highly morbid complications, such as steroid-refractory GVHD and infection, is critically needed.

Characteristics and Outcomes of Children, Adolescents and Young Adults with Relapsed/Refractory Non-Hodgkin Lymphoma Undergoing Autologous Stem Cell Transplant

There is paucity of data regarding outcomes of children, adolescents and young adults (CAYA) patients with non-Hodgkin lymphoma (NHL) undergoing autologous hematopoietic stem cell transplantation (ASCT). We analyzed 222 patients aged 0-39 years undergoing first ASCT for NHL between 2000 and 2020. The most common histological subtypes were DLBCL (44%), T-NHL (19%) and PMBCL (19%). Younger patients (age ≤ 25) had lower incidence of DLBCL and higher incidence of PMBCL and T-NHL compared to older patients (> 25 years) (P = 0.02). None of the younger patients had DH)/DE DLBCL, as compared to 14 patients in the older group (18%, P = 0.07). Younger patients had numerically better 15-year post-transplant PFS (67% vs. 54%) and OS (71% vs. 62%) compared to older patients, without statistically significant differences (P = 0.19 and P = 0.24, respectively). In MVA, not achieving a CR prior to ASCT was independently predictive of worse PFS (P < 0.0001). DH/DE status was an independent adverse predictor of PFS in MVA (HR 5.8, p = 0.03). 10 patients(4.5%) (all aged > 25 years) developed SPM Patients aged ≤ 25 years presented a distinct NHL histology as compared to older CAYA patients. Disease status at ASCT was predictive of both PFS and OS. DH/DE status was an adverse predictor of PFS.

Splenomegaly in patients with primary or secondary myelofibrosis who are candidates for allogeneic hematopoietic cell transplantation: a Position Paper on behalf of the Chronic Malignancies Working Party of the EBMT

Splenomegaly is a hallmark of myelofibrosis, a debilitating haematological malignancy for which the only curative option is allogeneic haematopoietic cell transplantation (HCT). Considerable splenic enlargement might be associated with a higher risk of delayed engraftment and graft failure, increased non-relapse mortality, and worse overall survival after HCT as compared with patients without significantly enlarged splenomegaly. Currently, there are no standardised guidelines to assist transplantation physicians in deciding optimal management of splenomegaly before HCT. Therefore, the aim of this Position Paper is to offer a shared position statement on this issue. An international group of haematologists, transplantation physicians, gastroenterologists, surgeons, radiotherapists, and radiologists with experience in the treatment of myelofibrosis contributed to this Position Paper. The key issues addressed by this group included the assessment, prevalence, and clinical significance of splenomegaly, and the need for a therapeutic intervention before HCT for the control of splenomegaly. Specific scenarios, including splanchnic vein thrombosis and COVID-19, are also discussed. All patients with myelofibrosis must have their spleen size assessed before allogeneic HCT. Myelofibrosis patients with splenomegaly measuring 5 cm and larger, particularly when exceeding 15 cm below the left costal margin, or with splenomegaly-related symptoms, could benefit from treatment with the aim of reducing the spleen size before HCT. In the absence of, or loss of, response, patients with increasing spleen size should be evaluated for second-line options, depending on availability, patient fitness, and centre experience. Splanchnic vein thrombosis is not an absolute contraindication for HCT, but a multidisciplinary approach is warranted. Finally, prevention and treatment of COVID-19 should adhere to standard recommendations for immunocompromised patients.

Clinical outcomes and impact of therapeutic intervention in patients with acute myeloid leukemia who experience measurable residual disease (MRD) recurrence following MRD-negative remission

Recurrence of MRD in AML is associated with imminent relapse unless intervened upon. Change in chemotherapy regimen and/or immediate transplant improve outcomes.

Engineered cord blood megakaryocytes evade killing by allogeneic T-cells for refractory thrombocytopenia

The current global platelet supply is often insufficient to meet all the transfusion needs of patients, in particular for those with alloimmune thrombocytopenia. To address this issue, we have developed a strategy employing a combination of approaches to achieve more efficient production of functional megakaryocytes (MKs) and platelets collected from cord blood (CB)-derived CD34+ hematopoietic cells. This strategy is based on ex-vivo expansion and differentiation of MKs in the presence of bone marrow niche-mimicking mesenchymal stem cells (MSCs), together with two other key components: (1) To enhance MK polyploidization, we used the potent pharmacological Rho-associated coiled-coil kinase (ROCK) inhibitor, KD045, resulting in liberation of increased numbers of functional platelets both in-vitro and in-vivo; (2) To evade HLA class I T-cell-driven killing of these expanded MKs, we employed CRISPR-Cas9-mediated β-2 microglobulin (β2M) gene knockout (KO). We found that coculturing with MSCs and MK-lineage-specific cytokines significantly increased MK expansion. This was further increased by ROCK inhibition, which induced MK polyploidization and platelet production. Additionally, ex-vivo treatment of MKs with KD045 resulted in significantly higher levels of engraftment and donor chimerism in a mouse model of thrombocytopenia. Finally, β2M KO allowed MKs to evade killing by allogeneic T-cells. Overall, our approaches offer a novel, readily translatable roadmap for producing adult donor-independent platelet products for a variety of clinical indications.

Venetoclax combined with induction chemotherapy in patients with newly diagnosed acute myeloid leukaemia: a post-hoc, propensity score-matched, cohort study

BACKGROUND

Venetoclax combined with intensive chemotherapy has been shown to be safe with promising activity in fit patients with newly diagnosed acute myeloid leukaemia. The aim of this study was to compare the activity of venetoclax plus intensive chemotherapy with intensive chemotherapy alone.

METHODS

This was a post-hoc propensity score matched analysis of prospective clinical trials (NCT03214562, NCT02115295, and NCT01289457) in patients at The University of Texas MD Anderson Cancer Center, Texas, USA between March 29, 2010, and June 15, 2021. Eligible patients were aged 18 years and older, and had newly diagnosed acute myeloid leukaemia or high-risk myelodysplastic syndrome, and were treated within trials incorporating purine analogues with an anthracycline and cytarabine either with venetoclax plus intensive chemotherapy or with intensive chemotherapy alone. Patients in the venetoclax plus intensive chemotherapy cohort were matched with patients in the intensive chemotherapy cohort. Morphological response and measurable residual disease (MRD) was assessed using bone marrow aspiration and biopsy and eight-colour multiparameter flow cytometry. The primary objectives were rate of MRD negative composite complete response and cumulative incidence of transition to allogeneic haematopoietic stem-cell transplantation (HSCT). All patients who had response within two treatment cycles (induction and re-induction) were included in the analyses. Secondary objectives included assessment of event-free and overall survival.

FINDINGS

The propensity matched cohort included 279 patients (median age 49 years [IQR 39-57]; 131 [47%] were men and 148 [53%] were women); 85 in the venetoclax plus intensive chemotherapy cohort and 194 in the intensive chemotherapy cohort. After a median follow up of 30 months (95% CI 26-36), 64 (86%) of 74 patients in the venetoclax plus intensive chemotherapy cohort had an MRD-negative composite complete response rate compared with 86 [61%] of 140 patients in the intensive chemotherapy cohort (odd ratio 3·2 [95% CI 1·5-6·7]; p=0·0028). The overall cumulative incidence of allogeneic HSCT in responding patients was higher with venetoclax plus intensive chemotherapy than intensive chemotherapy (79% [95% CI 67-88] vs 57% [49-65]; hazard ratio [HR] 1·52 [95% CI 1·11-2·08]; p=0·012). Venetoclax plus intensive chemotherapy improved event-free survival (median not reached [NR; 95% CI NR-NR] vs 14·3 months [10·7-33·5]; HR 0·57 [95% CI 0·34-0·95]; p=0·030), but overall survival did not significantly differ between the two cohorts (median NR [95% CI 24-NR] vs 32 months [19-NR]; HR 0·63 [95% CI 0·35-1·1], p=0·13).

INTERPRETATIONS

Venetoclax combined with intensive induction chemotherapy induced deep MRD-negative remissions, allowing transition to allogeneic HSCT in first remission, and improvement in event-free survival. These results highlight the incremental benefit of venetoclax added to intensive induction chemotherapy across European LeukemiaNet risk groups, and serve as a benchmark to inform enrolment on future confirmatory prospective clinical trials.

FUNDING

None.

Blinatumomab maintenance after allogeneic hematopoietic cell transplantation for B-lineage acute lymphoblastic leukemia

Patients with B-lineage acute lymphoblastic leukemia (ALL) are at high-risk for relapse after allogeneic hematopoietic cell transplantation (HCT). We conducted a single-center phase 2 study evaluating the feasibility of 4 cycles of blinatumomab administered every 3 months during the first year after HCT in an effort to mitigate relapse in high-risk ALL patients. Twenty-one of 23 enrolled patients received at least 1 cycle of blinatumomab and were included in the analysis. The median time from HCT to the first cycle of blinatumomab was 78 days (range, 44 to 105). Twelve patients (57%) completed all 4 treatment cycles. Neutropenia was the only grade 4 adverse event (19%). Rates of cytokine release (5% G1) and neurotoxicity (5% G2) were minimal. The cumulative incidence of acute graft-versus-host disease (GVHD) grades 2 to 4 and 3 to 4 were 33% and 5%, respectively; 2 cases of mild (10%) and 1 case of moderate (5%) chronic GVHD were noted. With a median follow-up of 14.3 months, the 1-year overall survival (OS), progression-free survival (PFS), and nonrelapse mortality (NRM) rates were 85%, 71%, and 0%, respectively. In a matched analysis with a contemporary cohort of 57 patients, we found no significant difference between groups regarding blinatumomab's efficacy. Correlative studies of baseline and posttreatment samples identified patients with specific T-cell profiles as "responders" or "nonresponders" to therapy. Responders had higher proportions of effector memory CD8 T-cell subsets. Nonresponders were T-cell deficient and expressed more inhibitory checkpoint molecules, including T-cell immunoglobulin and mucin domain 3 (TIM3). We found that blinatumomab postallogeneic HCT is feasible, and its benefit is dependent on the immune milieu at time of treatment. This paper is posted on ClinicalTrials.gov, study ID: NCT02807883.

ABT199/venetoclax potentiates the cytotoxicity of alkylating agents and fludarabine in acute myeloid leukemia cells

The antineoplastic activity of pre-transplant regimens in hematopoietic stem cell transplantation (HSCT) is a critical factor for acute myeloid leukemia (AML) patients. There is an urgent need to identify novel approaches without jeopardizing patient safety. We hypothesized that combination of drugs with different mechanisms of action would provide better cytotoxicity. We, therefore, determined the synergistic cytotoxicity of various combinations of the alkylating agents busulfan (Bu) and 4-hydroperoxycyclophosphamide (4HC), the nucleoside analog fludarabine (Flu) and the BCL2 inhibitor ABT199/venetoclax in AML cells. [Bu+4HC] and [Bu+Flu] inhibited cell proliferation and activated apoptosis; addition of ABT199 to either combinations significantly increased these effects with combination indexes < 1. Apoptosis is suggested by cleavages of PARP1 and CASPASE 3, DNA fragmentation, increased reactive oxygen species, decreased mitochondrial membrane potential, and increased pro-apoptotic proteins in the cytoplasm. A similar enhancement of apoptosis was observed in patient-derived cell samples. ABT199/venetocalx upregulated anti-apoptotic MCL1 as a compensatory mechanism but addition of [Bu+4HC] or [Bu+Flu] negated this effect by CASPASE 3-mediated cleavage of MEK1/2 and its substrate MCL1. CASPASE 3 caused cleavage of pro-survival β-CATENIN, which likely contributed to the activation of stress signaling pathways involving SAPK/JNK and AMPK. The observed synergistic cytotoxicity was associated with an inhibition of pro-survival pathways involving STAT1, STAT5 and PI3K. These findings will be useful in designing clinical trials using these drug combinations as pre-transplant conditioning regimens for AML patients.

Impact of frontline treatment approach on outcomes in patients with secondary AML with prior hypomethylating agent exposure

BACKGROUND

Treated secondary acute myeloid leukemia (ts-AML)-i.e., AML arising from a previously treated antecedent hematologic disorder-is associated with very poor outcomes. The optimal frontline treatment regimen for these patients is uncertain.

METHODS

We retrospectively analyzed 562 patients who developed AML from preceding myelodysplastic syndrome or chronic myelomonocytic leukemia for which they had received a hypomethylating agent (HMA). Patients with ts-AML were stratified by frontline AML treatment with intensive chemotherapy (IC, n = 271), low-intensity therapy (LIT) without venetoclax (n = 237), or HMA plus venetoclax (n = 54).

RESULTS

Compared with IC or LIT without venetoclax, HMA plus venetoclax resulted in higher CR/CRi rates (39% and 25%, respectively; P = 0.02) and superior OS (1-year OS 34% and 17%, respectively; P = 0.05). The benefit of HMA plus venetoclax was restricted to patients with non-adverse risk karyotype, where HMA plus venetoclax resulted in a median OS of 13.7 months and 1-year OS rate of 54%; in contrast, for patients with adverse risk karyotype, OS was similarly dismal regardless of treatment approach (median OS 3-5 months). A propensity score analysis accounting for relevant clinical variables confirmed the significant OS benefit of HMA plus venetoclax, as compared with other frontline treatment approaches. In a landmark analysis, patients with ts-AML who underwent subsequent hematopoietic stem cell transplantation (HSCT) had superior 3-year OS compared to non-transplanted patients (33% vs. 8%, respectively; P = 0.003).

CONCLUSIONS

The outcomes of ts-AML are poor but may be improved with use of an HMA plus venetoclax-based regimen, followed by HSCT, particularly in those with a non-adverse risk karyotype.

Third-Party BK Virus-Specific Cytotoxic T Lymphocyte Therapy for Hemorrhagic Cystitis Following Allotransplantation

PURPOSE

BK virus-associated hemorrhagic cystitis (BKV-HC) is a common complication of allogenic hematopoietic stem cell transplantation (AHSCT), particularly in recipients of alternative donor transplants, which are being performed in increasing numbers. BKV-HC typically results in painful hematuria, urinary obstruction, and renal dysfunction, without a definitive therapeutic option.

METHODS

We performed a clinical trial (ClinicalTrials.gov identifier: NCT02479698) to assess the feasibility, safety, and efficacy of administering most closely HLA-matched third-party BKV-specific cytotoxic T lymphocytes (CTLs), generated from 26 healthy donors and banked for off-the-shelf use. The cells were infused into 59 patients who developed BKV-HC following AHSCT. Comprehensive clinical assessments and correlative studies were performed.

RESULTS

Response to BKV-CTL infusion was rapid; the day 14 overall response rate was 67.7% (40 of 59 evaluable patients), which increased to 81.6% among evaluable patients at day 45 (40 of 49 evaluable patients). No patient lost a previously achieved response. There were no cases of de novo grade 3 or 4 graft-versus-host disease, graft failure, or infusion-related toxicities. BKV-CTLs were identified in patient blood samples up to 3 months postinfusion and their in vivo expansion predicted for clinical response. A matched-pair analysis revealed that, compared with standard of care, after accounting for prognostic covariate effects, treatment with BKV-CTLs resulted in higher probabilities of response at all follow-up timepoints as well as significantly lower transfusion requirement.

CONCLUSION

Off-the-shelf BKV-CTLs are a safe and effective therapy for the management of patients with BKV-HC after AHSCT.

Fludarabine and Melphalan Compared with Reduced Doses of Busulfan and Fludarabine Improve Transplantation Outcomes in Older Patients with Myelodysplastic Syndromes

Reduced-intensity conditioning (RIC) regimens developed to extend the use of allogeneic hematopoietic stem cell transplantation (HSCT) to older patients have resulted in encouraging outcomes. We aimed to compare the 2 most commonly used RIC regimens, i.v. fludarabine with busulfan (FluBu) and fludarabine with melphalan (FluMel), in patients with myelodysplastic syndrome (MDS). Through the Center for International Blood and Marrow Transplant Research (CIBMTR), we identified 1045 MDS patients age ≥60 years who underwent first HSCT with a matched related or matched (8/8) unrelated donor using an RIC regimen. The CIBMTR's definition of RIC was used: a regimen that incorporated an i.v. busulfan total dose ≤7.2 mg/kg or a low-dose melphalan total dose ≤150 mg/m². The 2 groups, recipients of FluBu (n = 697) and recipients of FluMel (n = 448), were comparable in terms of disease- and transplantation-related characteristics except for the more frequent use of antithymocyte globulin or alemtuzumab in the FluBu group (39% versus 31%). The median age was 67 years in both groups. FluMel was associated with a reduced relapse incidence (RI) compared with FluBu, with a 1-year adjusted incidence of 26% versus 44% (P ≤ .0001). Transplantation-related mortality (TRM) was higher in the FluMel group (26% versus 16%; P ≤ .0001). Because the magnitude of improvement with FluMel in RI was greater than the improvement in TRM with FluBu, disease-free survival (DFS) was better at 1 year and beyond with FluMel compared with FluBu (48% versus 40% at 1 year [P = .02] and 35% versus 27% at 3 years [P = .01]). Overall survival (OS) was comparable in the 2 groups at 1 year (63% versus 61%; P = .4) but was significantly improved with FluMel compared with FluBu at 3 years (46% versus 39%; P = .03). Our results suggest that FluMel is associated with superior DFS compared with FluBu owing to reduced RI in older patients with MDS patients. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Outcomes of Second Allogeneic Hematopoietic Cell Transplantation for Patients With Acute Myeloid Leukemia

Relapse after allogeneic hematopoietic cell transplantation (HCT) leads to poor survival in patients with acute myeloid leukemia (AML). A second HCT (HCT2) may achieve durable remission. To determine the outcomes of patients who received an HCT2 for relapsed AML and to evaluate the predictors of overall survival (OS) and progression-free survival (PFS). We retrospectively reviewed medical records of adult patients who underwent an HCT2 for relapsed AML at our institution during 2000 to 2019. Ninety-one patients were identified with a median age of 44 years (range 18-73) at HCT2. Donor types were HLA-identical sibling (n = 37 [41%]), HLA-matched-unrelated (n = 34 [37%]), haploidentical (n = 19 [21%]), and cord blood (n=1 [1%]). Donors were different at HCT2 in 53% of patients. The majority of patients received reduced intensity conditioning (n = 71 [78%]) and were in remission (n = 56 [61%]) at HCT2. The median remission duration after HCT1 was 8.4 months (range 1-70) and the median time between transplants was 14 months (range 3-73). The median follow-up of surviving patients after HCT2 was 66 months (range 2-171), with 32% alive at time of analysis. The most common cause of death was disease recurrence (n = 45 [73%]). At 2 years, the rates of OS, PFS, progression, and nonrelapse mortality were 36%, 27%, 42%, and 18%, respectively. The development of chronic graft-versus-host disease (GVHD) after first HCT and HCT comorbidity index (HCT-CI) ≥2 at HCT2 were associated with inferior PFS and OS after HCT2. A second HCT is feasible in selected patients with AML who have relapsed after HCT1. Long-term survival benefit is possible in patients without chronic GVHD after HCT1 and HCT-CI <2 at HCT2.

Long-term results of low-intensity chemotherapy with clofarabine or cladribine combined with low-dose cytarabine alternating with decitabine in older patients with newly diagnosed acute myeloid leukemia

The treatment of older patients with newly diagnosed acute myeloid leukemia (AML) using intensive chemotherapy is associated with treatment intolerance and poor survival. We evaluated two new lower-intensity regimens with clofarabine (n = 119) or cladribine (n = 129) combined with low-dose cytarabine (LDAC) alternating with decitabine. We reviewed response rates by subgroup and long term outcomes of 248 patients with newly diagnosed non core-binding-factor AML treated on two clinical trials investigating double nucleoside-analogue therapy (DNT) alternating with HMA from October, 2008 to April, 2018. Of 248 patients with a median age of 69 years (range, 49-85 years), 102 patients (41%) were ≥ 70 years, and 108 (44%) had adverse karyotype. Overall, 164 patients (66%) responded: 147 (59%) complete remission (CR) and 17 (7%) CR with incomplete count recovery (CRi). With a median follow up of 60 months, median relapse-free and overall survival (OS) were 10.8 and 12.5 months, respectively. The 2-year OS was 29%. Among patients with normal karyotype, the CR/CRi rate was 79% and the median OS 19.9 months. High response rates and OS were observed in patients with mutations in NPM1, FLT3, IDH2, and RUNX1. The 4- and 8-week mortality rates were 2% and 11%, respectively. The backbone of clofarabine or cladribine and LDAC alternating with decitabine was effective and safe for the treatment of older patients with newly diagnosed AML. Incorporating targeted therapies could extend the efficacy of this approach and provide more curative therapeutic options in this AML population.

Brain volume change after high-dose immunosuppression and autologous hematopoietic cell transplantation for relapsing-remitting multiple sclerosis

BACKGROUND

Brain volume loss (BVL) is commonly observed after high-dose immunosuppression and autologous hematopoietic cell transplantation (HDIT/HCT) for treatment of multiple sclerosis (MS). To better understand the mechanisms of underlying BVL associated with this treatment, we characterized the time courses of whole-brain (WB), grey-matter (GM) and white-matter (WM) volume loss in relapsing-remitting MS (RRMS) patients who received BEAM-based HDIT/HCT.

METHODS

We used Jacobian integration to measure MRI-based WB, GM and WM volume changes up to 5 years after transplant in twenty-four RRMS participants who underwent BEAM-based HDIT/HCT. Using a two-piecewise mixed-effects model, we estimated the short-term (baseline to 1 year) and long-term (beyond 1 year) rates of BVL after HDIT/HCT. We also compared the rates based on the presence of gadolinium-enhancing lesions at baseline, and the maintenance of event-free survival during follow-up.

RESULTS

On average, accelerated short-term BVL of -1.37% (SE: 0.21), -0.86% (SE: 0.28) and -2.18% (SE: 0.26) occurred in WB, GM and WM, respectively. Baseline T1-weighted MRI WM lesion volume was a significant predictor in the WB (short-term) and the WM (short-term and long-term). The average rates of BVL after the initial acceleration were -0.22%/y (SE: 0.10), -0.13%/y (SE: 0.11) and -0.36%/y (SE: 0.11) in the WB, GM and WM, respectively. Participants with gadolinium-enhancing lesions at baseline had significantly higher short-term rates of GM (-1.56% vs. -0.27%, p = 0.01) and WB volume loss (-1.94% vs. -0.81%, p = 0.006) at 1 year follow-up as compared to those without gadolinium-enhancing lesions. WM volume loss was not significantly different (-2.59% vs. -1.66%, p = 0.16). Participants who maintained event-free survival had similar rates of BVL compared to those who did not.

CONCLUSIONS

BVL may accelerate for months after HDIT/HCT. However, over the long-term, adequate HDIT/HCT may reduce BVL rates to those similar to normal aging at the WB level.

Donor clonal hematopoiesis increases risk of acute graft versus host disease after matched sibling transplantation

Clonal hematopoiesis (CH) is associated with older age and an increased risk of myeloid malignancies and cardiovascular complications. We analyzed donor DNA samples in patients with AML/MDS who underwent first allogeneic stem cell transplant (SCT) to investigate the association between donor CH and transplant outcomes. We performed targeted deep sequencing of 300 genes on donor blood samples and identified CH with the minimum variant allele frequency of 2%. Among 363 donors, 65 (18%) had CH. The most frequently mutated genes were DNMT3A (31 of 65; 48%), TET2 (16 of 65; 25%), PPM1D (5 of 65, 8%), and ASXL1 (7 of 65; 11%). Transplant outcomes: time to neutrophil and platelet recovery, relapse incidence, transplant-related mortality and progression-free survival, were comparable by donor CH. However, risk of grade II-IV and III-IV acute graft versus host disease (aGvHD) at 6 months after transplant was higher with donor CH vs. without donor CH (hazard ratio (HR) = 2.4, 95% Confidence Interval (CI) = 1.6-3.6, p < 0.001 and HR = 3.8, 95% CI = 1.6-8.9, p = 0.003). In this homogenous population of AML/MDS patients, donor CH was associated with increased risk of grade II-IV and III-IV aGvHD. Further studies to investigate the mechanisms of increased aGvHD and therapeutic interventions to improve aGvHD in the context of donor CH are warranted.

Improved outcomes of high-risk relapsed Hodgkin lymphoma patients after high-dose chemotherapy: a 15-year analysis

High-dose chemotherapy and autologous stem-cell transplant (HDC/ASCT) is standard treatment for chemosensitive relapsed classical Hodgkin lymphoma, although outcomes of high-risk relapse (HRR) patients remain suboptimal. We retrospectively analyzed all HRR classical Hodgkin lymphoma patients treated with HDC/ASCT at our institution between 01/01/2005 and 12/31/2019. HRR criteria included primary refractory disease/relapse within 1 year, extranodal extension, B symptoms, requiring more than one salvage line, or positron emission tomography (PET)-positive disease at ASCT. All patients met the same ASCT eligibility criteria. We treated 501 patients with BEAM (n=146), busulphan/melphalan (BuMel) (n=38), gemcitabine( Gem)/BuMel (n=189) and vorinostat/Gem/BuMel (n=128). The Gem/BuMel and vorinostat/Gem/BuMel cohorts had more HRR criteria and more patients with PET-positive disease at ASCT. Treatment with brentuximab vedotin (BV) or anti-PD1 prior to ASCT, PET-negative disease at ASCT, and maintenance BV increased over time. BEAM and BuMel predominated in earlier years (2005-2007), GemBuMel and BEAM in middle years (2008-2015), and vorinostat/GemBuMel and BEAM in later years (2016-2019). The median follow-up is 50 months (range, 6-186). Outcomes improved over time, with 2-year progressionfree survival (PFS)/overall survival (OS) rates of 58%/82% (2005-2007), 59%/83% (2008-2011), 71%/94% (2012-2015) and 86%/99% (2016- 2019) (P<0.0001). Five-year PFS/OS rates were 72%/87% after vorinostat/ GemBuMel, 55%/75% after GemBuMel, 45%/61% after BEAM, and 39%/57% after BuMel (PFS: P=0.0003; OS: P<0.0001). These differences persisted within the PET-negative and PET-positive subgroups. Prior BV and vorinostat/GemBuMel were independent predictors of more favorable outcome, whereas primary refractory disease, ≥2 salvage lines, bulky relapse, B symptoms and PET-positivity at ASCT correlated independently with unfavorable outcomes. In conclusion, post-HDC/ASCT outcomes of patients with HRR classic Hodgkin lymphoma have improved over the last 15 years. Pre-ASCT BV treatment and optimized synergistic HDC (vorinostat/GemBuMel) were associated with this improvement.

Vedolizumab for Steroid Refractory Lower Gastrointestinal Tract Graft-Versus-Host Disease

Steroid-refractory (SR) lower gastrointestinal (LGI) acute graft-versus-host disease (aGVHD) has poor prognosis, and novel drugs are needed. We describe outcomes of patients with SR-LGI aGVHD treated with vedolizumab. The primary objective was to determine overall response rate (ORR) at days 14, 28, and 56. Secondary outcomes included overall survival (OS), non-relapse mortality and toxicities. Twenty patients, median age 46 years (range, 23-71), were included. All but 2 patients (90%) had grade 3 to 4 aGVHD (45% stage 4, 40% stage 3 LGI). Median time to vedolizumab was 21 days (range, 5-1031) and 13 days (range, 0-533) after diagnosis of LGI aGVHD and SR-LGI aGVHD, respectively. It was given as ≥3rd line (median 3; range 2-6) in 75% after failure of steroids, and additional treatments including ruxolitinib (n = 12) and others. Median follow-up was 17 months (range, 10-34). The days 14, 28 and 56 ORRs were 45% (9/20; complete response [CR] 25%), 35% (7/20; CR 20%), and 25% (5/20; CR 20%), respectively. Among ruxolitinib failures, it was 50% (6/12; CR 25%), 50% (6/12; CR 25%) and 25% (3/12; CR 16.7%), respectively. Fifteen patients died (14 GVHD, 1 leukemia relapse). The actuarial 6-month OS was 35% (95% confidence interval 16-55). No progressive multifocal leukoencephalopathy or infusion reaction occurred. Forty-four infection events (22 viral, 18 bacterial, and 4 fungal) were noted in 16 patients. Vedolizumab was well tolerated and demonstrated potential efficacy even after ruxolitinib failure for SR-LGI aGVHD. Yet the responses were suboptimal, and its use requires further investigation.

Development and validation of a risk assessment tool for BKPyV Replication in allogeneic stem cell transplant recipients

BACKGROUND

BK polymavirus (BKPyV), a member of the family Polyomaviridae, is associated with increased morbidity and mortality in allogeneic stem cell transplant recipients.

METHODS

In our previous retrospective study of 2477 stem cell transplant patients, BKPyV replication independently predicted chronic kidney disease and poor survival. In this study, using the same cohort, we derived and validated a risk grading system to identify patients at risk of BKPyV replication after transplantation in a user-friendly modality. We used 3 baseline variables (conditioning regimen, HLA match status, and underlying cancer diagnosis) that significantly predicted BKPyV replication in our initial study in a subdistribution hazard model with death as a competing risk. We also developed a nomogram of the hazard model as a visual aid. The AUC of the ROC of the risk-score-only model was 0.65. We further stratified the patients on the basis of risk score into low-, moderate-, and high-risk groups.

RESULTS

The total risk score was significantly associated with BKPyV replication (P < .0001). At 30 days after transplantation, the low-risk (score ≤ 0) patients had a 9% chance of developing symptomatic BKPyV replication, while the high-risk (score ≥ 8) of the population had 56% of developing BKPyV replication. We validated the risk score using a separate cohort of 1478 patients. The AUC of the ROC of the risk-score-only model was 0.59. Both the total risk score and 3-level risk variable were significantly associated with BKPyV replication in this cohort (P < .0001).

CONCLUSIONS

This grading system for the risk of symptomatic BKPyV replication may help in early monitoring and intervention to prevent BKPyV-associated morbidity, mortality, and kidney function decline.

Haploidentical transplants for patients with relapse after the first allograft

Relapse after allogeneic hematopoietic stem-cell transplantation (AHSCT) is associated with very poor outcomes. A second transplant offers the possibility of long-term disease control. We analyzed outcomes with haploidentical donors for second allograft at our institution. All consecutive patients with hematological malignancies (N = 29) who relapsed after AHSCT and underwent a haploidentical transplant (haploSCT) as second transplant between February 2009 and October 2018 were included. Median age was 36 years (interquartile range (IQR) 24-60); 83% of patients had high/very high disease risk index; 61% of AML/MDS patients had high-risk cytogenetics; and only 24% were in complete remission at transplant. With a median follow-up of 46.9 months, the 3-year relapse, non-relapse mortality (NRM), progression-free survival (PFS) and overall survival (OS) were 30%, 39%, 31% and 40%, respectively. In multivariable analysis (MVA), comorbidity index (HCT-CI) and detectable donor-specific anti-HLA antibodies (DSA) prior to second transplant were significantly associated with worse outcomes. Patients with HCT-CI <3 and without DSA had 3-year PFS and OS of 53% and 60.3%, respectively. Our findings suggest that haploSCT as second AHSCT is feasible and potentially curative. Lower HCT-CI and no DSA were associated with lower NRM and improved survival. Haploidentical grafts might be a preferred donor source for second AHSCT as these are high-risk patients who frequently need to proceed urgently to transplant.

A Mildly Symptomatic Middle-Aged Woman with INT-1 Primary Myelofibrosis

In patients with myelofibrosis (MF), allogeneic stem cell transplantation (SCT) is a curative treatment, but does entail risk of treatment-related mortality (TRM). Furthermore, a minority of patients cured of myelofibrosis are at risk of chronic graft-versus-host disease (GvHD) that may impair their quality of life. It is also pertinent to note that transplant early in the disease course results in better transplant outcome than transplant late in the disease course.¹ Thus, the survival benefit of SCT needs to be weighed against early transplant related mortality (TRM) and morbidity, as well as impaired quality of life due to chronic GvHD, when deciding about timing of transplant in the natural history of disease.

A Personalized Prediction Model for Outcomes after Allogeneic Hematopoietic Cell Transplant in Patients with Myelodysplastic Syndromes

Allogeneic hematopoietic stem cell transplantation (HCT) remains the only potentially curative option for myelodysplastic syndromes (MDS). Mortality after HCT is high, with deaths related to relapse or transplant-related complications. Thus, identifying patients who may or may not benefit from HCT is clinically important. We identified 1514 patients with MDS enrolled in the Center for International Blood and Marrow Transplant Research Registry and had their peripheral blood samples sequenced for the presence of 129 commonly mutated genes in myeloid malignancies. A random survival forest algorithm was used to build the model, and the accuracy of the proposed model was assessed by concordance index. The median age of the entire cohort was 59 years. The most commonly mutated genes were ASXL1(20%), TP53 (19%), DNMT3A (15%), and TET2 (12%). The algorithm identified the following variables prior to HCT that impacted overall survival: age, TP53 mutations, absolute neutrophils count, cytogenetics per International Prognostic Scoring System-Revised, Karnofsky performance status, conditioning regimen, donor age, WBC count, hemoglobin, diagnosis of therapy-related MDS, peripheral blast percentage, mutations in RAS pathway, JAK2 mutation, number of mutations/sample, ZRSR2, and CUX1 mutations. Different variables impacted the risk of relapse post-transplant. The new model can provide survival probability at different time points that are specific (personalized) for a given patient based on the clinical and mutational variables that are listed above. The outcomes' probability at different time points may aid physicians and patients in their decision regarding HCT.

Timing of allogeneic hematopoietic cell transplantation (alloHCT) for chronic myeloid leukemia (CML) patients

While TKI are the preferred first-line treatment for chronic phase (CP) CML, alloHCT remains an important consideration. The aim is to estimate residual life expectancy (RLE) for patients initially diagnosed with CP CML based on timing of alloHCT or continuation of TKI in various settings: CP1 CML, CP2 + [after transformation to accelerated phase (AP) or blast phase (BP)], AP, or BP. Non-transplant cohort included single-institution patients initiating TKI and switched TKI due to failure. CIBMTR transplant cohort included CML patients who underwent HLA sibling matched (MRD) or unrelated donor (MUD) alloHCT. AlloHCT appeared to shorten survival in CP1 CML with overall mortality hazard ratio (HR) for alloHCT of 2.4 (95% CI 1.2-4.9; p = .02). In BP CML, there was a trend toward higher survival with alloHCT; HR = 0.7 (0.5-1.1; p = .099). AlloHCT in CP2 + [HR = 2.0 (0.8-4.9), p = .13] and AP [HR = 1.1 (0.6-2.1); p = .80] is less clear and should be determined on a case-by-case basis.

Optimizing the Conditioning Regimen for Hematopoietic Cell Transplant in Myelofibrosis: Long-Term Results of a Prospective Phase II Clinical Trial

Optimal conditioning regimens for older patients with myelofibrosis undergoing allogeneic hematopoietic cell transplant are not known. Likewise, the role of dose intensity is not clear. We conducted a nonrandomized, prospective, phase II trial using low-dose, later escalated to high-dose (myeloablative conditioning), busulfan with fludarabine (Bu-Flu) in myelofibrosis patients up to age 74 years. The first 15 patients received i.v. busulfan 130 mg/m²/day on days -3 and -2 ("low dose"); 31 patients received high-dose conditioning, either 100 mg/m²/day (days -5 to -2; n = 4) or pharmacokinetic-guided area under the curve of 4000 μmol/min (days -5 to -2; n = 27). The primary endpoint was day 100 nonrelapse mortality (NRM). Median age was 58 years (interquartile range [IQR], 53-63). Dynamic international prognostic scoring system-plus was intermediate (n = 28) or high (n = 18). Donors were related (n = 19) or unrelated (n = 27). Cumulative incidence of NRM was 9.7% (95% confidence interval [CI], 0-20.3) at day 100 and at 3 years in the high-dose group and 0% in the low-dose group at day 100, which increased to 20% (95% CI, 0-41.9) at 3 years. With a median follow-up of 5.1 years (IQR, 3.8-6), 3-year relapse was 32.3% (95% CI, 15.4-49.1) in high dose versus 53.3% (95% CI, 26.6-80.1) in low dose. Event-free survival was 58% (95% CI, 43-78) versus 27% (95% CI, 12-62), and overall survival was 74% (95% CI, 60-91) versus 60% (95% CI, 40-91). In multivariate analysis, high-dose busulfan had a trend toward lower relapse (hazard ratio, .44; 95% CI, .18-1.07; P = .07), with no impact on NRM. Intensifying the Bu-Flu regimen using pharmacokinetic-monitoring appears to be promising in reducing relapse without increasing NRM.

The Role of Donor Lymphocyte Infusion (DLI) in Post-Hematopoietic Cell Transplant (HCT) Relapse for Chronic Myeloid Leukemia (CML) in the Tyrosine Kinase Inhibitor (TKI) Era

Treatment for relapse of chronic myeloid leukemia (CML) following hematopoietic cell transplantation (HCT) includes tyrosine kinase inhibitors (TKIs) with or without donor lymphocyte infusions (DLIs), but the most effective treatment strategy is unknown. This study was performed through the Center for International Blood and Marrow Transplant Research (CIBMTR) database. We retrospectively reviewed all patients reported to the CIBMTR registry from 2002 to 2014 who underwent HCT for CML and were alive 30 days postrelapse. A total of 215 HCT recipients relapsed and were analyzed in the following groups: (1) TKI alone (n = 128), (2) TKI with DLI (n = 48), and (3) DLI without TKI (n = 39). In multivariate analysis, disease status prior to HCT had a significant effect on overall survival (OS). Patients who received a DLI alone compared with a TKI with a DLI had inferior survival (hazard ratio, 2.28; 95% confidence interval, 1.23 to 4.24; P= .009). Those who received a TKI alone had similar survival compared with those who received a TKI with a DLI (P = .81). These data support that despite use of TKIs pretransplantation, TKI salvage therapy continues to provide significant survival following relapse in patients with CML following HCT. These data do not suggest that adding a DLI to a TKI adds an improvement in OS.

Age Is a Prognostic Factor for the Overall Survival of Patients with Multiple Myeloma Undergoing Upfront Autologous Hematopoietic Stem Cell Transplantation

In this retrospective analysis, we evaluated the impact of age on the outcome of patients with multiple myeloma who received an autologous hematopoietic stem cell transplantation (auto-HCT) at our institution. A total of 1128 patients were divided into the older (>70 years; 182 [16%]) and the younger (≤70 years; 946 [84%]) groups. Compared with the younger cohort, older patients had a higher International Staging System (ISS) stage (ISS-II, 57 [31%] versus 215 [23%]; ISS-III, 52 [28%] versus 211 [22%]; P = .01), higher use of reduced-dose melphalan as a conditioning regimen (140 mg/m², 59 [32%] versus 29 [3%]; P < .001), and a higher comorbidity index (median, 3 versus 2; P = .01). Nonrelapse mortality at 1 year after auto-HCT was significantly higher in older patients (7 [4%] versus 9 [1%]; hazard ratio [HR], 4.1; P = .005). Complete remission rates after auto-HCT for the older and the younger groups were 41% and 46%, respectively. With a median follow-up of 52 months, the 5-year progression-free survival (PFS) was 24% (95% confidence interval [CI], 17% to 32%) and 37% (95% CI, 33% to 40%) in the older and younger groups, respectively (HR, 1.3; P = .02). Five-year OS for the older and younger groups was 56% (95% CI, 47% to 64%) and 73% (95% CI, 70% to 76%; P < .001), respectively. Older age emerged as one of the predictors of shorter OS but not PFS in the multivariate classification and regression tree analysis. In conclusion, age ≥70 years was associated with shorter PFS and OS in patients with multiple myeloma who underwent an auto-HCT.

Haploidentical transplantation for acute myeloid leukemia patients with minimal/measurable residual disease at transplantation

There have been conflicting results regarding the impact of minimal/measurable disease at transplant on acute myeloid leukemia (AML) outcomes after haploidentical transplantation (haplo-SCT). We assessed the impact of pre-transplant disease status on post-transplant outcomes of 143 patients treated with haplo-SCT using fludarabine-melphalan (FM) conditioning and post-transplant cyclophosphamide (PTCy). With a median follow-up of 29 months, the two-year PFS for all patients was 41%. Compared to patients in complete remission (CR) at transplant, those with active disease (n = 29) and CR with incomplete count recovery (CRi) (n = 39) had worse PFS. They had hazard ratios (HR) of 3.5 (95% CI: 2.05-6.1; P < .001) and 2.3 (95% CI: 1.3-3.9; P = .002), respectively. Among patients who were in CR at transplant, there were no differences in PFS between those who had minimal residual disease (MRD) positive (n = 24), and MRD negative (n = 41) (HR 1.85, 95%CI: 0.9-4.0; P = .1). In multivariable analysis for patients in CR, only age was predictive for outcomes, while MRD status at transplant did not influence the treatment outcomes. Our findings suggest that haplo-SCT with FM conditioning regimen and PTCy-based GVHD prophylaxis has a protective effect, and may potentially abrogate the inferior outcomes of MRD positivity for patients with AML. Patients with positive MRD may benefit from proceeding urgently to a haplo-SCT, as this does not appear to negatively impact transplant outcomes.

Maintenance Tyrosine Kinase Inhibitors Following Allogeneic Hematopoietic Stem Cell Transplantation for Chronic Myelogenous Leukemia: A Center for International Blood and Marrow Transplant Research Study

It remains unknown whether the administration of tyrosine kinase inhibitors (TKIs) targeting BCR-ABL1 after allogeneic hematopoietic cell transplantation (HCT) is associated with improved outcomes for patients with chronic myelogenous leukemia (CML). In this registry study, we analyzed clinical outcomes of 390 adult patients with CML who underwent transplantation between 2007 and 2014 and received maintenance TKI following HCT (n = 89) compared with no TKI maintenance (n = 301), as reported to the Center for International Blood and Marrow Transplant Research. All patients received TKI therapy before HCT. The majority of patients had a disease status of first chronic phase at HCT (n = 240; 62%). The study was conducted as a landmark analysis, excluding patients who died, relapsed, had chronic graft-versus-host disease, or were censored before day +100 following HCT. Of the 89 patients who received TKI maintenance, 77 (87%) received a single TKI and the other 12 (13%) received multiple sequential TKIs. The most common TKIs used for maintenance were dasatinib (n = 50), imatinib (n = 27), and nilotinib (n = 27). As measured from day +100, the adjusted estimates for 5-year relapse (maintenance, 35% versus no maintenance, 26%; P = .11), leukemia-free survival (maintenance, 42% versus no maintenance, 44%; P = .65), or overall survival (maintenance, 61% versus no maintenance, 57%; P = .61) did not differ significantly between patients receiving TKI maintenance or no maintenance. These results remained unchanged in multivariate analysis and were not modified by disease status before transplantation. In conclusion, our data from this day +100 landmark analysis do not demonstrate a significant impact of maintenance TKI therapy on clinical outcomes. The optimal approach to TKI administration in the post-transplantation setting in patients with CML remains undetermined.

Prognostic Score and Cytogenetic Risk Classification for Chronic Lymphocytic Leukemia Patients: Center for International Blood and Marrow Transplant Research Report

PURPOSE

To develop a prognostic model and cytogenetic risk classification for previously treated patients with chronic lymphocytic leukemia (CLL) undergoing reduced intensity conditioning (RIC) allogeneic hematopoietic cell transplantation (HCT).

EXPERIMENTAL DESIGN

We performed a retrospective analysis of outcomes of 606 patients with CLL who underwent RIC allogeneic HCT between 2008 and 2014 reported to the Center for International Blood and Marrow Transplant Research.

RESULTS

On the basis of multivariable models, disease status, comorbidity index, lymphocyte count, and white blood cell count at HCT were selected for the development of prognostic model. Using the prognostic score, we stratified patients into low-, intermediate-, high-, and very-high-risk [4-year progression-free survival (PFS) 58%, 42%, 33%, and 25%, respectively, P < 0.0001; 4-year overall survival (OS) 70%, 57%, 54%, and 38%, respectively, P < 0.0001]. We also evaluated karyotypic abnormalities together with del(17p) and found that del(17p) or ≥5 abnormalities showed inferior PFS. Using a multivariable model, we classified cytogenetic risk into low, intermediate, and high (P < 0.0001). When the prognostic score and cytogenetic risk were combined, patients with low prognostic score and low cytogenetic risk had prolonged PFS (61% at 4 years) and OS (75% at 4 years).

CONCLUSIONS

In this large cohort of patients with previously treated CLL who underwent RIC HCT, we developed a robust prognostic scoring system of HCT outcomes and a novel cytogenetic-based risk stratification system. These prognostic models can be used for counseling patients, comparing data across studies, and providing a benchmark for future interventions. For future study, we will further validate these models for patients receiving targeted therapies prior to HCT.