Allogeneic CD19/CD22 CAR T-Cell Therapy for B-Cell Acute Lymphoblastic Leukemia.

This case series reports durable remissions in 2 patients with relapsed/refractory B-cell acute lymphoblastic leukemia treated with allogeneic bispecific CD19/CD22-targeting chimeric antigen receptor T cells.

Allogeneic hematopoietic cell transplantation for adult metachromatic leukodystrophy: a case series.

ABSTRACT: Metachromatic leukodystrophy (MLD) is a rare genetic disorder caused by pathogenic variants of the ARSA gene, leading to a deficiency of the arylsulfatase A enzyme (ARSA) and consecutive accumulation of galactosylceramide-3-0-sulfate in the nervous system. The condition leads to severe neurological deficits and subsequently results in profound intellectual and motoric disability. Especially, the adult form of MLD, which occurs in individuals aged >16 years, poses significant challenges for treating physicians because of the rarity of cases, limited therapeutic options, and different allogeneic hematopoietic cell transplantation (allo-HCT) protocols worldwide. Here, we report the results of allo-HCT treatment in 4 patients with a confirmed adult MLD diagnosis. Bone marrow or mobilized peripheral progenitor cells were infused after a reduced intensity conditioning regime consisting of fludarabine and treosulfan. In 3 patients, allo-HCT was followed by an infusion of mesenchymal cells to further consolidate ARSA production. We observed a good tolerability and an increase in ARSA levels up to normal range values in all patients. A full donor chimerism was detected in 3 patients within the first 12 months. In a 1-year follow-up, patients with complete donor chimerism showed a neurological stable condition. Only 1 patient with an increasing autologous chimerism showed neurological deterioration and a decline in ARSA levels in the first year. In summary, allo-HCT offers a therapeutic option for reconstituting ARSA enzyme levels in adult patients with MLD, with tolerable side effects.

Allogeneic hematopoietic stem cell transplantation in patients aged 60-79 years in Germany (1998-2018): a registry study.

Incidences of diseases treated with transplantation frequently peak at higher age. The contribution of age to total risk of transplantation has not been estimated amidst an aging society. We compare outcomes of 1,547 patients aged 70-79 years and 9,422 patients aged 60-69 years transplanted 1998-2018 for myeloid, lymphoid and further neoplasia in Germany. To quantify the contribution of population mortality to survival, we derive excess mortality based on a sex-, year- and agematched German population in a multistate model that incorporates relapse and graft-versus-host-disease (GvHD). Overall survival, relapse-free survival (RFS) and GvHD-free-relapse-free survival (GRFS) is inferior in patients aged 70-79 years, compared to patients aged 60-69 years, with 36% (95% Confidence Interval [CI]: 34-39%) versus 43% (41-44%), 32% (30- 35%) versus 36% (35-37%) and 23% (21-26%) versus 27% (26-28%) three years post-transplant (P<0.001). Cumulative incidences of relapse at three years are 27% (25-30%) for patients aged 70-79 versus 29% (29-30%) (60-69 years) (P=0.71), yet the difference in non-relapse mortality (NRM) (40% [38-43%] vs. 35% [34-36%] in patients aged 70-79 vs. 60-69 years) (P<0.001) translates into survival differences. Median OS of patients surviving >1 year relapse-free is 6.7 (median, 95% CI: 4.5-9.4, 70-79 years) versus 9 (8.4-10.1, 60-69 years) years since landmark. Three years after RFS of one year, excess NRM is 14% (95% CI: 12-18%) in patients aged 70-79 versus 12% [11-13%] in patients aged 60-69, while population NRM is 7% (6-7%) versus 3% (3-3%). Mortality for reasons other than relapse, GvHD, or age is as high as 27% (24-29%) and 22% (22-23%) four years after transplantation. In conclusion, survival amongst older patients is adequate after allogeneic stem cell transplantation.

Developmental trajectories and cooperating genomic events define molecular subtypes of BCR::ABL1-positive ALL.

ABSTRACT: Distinct diagnostic entities within BCR::ABL1-positive acute lymphoblastic leukemia (ALL) are currently defined by the International Consensus Classification of myeloid neoplasms and acute leukemias (ICC): "lymphoid only", with BCR::ABL1 observed exclusively in lymphatic precursors, vs "multilineage", where BCR::ABL1 is also present in other hematopoietic lineages. Here, we analyzed transcriptomes of 327 BCR::ABL1-positive patients with ALL (age, 2-84 years; median, 46 years) and identified 2 main gene expression clusters reproducible across 4 independent patient cohorts. Fluorescence in situ hybridization analysis of fluorescence-activated cell-sorted hematopoietic compartments showed distinct BCR::ABL1 involvement in myeloid cells for these clusters (n = 18/18 vs n = 3/16 patients; P < .001), indicating that a multilineage or lymphoid BCR::ABL1 subtype can be inferred from gene expression. Further subclusters grouped samples according to cooperating genomic events (multilineage: HBS1L deletion or monosomy 7; lymphoid: IKZF1-/- or CDKN2A/PAX5 deletions/hyperdiploidy). A novel HSB1L transcript was highly specific for BCR::ABL1 multilineage cases independent of HBS1L genomic aberrations. Treatment on current German Multicenter Study Group for Adult ALL (GMALL) protocols resulted in comparable disease-free survival (DFS) for multilineage vs lymphoid cluster patients (3-year DFS: 70% vs 61%; P = .530; n = 91). However, the IKZF1-/- enriched lymphoid subcluster was associated with inferior DFS, whereas hyperdiploid cases showed a superior outcome. Thus, gene expression clusters define underlying developmental trajectories and distinct patterns of cooperating events in BCR::ABL1-positive ALL with prognostic relevance.

CD19-Targeting CAR T Cells for Myositis and Interstitial Lung Disease Associated With Antisynthetase Syndrome.

Importance: Autoimmune disorders can affect various organs and if refractory, can be life threatening. Recently, CD19-targeting-chimeric antigen receptor (CAR) T cells were efficacious as an immune suppressive agent in 6 patients with refractory systemic lupus erythematosus and in 1 patient with antisynthetase syndrome. Objective: To test the safety and efficacy of CD19-targeting CAR T cells in a patient with severe antisynthetase syndrome, a complex autoimmune disorder with evidence for B- and T-cell involvement. Design, Setting, and Participants: This case report describes a patient with antisynthetase syndrome with progressive myositis and interstitial lung disease refractory to available therapies (including rituximab and azathioprine), who was treated with CD19-targeting CAR T cells in June 2022 at University Hospital Tübingen in Tübingen, Germany, with the last follow-up in February 2023. Mycophenolate mofetil was added to the treatment to cotarget CD8+ T cells, hypothesized to contribute to disease activity. Exposure: Prior to treatment with CD19-targeting CAR T cells, the patient received conditioning therapy with fludarabine (25 mg/m2 [5 days before until 3 days before]) and cyclophosphamide (1000 mg/m2 [3 days before]) followed by infusion of CAR T cells (1.23×106/kg [manufactured by transduction of autologous T cells with a CD19 lentiviral vector and amplification in the CliniMACS Prodigy system]) and mycophenolate mofetil (2 g/d) 35 days after CD19-targeting CAR T-cell infusion. Main Outcomes and Measures: The patient's response to therapy was followed by magnetic resonance imaging of the thigh muscle, Physician Global Assessment, functional muscle and pulmonary tests, and peripheral blood quantification of anti-Jo-1 antibody levels, lymphocyte subsets, immunoglobulins, and serological muscle enzymes. Results: Rapid clinical improvement was observed after CD19-targeting CAR T-cell infusion. Eight months after treatment, the patient's scores on the Physician Global Assessment and muscle and pulmonary function tests improved, and there were no detectable signs of myositis on magnetic resonance imaging. Serological muscle enzymes (alanine aminotransferase, aspartate aminotransferase, creatinine kinase, and lactate dehydrogenase), CD8+ T-cell subsets, and inflammatory cytokine secretion in the peripheral blood mononuclear cells (interferon gamma, interleukin 1 [IL-1], IL-6, and IL-13) were all normalized. Further, there was a reduction in anti-Jo-1 antibody levels and a partial recovery of IgA (to 67% of normal value), IgG (to 87%), and IgM (to 58%). Conclusions and Relevance: CD19-targeting CAR T cells directed against B cells and plasmablasts deeply reset B-cell immunity. Together with mycophenolate mofetil, CD19-targeting CAR T cells may break pathologic B-cell, as well as T-cell responses, inducing remission in refractory antisynthetase syndrome.

Long-Term Results of Allogeneic Stem Cell Transplantation in Adult Ph- Negative High-Risk Acute Lymphoblastic Leukemia.

Allogeneic hematopoietic stem cell transplantation (HCT) is standard treatment for adult high-risk (HR) acute lymphoblastic leukemia (ALL) and contributed to the overall improved outcome. We report a consecutive cohort of prospectively defined HR patients treated on German Multicenter Acute Lymphoblastic Leukemia trials 06/99-07/03 with similar induction/consolidation therapy and HCT in first remission. A total of 542 patients (15-55 years) with BCR-ABL-negative ALL were analyzed. Sixty-seven percent received HCT from matched unrelated donors (MUD) and 32% from matched sibling donors (MSD). The incidence of non-relapse mortality (NRM) was 20% at 5 years. NRM occurred after median 6.6 months; the leading cause (46%) was infection. NRM after MUD decreased from 39% in trial 06/99 to 16% in trial 07/03 (P < .00001). Patient age was the strongest predictor of NRM. The 5-year relapse incidence was 23% using MSD and 25% using MUD. Minimal residual disease (MRD) was the strongest predictor of relapse (45% for molecular failure versus 6% for molecular CR; P < .0001). The median follow-up was 67 months, and the 5-year survival rate was 58%. Age, subtype/high risk feature, MRD status, trial and acute GvHD were significant prognostic factors. We provide a large reference analysis with long follow-up confirming a similar outcome of MSD and MUD HCT and improved NRM for MUD HCT over years. MRD has a strong impact on relapse risk, whereas age was the strongest predictor of NRM. New adapted conditioning strategies should be considered for older patients combined with the goal to reduce the MRD level before stem cell transplantation.

Value of CT-Textural Features and Volume-Based PET Parameters in Comparison to Serologic Markers for Response Prediction in Patients with Diffuse Large B-Cell Lymphoma Undergoing CD19-CAR-T Cell Therapy.

The goal of this study was to investigate the value of CT-textural features and volume-based PET parameters in comparison to serologic markers for response prediction in patients with diffuse large B-cell lymphoma (DLBCL) undergoing cluster of differentiation (CD19)-chimeric antigen receptor (CAR)-T cell therapy. We retrospectively analyzed the whole-body (WB)-metabolic tumor volume (MTV), the WB-total lesion glycolysis (TLG) and first order textural features derived from 18F-FDG-PET/CT, as well as serologic parameters (C-reactive protein [CRP] and lactate dehydrogenase [LDH], leucocytes) prior and after CAR-T cell therapy in 21 patients with DLBCL (57.7 ± 14.7 year; 7 female). Interleukin 6 (IL-6) and IL-2 receptor peaks were monitored after treatment onset and compared with patient outcome judged by follow-up 18F-FDG-PET/CT. In 12/21 patients (57%), complete remission (CR) was observed, whereas 9/21 patients (43%) showed partial remission (PR). At baseline, WB-MTV and WB-TLG were lower in patients achieving CR (35 ± 38 mL and 319 ± 362) compared to patients achieving PR (88 ± 110 mL and 1487 ± 2254; p < 0.05). The "entropy" proved lower (1.81 ± 0.09) and "uniformity" higher (0.33 ± 0.02) in patients with CR compared to PR (2.08 ± 0.22 and 0.28 ± 0.47; p < 0.05). Patients achieving CR had lower levels of CRP, LDH and leucocytes at baseline compared to patients achieving PR (p < 0.05). In the entire cohort, WB-MTV and WB-TLG decreased after therapy onset (p < 0.01) becoming not measurable in the CR-group. Leucocytes and CRP significantly dropped after therapy (p < 0.01). The IL-6 and IL-2R peaks after therapy were lower in patients with CR compared to PR (p > 0.05). In conclusion, volume-based PET parameters derived from PET/CT and CT-textural features have the potential to predict therapy response in patients with DLBCL undergoing CAR-T cell therapy.

Time-dependent analysis of adoptive immunotherapy following sequential FLAMSA-reduced intensity conditioning and allogeneic hematopoietic stem cell transplantation in patients with high-risk myeloid neoplasia.

Prophylactic donor lymphocyte infusions (DLI) are part of the sequential FLAMSA-reduced intensity conditioning (RIC) regimen to cure high risk myeloid neoplasia with allogeneic hematopoietic stem cell transplantation (HSCT). Although DLI themselves carry significant risks, their prophylactic use has not been analyzed in a time-dependent manner. One hundred and fourteen patients underwent FLAMSA-RIC HSCT between 2013 and 2020. Next to Kaplan-Meier estimation of overall, disease-free, and graft-versus-host relapse-free survival (OS, DFS, GRFS), cumulative incidences of relapse and death in remission were calculated in a competing risk model. Additionally, the contribution of prophylactic and preemptive DLI as time-dependent covariates was assessed using a time-varying model toward DFS (Simon-Makuch method, Mantel-Byar test). At 2 years, OS was 45.2% [95% CI 36.7-55.7%], DFS 31.8% [95% CI 24-42.2%] and GRFS 11.3 [95% CI 6.5-19.8]. Neither prophylactic nor preemptive DLI showed a significant influence on DFS when considered time-dependent covariates (Mantel-Byar, p = .3). This was further corroborated in competing risk analysis with DLI as time-dependent covariates. Both prophylactic and preemptive DLI miss significance in their impact on survival within a high-risk cohort in a time-varying model. Controlled trials to address the impact of postgrafting immunotherapy approaches are needed.

CAR-HEMATOTOX: a model for CAR T-cell-related hematologic toxicity in relapsed/refractory large B-cell lymphoma.

Hematotoxicity represents a frequent chimeric antigen receptor (CAR) T-cell-related adverse event and remains poorly understood. In this multicenter analysis, we studied patterns of hematopoietic reconstitution and evaluated potential predictive markers in 258 patients receiving axicabtagene ciloleucel (axi-cel) or tisagenlecleucel (tisa-cel) for relapsed/refractory large B-cell lymphoma. We observed profound (absolute neutrophil count [ANC] <100 cells per µL) neutropenia in 72% of patients and prolonged (21 days or longer) neutropenia in 64% of patients. The median duration of severe neutropenia (ANC < 500 cells per µL) was 9 days. We aimed to identify predictive biomarkers of hematotoxicity using the duration of severe neutropenia until day +60 as the primary end point. In the training cohort (n = 58), we observed a significant correlation with baseline thrombocytopenia (r = -0.43; P = .001) and hyperferritinemia (r = 0.54; P < .0001) on univariate and multivariate analysis. Incidence and severity of cytokine-release syndrome, immune effector cell-associated neurotoxicity syndrome, and peak cytokine levels were not associated with the primary end point. We created the CAR-HEMATOTOX model, which included markers associated with hematopoietic reserve (eg, platelet count, hemoglobin, and ANC) and baseline inflammation (eg, C-reactive protein and ferritin). This model was validated in independent cohorts, one from Europe (n = 91) and one from the United States (n = 109) and discriminated patients with severe neutropenia ≥14 days to <14 days (pooled validation: area under the curve, 0.89; sensitivity, 89%; specificity, 68%). A high CAR-HEMATOTOX score resulted in a longer duration of neutropenia (12 vs 5.5 days; P < .001) and a higher incidence of severe thrombocytopenia (87% vs 34%; P < .001) and anemia (96% vs 40%; P < .001). The score implicates bone marrow reserve and inflammation prior to CAR T-cell therapy as key features associated with delayed cytopenia and will be useful for risk-adapted management of hematotoxicity.

Long-Term Follow-Up After the Application of Mesenchymal Stromal Cells in Children and Adolescents with Steroid-Refractory Graft-Versus-Host Disease.

Steroid-refractory graft-versus-host disease (GvHD) is a life-threatening complication after allogeneic hematopoietic stem cell transplantation (alloHSCT). Alternative treatment options are often insufficient. Several studies have proven the efficacy of mesenchymal stromal cells (MSCs) in the treatment of therapy-refractory acute GvHD in adult and pediatric patients. Long-term data in pediatric patients are scarce. In this retrospective analysis, a total of 25 patients with a median age of 10.6 years (range 0.6-22.1 years) who received bone marrow-derived MSCs after alloHSCT for the treatment of steroid-refractory III and IV GvHD were analyzed. The median observation period of the surviving patients was 9.3 years (1.3-12.7 years) after HSCT. Among the 25 patients, 10 (40.0%) died [relapse (n = 3), multiorgan failure (n = 6), cardiorespiratory failure (n = 1)] at median 0.5 years (0.2-2.3 years) after HSCT. Partial response and complete remission (PR, CR) of the GvHD were achieved in 76.0% and 24.0% of the patients, respectively. Transplant-related mortality was 0% in the patients who achieved CR after MSC treatment and 26.3% for those with PR. A median improvement by one intestinal or liver GvHD stage (range 1-4) could be achieved after MSC application. No potentially MSC-related long-term adverse effects, for example, secondary malignancy, were identified. In conclusion, the intravenous application of allogeneic MSCs was safe and proved effective for the treatment of steroid-refractory GvHD. However, larger, prospective, and randomized trials are needed to evaluate these findings.

Autoantibody-mediated desialylation impairs human thrombopoiesis and platelet lifespan.

Immune thrombocytopenia is a common bleeding disease caused by autoantibody-mediated accelerated platelet clearance and impaired thrombopoiesis. Accumulating evidence suggests that desialylation affects platelet life span in immune thrombocytopenia. Herein, we report on novel effector functions of autoantibodies from immune thrombocytopenic patients which might interfere with the clinical picture of the disease. Data from our study show that a subgroup of autoantibodies is able to induce cleave of sialic acid residues from the surface of human platelets and megakaryocytes. Moreover, autoantibody-mediated desialylation interferes with the interaction between cells and extracellular matrix proteins leading to impaired platelet adhesion and megakaryocyte differentiation. Using a combination of ex vivo model of thrombopoiesis, a humanized animal model, and a clinical cohort study, we demonstrate that cleavage of sialic acid induces significant impairment in production, survival as well as function of human platelets. These data may indicate that prevention of desialylation should be investigated in the future in clinical studies as a potential therapeutic approach to treat bleeding in immune thrombocytopenia.

New Developments in the Pathophysiology and Management of Primary Immune Thrombocytopenia.

Immune thrombocytopenia (ITP) is an autoimmune disease that is characterized by a significant reduction in the number of circulating platelets and frequently associated with bleeding. Although the pathogenesis of ITP is still not completely elucidated, it is largely recognized that the low platelet count observed in ITP patients is due to multiple alterations of the immune system leading to increased platelet destruction as well as impaired thrombopoiesis. The clinical manifestations and patients' response to different treatments are very heterogeneous suggesting that ITP is a group of disorders sharing common characteristics, namely, loss of immune tolerance toward platelet (and megakaryocyte) antigens and dysfunctional primary hemostasis. Management of ITP is challenging and requires intensive communication between patients and caregivers. The decision to initiate treatment should be based on the platelet count level, age of the patient, bleeding manifestation, and other factors that influence the bleeding risk in individual patients. In this review, we present recent data on the mechanisms that lead to platelet destruction in ITP with a particular focus on current findings concerning alterations of thrombopoiesis. In addition, we give an insight into the efficacy and safety of current therapies and management of ITP bleeding emergencies.

Curative outcomes following blinatumomab in adults with minimal residual disease B-cell precursor acute lymphoblastic leukemia.

Minimal residual disease (MRD) is the strongest predictor of relapse in B-cell precursor acute lymphoblastic leukemia (BCP-ALL). In BLAST study (NCT01207388), adults with BCP-ALL in remission with MRD after chemotherapy received blinatumomab, a CD19 BiTE® immuno-oncotherapy, 15 µg/m2/day for up to four 6-week cycles (4 weeks continuous infusion, 2 weeks off). Survival was evaluated for 110 patients, including 74 who received HSCT in continuous complete remission. With a median follow-up of 59·8 months, median survival (months) was 36·5 (95% CI: 22.0-not reached [NR]). Median survival was NR (29.5-NR) for complete MRD responders (n = 84) and 14.4 (3.8-32.3) for MRD non-responders (n = 23; p = 0.002); after blinatumomab and HSCT, median survival was NR (25.7-NR) (n = 61) and 16.5 (1.1-NR) (n = 10; p = 0.065), respectively. This final analysis suggests complete MRD response during blinatumomab treatment is curative. Post-hoc analysis of study data suggests while post blinatumomab HSCT may be beneficial in appropriate patients, long-term survival without HSCT is also possible.

G-CSF administration prior to donor lymphocyte apheresis promotes anti-leukaemic effects in allogeneic HCT patients.

Donor lymphocyte infusion (DLI) is an effective method to establish full donor chimerism or to prevent and treat relapse after allogeneic haematopoietic cell transplantation (allo-HCT). Usually, DLIs are collected from naïve donors as steady-state lymphocytes. When donor lymphocytes are collected during stem cell apheresis, donors are pre-treated with granulocyte colony-stimulating factor (G-CSF). However, the impact of G-CSF stimulation and the resulting composition of DLIs on beneficial anti-leukaemic responses and survival remain elusive. Therefore, we performed a retrospective analysis to evaluate the role of G-CSF-DLIs: 44 patients received either steady-state DLIs or G-CSF-DLIs to prevent and treat relapse or establish full donor chimerism after allo-HCT. The G-CSF-DLI patient cohort showed an improved conversion to full donor chimerism and a lower cumulative incidence of relapse or disease progression without a significantly increased cumulative incidence of graft-versus-host disease (GVHD). CD34+ cells, monocytic myeloid-derived suppressor cells and monocytes as well as donor age and the subsequent occurrence of chronic GVHD were identified as risk factors that significantly improve overall survival after DLI administration. In conclusion, our data suggest that administration of G-CSF-DLIs results in graft-versus-leukaemia effects without exacerbating GVHD, therefore, improving survival after DLIs.

Second allogeneic hematopoietic cell transplantation enables long-term disease-free survival in relapsed acute leukemia.

Allogeneic hematopoietic cell transplantation (HCT) is the treatment of choice for high-risk myeloid and lymphoid leukemias. Relapse after allogeneic HCT is associated with a dismal prognosis and further therapeutic options are limited. One potential curative approach is a second allogeneic HCT. However, there is no consensus about optimal transplant modalities, suitable patients, and entities. We performed a retrospective analysis of our institutional database to evaluate risk factors that influence survival after a second allogeneic HCT for the treatment of relapsed acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). We identified 40 patients (AML, n = 29; ALL, n = 11) that received a second allogeneic HCT at our institution. At time of second HCT, 48% of patients were in complete remission (CR). Current overall survival (OS) was 14/40 patients with a median follow-up of 64 months (range 4-140) of patients alive resulting in a Kaplan-Meier estimated 2-year event-free survival (EFS) and OS of 32%, respectively. Cumulative incidence of non-relapse mortality (NRM) and relapse at 2 years was 31 and 37%, respectively. We identified several independent risk factors influencing OS: > 6 months from first to second transplant (p = 0.02), complete remission prior to transplant (p = 0.003), and the subsequent occurrence of chronic graft-versus-host disease (p = 0.003) were associated with a significantly improved OS. In conclusion, our data suggest that a second allogeneic HCT is a curative treatment option for relapsed acute leukemias in selected patients.

Relative Impact of HLA Matching and Non-HLA Donor Characteristics on Outcomes of Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia and Myelodysplastic Syndrome.

Increasing donor-recipient HLA disparity is associated with negative outcomes of allogeneic hematopoietic stem cell transplantation (HSCT), but its comparative relevance amid non-HLA donor characteristics is not well established. We addressed this question in 3215 HSCTs performed between 2005 and 2013 in Germany for acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Donors were HLA-matched related (MRD; n = 872) or unrelated (10/10 MUD, n = 1553) or HLA-mismatched unrelated (<10/10 MMUD, n = 790). Overall survival (OS) was similar after MRD compared with 10/10 MUD HSCT, reflecting opposing hazards of relapse (hazard ratio [HR], 1.32; P < .002) and nonrelapse mortality (HR, .63; P < .001). After UD HSCT, increasing HLA disparity was associated with inferior OS (HR, 1.21 [P < .02] and HR, 1.57 [P < .001] for 9/10 and ≤8/10 MMUD, respectively, compared with 10/10 MUD). Among non-HLA donor characteristics, age, sex mismatching (male recipient-female donor), and cytomegalovirus (CMV) mismatching (positive recipient-negative donor) impacted OS. Multivariate subgroup analysis showed that OS was similar after HSCT from the youngest 9/10 MMUD (<30 years) compared with the oldest 10/10 MUD (>40 years) (HR, 1.18; P = .25) and also in male patients transplanted from female 10/10 MUD compared with male 9/10 MMUD (HR, .89; P = .46). In contrast, OS of CMV-positive patients tended to be better with CMV-negative 10/10 MUDs compared with CMV-positive 9/10 MMUDs (HR, 1.31; P = .04). Because of low patient numbers in subgroups, definite conclusions and establishment of a hierarchy among HLA matching and non-HLA donor characteristics could not be made. Our data suggest that the impact of donor age and sex mismatch but not CMV mismatch on outcome of allogeneic HSCT may be comparable with that of single HLA disparity.

Blinatumomab for minimal residual disease in adults with B-cell precursor acute lymphoblastic leukemia.

Approximately 30% to 50% of adults with acute lymphoblastic leukemia (ALL) in hematologic complete remission after multiagent therapy exhibit minimal residual disease (MRD) by reverse transcriptase-polymerase chain reaction or flow cytometry. MRD is the strongest predictor of relapse in ALL. In this open-label, single-arm study, adults with B-cell precursor ALL in hematologic complete remission with MRD (≥10-3) received blinatumomab 15 µg/m2 per day by continuous IV infusion for up to 4 cycles. Patients could undergo allogeneic hematopoietic stem-cell transplantation any time after cycle 1. The primary end point was complete MRD response status after 1 cycle of blinatumomab. One hundred sixteen patients received blinatumomab. Eighty-eight (78%) of 113 evaluable patients achieved a complete MRD response. In the subgroup of 110 patients with Ph-negative ALL in hematologic remission, the Kaplan-Meier estimate of relapse-free survival (RFS) at 18 months was 54%. Median overall survival (OS) was 36.5 months. In landmark analyses, complete MRD responders had longer RFS (23.6 vs 5.7 months; P = .002) and OS (38.9 vs 12.5 months; P = .002) compared with MRD nonresponders. Adverse events were consistent with previous studies of blinatumomab. Twelve (10%) and 3 patients (3%) had grade 3 or 4 neurologic events, respectively. Four patients (3%) had cytokine release syndrome grade 1, n = 2; grade 3, n = 2), all during cycle 1. After treatment with blinatumomab in a population of patients with MRD-positive B-cell precursor ALL, a majority achieved a complete MRD response, which was associated with significantly longer RFS and OS compared with MRD nonresponders. This study is registered at www.clinicaltrials.gov as #NCT01207388.