Impact of inotuzumab ozogamicin on outcome in relapsed or refractory acute B-cell lymphoblastic leukemia patients prior to allogeneic hematopoietic stem cell transplantation and risk of sinusoidal obstruction syndrome/venous occlusive disease.

We evaluated 58 patients with relapsed or refractory (r/r) acute B-lymphoblastic leukemia (B-ALL; median age, 42.5 years; range, 16-69 years), treated with inotuzumab ozogamicin (INO) between 2016-2022 and who received an allogeneic hematopoietic stem cell transplantation (allo-HCT) consecutively. Forty-seven (81%) of the 58 patients were heavily pretreated receiving intensive chemotherapy +/- TKI, blinatumomab in 24 (41%) and allo-HCT at first-line in 11 (19%) patients. Complete remission (CR) rate prior to allo-HCT was 84%. Median follow-up was 30.5 months and median overall survival (OS) measured from start of INO was 11.2 months. Oneand 2-years OS rates were 50% (95%-CI, 38.4-56.1%) and 36.7% (95%-CI, 25.5-52.9%), respectively. Sinusoidal obstruction syndrome/venous occlusive disease (SOS/VOD) after allo-HCT occurred in 17 (29%) patients. Of those, 9 (53%) patients died due to SOS/VOD and multi-organ failure. Two had received >2 INO cycles (3 cycles, 5 cycles, n=1, each), all others ≤2 INO cycles prior to allo-HCT. Logistic regression analysis revealed conditioning with double alkylators (P=0.038) and allo-HCT during first-line therapy (P=0.050) as significant risk factors for SOS/VOD and in trend allo-HCT ≤ 60 days from last INO application (P=0.07), whereas number of INO cycles before allo-HCT and time between last INO application and allo-HCT were not significant. Relapse/progressive disease occurred in 20 (34%) patients. Of those, five (25%) patients are still alive, whereas 15 succumbed of their disease. Treatment with INO seems to be an effective approach with successful bridge-to-transplant. However, risk of SOS/VOD is high, necessitating continuous monitoring and recognition of SOS/VOD risk factors.

Thiotepa-busulfan-fludarabine Compared to Treosulfan-based Conditioning for Haploidentical Transplant With Posttransplant Cyclophosphamide in Patients With Acute Myeloid Leukemia in Remission: A Study From the Acute Leukemia Working Party of the EBMT.

We conducted a registry analysis including adult acute myeloid leukemia (AML) patients in remission who had received thiotepa, busulfan, and fludarabine (TBF) or treosulfan-based (Treo) conditioning for haplo-hematopoietic stem cell transplant (HSCT) with posttransplant cyclophosphamide (PTCy) between 2010 and 2020. A total of 1123 patients met the inclusion criteria (968 received TBF and 155 received Treo). A 1:1 matched-pair analysis was performed on 142 TBF and 142 Treo patients. In the Treo group, 68% of patients received treosulfan at a dose ≥36 g/m2 and 54% of patients received a second alkylator (thiotepa or melphalan). We observed a trend toward increased incidence of grade II-IV acute (a) graft-versus-host disease (GVHD) at 180 days in the TBF group compared with Treo (29% versus 20%; P = 0.08), while incidence of grade III-IV aGVHD was not statistically different. Similarly, the incidence of chronic (c) GVHD was not statistically different in the 2 groups. Incidence of nonrelapse mortality at 2 years was 19% in TBF and 14% in Treo (P = 0.4). Relapse incidence at 2 years was not statistically different in the 2 groups (16% and 18% in TBF and Treo, respectively; P = 0.9). Leukemia-free survival, overall survival, and GVHD-free, relapse-free survival was 65% versus 68% (P = 0.6), 73% versus 76% (P = 0.5), and 54% versus 53% (P = 0.8) in TBF versus Treo, respectively. In conclusion, we did not find a significant difference between the 2 conditioning in the present study; Treo and TBF represent 2 valid alternative regimens for haplo-HSCT with PTCy for AML in remission.

Overcoming Resistance: FLT3 Inhibitors Past, Present, Future and the Challenge of Cure.

FLT3 ITD and TKD mutations occur in 20% and 10% of Acute Myeloid Leukemia (AML), respectively, and they represent the target of the first approved anti-leukemic therapies in the 2000s. Type I and type II FLT3 inhibitors (FLT3i) are active against FLT3 TKD/ITD and FLT3 ITD mutations alone respectively, but they still fail remissions in 30-40% of patients due to primary and secondary mechanisms of resistance, with variable relapse rate of 30-50%, influenced by NPM status and FLT3 allelic ratio. Mechanisms of resistance to FLT3i have recently been analyzed through NGS and single cell assays that have identified and elucidated the polyclonal nature of relapse in clinical and preclinical studies, summarized here. Knowledge of tumor escape pathways has helped in the identification of new targeted drugs to overcome resistance. Immunotherapy and combination or sequential use of BCL2 inhibitors and experimental drugs including aurora kinases, menin and JAK2 inhibitors will be the goal of present and future clinical trials, especially in patients with FLT3-mutated (FLT3mut) AML who are not eligible for allogeneic transplantation.

Autologous Stem Cell Transplantation in Multiple Myeloma: Where Are We and Where Do We Want to Go?

The introduction of high-dose therapy in the 1990s as well as the development of drugs such as thalidomide, lenalidomide, and bortezomib in the 2000s led to an impressive improvement in outcome of patients with multiple myeloma (MM) eligible for autologous stem cell transplantation (ASCT). Clinical trials conducted in the first ten years of the twenty-first century established as standard therapy for these patients a therapeutic approach including induction, single or double ASCT, consolidation, and maintenance therapy. More recently, incorporating second-generation proteasome inhibitors carfilzomib and monoclonal antibody daratumumab into each phase of treatment significantly improved the efficacy of ASCT in terms of measurable residual disease (MRD) negativity, Progression Free Survival (PFS), and Overall Survival (OS). The availability of techniques such as multiparameter flow cytometry (MFC) and next-generation sequencing (NGS) for MRD assessment allowed the design of MRD-based response-adjusted trials that will define, in particular, the role of consolidation and maintenance therapies. In this review, we will provide an overview of the most recent evidence and the future prospects of ASCT in MM patients.

Conditioning Regimens for Frail Patients with Acute Leukemia Undergoing Allogeneic Stem Cell Transplant: How to Strike Gently.

Despite the recent dramatic progress in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) therapy, allogeneic transplant remains a mainstay of treatment for patients with acute leukemia. The availability of novel compounds and low intensity chemotherapy regimens made it possible for a significant proportion of elderly and comorbid patients with AML or ALL to undergo curative treatment protocols. In addition, the expansion of donor availability and the recent dramatic progress in haploidentical stem cell transplant, allow the identification of an available donor for nearly every patient. Therefore, an increasing number of transplants are currently performed in elderly and frail patients with AML or ALL. However, allo-Hematopoietic stem cell transplant (HSCT) in this delicate setting represents an important challenge, especially regarding the selection of the conditioning protocol. Ideally, conditioning intensity should be reduced as much as possible; however, in patients with acute leukemia relapse remains the major cause of transplant failure. In this article we present modern tools to assess the patient health status before transplant, review the available data on the outcome of frail AML an ALL patients undergoing allo-HSCT, and discuss how preparatory regimens can be optimized in this setting.

Gastrointestinal Complications after Allogeneic Hematopoietic Stem Cell Transplant: A Multidisciplinary Approach with Early Endoscopic Evaluation.

Gastrointestinal complications (GICs) represent the major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Differential diagnosis of GICs is of paramount importance since early and reliable identification of graft-versus-host disease (GVHD) is essential for a correct management of the patients. The aim of the present retrospective study was to evaluate the occurrence of GICs after allo-HSCT and to assess the diagnostic performance of a quick endoscopic and histological assessment in the differential diagnosis between GVHD and other GI conditions. Between January 2015 and August 2019, 122 consecutive patients receiving an allo-HSCT were managed by an interdisciplinary team, supported by a dedicated endoscopic service. Clinical, therapeutic, endoscopic and histological data were analyzed for each patient. Collectively, 94 of the patients developed GICs (77%). A moderate-severe mucositis was the most frequent complication, occurring in 79 patients (84%). Acute GI-GVHD was diagnosed in 35 patients (37% of whom with GICs) and 19 of them with a moderate-severe grade. Infective acute colitis developed in eight patients, mainly due to Clostridium difficile (CD) and Cytomegalovirus infections (8.5%). Rectal biopsy showed the highest sensitivity and specificity (80% and 100%, respectively). However, when biopsy procedures were guided by symptoms and performed on apparently intact mucosa, upper histology also provided a high negative predictive value (80%). Our multidisciplinary approach with a quick endoscopic/histologic investigation in the patients receiving an allo-HSCT and who suffered GICs could improve diagnostic and therapeutic management in this challenging setting.

Low-Dose Cyclophosphamide versus Intermediate-High-Dose Cyclophosphamide versus Granulocyte Colony-Stimulating Factor Alone for Stem Cell Mobilization in Multiple Myeloma in the Era of Novel Agents: A Multicenter Retrospective Study.

The optimal stem cell (SC) mobilization strategy for patients with multiple myeloma (MM) remains a matter of debate. Possible approaches include low or high doses of cyclophosphamide (Cy), other chemotherapeutic agents, or granulocyte colony-stimulating factor (G-CSF) alone. The scope of the study was to compare low-dose Cy plus G-CSF versus intermediate-high-dose Cy plus G-CSF versus G-CSF alone for SC mobilization in MM, in terms of efficacy and safety. We retrospectively analyzed 422 MM patients undergoing SC mobilization in 6 Italian centers, including 188 patients who received low-dose Cy (LD-Cy group, defined as 2 g/m2), 163 patients who received intermediate-high-dose Cy (HD-Cy group, defined as ≥ 3 g/m2), and 71 patients who received G-CSF alone (G-CSF group). The median peak of circulating CD34+ cells was 77/µL in the LD-Cy group, 92/µL in the HD-Cy group, and 55/µL in the G-CSF group (P = .0001). The median amount of SCs collected was 9.1 × 106/kg, 9.7 × 106/kg, and 5.6 × 106/kg in the 3 groups, respectively (P = .0001). The rate of mobilization failure (defined as failure to collect ≥2 × 106/kg) was 3.7% in the LD-Cy group, 3.4% in the HD-Cy group, and 4.3% in the G-CSF group (P = .9). The target SC dose of at least 4 × 106/kg was reached in 90.4%, 91.1%, and 78.6% of the patients in these 3 groups, respectively (P = .014). The "on demand" use of plerixafor was higher in the G-CSF group (76%) compared with the LD-Cy group (19%) and the HD-Cy group (6%). In multivariate analysis, G-CSF mobilization and previous use of melphalan or radiotherapy were independently associated with failure to collect the target SC dose of ≥4 × 106/kg. No impacts of age, blood counts, or previous treatment with lenalidomide, bortezomib, or carfilzomib were observed. Our results suggest that LD-Cy may be considered for successful SC mobilization in patients with MM.

Allogeneic stem cell transplant in patients with acute myeloid leukemia and karnofsky performance status score less than or equal to 80%: A study from the acute leukemia working party of the European Society for Blood and Marrow Transplantation (EBMT).

Limited data are currently available on the outcome of patients with acute myeloid leukemia (AML) undergoing allogeneic stem cell transplantation (allo-SCT) with a reduced performance status. We herein present the results of a registry study on 2,936 AML patients undergoing allo-SCT in first remission (CR1) with a Karnofsky Performance Status (KPS) score less than or equal to 80%. Two-year leukemia-free survival (LFS), overall survival (OS) and graft-versus-host disease (GVHD)-free, and relapse-free survival (GRFS) rates were 54%, 59%, and 41%, respectively. In multivariable analysis, patients with a KPS score = 80% had lower non-relapse mortality (NRM) and superior OS in comparison to patients with a KPS score <80% (p < 0.001). In the subgroup of patients with a KPS score =80%, a reduced-intensity conditioning (RIC) regimen was associated with an increased risk of relapse (p = 0.002) and lower GRFS (p < 0.001) compared to myeloablative conditioning (MAC). Differently, in patients with a KPS score <80%, a RIC regimen resulted in lower NRM (p < 0.001), whereas relapse incidence did not differ, thus leading to an improved GRFS (p = 0.008) as compared to MAC. A transplant from a matched sibling donor (MSD) was associated with a reduced incidence of grade III-IV acute GVHD (p < 0.01) and NRM (p < 0.01) in comparison to other donor types. In conclusion, allo-SCT appears feasible in AML patients with a jeopardized KPS score. Survival is significantly affected by the conditioning intensity, which should be adjusted according to the severity of KPS impairment.

Severe COVID-19 in a patient with chronic graft-versus-host disease after hematopoietic stem cell transplant successfully treated with ruxolitinib.

Graft-versus-host disease (GVHD) is a common complication of hematopoietic stem cell transplant, which is known to be mediated by cytotoxic T-cell effectors and dysregulated inflammatory cytokines. Similarly, the lung injury observed in severe COVID-19 cases appears to be related to a massive production of pro-inflammatory cytokines. The selective JAK1/2 inhibitor ruxolitinib has shown promising results in the context of GVHD, and different trials are currently underway in patients with severe COVID-19; nevertheless, no clinical observation of safety or efficacy of treatment with ruxolitinib in this context has been published yet. We describe a first case of severe COVID-19 developed after hematopoietic stem cell transplantation in a patient with a concomitant chronic GVHD (cGVHD), in which a treatment with ruxolitinib was administered with good tolerance and positive outcome.

New monoclonal antibodies and tyrosine kinase inhibitors in B-cell acute lymphoblastic leukemia.

Patients with acute lymphoblastic leukemia (ALL) are characterized by an unfavorable outcome in the majority of adult cases. Several clinical trials have confirmed the usefulness of a pediatric-type therapy applied to adult patients. Adults present with higher risk features at diagnosis that predispose them to chemotherapy resistance and disease relapse after an initial achievement of complete remission. The recent introduction of novel immune-targeted therapies, including monoclonal antibodies (MoAbs) targeting B cell-associated antigens such as CD19 (blinatumumab) and CD22 (inotuzumab), tyrosine kinase inhibitors targeting BCR-ABL1 tyrosine kinase, bispecific antibodies and chimeric antigen receptor T- cell therapy (CAR-T), circumvent B-ALL cell chemo-refractoriness through novel mechanisms of action, potentially eradicating minimal residual disease (MRD) and enabling more patients to receive allogeneic hematopoietic stem cell transplantation and to achieve a better clinical outcome.

The Time Has Come for Targeted Therapies for AML: Lights and Shadows.

Acute myeloid leukemia (AML) is a complex disease characterized by genetic and clinical heterogeneity and high mortality. After 40 years during which the standard of care for patients evolved very little, the therapeutic landscape has recently seen rapid changes, with the approval of eight new drugs by the Food and Drug Administration (FDA) within the last 2 years, providing new opportunities, as well as new challenges, for treating clinicians. These therapies include FLT3 inhibitors midostaurin and gilteritinib, CPX-351 (liposomal cytarabine and daunorubicin), gemtuzumab ozogamicin (GO, anti-CD33 monoclonal antibody conjugated with calicheamicin), IDH1/IDH2 inhibitors ivosidenib and enasidenib, Hedgehog inhibitor glasdegib, and BCL-2 inhibitor venetoclax. In this review, we summarize currently available data on these new drugs and discuss the rapidly evolving therapeutic armamentarium for AML, focusing on targeted therapies.

Feasibility and Outcome of a Phase II Study of Intensive Induction Chemotherapy in 91 Elderly Patients with AML Evaluated Using a Simplified Multidimensional Geriatric Assessment.

INTRODUCTION: We prospectively tested in a phase II study high-dose aracytin and idarubicin plus amifostine as induction regimen in 149 patients with acute myeloid leukaemia (AML) aged ≥ 60 years, evaluated by a simplified multidimensional geriatric assessment (MGA). METHODS: Ninety-one fully or partially fit patients (61%) were allocated to intensive chemotherapy and 58 (39%) frail patients to best supportive care (BSC). Intensively treated patients, showing early death and complete response (CR) rate respectively of 5.5% and 73.6%, received 61 consolidations, followed by autologous transplant (ASCT), stem cell transplantation (SCT) or gemtuzumab ozogamicin, depending on mobilization outcome and donor availability. RESULTS: The 8-year overall survival (OS) of these patients was 20.4%, with median duration of 11.4 months significantly superior to the 1.5 months of BSC arm (p < 0.001). Hyperleukocytosis and cytogenetics were predictors of survival with a relative risk of 1.8 in patients with poor karyotype without hyperleukocytosis (p = 0.02) and 3 in those with hyperleukocytosis (≥ 50,000/µl) (p = 0.002). CONCLUSION: MGA allowed tailored post-consolidation in 53.8% of patients after high-dose aracytin induction, with long-term survival doubling that reported in the literature after standard-dose cytarabine regimens. TRIAL REGISTRATION: The study was registered with the Umin Clinical Trial Registry (www.umin.ac.jp/ctr), number R000014052.

Fludarabine-treosulfan compared to thiotepa-busulfan-fludarabine or FLAMSA as conditioning regimen for patients with primary refractory or relapsed acute myeloid leukemia: a study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation (EBMT).

BACKGROUND: Limited data is available to guide the choice of the conditioning regimen for patients with acute myeloid leukemia (AML) undergoing transplant with persistent disease. METHODS: We retrospectively compared outcome of fludarabine-treosulfan (FT), thiotepa-busulfan-fludarabine (TBF), and sequential fludarabine, intermediate dose Ara-C, amsacrine, total body irradiation/busulfan, cyclophosphamide (FLAMSA) conditioning in patients with refractory or relapsed AML. RESULTS: Complete remission rates at day 100 were 92%, 80%, and 88% for FT, TBF, and FLAMSA, respectively (p = 0.13). Non-relapse mortality, incidence of relapse, acute (a) and chronic (c) graft-versus-host disease (GVHD) rates did not differ between the three groups. Overall survival at 2 years was 37% for FT, 24% for TBF, and 34% for FLAMSA (p = 0.10). Independent prognostic factors for survival were Karnofsky performance score and patient CMV serology (p = 0.01; p = 0.02), while survival was not affected by age at transplant. The use of anti-thymocyte globulin (ATG) was associated with reduced risk of grade III-IV aGVHD (p = 0.02) and cGVHD (p = 0.006), with no influence on relapse. CONCLUSIONS: In conclusion, FT, TBF, and FLAMSA regimens provided similar outcome in patients undergoing transplant with active AML. Survival was determined by patient characteristics as Karnofsky performance score and CMV serology, however was not affected by age at transplant. ATG appears able to reduce the incidence of acute and chronic GVHD without influencing relapse risk.

Treatment of Adult Patients with Relapsed/Refractory B-Cell Philadelphia-Negative Acute Lymphoblastic Leukemia.

The majority of adult patients affected by B-cell acute lymphoblastic leukemia (B-ALL) will relapse after an initial response, while approximately 20% will display primary resistant disease. Patients suffering from relapsed/refractory B-ALL have a very poor outcome. Allogeneic hematopoietic cell transplantation (HCT) still represents the only curative approach, but is not so frequently feasible, because of patient's fitness, donor availability, and the ability to achieve a remission prior to HCT. The estimated remission rates with conventional cytotoxic agents are around 30%, but they are short-lived. These disappointing results led to the introduction of new immunologic-based treatments-blinatumomab and inotuzumab. They produced a substantial improvement in terms of response rates, with the ability, in most cases, to induce a minimal residual disease (MRD)-negative status. Similarly, T cells engineered to express a CD19-specific chimeric antigen receptor (CAR-T) have yielded sensational results among patients with relapsed/refractory B-ALL, with unexpectedly high MRD-negative complete remissions rates. However, the first studies looking at long-term outcomes after CAR-T infusions told us that a significant fraction of such responses are not durable, and may benefit from a consolidation approach such as an allogeneic HCT.

Allogeneic stem cell transplantation following relapse post autologous stem cell transplantation in adult patients with acute myeloid leukemia: A retrospective analysis of 537 patients from the Acute Leukemia Working Party of the EBMT.

Patients with acute myeloid leukemia (AML) who relapse after autologous stem cell transplantation (ASCT) can be rescued by allogeneic SCT. We identified 537 adult patients with AML allografted in second complete remission (CR2) or first relapse after ASCT in the European Society for Blood and Marrow Transplantation (EBMT) registry. At 3 years post allograft, leukemia free survival (LFS) was 31.4% [95%CI 27.3-35.6], overall survival (OS) 39.5% [95%CI 35.1-43.9], relapse incidence (RI) 34.6% [95%CI 30.4-38.8], and nonrelapse mortality (NRM) 33.7% [95%CI 29.6-37.9]. RI was higher in patients transplanted in relapse in comparison to those transplanted in CR2 (HR 1.76, P = .004) and in patients who relapsed later after ASCT (HR 0.97 per month, P < 10-3 ), both translating into better LFS/ OS. Relapse was also lower in patients undergoing allogeneic stem cell transplantation (allo-HSCT) from an unrelated donor (UD) in comparison to those transplanted from a matched sibling donor (MSD) (HR 0.49, P < 10-3 ). NRM was increased in patients who received total body irradiation (TBI) pre-ASCT (HR 2.43; P < 10-4), translating into worse LFS/OS. LFS/OS did not differ between patients allotransplanted with reduced intensity (RIC) or myeloablative (MAC) conditioning. In conclusion, one third of adult patients with AML relapsing post ASCT can be rescued with allo-HSCT, with better LFS/OS in patients who relapsed later post ASCT, those transplanted in CR2 and those who had not received TBI pre-ASCT.