Veno-occlusive Research Articles

Role of endothelial cells in graft-versus-host disease.

To date, the only curative treatment for high-risk or refractory hematologic malignancies non-responsive to standard chemotherapy is allogeneic hematopoietic transplantation (allo-HCT). Acute graft-versus-host disease (GVHD) is a donor T cell-mediated immunological disorder that is frequently fatal and the leading cause of non-relapse mortality (NRM) in patients post allo-HCT. The pathogenesis of acute GVHD involves recognition of minor and/or major HLA mismatched host antigens by donor T cells followed by expansion, migration and finally end-organ damage due to combination of inflammatory cytokine secretion and direct cytotoxic effects. The endothelium is a thin layer of endothelial cells (EC) that line the innermost portion of the blood vessels and a key regulator in vascular homeostasis and inflammatory responses. Endothelial cells are activated by a wide range of inflammatory mediators including bacterial products, contents released from dying/apoptotic cells and cytokines and respond by secreting cytokines/chemokines that facilitate the recruitment of innate and adaptive immune cells to the site of inflammation. Endothelial cells can also be damaged prior to transplant as well as by alloreactive donor T cells. Prolonged EC activation results in dysfunction that plays a role in multiple post-transplant complications including but not limited to veno-occlusive disease (VOD), transplant associated thrombotic microangiopathy (TA-TMA), and idiopathic pneumonia syndrome. In this mini review, we summarize the biology of endothelial cells, factors regulating EC activation and the role of ECs in inflammation and GVHD pathogenesis.

Early vascular endothelial complications after hematopoietic cell transplantation: Role of the endotheliopathy in biomarkers and target therapies development.

This work aims to review the role of endothelial dysfunction underlying the main complications appearing early after autologous and allogeneic hematopoietic cell transplantation (HCT). The endothelial damage as the pathophysiological substrate of sinusoidal obstruction syndrome (SOS) is well established. However, there is growing evidence of the involvement of endothelial dysfunction in other complications, such as acute graft-versus-host disease (aGVHD) and transplant-associated thrombotic microangiopathy (TA-TMAs). Moreover, HCT-related endotheliopathy is not only limited to the HCT setting, as there is increasing evidence of its implication in complications derived from other cellular therapies. We also review the incidence and the risk factors of the main HCT complications and the biological evidence of the endothelial involvement and other linked pathways in their development. In addition, we cover the state of the art regarding the potential use of the biomarkers of endotheliopathy in the prediction, the early diagnosis, and the follow-up of the HCT complications and summarize current knowledge points to the endothelium and the other linked pathways described as potential targets for the prevention and treatment of HCT-complications. Lastly, the endothelium-focused therapeutic strategies that are emerging and might have a potential impact on the survival and quality of life of post-HCT-patients are additionally reviewed.

Characteristics of Patients With Pulmonary Arterial Hypertension in a Pulmonary Hypertension Association-Accredited Comprehensive Care Center: A Contrast in Features When Compared With US National Registry Data.

Background Since the initial description in the 1980s, our understanding of the diversity of pulmonary arterial hypertension (PAH) has continued to evolve. In this study, we report the characteristics of patients seen in an academic medical center for PAH from August 2020 through November 2021 and contrast those with nationally reported data from the United States Pulmonary Hypertension Scientific Registry (USPHSR). Study Design Investigators at the University of Utah Pulmonary Hypertension Program prospectively enrolled adult patients diagnosed with WHO Group 1 PAH, who were evaluated between August 2020 and November 2021 in a program-specific registry. Patient exposure and health histories were collected through structured interviews and questionnaires, along with clinical data and medication use. A total of 242 patients were enrolled in the University of Utah Pulmonary Hypertension Registry (UUPHR). Results Of the 242 enrolled patients, the most common etiology was associated PAH (APAH), accounting for 71.1% of the population. The second largest etiology was idiopathic PAH (IPAH) at 26.4%. The remaining patients were distributed between familial PAH (FPAH), pulmonary veno-occlusive disease (PVOD), and others. Of the total population classified as APAH, 39% of cases were noted as secondary to connective tissue disease (CTD) and 33% as toxin-induced. These represented 28% and 24% of the total population, respectively. Conclusions In this US-based accredited academic medical center, the etiology of PAH in our patient population contrasts with national registry data. In the UUPHR, APAH, specifically CTD-PAH and toxin-associated PAH, accounts for the majority of patients with PAH. This contrasts with IPAH, which nationally is the most reported cause of PAH. Differences in our population may reflect the regional variation of the referral site, but it is noteworthy for its contrast with historically reported phenotypes.

Sinusoidal Obstruction Syndrome in Adult Patients with B-Cell Acute Lymphoblastic Leukemia Treated with Inotuzumab Prior to Hematopoietic Stem Cell Transplantation

BACKGROUND: Sinusoidal obstruction syndrome (SOS), also known as veno-occlusive disease, is a potentially life-threatening toxicity observed post allo-HCT, with the reported incidence estimated to be 10-15% and mortality as high as 80% based on the severity (Coppell et al. BBMT 2010). Current management of SOS focusses on minimizing transplant- and patient-related factors. Inotuzumab ozogamicin (InO) is a humanized monoclonal antibody-drug conjugate targeting the CD22 antigen and has proven to be more efficacious than conventional chemotherapy in relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL) in the INO-VATE ALL phase 3 trial. However, liver-adverse events were more frequently encountered in the InO group with SOS occurring in 22.8% (n=18) of patients who proceeded to allo-HCT (Kantarjian et al. NEJM 2016). Given the effectiveness of InO as salvage therapy pre-HCT, we aimed to investigate incidence and outcomes of SOS in adult patients with R/R ALL that received InO and proceeded to consolidation with HCT. METHODS: We retrospectively studied adult patients (pts) with R/R B-ALL that received InO as salvage therapy and underwent consolidation with allo-HCT at City of Hope from 2014 to 2022. Graft source was peripheral blood for all patients. All pts. received prophylactic therapy with ursodiol and heparin was added to pts receiving myeloablative conditioning. Diagnosis and severity grading for SOS was in accordance with the revised EBMT criteria (Mohty et al. Bone Marrow Transplantation 2016). All pts. with SOS were treated with defibrotide. Fischer's exact test was used to complete the case-control analysis of patients with SOS vs. those without, and univariable analysis was completed using Cox regression. RESULTS: We identified 47 patients in our study, with 12 pts (25.5%) developing SOS post-HCT. Median time to diagnosis of SOS was 11 days (range: 3-41) and grade was very severe in 50% (n=6), severe in 25% (n=3), and mild in 25% (n=3). All pts. received treatment with defibrotide for median 20.5 days (range: 3-34), with resolution of SOS in 66.7% (n=8) of patients. Mortality from SOS was 33.3% (n=4) within a median of 10 days from diagnosis (range: 3-31), with pts. being graded as very severe (n=3, 75%) or severe (n=1, 25%). The group of pts with SOS compared to those without SOS did not have any significant difference in median duration between last dose of InO and HCT (46 vs. 53 days, P=0.37), myeloablative conditioning regimen (42% vs. 49%, P=0.75), TBI-based preparative regimen (50% vs. 57%, P=0.74), or disease status at transplant >CR1 (83% vs. 68%, P=0.83). There was no significant difference between the groups in lines of therapy prior to InO (P=0.79). Both groups received median 2 cycles of InO (P=0.14) and received InO as last therapy prior to HCT in 67% of patients with SOS and 66% in those patients without SOS (P=1.0). Sirolimus-based GVHD prophylaxis was more common in the SOS group (75% vs. 29%, P<0.01), but there was no difference in peak sirolimus level (P=0.81) or median time to peak sirolimus level (7 vs. 3.5 days, P=0.39) between the two subgroups. On univariable analysis, the use of sirolimus as GVHD prophylaxis was the only variable significant for SOS development, HR=7.50 [95% CI:1.7-33.6, P<0.01]. In the SOS group, the 100-day mortality rate was 33.3% (n=4) with median overall survival (OS) post-SOS of 4.3 months (range: 0.2 - 57.2). In the group without SOS, the 100-day mortality rate was 14.2% (n=5) and median OS post-HCT was 10.7 months (range: 0.52 - 39.6). CONCLUSION: To our knowledge, this is the largest single-center retrospective analysis of R/R ALL patients that received InO as salvage therapy pre-HCT. The incidence of SOS was high, and prompt initiation of defibrotide demonstrated efficacy in treating SOS. Despite the effectiveness of Ino as salvage therapy, the risk of SOS can potentially be mitigated by minimizing risk factors, especially the use of sirolimus-based GVHD prophylaxis. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Hypofibrinolysis in Pediatric Patients with Veno-Occlusive Disease in Hematopoietic Stem Cell Transplantation

Background Veno-occlusive disease (VOD) is a serious complication of hematopoietic stem cell transplantation (HSCT) with a high incidence in pediatric patients (11-27%). In clinical practice, VOD is diagnosed with criteria including weight gain, ascites, hepatomegaly, hyperbilirubinemia, and refractory thrombocytopenia. To date, there are no established markers for an earlier diagnosis of VOD. The aspect of assessing hypofibrinolysis, which plays a role in VOD pathogenesis, has not been elucidated. This study aimed to detect signs of hypofibrinolysis in HSCT and VOD patients using thrombelastography parameters and to discover correlations between alterations of these parameters and established symptoms of VOD. Patients and Methods Patients admitted for HSCT to the pediatric HSCT ward at the University Children's Hospital Tübingen, Germany, between May 2020 and November 2021 were prospectively enrolled (study group). Patients who underwent minor surgical procedures or follow-up blood tests years after recovering from oncological diseases and who were otherwise healthy, were recruited as a control group. Blood samples for thrombelastography (EX and TPA test, including the coagulation time (CT), clot formation time (CFT), clot amplitude after 5 minutes (A05), maximum clot firmness (MCF), maximum lysis (ML), α-angle, and lysis time (LT)) were taken once to twice weekly in addition to daily routine blood tests in patients undergoing HSCT. Routine testing included blood counts, coagulation parameters, d-dimers, and bilirubin. VOD symptoms were monitored daily and body weight was measured twice a day. Ultrasound screenings for ascites, progredient hepatomegaly, and portal venous flow velocity were performed in case of suspected VOD. All patients received intravenous anticoagulation with 100 IU/kg and day of unfractionated heparin. Of the control group patients, 6 ml blood was collected once per patient for routine coagulation testing and thrombelastography. Results A total of 51 patients with a median age of 7.8 years were recruited in the study group. Of these patients, five (9.8%) developed VOD and received defibrotide treatment. The VOD was graded moderate (n=2; 4%), severe (n=1; 2%) or very severe (n=2; 4%). Defibrotide treatment was initiated for 4 weeks or until the resolution of symptoms in standard dosing (25 milligrams per kilogram per day (mg/kg/d)) in four doses over 2 hours). The control group consisted of 55 patients with a median age of 6.7 years. A significant difference in thrombelastographic measurements was observed when comparing the VOD to the HSCT group. The lysis time after activation of fibrinolysis in the TPA test was prolonged in the VOD group at 3 weeks after HSCT (d+14 to +21: VOD: 330±67 seconds, HSCT: 246±53 seconds, p=0.0106). Additionally, a significant difference between the VOD and control groups was observed in days +14 to +21 (control: LT 234±50 seconds, p=0.0299). For the time points of day 0 to +6 and day +7 and +13 after HSCT lysis time was also prolonged in VOD patients, but without statistical significance (LT: d0 to +6: VOD: 304±57 seconds; HSCT: 251±67 seconds, p=0.06; d+7 to +13: VOD: 278±34 seconds; HSCT: 255±70 seconds, p=0.12). It was observed that LT correlated positively with weight gain (>5%), progredient hepatomegaly, right upper quadrant pain and reduced portal venous flow velocity (d0 to d+6: weight gain: r=0.31, p=0.0351; pain: r=0.44, p=0.0018; hepatomegaly: r=0.37, p=0.0108; d+7 to +13: pain: r=0.35, p=0.0143; hepatomegaly: r=0.39, p=0.0058; d+14 to d+21: weight gain: r=0.42, p=0.0035; pain: r=0.37, p=0.0103; hepatomegaly: r=0.44, p=0.0020; reduced portal venous flow velocity: r=0.35, p= 0.0167). Conclusions The results suggest that HSCT patients and patients diagnosed with VOD show signs of hypofibrinolysis. Fibrinolysis can be assessed in a rapid and accessible way via thrombelastography. Therefore, thrombelastography might be a useful tool to facilitate early diagnosis of VOD and to identify high-risk patients. Larger studies are needed to determine specific cut-off-values. Stefanie Hammer and Michaela Döring contributed equally to this work.

Easix Application in Adults Undergoing Allogeneic Hematopoietic Cell Transplantation with Post-Transplant Cyclophosphamide-Based Prophylaxis

INTRODUCTION The Endothelial Activation and Stress Index (EASIX) is a biomarker-based laboratory formula applicable in patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) which has been proposed to predict non-relapse mortality (NRM), overall survival (OS), and thrombotic microangiopathy (TMA) incidence when measured during the pre-transplant evaluation, and sinusoidal obstruction syndrome (SOS), when measured on day 0. The use of post-transplant cyclophosphamide (PTCY) for graft vs. host disease (GVHD) prevention has become a standard in haploidentical hematopoietic cell transplantation (HCT) and it is increasingly used for allo-HCT performed with unrelated (UD) and matched sibling donors. PTCY-based prophylaxis was incorporated at our Institution between 2014 and 2018. Since then, lower rates of endothelial complications including acute GVHD (aGHVD) have been documented. The predictive ability of EASIX has been validated mainly in patients receiving GVHD prophylaxis that did not contain PTCY. Considering that fewer endothelial complications have been diagnosed at our Institution since the use of PTCY-based prophylaxis, and that EASIX is considered a surrogate parameter of endothelial activation, this study investigates whether the dynamics of EASIX differ between patients receiving PTCY vs. other prophylaxis, and if the predictive ability of EASIX persists in PTCY-based allo-HCT. METHODS Between 2014 and 2020, 328 consecutive adults underwent first allo-HCT at our Institution and were included in the study. EASIX [(creatinine*LDH)/platelets] was calculated based on the information provided at the bloodwork collected at the pre-transplant assessment, on days 0, +7, +21, +28, +100, and +180. EASIX was transformed to a base-2 logarithm to perform the statistical analysis. The ability of EASIX to predict outcomes (OS and NRM) and post-transplant complications (SOS, TMA, and grade 2-4 aGVHD) was explored using landmark and regression analyses. Patients who died or who were diagnosed with the study time-dependent adverse event before each landmark point were excluded from the next time point. RESULTS The study cohort was divided into two groups according to the GVHD prophylaxis (PTCY n=201 vs. others n=127). Median age was 52 years and 81 patients (40.4%) received myeloablative conditioning regimens. One hundred and nine patients (65.2%) received transplants from mismatched donors [68 (44.8%) from mismatched UD and 41 (20.4%) haploidentical]. The dynamics of EASIX, in conjunction to creatinine, LDH, and platelets counts consecutively recorded from day 0 to +180 are depicted in Figure 1. As reported, the values of EASIX differed significantly from day 0 to day +28 between the two groups. These differences were attributed to lower LDH levels from day 0 to day +180, a lower platelet count documented between days +14 and +180 in patients receiving PTCY. The ability of EASIX to predict outcomes and complications was explored in patients receiving PTCY. The cumulative incidence functions of SOS, TMA, and grade 2-4 aGVHD day +100 were 2.0%, 3.5%, and 21.4%, respectively. The 2-years OS and NRM were 69.0% and 16.4%, respectively. As reported in Table 1, higher values of EASIX , measured at the pre-transplant assessment, days 0, +7, +14, +28, and +180 were associated with a higher probability of NRM and lower OS. Moreover, increased values of EASIX, measured at the pre-transplant assessment, days 0, +7, and +14 were predictors for TMA, and higher values of EASIX, measured before allo-HCT, on days +21 and +28 were predictors for grade 2-4 aGVHD. No association was observed between EASIX and SOS prediction. CONCLUSIONS The dynamic of EASIX differs between patients receiving PTCY and those that did not. However, despite this difference, the ability of pre-transplant EASIX to predict NRM and OS persists in patients receiving PTCY. Higher values of EASIX, measured not only at the pre-transplant evaluation, but also on days 0, +7, +21, +28 and +180 were associated with higher NRM and lower OS in patients receiving PTCY. In addition, pre-transplant EASIX was found to be a useful predictor for TMA and grade 2-4 aGVHD in these patients. This analysis validates the predictive ability of EASIX in patients receiving PTCY for GVHD prevention, and enhances the relevance of the assessment of endothelial dysfunction markers for the prognosis of PTCY-based allo-HCT. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Baseline Liver Elastography Does Not Predict Risks of Hepato-Toxicity to Reduced Dose Inotuzumab Therapy Combined with Minihcvd in B-Cell Acute Lymphoblastic Leukemia

Background: Inotuzumab ozogamicin (InO) is an anti-CD22 antibody drug conjugate that is FDA approved for the treatment of relapsed/refractory B-cell acute lymphoblastic leukemia (B-cell ALL). Liver toxicity, particularly veno-occlusive disease (VOD) was the most important grade 3 toxicity in the Phase III INO-VATE study of InO, driven by the active cytotoxic agent calicheamicin conjugated to InO, especially in pts who underwent subsequent stem cell transplantation (SCT) (Kantarjian et. al, NEJM 2016). However proper assessment of liver function and fibrosis through elastographic measurements might predict the risks of subsequent liver toxicity with InO. Aim: We aimed to study the extent of liver toxicity, including VOD, in pts treated with InO and its correlation to baseline liver elastography. Methods: Pts with B-cell ALL treated with InO containing low intensity combination regimen [miniCVD-InO- blinatumomab-rituximab (previously published; Jabbour et. al. Cancer 2018)] as part of a clinical trial (NCT01371630) underwent baseline liver elastography and were prospectively monitored for any evidence of liver toxicity, including VOD. Elastography was done within 4 weeks prior to the first infusion of InO and liver stiffness was stratified based on the median shear wave velocity (SWV) using the acoustic radiation force impulse (ARFI) technique. Elastographic median SWV >1.7 m/s was considered as evidence of definite liver fibrosis. We captured the patient characteristics, history of known liver disorders, baseline liver function tests, total dose of InO administered and any subsequent liver toxicities including VOD. Any antecedent or subsequent history of SCT was noted; liver toxicity was graded according to the NCI CTCAE, v5. The dose of InO was capped at a cumulative maximum of 2.7mg/m2 of body surface area (administered in fractionated doses) and all pts received concurrent ursodiol prophylaxis with InO. Results: From Jan 2018- April 2022, 50 consecutive pts treated with the above regimen and with baseline elastography reports available as part of the research protocol were analyzed. The median age of the pts was 54.9 years (yrs) (range, 21.7-87.7 yrs) and only 1 pt had a known prior liver ailment of non-alcoholic fatty liver disease (NAFLD). Baseline characteristics are mentioned in Table 1. The median InO dose received by the pts were 1.5 mg/m2 (range, 0.9-2.7 mg/m2) and only 11 pts (22%) received the maximum cumulative InO dose of 2.7 mg/m2. A total of 11 pts (22%) had a baseline maximum SWV >1.7 m/s which radiologically corresponds to possible compensated advanced chronic liver disease (cACLD) and no pts had a SWV >2.1 m/s (corresponds to clinically significant portal hypertension; CSPH). All pts achieved CR/CRi as best response and 14 pts (28%) underwent consolidative SCT. Only one pt developed a VOD of the liver, diagnosed based on clinical and radiological findings, at D+60 post haploidentical-SCT with Flu/Mel140 conditioning and post-transplant cyclophosphamide. This pt had normal baseline liver elastography and had received a cumulative InO dose of 1.5 mg/m2. Another 5-pts (10%) had ≥ grade 3 liver toxicity (1 pt with hyperbilirubinemia and 4 pts with ALT elevation), all of whom had baseline SWV <1.7 m/s on elastography. On regression analysis using age, cumulative InO dose, baseline values of total bilirubin, ALT and INR, and SWV cutoffs as covariates, no factor significantly affected the risks of ≥ grade 3 liver toxicity. After adopting the use of reduced dose fractionated InO administration regimen, routine ursodiol prophylaxis and avoiding peri-transplant azole antifungal prophylaxis in InO exposed B-cell ALL pts at our center, the frequency of liver toxicites including VOD has significantly reduced compared to the 11% rate of VOD described in the INO-VATE study. With these improvisations reducing the overall frequency of InO induced liver toxicity, the positive predictive value of a pre-InO elastography to envisage the risks of subsequent VOD and other liver toxicity in these pts is highly limited. Conclusion: In a prospectively monitored group of pts of B-cell ALL treated with fractionated InO containing combination regimen, baseline liver elastography did not predict the risk of subsequent liver toxicity. Sequential liver elastographies to monitor dynamic changes in SWV needs to be analyzed in future studies to further assess its predictive role for InO induced liver toxicity. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Multicenter Phase I Study of Post-Transplant Low-Dose Inotuzumab Ozogamicin to Prevent Relapse of Acute Lymphoblastic Leukemia

Background: The curative potential of allogeneic transplant (alloHCT) in patients with acute lymphoblastic leukemia (ALL) is hampered by relapse, the major cause of treatment failure. Risk factors for relapse include measurable residual disease (MRD) before or after alloHCT, transplantation in second complete remission (CR) or beyond, and reduced intensity conditioning (RIC) regimens. In ALL patients, relapse rates range from 30% to 50%, with most relapses occurring within the first year after alloHCT. After relapse, options for disease control are limited, and consequently overall survival (OS) is poor. Post-alloHCT maintenance may reduce MRD, provide time for a graft-versus-leukemia effect to develop, and ultimately decrease relapse rates and prolong progression-free-survival (PFS) and overall survival (OS). Inotuzumab ozogamicin (INO) is an anti-CD22 monoclonal antibody bound to calicheamicin and approved to treat relapsed ALL. With the hypothesis that low-dose INO would be safe and reduce relapse rates, we conducted a phase I study to define INO dose in this setting. Herein we present the results of this multicenter study. Methods: Eligibility included patients aged 16-75 who underwent alloHCT for CD22+ALL and were in CR after transplant, had a high risk for relapse after alloHCT (MRD before or after alloHCT, transplantation,in second CR or beyond, RIC regimen, lymphoid blast crisis of chronic myeloid leukemia, or Ph-like ALL), had adequate graft and organ function after transplant (platelets > 50 ANC > 1000), did not have active grade III/IV aGVHD or any active liver GVHD, and had no history of hepatic VOD. Patients were consented after transplant. The primary objective was to define a post-alloHCT maximum tolerated dose (MTD) of INO. Secondary objectives included describing the safety profile of INO, determining the rate of hepatic veno-occlusive disease (VOD) in this setting, evaluating non-relapse mortality (NRM), PFS and OS at 1-year post-alloHCT, and determining if INO at these doses is effective at eradicating MRD. Pre-treatment tests included a bone marrow biopsy and aspirate to assess disease state and MRD. The trial design was a 3+3 model. The study treatment consisted of 28-day cycles (initially planned for 4 cycles, increased up to 12 cycles) of INO starting at dose level 0 (0.3mg/m2; n= 4), then 0.4 mg/m2 (n= 3), 0.5 mg/m2 (n= 6) and 0.6 mg/m2 (n= 5) given on cycle day 1. The first cycle was initiated between day 40 and 100 post-alloHCT. Pre-defined dose limiting toxicities (DLT) included VOD, prolonged cytopenia (more than 28 days), severe toxicities ascribed to INO, and death. If there were no DLTs experienced in first two cycles of a cohort, subsequent patients were enrolled in the next highest dose level. Results: We have enrolled 19 patients (18 treated, Table 1) with a median follow up of 18.1 months and a median number of 3 doses (range, 1-9). Only treated patients are included in analyses. The median time to first INO dose was 84 days (range, 47-100) after alloHCT. There was one DLT (prolonged thrombocytopenia) and the study reached the final pre-defined dose of 0.6mg/m2. No VOD was observed. The most common toxicity was thrombocytopenia (42.1% of patients; 31.6% experienced grade 3 or 4 thrombocytopenia), neutropenia (31.6% of patients, 15.8% experienced grade 3 or 4 neutropenia), and nausea/vomiting (42% of patients, all grade 1 or 2). 68% of patients received reduced intensity or non-myeloablative conditioning. OS at 1-year post-alloHCT was 94.4% and PFS was 88.9%. One-year NRM was 5.5%. One patient died of aGVHD on 0.6mg/m2 and one patient relapsed on 0.5mg/m2 at 7 months post-alloHCT. Another patient relapsed from Ph-like ALL 23 months post-alloHCT. Seven of the patients enrolled either had MRD before (n = 4) or after alloHCT (n = 3) as measured by flow cytometry, PCR, or NGS. For patients with MRD before or after alloHCT, 1-year OS and PFS are 100% (Figure 1). The 1-year PFS and OS of recipients of RIC transplants was 83.3% and 91.7%. Conclusions: We have determined that INO at doses of 0.3, 0.4, 0.5 and 0.6mg/m2 was well tolerated and that 0.6 mg/m2 is the MTD. Thrombocytopenia may be the DLT. The low observed relapse rate and favorable safety profile justify investigating low-dose INO as maintenance therapy after alloHCT in a phase II trial. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Gemtuzumab Ozogamicin Plus Standard Induction Chemotherapy Improves Outcomes in Intermediate Risk Cytogenetic Acute Myeloid Leukemia

Background: Gemtuzumab ozogamicin (GO) is a CD33-directed antibody-drug conjugate approved for the treatment of newly diagnosed (ND) and refractory/relapsed CD33-positive acute myeloid leukemia (AML). Meta-analysis of individual patient (pt) data from 5 randomized controlled trials (n=3325) confirmed a significant survival benefit of GO added to intensive induction chemotherapy for pts with AML without adverse cytogenetics. While favorable-risk ND-AML pts, specifically core-binding factor AML (CBF-AML), particularly benefited with a 5-year overall survival (OS) improvement of 20.7% (log rank p= 0.0006), pts with intermediate-risk AML also showed a significant 5-yr survival improvement of 5.7% (p=0.005) (Hills RK et al Lancet Oncol 2014: 15, 986). However, the smaller difference in these latter pts coupled with apprehension for risk of sinusoidal obstruction syndrome (SOS) following hematopoietic stem cell transplantation (HSCT) has led many clinicians to not use 7+3 plus GO in the intermediate-risk AML population. Aim/Objective: To perform a retrospective analysis of outcomes of 7+3 plus GO vs 7+3 in ND intermediate-risk cytogenetic AML pts treated at a single comprehensive cancer center. Methods: We studied the demographic, clinical and genetic data of intermediate risk ND-AML pts treated at Roswell Park Comprehensive Cancer Center (n=113) between 2015-2022. Conventional cytogenetics and fluorescence in situ hybridization (FISH) were performed. Genomic profiling was performed using next-generation sequencing methods (FoundationOne®CDx). Risk stratification was defined per the European LeukemiaNet (ELN)-2017 classification. 7+3 plus GO pts received at least one dose of GO 3 mg/m2 (up to one 4.5 mg vial) plus cytarabine 100 mg/m² continuous IV infusion on days 1-7, and daunorubicin 60 mg/m² IV on days 1-3 (7+3). Control pts received 7+3 alone. Prophylactic heparin was administered to prevent hepatic SOS based on institutional standards if not thrombocytopenic. Outcomes included response rate to induction, successful bridging to HSCT, relapse rate, and overall survival. Results: 113 intermediate-risk ND-AML pts were studied: 33 received 7+3 plus GO and 80 received 7+3. Median age was 57 vs. 59 years, respectively (range: 19-76 years). Moreover, there was no significant difference in the percentage of pts > 60 yrs (45% vs 48%). Gender was equally distributed. Pts treated with 7+3 plus GO had a significantly higher rate (p=0.019) of complete remission (CR) and complete remission with incomplete count recovery (CRi) (27/33, 82%) than 7+3 (44/80, 55%; Figure 1A). Among pts with available minimal residual disease (MRD) status detected by multiparameter flow cytometry, 100% achieved MRD-negative status after 7+3 plus GO (18/18) compared to 86% with 7+3 (12/14). Non-responders to 7+3 plus GO were enriched for ASXL1, DNMT3A, TET2, and TP53 mutations as compared to responders who harbored more FLT3, IDH1/2, KRAS/NRAS and RUNX1 mutations. Among pts achieving CR/CRi, 48% after 7+3 plus GO vs 30% after 7+3 (p=0.13) were successfully bridged to HSCT. Cumulative incidence of relapse after CR/CRi was significantly lower after 7+3 plus GO (11%) than 7+3 (43%; p=0.007). Finally, 7+3 plus GO pts demonstrated a superior, yet not statistically significant, median overall survival (OS) benefit (median OS not reached) compared to 7+3 alone (median OS = 35 months; Figure 1B). No pts receiving 7+3 plus GO developed SOS. Conclusions: Intermediate risk ND-AML pts treated with 7+3 plus GO at our academic center had significantly higher rates of MRD-negative CR and CRi, lower rates of relapse, and higher percentage of pts receiving HSCT as compared with 7+3 alone. Non-responders in the 7+3 plus GO group harbored adverse risk genetic mutations that likely dictated the failure to response. Although addition of GO was associated with a non-significant trend towards improved overall survival, longer follow-up is warranted to decipher an absolute survival advantage of this regimen. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

The Easix Score Predicts Overall Survival and Late Relapse in Patients Undergoing Reduced Intensity Conditioned Allogeneic Stem Cell Transplantation for Myeloid Disease

Background Allogeneic hematopoietic stem cell transplantation (alloSCT) is an effective treatment for myeloid malignancies, however outcomes post-transplant are variable and predictive scores limited. The Endothelial Activation and Stress Index (EASIX) measured at key timepoints pre- and post-transplant has been shown to predict outcomes in alloSCT, including overall survival, non-relapse mortality and incidence of sinusoidal obstructive syndrome (SOS). It can be readily calculated using standard biomarkers (LDH (U/L) x creatinine (mg/dL)/platelets (x109/L). We sought to examine its predictive role in a homogenous population of patients. Methods We conducted a retrospective national review of 117 patients undergoing reduced-intensity alloSCT for myeloid disease including AML (n=56), MDS (n=35) and MPN (n=26). All included received fludarabine, busulfan and rabbit anti-thymocyte globulin (Flu/Bu/ATG) conditioning from 2015-2020. We calculated the EASIX score on the day prior to conditioning, on day 0, at onset of acute graft versus host disease and 1 year post transplant. Univariate analysis was conducted in the STATA statistical package. Results At the pre-conditioning time-point the mean EASIX was 3.11 (0.3-17.54). Increased scores correlated with and were reliably predictive of reduced overall survival (p=0.034) (fig. 1). Higher scores at this time-point did not predict chronic GVHD or relapse, however an increased rate of acute GVHD was seen in those with lower EASIX (p=0.012). At day 0 the mean EASIX was 15.38 (1.07-179.02), however we could not demonstrate a predictive effect on SOS as no events occurred in this cohort. Nor did we identify a predictive value at this point for GVHD risk or relapse. At onset of acute GVHD (n=67, mean 3.52, 0.44-51.43), the EASIX score was predictive of overall survival (p=0.027) but did not predict risk of chronic GVHD or relapse. At 1 year post-transplant (n=88, mean 2.09, 0.48-13.59) a higher score showed a trend towards decreased overall survival (p=0.1) but was associated with an increased risk of subsequent relapse (p=0.01)(fig. 2). Conclusions The EASIX score is an easily applicable clinical tool using real world biomarkers readily available at serial time-points in transplant recipients. When applied to our homogenously treated cohort it retains its value in predicting overall mortality at the key time points of pre-conditioning and at onset of GVHD. Adoption of this simple score may be of benefit in risk stratifying the transplant process for reduced intensity conditioned allograft recipients, particularly when combined with established prediction tools for non-relapse mortality such as the HCT-CI. In addition to this, we have shown that the EASIX score may be a useful predictive tool for late relapse in those patients who are alive at 1 year post transplant. We suspect that this effect is primarily reflective of those patients with persistent thrombocytopenia and raised LDH, both markers of potential disease activity. Importantly, the use of this score in the reduced intensity population may be particularly relevant due to the increasing age of transplant eligibility and its use as a surrogate of endothelial dysregulation and potential for end organ complications through the transplant process. To assess the underlying T cell mediated and cytokine secretome effects on endothelial dysfunction, an observational study is ongoing at our institution, examining the interplay of immunomodulatory therapy, graft T cell content, early T and NK cell recovery and the cytokine secretion patterns at various time points before, during and after transplant in reduced intensity conditioned patients with myeloid disease. We plan to correlate these data with serial EASIX assessments to identify the determinants of the underlying biological process and identify potential time-points and biological targets for future study.

A Phase II Study of Mini-Hyper-CVD Plus Inotuzumab Ozogamicin, with or without Blinatumomab, in Older Adults with Newly Diagnosed Philadelphia Chromosome-Negative B-Cell Acute Lymphoblastic Leukemia: Updated Results and Predictors for Outcomes

Background: Inotuzumab ozogamicin (INO) and blinatumomab are superior to chemotherapy for relapsed/refractory B-cell acute lymphoblastic leukemia (ALL). Incorporation of these agents in the frontline setting could improve remission durations and OS in older adults with newly diagnosed B-cell ALL. Methods: Patients (pts) ≥60 years of age with newly diagnosed Philadelphia chromosome (Ph)-negative pre-B-cell ALL were eligible. Pts were required to have a performance status of ≤3, total bilirubin ≤1.5 mg/dl, AST/ALT ≤3x ULN and creatinine ≤2 mg/dl. Pts received mini-hyper-CVD (cyclophosphamide and dexamethasone at 50% dose reduction, no anthracycline, methotrexate at 75% dose reduction, cytarabine at 0.5 g/m2 x 4 doses) for up to 8 cycles. INO was given at a dose of 1.3-1.8mg/m2 on day 3 of cycle 1 and 0.8-1.3mg/m2 on day 3 of cycles 2-4. Rituximab (if CD20+) and prophylactic IT chemotherapy were given for the first 4 cycles. Responding pts received POMP maintenance for up to 3 years. To decrease the risk of veno-occlusive disease (VOD), the protocol was amended in 3/2017 (pts 50+) to give INO in fractionated doses each cycle (0.6 mg/m2 on day 2 and 0.3 mg/m2 on day 8 of cycle 1; 0.3 mg/m2 on day 2 and 8 of cycles 2-4) and to administer 4 cycles of blinatumomab following 4 cycles of hyper-CVD plus INO, followed by maintenance with 12 cycles of POMP and 4 cycles of blinatumomab (1 cycle of blinatumomab after every 3 cycles of POMP). The cumulative dose of INO given before and after this most recent amendment was 4.3 mg/m2 and 2.7 mg/m2, respectively. Results: To date, 80 pts have been treated. Six pts were in complete remission (CR) at the time of enrollment. Baseline characteristics are shown in Table 1. The median age was 68 years (range, 60-87 years); 30 pts (39%) were ≥70 years. From all pts, 39% were positive for TP53 mutation and 24% had an adverse-risk karyotype. Among 74 pts evaluable for morphologic response, 73 (99%) responded (CR, n=66; CRp, n=6; CRi, n=1). MRD negativity by flow cytometry was achieved in 61/76 pts (80%) after 1 cycle and 74/79 pts (94%) overall. The 30-day and 60-day mortality rates were 0% and 3%, respectively. Among 79 pts who achieved remission, 11 (14%) relapsed, 4 (5%) underwent allogeneic SCT in first remission (1 of whom subsequently relapsed), 32 (40%) are alive in remission without SCT, and 32 (40%) died in remission. Among the 32 deaths in remission, 9 were from sepsis, 3 from VOD, 9 from development of MDS or AML; the rest from miscellaneous causes. Overall, 9 pts (11%) developed MDS/AML after a median of 33 months (range 3-66); 7 of these pts had a detectable TP53 mutation in the myeloid malignancy. Notably, 6 pts (8%) developed VOD, 1 after subsequent allogeneic SCT. With a median follow-up of 61 months (range, 7-123 months), the 5-year CR and OS rates were 76% and 46%, respectively. Outcomes were superior in pts who were 60-69 years old versus those who were ≥70 years (5-year OS rates: 57% and 28%, respectively; P=0.05) and for those without poor-risk cytogenetics (e.g. KMT2A-rearranged, low hypodiploidy/near triploidy, complex cytogenetics) versus poor-risk cytogenetics (5-year OS rates: 55% and 21%, respectively; P=0.005). The 5-year OS for pts with and without TP53 mutation were 35% and 47%, respectively (P=0.34). The 5-year OS for pts age 60-64 was 65%, for those age 65-69 was 50%, and for those age ≥70 was 28%. The 3-year OS for patients with and without CRLF2+ ALL were 25% and 60%, respectively (P=0.12). Pts ≥70 years of age were more likely to die in remission (19/30 [63%]) and those who were 60-69 years of age (15/50 [30%]) (P=0.004), which was a major driver of the poor survival in this age group. Outcomes were favorable for pts age 60-69 years with poor risk cytogenetics (5-year OS 70%), intermediate for pts age 60-69 with poor risk cytogenetics (5-year OS 31%) or those age ≥70 with low risk cytogenetics (5-year OS 36%), and were very poor for pts age ≥70 with poor risk cytogenetics (5-year OS 0%) (Figure 1). Conclusion: Low-intensity chemotherapy with hyper-CVD plus INO, with or without blinatumomab, in older adults with newly diagnosed Ph-negative ALL resulted in very high rates of response (99%), including an MRD-negative response rate of 94%. This led to a 5-year OS rate of 46%. Despite the reduced intensity of this regimen, a substantial proportion of pts >70 years of age died in remission. Ongoing efforts are evaluated for INO and blinatumomab without chemotherapy for these pts. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

A Phase II Study of Inotuzumab Ozogamicin for the Treatment of Measurable Residual Disease-Positive B-Cell Acute Lymphoblastic Leukemia

Background: Persistence or re-emergence of measurable residual disease (MRD) after remission induction therapy in B-cell acute lymphoblastic leukemia (B-ALL) is strongly associated with shorter relapse-free survival (RFS) and overall survival (OS). Inotuzumab ozogamicin (INO) is an anti-CD22 antibody-drug conjugate with the potential to eradicate MRD in patients (pts) with B-ALL, including in pts with prior exposure to blinatumomab. Methods: This is a single-arm phase II trial of pts with B-ALL in complete remission (CR) who did not achieve MRD negativity (MRD-ve) or had MRD-positive (MRD+ve) relapse after at least 3 months (mos) from the start of frontline therapy or 1 month from the start of any salvage therapy. Eligibility was defined by MRD+ve at ≥ 0.01% by multiparametric flow cytometry (MFC) for Philadelphia chromosome (Ph) negative (Ph-) B-ALL and ≥ 0.01% by MFC and/or BCR::ABL1 transcripts for Ph positive (Ph+) B-ALL. MRD-ve was defined as undetectable MRD by MFC at a minimum sensitivity of 10-4 for Ph- B-ALL and undetectable MRD by both MFC and BCR::ABL1 transcripts at 10-4 for Ph+ B-ALL. For pts with p210 BCR::ABL1 transcript, the international scale (IS) was used for reporting. INO was administered at a dose of 0.6 mg/m2 on D1 and 0.3 mg/m2 on D8 of cycle 1 and 0.3 mg/m2 on D1 and D8 of cycles 2-6 (cycles given every 21-28 days). Pts received ursodiol prophylaxis while on INO. Pts with Ph+ ALL could receive a concomitant BCR::ABL1 tyrosine kinase inhibitor (TKI). Results: Between 11/2018 and 6/2022, 27 pts with MRD+ve B-ALL were treated. The median age was 44 years (range, 19-70). Seventeen pts (63%) had Ph+ ALL (12 pts with p190 transcript and 5 pts with p210 transcript), 15 of whom received concurrent ponatinib and 2 dasatinib. Ten pts were Ph- (including 3 with Ph-like ALL). Twenty pts (74%) were in CR1, and 7 pts (26%) were in ≥ CR2 (4 in CR2, 2 in CR3 and 1 in CR4). Fourteen pts (52%) had received prior blinatumomab and 5 pts (18%) had prior stem cell transplantation (SCT). The median level of BCR::ABL1 by PCR in pts with Ph+ ALL was 0.21% (range, 0-18.9%) and median level by MFC in pts with Ph- ALL was 0.21% (range, 0.05-1.24%). Seven pts with Ph+ ALL were MRD+ve by MFC at a median of 0.04%, and 1 pt with Ph+ B-ALL was MRD+ve by MFC (1.15%%) but negative by PCR. Eighteen pts (67%) responded and became MRD-ve, 16 after cycle 1 and 2 after cycle 2. In the Ph+ group, 10 pts (59%) responded; another 3 of 5 pts who had >0.1% BCR::ABL1 transcripts at enrollment attained major molecular response as best response. Eight of 10 (80%) pts with Ph- ALL responded. The median number of cycles was 3 (range, 1-6). Eleven of 13 pts (85%) without prior blinatumomab exposure became MRD-ve compared with 7/14 (50%) pts with prior blinatumomab exposure (p=0.1). At a median follow up of 18 months (mos) (range, 1.1- 35 mos), 14 of the 18-responding pts (78%) are in ongoing MRD-ve CR. The median RFS and OS of the pts were not reached. The estimated 18-mos RFS and OS were 56% and 65%, respectively, for the whole group. 18-mos OS was 73% and 60% for responders and non-responders, respectively (p=0.7). Amongst the 18 responders, 5 pts were consolidated with SCT after a median of 3 cycles (range, 1-3) of INO, all in MRD-ve CR prior to SCT. Four (22%) responders had morphological relapse (including one relapse after SCT and one isolated CNS relapse). One pt died in MRD-ve CR due to SCT-related complications. Survival was similar between pts with Ph+ ALL vs. Ph- ALL (p=0.41), pts in CR1 vs. ≥ CR2 (p=0.23) and those with prior blinatumomab exposure vs. no prior exposure (p=40). INO was overall well-tolerated with no grade 4 non-hematological toxicities. Two pts (7%) developed veno-occlusive disease (VOD); both had Ph+ ALL and were on concurrent ponatinib. One pt developed VOD (diagnosed radiologically) 1 month after ponatinib dose of 15mg/day) and another pt developed VOD (diagnosed by liver biopsy) during cycle 5 (cumulative INO dose of 3.3 mg/m2, ponatinib dose of 15mg/day). The overall 60-day mortality was 0%. Conclusion: Lower doses of fractionated INO is a well-tolerated option for MRD eradication in pts with Ph+ or Ph- B-ALL, including in those with prior blinatumomab exposure or SCT. This approach can also facilitate consolidative SCT in these pts. The therapy is well tolerated, but pts should be monitored for development of VOD of the liver, though the absolute risks remain low. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Adct-602, a CD22 Targeting Antibody Drug Conjugate Bound to PBD Toxin in Adult Patients with Relapsed or Refractory B-Cell Acute Lymphoblastic Leukemia: A Phase 1 Trial

Introduction: Outcomes of patients (pts) with relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL) remain dismal. CD22 is expressed on lymphoblasts in >90% of pts with B-ALL and is an established therapeutic target. Inotuzumab ozogamicin is an approved CD22 targeting antibody for pts with R/R B-ALL; however, the toxin calicheamicin can lead to veno-occlusive disease (VOD) of the liver, especially after allogeneic SCT (allo-SCT). ADCT-602 is an antibody drug conjugate composed of a humanized monoclonal antibody directed against CD22 and conjugated to SG3199, a pyrrolobenzodiazepine (PBD) dimer cytotoxin. In preclinical studies, ADCT-602 demonstrated potent anti-tumor activity in mouse models of B-cell malignancies. We present here results from an ongoing phase 1/2 trial evaluating ADCT-602 in pts with R/R B-ALL (NCT03698552). Methods: This is an investigator-initiated phase 1/2 trial of ADCT-602 monotherapy in pts with R/R B-ALL. The primary objective of the phase 1 part is to assess the safety and determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of ADCT-602. The primary objective of phase 2 is to evaluate efficacy (CR/CRi rate). Eligible pts must be ≥18 years of age with R/R B-ALL with bone marrow blasts ≥5%. CD22 must be expressed in ≥20% blasts. Pts must have adequate organ function (creatinine ≤1.5 mg/dL; ALT and AST ≤2 times upper limit of normal (ULN), ≤5 times ULN if there is liver or bone involvement; total bilirubin ≤1.5 times ULN; LVEF ≥45%). A 3+3 dose-escalation design was used for phase 1. ADCT-602 was initially given IV once every 3 weeks; based on the PK data, the administration schedule was later amended to weekly infusions. Results: From November 2018 to July 2022, 21 pts (11 women, 10 men) with R/R B-ALL were enrolled and received treatment with ADCT-602. The median age was 39 years (range, 21-82) and pts had received a median of 5 (range, 2-9) prior therapies [inotuzumab ozogamicin 12/21 (57%); blinatumomab 18/21 (86%); venetoclax 12/21 (57%)]. A total of 8/21 (38%) had a prior CD19 CAR-T, including 1 pt who had both CD19 and CD22 CAR-T. Ten (10/21, 48%) pts had a prior allo-SCT, including 3 pts with 2 prior allo-SCT. The median pretreatment bone marrow blasts were 70% (range, 16-96). The median CD22 expression on blasts was 97% (range, 33.6-100). A total of 11 pts were treated in the Q3week schedule [30µg/kg, n=3; 60µg/kg, n=4; 90µg/kg, n=4]. As the PK data indicated rapid clearance of the antibody, the trial was amended to allow for weekly dosing. A total of 10 pts were treated at the weekly dose level [30µg/kg, n=3; 40µg/kg, n=4; 50µg/kg, n=3]. One pt (30µg/kg weekly dose level) had grade 4 thrombocytopenia possibly related to ADCT-602. One pt (50µg/kg weekly dose level) had a DLT of prolonged myelosuppression (marrow blast clearance without blood count recovery). No pt had VOD. Notably, all 3 pts treated at the 50µg/kg weekly dose level (a dose level expected to be close to RP2D) had evidence of anti-tumor activity (2 pts achieved MRD negative CR; one pt had bone marrow blast clearance). First pt at this dose level was a 26-yr-old with R/R B-ALL with PAX5-JAK2 fusion with 5 prior therapies including 2 CD19 CAR-T and an allo-SCT who achieved MRD negative CR and is receiving ongoing therapy in Cycle 5. Second pt at this dose level was a 66-yr-old with TP53- and KRAS-mutated B-ALL with 2 prior therapies including modified BFM regimen and blinatumomab who achieved MRD negative CR and is receiving ongoing therapy in Cycle 4. Third pt at this dose level was a 21-yr-old with TP53- and KRAS-mutated B-ALL with 4 prior therapies including inotuzumab and a CD19 CAR-T who had morphologic blast clearance without blood count recovery. Two additional pts treated at lower doses levels (1 each at 30µg/kg Q3week and 30µg/kg weekly schedule) achieved MRD negative CR. All responding pts had CD22 expression noted in >97% of the blasts by flow cytometry. Conclusions: In this phase 1 study in pts with very heavily pretreated R/R B-ALL with a median of 5 prior lines of therapy and high baseline bone marrow tumor burden, single-agent ADCT-602 was well tolerated with one pt with DLT noted at the 50µg/kg weekly dose level. Notably, all 3 pts treated at this dose level had evidence of clinical activity with 2/3 pts achieving MRD negative CR. Due to 1 pt with DLT at this dose level, this cohort is being expanded to treat 3 additional pts. This trial continues to accrue pts and updated data will be presented at the ASH meeting.

Impact of Inotuzumb Ozogamicin on Outcome in Relapsed or Refractory Acute B-Lymphoblastic Leukemia Patients Prior to Allogeneic Hematopoietic Stem Cell Transplantation

Background: The outcome of patients with relapsed or refractory (r/r) acute lymphoblastic leukemia (ALL) is poor. At present, allogeneic hematopoietic stem cell transplantation (allo-HCT) is considered the only curative option for patients with r/r B-ALL with best outcomes achieved after effective salvage re-induction therapy and transplantation in complete remission (CR). Veno-occlusive disease, also known as sinusoidal obstruction syndrome (VOD/SOS), is a potentially life-threatening complication of allo-HCT. Inotuzumab ozogamicin (INO) is a humanized anti-CD22 monoclonal antibody conjugated to calicheamicin, developed as a targeted therapy for B-cell malignancies. Rate of VOD/SOS is increased after therapy with INO. Aims: To characterize a series of relapsed/refractory (r/r) ALL patients (pts) and evaluate outcome after treatment with INO prior to allo-HCT, particularly with respect to risk of VOD/SOS. Methods: We studied 25 r/r pts (median age, 34 years; range, 16-64 years), who were treated with INO between 2016 and 2022 within a compassionate use program (n=7) or in-label after EMA approval (n=18) One of the 25 pts were previously treated with tyrosine kinase inhibitors for chronic myeloid leukemia and progressed to blast crisis of B-lymphoid lineage. All 25 pts were CD22 positive at relapse/progressive disease. Up to 4 INO cycles (≤2 cycles, n=22; 3-4 cycles, n=3) were administered according to the previously approved regimen. Results: At the time of r/r B-ALL median white blood cell and platelet counts were 47.1/nl (range, 1.3-300/nl) and 33.5/nl (range, 5-313/nl), respectively. Five pts (20%) were female; ECOG was ≤ 2 in all pts. Cytogenetic analysis at the time of r/r EM-ALL was available in 14 pts. Six pts displayed a t(9;22), 6 had a normal karyotype, 1 was complex and 1 had a deletion 6q as well as trisomy 13. Seventeen (68%) patients achieved CR after the first INO cycle. Prior to allo-HCT, 17 (68%) pts achieved CR, 3 (12%) a partial remission, 4 (16%) were refractory and one (4%) relapsed after CR achievement. Median follow-up was 41.6 months (95%-CI, 31.1-NR) and median overall survival (OS) was 9.0 months (95%-CI, 5.78-RD months; Figure 1). One- and two-years OS rates were 45.2% (95%-CI, 28.8-70.8%) and 40.7% (95%-CI, 24.8-66.7%), respectively. VOD/SOS after allo-HCT occurred in 7 (28%) pts. Of those, 5 pts died due to VOD and multi-organ failure, all had received ≤2 INO cycles. Risk factor for VOD/SOS was allo-HCT during first-line therapy (p=0.05), whereas age, gender, donor, dose intensity of conditioning or remission status before allo-HCT had no impact. Relapse/progressive disease occurred in eight (32%) pts and all pts succumbed of their disease. Cumulative incidences of relapse/progression or death after 12 months were 20.7% (standard error,E 8.5%) and 32.7% (standard error, 9.8%). Eight (32%) pts died in remission and nine (36%) pts are in ongoing CR. Conclusions: This outcome analysis demonstrates that treatment with INO is an effective approach with successful bridge-to-transplant. However, risk of VOD/SOS is high, necessitating continuous monitoring and recognition of VOD/SOS risk factors.

Fractionated Inotuzumab Ozogamicin Combined with Low-Intensity Chemotherapy in Older Patients with Newly Diagnosed CD22+ Philadelphia Chromosome (Ph)-Negative B-Cell Precursor (BCP) Acute Lymphoblastic Leukemia (ALL): Results of the EWALL-INO Study

Introduction. We report here the results of the EWALL-INO Phase 2 study (ClinicalTrials.gov: NCT03249870) evaluating the activity and safety of frontline inotuzumab ozogamicin (INO), an anti-CD22 antibody conjugated to calicheamicin, combined to low-intensity chemotherapy in 131 older patients with CD22+ Ph-negative BCP-ALL. Methods. This single arm prospective study has been conducted in several European centers from the European Working group on adult ALL (EWALL). Eligibility criteria were patients aged ≥55 years, with an ECOG performance status ≤2, newly diagnosed with CD22+ (20% or more of positive blast cells) Ph-negative BCP-ALL without central nervous system (CNS) involvement. After a prephase including 5 days (D) of dexamethasone (DEX) 10mg per D and intrathecal (IT) methotrexate (MTX), the induction regimen was delivered in 2 parts. Induction part I (Ind1) consisted of one triple IT, vincristine (VCR) 2 mg (1 mg over 70 years of age) D1 D8 D15 D22 and DEX 20 mg D1D2 D8D9 D15D16 D22D23 combined with 3 injections of INO (0.8 mg/m² D1, 0.5 mg/m² D8 and D15). Induction part II (Ind2) was offered to patients in CR or CRp (CR with platelets <100 x 109/L) after Ind1 or as salvage therapy. Ind2 consisted of DEX 20mg D1D8, cyclophosphamide (CY) 300 mg/m² D1 to D3, one triple IT D2 and 2 injections of INO (0.5 mg/m² D1 and D8). Patients in CR/CRp were programmed to receive 6 blocks of consolidation (Ara-C 1.5g/m²/12h adapted to renal clearance D1D2 and DEX 10mg/12h D1D2, cycles 1 and 4; MTX 1.5 g/m² over 24h D1, VCR 1 or 2 mg D1, one triple IT D2 and 6-mercaptopurin (6-MP) D1 to D7, cycles 2 and 5; CY 500 mg/m² D1D2, VP16 75 mg/m² D1D2, one triple IT D2 and MTX 25 mg/m² D1, cycles 3 and 6) followed by a POMP maintenance (VCR, 6-MP, MTX, DEX) during 18 months. Allogeneic hematopoietic stem cell transplant (HSCT) was allowed after at least 3 blocks of consolidation at the discretion of the investigator. The primary endpoint of the study was overall survival (OS) with an expected 1-year OS rate of 70%. The evaluable population consisted of patients who received at least 1 dose of INO. Minimal residual disease (MRD) was assessed on bone marrow aspirates after Ind1 and Ind2 using quantification of clonal molecular rearrangements. The study was planned to recruit up to 130 patients. All patients provided informed consent. Results. Between 12/2017 and 03/2022, 6 screen failures occurred (including one Ph+ ALL) and 131 patients were enrolled and received at least one dose of INO. These 131 patients were considered for the intent-to-treat analysis. However, among them, 5 patients had CD22 expression <20% and 3 had CNS involvement. Patient characteristics are shown on Table 1. After Ind1, the CR/CRp rate was 88.5% (116/131, 9 CRp) and 4/131 (3%) patients had died. MRD <10-4 was achieved in 56 of 97 (56.6%) CR/CRp tested patients. A total of 120 patients received Ind2 (115 CR/CRp patients, as 1 death in CR occurred between Ind1 and Ind2 and 5 patients received Ind2 after failure of Ind1) and 118 patients eventually achieved CR/CRp (112 CR, including 3 late CR after Ind2; 6 CRp) resulting in a CR/CRp rate of 90% (118/131) after Ind1 + Ind2. No patient died during Ind2. MRD <10-4 was achieved in 80 of 99 CR/CRp tested patients (80.8%) after Ind2. Overall, the full planned INO dosing was administered to 108 patients (82.5%). With a median follow-up of 15 months (range 3-42), 29 patients relapsed and 50 patients died, including 29 deaths after relapse. Only 11/118 CR/CRp patients received an HSCT (9.4%). With a 1-year OS of 72.5% (95% CI, 64-81), the primary endpoint was reached. At 2 years, OS was 53.6% (95% CI, 44-64). Leukemia- free survival was 64.9% (95% CI, 56-74) at 1 year and 49.8% (95% CI, 40-61) at 2 years. (Figure 1) A grade 3-4 liver toxicity was observed in 21 patients (16%), including 3 patients (2.2%) with transient sinusoidal obstruction syndrome (SOS), 2 during Ind1 and 1 after HSCT. Conclusion. These results confirm that fractionated INO combined to low-intensity chemotherapy is a very active and well tolerated frontline therapy for older patients with CD22+ Ph-neg BCP-ALL, as previously reported in the MDACC INO/mini-HCVD study (Jabbour et al. Cancer 2019). An updated analysis will be provided at ASH meeting. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Gimema ALL2418: Interim Analysis of a Phase Iia Study of Feasibility and Effectiveness of Inotuzumab Ozogamicin in Adult Patients with B-Cell Acute Lymphoblastic Leukemia with Positive Minimal Residual Disease before Any Hematopoietic Stem Cell Transplantation

Background: Persistence of minimal residual disease (MRD) is associated with a high rate of treatment failure, relapse, and death in B-cell acute lymphoblastic leukemia (B-ALL). Particularly, patients who remain MRD positive before an allogeneic hematopoietic stem cell transplant (HSCT) have an expected disease-related death rate due to the disease of about 60%. The T cell-engager CD19-directed therapy blinatumomab demonstrated considerable efficacy in this setting, however resistant or unsuitable patients have no alternative therapy. Inotuzumab Ozogamicin (IO) is a CD22-directed antibody-drug conjugate with remarkable efficacy in B-ALL with overt disease. Furthermore, IO does not need a high effective immune system to exert activity. Methods: In this multicenter phase 2 trial (NCT03610438), we are investigating the efficacy of IO in obtaining MRD negativity in two cohorts of 38 Ph+ and 38 Ph- B-ALL patients. IO was administered at the dose of 0.5 mg/sqm on days 1, 8, and 15 of a 28-days cycle. Patients who did not obtain MRD negativity after the 1st IO cycle had the option to receive the 2nd IO cycle maintaining the same dosage. Responding Ph- patients received short-term maintenance with low-dose chemotherapy (alternating vincristine, cyclophosphamide, prednisone, methotrexate, and 6-mercaptopurine), responding PH+ patients received tyrosine kinase inhibitor (TKI) for up to 12 weeks, allowing proper IO washout before HSCT. HSCT ineligible patients entered into low-dose chemotherapy or TKI maintenance for up to 2 years. For the primary endpoint, MRD was centrally assessed at baseline, after course 1, after course 2, and eventually before transplant with high sensitive molecular methods for BCR-ABL1 or V(d)J fusion transcripts. Here, we present the results of an unplanned interim analysis that was generated to evaluate the continuation of the study considering the slow accrual due to the Sars-COV2 pandemic. Results: To date, 51 patients underwent screening procedures, and 43 were considered eligible. We report data from the first 39 patients treated in the study. Nineteen out of 39 patients had Ph- B-ALL and 20/39 Ph+ B-ALL. Eighteen out of 39 (46%) patients were male. The median age was 55 years (22-84), 15/39 patients (38%) were older than 65 years. Demographics were comparable between Ph+ and Ph- patients. Within Ph+, ALL 39% of patients harbored p190 and 61% p210 fusion transcript. Within Ph- B-ALL, 1 patient harbored ALL1/AF4 and 1 patient harbored ALL1/ENL fusion transcript. Most of the patients received 1 (16/39, 42%) or 2 (19/39, 50%) previous lines of therapy; 5 patients (13%) were resistant to blinatumomab, and all of them had Ph- B-ALL. Twelve out of 19 (63%) Ph- B-ALL patients received only 1 IO cycle, 7/19 (37%) received 2 cycles; 5/20(25%) Ph+ B-ALL received only 1 IO cycle, and 15/20 (75%) received 2 cycles. To date, central MRD monitoring is available for 20 patients (12 Ph- and 8 Ph+ B-ALL, ongoing for the remaining cases). Overall, MRD negativity was obtained in 7/20 patients (35%); Particularly, in Ph- B-ALL cohort 5/12 (42%) patients achieved MRD negativity, 4/12 (38%) achieved disease reduction at low level MRD positivity (<10-4); in Ph+ B-ALL cohort, 2/8 (25%) patients achieved MRD negativity. One out of 5 (20%) blinatumomab pre-treated patients obtained MRD negative response. IO was an effective bridge to HSCT for 10/39 patients (26%; in patients <65 years old, 9/24 patients, 37%); Specifically, all 7 patients who obtained MRD negativity after IO, a patient with low-positive MRD and 2 patients with non yet available MRD data were bridged to HSCT. Accordingly, with the caveat of a short median follow-up (2.8 months, range 0.6-20.0 months), overall survival in the study population seems promising (figure 1, median OS not reached). Overall, adverse events collected during the study were limited in number and grading. Also, myelotoxicity was manageable. Out of 39 patients, we documented 1 veno-occlusive disease (2.5%) that occurred within 20 days from the last IO dose and before any HSCT. Conclusions: IO administration demonstrated activity with a good safety profile in the setting of MRD positive B-ALL, including blinatumomab resistant patients. Importantly, IO was capable to bridge 37% of eligible patients to HSCT, augmenting the chance to achieve a cure. The continuation of the study will deliver mature efficacy and survival data for a proper evaluation of this promising strategy. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Improved Outcomes with Low-Dose Inotuzumab and Mini-Hyper-CVD Followed By Blinatumomab Consolidation in Relapsed-Refractory Acute Lymphoblastic Leukemia: Results of a Phase II Study

Background: Patients (pts) with relapsed-refractory (R-R) acute lymphoblastic leukemia (ALL) have a poor prognosis. The combination of low-intensity chemotherapy with mini-hyper-CVD (mini-HCVD) and inotuzumab has shown encouraging results. The aim of this study is to evaluate whether the sequential addition of blinatumomab to mini-HCVD-inotuzumab with lower doses of weekly inotuzumab might further improve outcomes. Methods: Pts with Philadelphia chromosome-negative B-cell ALL were included. Odd cycles of mini-HCVD consisted of cyclophosphamide (150 mg/m2 every 12 h on days 1-3), vincristine (2 mg flat dose on days 1 and 8), and dexamethasone (20 mg on days 1-4 and days 11-14) without anthracyclines. Even cycles consisted of cytarabine (0.5 g/m2 given every 12 h on days 2 and 3) and methotrexate (250 mg/m2 on day 1). During the first 4 courses, pts received rituximab when CD20 expression was ≥20%, and intrathecal chemotherapy. Initially, inotuzumab was administered on day 3 of the first 4 cycles at the dose of 1.3-1.8 mg/m2 in course 1, followed by 1.0-1.3 mg/m2 in subsequent courses. Pts received maintenance therapy with POMP, consisting of 1 year of monthly prednisone 50 mg/d for 5 days and vincristine at 2 mg every month, along with 3 years of 6-mercaptopurine 50 mg twice daily and weekly oral methotrexate 10 mg/m2. An amendment to the protocol was made after the inclusion of 67 pts to add 4 cycles of blinatumomab after 4 cycles of the combination mini-HCVD + inotuzumab. Inotuzumab was given on days 2 and 8 at the dose of 0.6 and 0.3 mg/m2 in course 1, respectively, followed by days 2 and 8 at the dose of 0.3 and 0.3 mg/m2 in subsequent courses; blinatumomab was continuously infused over 28 days every 42-day cycle for 4 cycles. Maintenance therapy was reduced to 12 courses of POMP with 1 course of blinatumomab after each 3 courses of POMP for a total of 4 courses. The decision to undergo allogeneic stem cell transplantation (ASCT) was based on the discretion of the treating physician after discussion with the patient. Results: Between February 2013 and July 2021, 112 pts were treated on study, including 45 pts with mini-HCVD + inotuzumab + blinatumomab. Baseline characteristics and outcomes are summarized in Table 1. The median follow-up is 41 months (range, 3-112). Before the study amendment, 67 pts were treated: 38 (57%) in salvage(S)1, and 29 (43%) in S2+. Nineteen pts (28%) had received prior ASCT. After the amendment, additional 45 pts were treated: 42 (93%) in S1, and 3 (7%) in S2+; 3 (7%) pts had prior ASCT. The overall response rate (ORR) was 83% (CR, 63%) in the entire cohort, 76% (CR, 60%) pre-amendment, and 93% (CR, 67%) post-amendment. Among 91 responders evaluable for measurable residual disease (MRD), 76 pts (82%) achieved MRD negativity by multicolor flow cytometry, with higher rates of MRD negativity in S1 (89%). The rates of MRD negativity before and after the amendment were 82% and 85%, respectively. Overall, 53 (47%) pts underwent ASCT: 29 (43%) pts pre-amendment and 24 (53%) post-amendment. The median overall survival (OS) for the entire cohort was 17 months, with a 3-year OS rate of 41%. After the amendment, the addition of blinatumomab resulted in superior median OS (37 months vs 14 months) and 3-year OS rates (55% versus 34%) (Figure 1). Pts in S1 had better survival compared with those in S2+, with 3-year OS of 51% and 17%, respectively (P=0.001). In a 2-month landmark analysis among pts in S1, the median OS was 57 months in those who received blinatumomab compared with 31 months in those who did not. Overall, pts who achieved MRD negativity had higher 3-year OS rate of 55% compared to 10% in pts who were MRD-positive at best response (P=0.0001). Survival with mini-HCVD + inotuzumab +/- blinatumomab compared favorably to that of inotuzumab monotherapy: 17 months vs 6 months; P<0.0001. A 3-month landmark analysis among responders showed similar 3-year OS rates between pts who underwent subsequent ASCT and those who did not (55% vs 48%, respectively). Veno-occlusive disease (VOD) was observed in 10 of the 112 pts (9%), and its incidence was reduced from 13% with single dose of inotuzumab to 2% with fractionated dose schedule (P=0.056). Conclusion: The addition of blinatumomab to mini-HCVD-inotuzumab, along with a lower weekly dose of inotuzumab, further improves the outcomes of pts with R-R ALL. These adjustments reduced the rate of VOD and improved survival. Long-term survival was similar regardless of subsequent ASCT. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Dosage, Safety and Efficacy of Posaconazole As Primary Antifungal Prophylaxis in High-Risk Recipients of Allogeneic Stem Cell Transplantation

Introduction: The use of anti-mold prophylaxis with anti-aspergillus activity is recommended for patients (pts) undergoing allogeneic hematopoietic stem cell transplantation (Allo-HSCT) with high risk of fungal infection (Maertens, J Antimicrob Chemother 2018). Yet, few data are available regarding the use of posaconazole. Methods: This retrospective study included all Allo-HSCT adult recipients having benefited from posaconazole therapy in our center as a primary anti-fungal prophylaxis for high-risk of fungal infection. The latter was defined as use of i)an alternative donor, ii)sequential conditioning regimen, iii)a regimen associated with severe mucositis, iv) post-transplant cyclophosphamide (PT-Cy) or v) previous allo-HSCT. Posaconazole was programmed to be initiated at day (D) 0 or D5/6 (in case of PT-Cy) and administered up to day 100. We report here on the residual concentration of posaconazole during the neutropenic phase then on the tolerance and efficacy of such prophylaxis in this cohort. Results: Seventy high-risk pts (males 63.3%, median age 54 years old, range 20-73) received Allo-HSCT between April 2020 and December 2021 for a myeloid (n=51), lymphoid (n=17) or non-malignant hematological (n=2) disease and received posaconazole as a primary prophylaxis. The Sorror score at transplant time was ≥ 3 for 24 pts (33.8%). Twenty-two patients had already received posaconazole as a primary prophylaxis before Allo-SCT including 26 during the neutropenic phase of their induction for AML or MDS, 3 for prolonged neutropenia, 2 during treatment with alemtuzumab for T-cell leukemia/lymphoma, and 1 during a previous AlloHCST. Four patients had also received other antifungal agentsbefore Allo-SCT (caspofongine (n=1), voriconazole (n=1) or liposomal amphotericin B (n=2)) because of a suspected mold infection which has been finally excluded. All pts had at least one high-risk criterion of fungal infection. These included the use of an alternative donor in 42 pts (haplo-identical donor n= 41, umbilical cord blood n=1), sequential conditioning regimen in 9, with PT-Cy in 57, second or third allo-HSCT in 8 and conditioning regimen associated with severe mucositis in 11 (TBI 8-12gy n=3, thiotepa-based n=8). All but one pts received posaconazole using the gastroresistant tablet form at a dose of 300mg/day. One patient received the drinkable suspension form at a dose of 200mg 3 times a day. Following prophylaxis initiation, serum posaconazole concentrations were available in 51 and 16 patients at medians of 9 and 39 days, respectively. A protective residual level of posaconazole (> 0.5mg/L) was achieved in 57% of the patients (n=29) at first assessment and 87.5% (n=12) at second evaluation. Posaconazole was stopped early due to related-toxicity in 9 cases (12.6%), including liver toxicity in 7 pts, QT prolongation in 1 and skin hyperesthesia in 1. Treatment was restarted without recurrence of toxicity in 2 cases. Posaconazole was stopped early in 2 patients due to non-related toxicity, including one veno-occlusive disease and one hepatic acute GVHD. Posaconazole was temporary discontinued in 4 patients due to a suspected fungal infection before being restarted. Most patients (n=59/70, 84.2%) did not present fungal infections while being under posaconazole therapy. Only 11 cases were documented with this complication (Table 1), including 8 invasive pulmonary aspergillosis (IPA; possible n=3; probable n=5), one possible invasive fungal infection and 2 mucormycoses (1 with possible IPA). Fungal infections occurred despite documentation of a protective residual level of posaconazole (> 0.5mg/L) in 5 of 6 evaluable patients. Of note, 9/11 patients had received PTCY as GVHD prophylaxis. Posaconazole was stopped (before D7 in 3) and other antifungal drugs started (voriconazole or liposomal amphotericin B) allowing to fungal infection cure in 5 pts. However, 7 pts died including 2 of an uncontrolled fungal infection. Conclusion: Posaconazole is a well-tolerated and efficient primary prophylaxis in recipients of Allo-HSCT at high-risk of fungal infection. As some fungal infections occured very early after D0 while prophylaxis started only a D5/6 after PTCY, our results suggests to propose posaconazole as early as the beginning of the conditionning together with dose monitoring. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Predictors of Veno-Occlusive Disease (VOD) of the Liver in Patients Treated with Inotuzumab Ozogamicin (InO) Containing Regimen in B-Cell Acute Lymphoblastic Leukemia

Predictors of Veno-Occlusive Disease (VOD) of the Liver in Patients Treated with Inotuzumab Ozogamicin (InO) Containing Regimen in B-Cell Acute Lymphoblastic Leukemia

Updated Analyses: Safety and Efficacy of Gemtuzumab Ozogamicin and Venetoclax in Patients with Relapsed or Refractory CD33+ Acute Myeloid Leukemia: A Phase Ib/II Study

Background: Results of therapy for relapsed/refractory (R/R) AML patients (pts) remain poor, with few surviving >2 years. Refractoriness to treatment may be due to the resistance of quiescent leukemia stem cells (LSCs) to conventional chemotherapy. Gemtuzumab Ozogamicin (GO), a monoclonal antibody linked to the cytotoxin calicheamicin, targets CD33, an antigen with variable expression on LSC. However, decreased blast CD33 expression, p-glycoprotein upregulation and decreased mitochondrial apoptosis are recognized mechanism of resistance to GO (Linenberger et al Leukemia 2005; 19:176-82). GO-induced apoptosis requires Bax and Bak effectors and is opposed by the anti-apoptotic proteins BCL-2 and BCL-XL. Thus, Venetoclax (VEN), a BH3 mimetic with high affinity for BCL-2 should facilitate GO-mediated LSC apoptosis. In addition, LSC, due to their reliance on oxidative phosphorylation (Lagadinou, Cell Stem Cell 2013, 12:329-41) are also uniquely sensitive to BCL-2 inhibition. Thus, we hypothesized a potential synergy between these drugs in targeting LSC in R/R AML. Study design: Big Ten Cancer Research Consortium (BTCRC)-AML17-113 is a single arm, open-label, multi-center, dose-escalation phase Ib/II study of the combination of GO and escalating doses of VEN in R/R AML pts (18-75y), using a 3+3 design. Correlative studies include pre-treatment AML blast CD33 expression and BH3 profiling, minimal residual disease (MRD) measurements at post-therapy time points using digital drop PCR technology, and quality of life (QOL) assessments (EORTC QLQ-C30, FACT-Fatigue). Methods: The primary endpoint is to determine the maximum tolerated dose (MTD) of VEN with GO. Secondary endpoints include overall response rate (ORR), anti-leukemic activity, characterization of treatment emergent adverse events (TEAEs), and estimates of relapse free survival (RFS), event free survival (EFS), and overall survival (OS). Eligibility: ECOG 0-2, adequate organ function, CD33+ in ≥20% AML blasts, ≤2 lines of prior therapy, no prior use of GO, no history of veno-occlusive disease (VOD), no BMT within 2 months, no CNS disease or HIV. Induction: 3-day VEN ramp-up to the target dose of 200 (cohort #1), 400 (#2), or 600 (#3) mg daily x 28d, with GO 3mg/m2 infused d1, 4, and 7. Consolidation/Maintenance: If CR/CRi achieved, pts proceed to BMT if applicable. If no BMT, or if partial response (PR), pts are consolidated with VEN at the prescribed dose x 28d with GO 3mg/m2 given d1 and 4 (Cycle 2). If BMT not applicable, and in CR/CRi, VEN alone is then given as maintenance in cycles 3+ until disease progression or toxicity. Updated Analysis: Trial design was previously described by Arain, S et al. JCO 2020, 15:suppl. TPS7566. Cohort#3 is completing accrual with the last of 6 patients currently undergoing induction treatment. Enrollment n=12 pts. Barriers to accrual have been the COVID-19 pandemic and widespread use of VEN/HMA by referring community oncologists. The study has been amended to allow for prior use of VEN containing regimens. SAE: Respiratory failure gr 3 (n=1), febrile neutropenia (FN) gr 3/4 (n=3), Anemia/rectal pain gr 3/4 (n=1). TEAE:(%;max grade (gr)): thrombocytopenia and anemia (both 60%;gr 4); neutropenia (40%;gr 4); pruritus (30%;gr 3); FN (20%;gr 4), weight loss, diarrhea , headache, constipation (all 20%;gr 1-2). Outcomes: None of the 6 pts in cohorts #1 and #2 responded to treatment. One pt developed VOD gr 4, related to the use of total marrow irradiation conditioning regimen post-induction with GO/VEN. In cohort #3, 3 patients are in CR (one post-HSCT), 2 are undergoing induction and 1 has progressed. Conclusion: The updated analysis of this study reveals a well tolerated drug combination with low toxicities, demonstrating responses in cohort#3 (VEN 600 mg). We plan to expand accrual to this cohort adding 6-12 pts. This trial is registered at clinicaltrials.gov as NCT040768.