Secondary acute myeloid leukemia (sAML) poorly responds to conventional treatments and allogeneic stem cell transplantation (HSCT). We evaluated toxicity and efficacy of CPX-351 in 71 elderly patients (median age 66 years) with sAML enrolled in the Italian Named (Compassionate) Use Program. Sixty days treatment-related mortality was 7% (5/71). The response rate at the end of treatment was: CR/CRi in 50/71 patients (70.4%), PR in 6/71 (8.5%), and NR in 10/71 (19.7%). After a median follow-up of 11 months relapse was observed in 10/50 patients (20%) and 12 months cumulative incidence of relapse (CIR) was 23.6%. Median duration of response was not reached. In competing risk analysis, CIR was reduced when HSCT was performed in first CR (12 months CIR of 5% and 37.4%, respectively, for patients receiving (=20) or not (=30) HSCT, p = 0.012). Twelve-months OS was 68.6% (median not reached). In landmark analysis, HSCT in CR1 was the only significant predictor of longer survival (12 months OS of 100 and 70.5%, for patients undergoing or not HSCT in CR1, respectively, p = 0.011). In conclusion, we extend to a real-life setting, the notion that CPX is an effective regimen for high risk AML patients and may improve the results of HSCT.

Background: Venetoclax in combination with hypomethylating agents (HMA) is revolutionizing the therapy of acute myeloid leukemia (AML). However, evidence on large sets of patients is lacking, especially in relapsed or refractory leukemia. Methods:AVALON is a multicentric cohort study that was conducted in Italy on patients with AML who received venetoclax-based therapies from 2015 to 2020.The study was approved by the ethics committee of the participating institution and was conducted in accordance with the Declaration of Helsinki. The effectiveness and toxicity of venetoclax + HMA in 190 (43 newly diagnosed, 68 refractory, and 79 relapsed) patients with AML are reported here. Results:In the newly diagnosed AML, the overall response rate and survival confirmed the brilliant results demonstrated in VIALE-A. In the relapsed or refractory AML, the combination demonstrated a surprisingly complete remission rate (44.1% in refractory and 39.7% in relapsed evaluable patients) and conferred to treated patients a good expectation of survival. Toxicities were overall manageable, and most incidents occurred in the first 60 days of therapy. Infections were confirmed as the most common nonhematologic adverse event.Conclusions: Real-life data show that the combination of venetoclax and HMA offers an expectation of remission and long-term survival to elderly, newly diagnosed patients, and to relapsed or chemoresistant AML, increasing the chance of cure through a TODISCO ET AL.-993 different mechanism of action. The venetoclax + HMA combination is expected to constitute the base for triplet combinations and integration of target therapies. Our data contribute to ameliorate the understanding of venetoclax + HMA effectiveness and toxicities in real life.

The translocation t(8;9)(p22;p24) results in the production of a chimeric PCM1 ‐ JAK2 fusion protein leading to the constitutive activation of the Janus Kinase 2 that renders this disease potentially sensitive to ruxolitinib. Here, we report an interesting case of PCM1 ‐ JAK2 myeloproliferative neoplasm evolving in myeloid sarcoma and B precursor ALL.

Introduction Allogeneic Chimeric Antigen Receptor (CAR) T cells engineered with non-viral methods offer a modality to reduce costs and logistical complexity of the viral process and allow lymphodepleted patients to access CAR T cell treatment. We recently proposed the use of Sleeping Beauty (SB) transposon to engineer donor-derived T cells differentiated according to the cytokine-induced killer (CIK) cell protocol (Magnani CF et al. J Clin Invest. 2021). We report here outcomes on B-cell acute lymphoblastic leukemia (B-ALL) patients, relapsing after transplantation, treated with donor-derived anti-CD19 CAR T cells (CARCIK-CD19). Methods We conducted an academic, multi-center, phase I/II dose-escalation trial in patients relapsed after allogeneic hematopoietic stem cell transplantation (HSCT). The infusion product was manufactured in-house starting from 50 mL of peripheral blood from the HSCT donor by electroporation with GMP-grade plasmids. All patients underwent lymphodepletion with Fludarabine (30 mg/m 2/day x 4 days) and Cyclophosphamide (500 mg/m 2/day x 2 days), before proceeding to CARCIK-CD19 infusion. We used the Bayesian Optimal Interval (BOIN) design to define a four-dose escalation scheme. Primary objectives were to define the Maximum Tolerated Dose (MTD), safety, and feasibility. Secondary objectives included the assessment of complete hematologic response (CR), duration of response (DOR), progression-free (PFS), event-free (EFS), and overall survival (OS). This study was registered at ClinicalTrials.gov, NCT03389035. Results From January 2018 to June 2021, a total of 32 patients were screened, 26 enrolled (6 children and 20 adults) and 21 infused (4 children and 17 adults). Reasons for not receiving infusion included consent withdrawal (N=1), disease progression not controlled by bridging therapy (N=3), acquisition of myeloid phenotype (N=1). The median number of prior therapies was 4 (range, 1-7) with a median time interval from HSCT to relapse of 9 months. The median BM blasts was 60% (range, 5-100%) at enrollment and 7% (range, 0-96%) post lymphodepletion. Of the 21 patients infused, CARCIK-CD19 were obtained by HLA-identical sibling (n=6, 29%), matched unrelated (n= 7, 33%), and haploidentical donors (n=8, 38%). Three patients (14%) received the first dose level of 1x10 6 CARCIK-CD19 cells/Kg, three (14%) the second of 3x10 6, and three (14%) the third of 7.5x10 6 whereas 12 patients (57%) received the fourth and last planned dose level of 15x10 6 cells/Kg, as no dose limiting toxicity (DLT) was observed. CRS was observed in six patients (three grade I and three grade II) and immune effector cell-associated neurotoxicity in two patients at the highest dose. Although 9 out of 21 had experienced acute or chronic graft-versus-host disease (GvHD) after the previous HSCT, secondary GvHD was never induced by CARCIK-CD19. Complete response was achieved by 13 out of 21 patients (61.9%, 95%CI=38-82%) and by 11 out of 15 patients treated with the 2 highest doses (73.3%, 95%CI=45-92%). Eleven of these responders were MRD-negative. Notably, the type of donor did not influence the achievement of CR 28 days post-infusion. At a median follow up of 21.6 months (range, 1.0-38.4 months), 10 patients (47.6%) are alive in CR (9 in the 2 highest dose levels). Overall, the median OS and EFS were 9.7 and 3.2 months, respectively, with a median DOR of 4.0 months (range, 1.0-23.5 months). Patients in CR at 28-days had a 6-months relapse-free survival of 48.4% (SE=14.9). EFS at 6 months was 26.5% (SE=9.9) and OS was 67.6% (SE=11.1). Among the 13 patients who achieved CR, two children underwent consolidation with a second allo-HSCT in complete remission. Adult patients did not receive any additional anti-leukemic therapies unless a relapse occurred, and four of them remained in remission and alive (+24, +9, +6, and +4 months). Robust CARCIK-CD19 cell expansion was achieved in most patients and CARCIK-CD19 cells were measurable for up to 22 months. Conclusions SB-engineered CAR T cells induce sustained responses in B-ALL patients relapsed after HSCT irrespective of the donor type and without severe toxicities. Disclosures Lussana: Incyte: Honoraria; Pfizer: Honoraria; Astellas Pharma: Honoraria; Amgen: Honoraria. Gritti: Takeda: Consultancy; Roche: Consultancy; Kite Gilead: Consultancy; IQvia: Consultancy; Italfarmaco: Consultancy; Clinigen: Consultancy. Biondi: Incyte: Consultancy, Other: Advisory Board; Bluebird: Other: Advisory Board; Novartis: Honoraria; Amgen: Honoraria; Colmmune: Honoraria.

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Background Significant efforts over the past few years led Chimeric Antigen Receptor (CAR) T cell therapy to success in relapsed and refractory (r/r) B-cell malignancies. Still logistical complexity, high costs and toxicities are currently the main barriers to the use of CAR T cell therapy. We therefore propose non-viral engineering of an allogeneic T cell population according to cytokine induced killer (CIK) cell protocol of differentiation. Methods We reported the updated results of our phase I/II trial in B-cell acute lymphoblastic leukemia (B-ALL) patients relapsed after allogeneic hematopoietic stem cell transplantation (HSCT) using donor-derived CD19 CAR T cells generated with the Sleeping Beauty (SB) transposon and differentiated into CIK (CARCIK-CD19) according to the method enclosed in the filed patent EP20140192371. After lymphodepletion with Fludarabine (30 mg/m2/day) x 4 days and Cyclophosphamide (500 mg/m2/day) x 2 days, CARCIK-CD19 were infused following a four-dose escalation scheme (1x106, 3x106, 7.5x106 and 15x106 transduced CAR+ T cells/kg) according to the Bayesian Optimal Interval Design (BOIN). During the cell manufacturing period, bridging anti leukemic therapy from patient registration to the beginning of the lymphodepletion, was allowed. The primary endpoint was to define the Maximum Tolerated Dose (MTD) and the safety assessment. Key secondary endpoints included the assessment of complete hematologic response (CR), defined as < 5% bone marrow (BM) blasts, circulating blasts < 1%, no clinical evidence of extramedullary disease, as well as the characterization of CARCIK-CD19 persistence in PB and BM (NCT03389035). Results The cellular product was produced successfully for all patients starting from the donor-derived peripheral blood (PB) and consisted mostly of CD3+ lymphocytes (mean 98.85% ±SD 1.19%) with a mean of 38.6% CAR expression (range 15.10%-73.17%). From January 2018 to July 2020, a total of 24 patients were screened, and 15 were enrolled (4 children and 11 adults) and infused with a single dose of CARCIK-CD19 (n=3 HLA identical sibling, n=4 MUD, n=8 haploidentical donor). The leukemic burden in the BM post lymphodepletion/pre-infusion ranged from 0% to 96%. Robust expansion was achieved in the majority of the patients. The maximal expansion reached about 1x106 transgene copies per μg DNA and 70% of CAR+ T cells in PB. CD8+ T cells represented the predominant circulating CAR+ T cell subset. Persistence of central memory CAR+ T cells was observed after infusion and CAR T cells were measurable up to 9 months. CARCIK-CD19 were characterized by a high profile of safety in all treated patients. Toxicities reported were two grade I and two grade II cytokine release syndrome (CRS) cases at the highest dose in the absence of graft-versus-host disease (GvHD), neurotoxicity, or dose-limiting toxicities. Seven out of 9 patients, receiving the highest doses, achieved CR and CRi at day 28. MRD-negative status for all responders was achieved by 6 out of 9 patients (1 currently in evaluation). The two patients in CR but with MRD+ relapsed with a CD19+ disease at +2.3 and +1.9 months post infusion, respectively. Among the 6 patients who achieved MRD-negative CR, two children underwent consolidation with a second allo-HSCT and are still alive and disease free (+17 and +13 months), two adult patients died of subsequent CD19+ disease relapse and two adult patients are still alive and disease free (+14 and +12 months) without additional therapies. The distribution profile of integration sites (IS) showed no preference for gene dense or promoter regions, and no particular differences between pre- and post- infusion sample IS. Samples harvested at early time points after infusion showed a highly polyclonal repertoire. At later time points (≥ 28 days after infusion) the repertoire of IS showed a marked reduction towards oligoclonality, in absence of specific dominant clones. Conclusions We can conclude that SB-engineered CAR T cells expand and persist in pediatric and adult B-ALL patients relapsed after HSCT. Sustained response was achieved without severe toxicities. All analyzed samples appear to have a highly polyclonal IS repertoire and no signs of genotoxicity by transposon insertions could be observed. Disclosures Gritti: IQVIA: Consultancy; Amgen: Honoraria; Autolus: Consultancy; Italfarmaco: Consultancy; F. Hoffmann-La Roche Ltd: Honoraria; Jannsen: Other: Travel Support; Takeda: Honoraria; Kite: Consultancy. Rambaldi:Sanofi: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Omeros: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Research grant from Amgen Inc.; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Advisory board and speaker fees from Pfizer.; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support from Gilead.; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support of parent study and funding of editorial support. Received travel support., Research Funding; University of Milan: Current Employment; BMS/Celgene: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Astellas: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company).

The translocation t(8;9)(p22;p24) results in the production of a chimeric PCM1-JAK2 fusion protein leading to the constitutive activation of the Janus Kinase 2 that renders this disease potentially sensitive to ruxolitinib. Here we report an interesting case of PCM1-JAK2 myeloproliferative neoplasm evolving in myeloid sarcoma and B precursor ALL.

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