Complete Hematologic Remission Research Articles

A complete oral regimen for induction therapy of patients with high-risk APL: An oral etoposide instead of intravenous infusion for cytoreductive chemotherapy.

There is an urgent need for an oral, efficient and safe regimen for high-risk APL under the pandemic of COVID-19. We retrospectively analysed 60 high-risk APL patients. For induction therapy (IT), in addition to all-trans retinoic acid (ATRA) and oral arsenic (RIF), 22 patients received oral etoposide (VP16) as cytotoxic chemotherapy (CC), and 38 patients received intravenous CC as historical control group. The median dose of oral VP16 was 1000 mg [interquartile rage (IQR), 650-1250]. One patient died during IT in the control group, 59 evaluable patients (100%) achieved complete haematological remission (CHR) after IT and complete molecular remission (CMR) after consolidation therapy. The median time to CHR and CMR was 36 days (33.8-44) versus 35 days (32-42; p = 0.75) and 3 months (0.8-3.5) versus 3.3 months (2.4-3.7; p = 0.58) in the oral VP16 group and in the control group. Two (9.1%) and 3 (7.9%) patients experienced molecular relapse in different group respectively. The 2-year estimated overall survival and event-free survival were 100% versus 94.7% (p = 0.37) and 90.9% versus 89.5% (p = 0.97) respectively. A completely oral, efficient and safe induction regimen including oral VP16 as cytoreductive chemotherapy combined with ATRA and RIF is more convenient to administer for patients with high-risk APL.

Allogeneic hematopoietic cell transplantation for acute myeloid leukemia with BCR::ABL1 fusion.

BCR::ABL1 fusion is found in<1% of de novo acute myeloid leukemia (AML) cases and confers a poor prognosis. This Japanese nationwide survey analyzed patients with AML (n=22) and mixed phenotype acute leukemia (MPAL) (n=10) with t(9;22) or BCR::ABL1 who underwent allogeneic hematopoietic cell transplantation (allo-HCT) between 2002 and 2018. The 3-year overall survival (OS) rates were 81.3% and 56.0%, respectively (p=0.15), and leukemia-free survival (LFS) rates were 76.2% and 42.0%, respectively (p=0.10) in patients with AML and MPAL. The relapse rates were 9.5% and 14.0% (p=0.93), and the non-relapse mortality (NRM) rates were 14.3% and 44.0%, respectively (p=0.10) in patients with AML and MPAL. One in 17 patients with AML, with pre-transplant tyrosine kinase inhibitors (TKI), and three in five patients with AML, without pre-transplant TKI, did not achieve complete remission (CR) before allo-HCT (p=0.024). Among the 20 patients with known disease status after allo-HCT, 95.0% were in hematological or molecular CR. None of the four patients who received post-transplant TKI for prophylaxis or measurable residual disease relapse experienced hematological relapse. In conclusion, our results suggest that pre-transplant TKI could improve disease status before allo-HCT. Moreover, allo-HCT resulted in high OS, high LFS, low relapse, and low NRM rates in patients with AML with BCR::ABL1.

Flow Cytometric Assessment of CD26-Positive Leukemic Stem Cells: A Rapid and Valuable Tool in the Diagnosis and Follow-Up of Chronic Myeloid Leukemia.

Context Chronic myeloid leukemia (CML) is a clonal myeloproliferative neoplasm. Recent studies have suggested that CD26-positive leukemic stem cells (LSCs) circulating in peripheral blood are specific for CML. Objective This study was undertaken to determine the proportion of CD26-positive LSCsat diagnosis and its change during tyrosine kinase inhibitor therapy. Design This prospective study was conducted on 43 cases of CML at diagnosis. For flow cytometry, peripheral blood cells were stained with CD45, CD34, CD38, CD3, and CD26. A sequential gating strategy with CD45/SSC (side scatter), CD34/SSC, and CD34/CD38 was applied to identify CD45+/34+/38- populations, from which CD26-positive stem cells were identified and compared with controls. Data analysis was done with Kaluza software. Results All patients diagnosed with CML were detected with CD26-positive LSCs. The median percentage of CD26-positive CML LSCs was 0.02 with a range of 0.001 to 1.77. None of the control samples showed CD26 positivity. The percentage and absolute count of CD26-positive CML LSCs were reduced after six months of tyrosine kinase therapy in patients with complete hematological remission. Conclusion Flow cytometric analysis of circulating CD26-positive CML LSCs is a non-invasive, rapid, and useful tool in the diagnosis and follow-up of CML.

BCR/ABL-Positive Chronic Myeloid Leukemia in Children: Current Treatment Approach.

The purpose of this review is to summarize the most updated treatment recommendations for pediatric CML, and to discuss current areas of investigation. There is new phase 1 data to support the safety of the non-ATP competitive tyrosine kinase inhibitor (TKI) asciminib in the pediatric cohort. Ongoing studies are investigating the role of treatment-free remission in children. Chronic phase CML in children is managed with lifelong TKI therapy; however, evidence of deeper remissions sustained with second-generation TKIs may permit shorter treatment courses. Use of more specific TKIs may mitigate some of the side effects specific to the pediatric cohort. Children with advanced phase CML should achieve a complete hematologic remission with use of a second-generation TKI prior to transplant to achieve the best outcome.

Donor Lymphocyte Infusion for Relapsed Acute Leukemia or Myelodysplastic Syndrome after Hematopoietic Stem Cell Transplantation: A Single-Institute Retrospective Analysis.

Objective The prognosis of the patients who relapsed after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is poor, and therapeutic options are limited. In the present study, we investigated the efficacy and factors associated with the survival in patients with acute leukemia or myelodysplastic syndrome (MDS) who relapsed following allo-HSCT and were treated with donor lymphocyte infusion (DLI) in real-world practice. Patients Twenty-nine patients with acute myeloid leukemia21, acute lymphoid leukemia4 or MDS4 were enrolled. Eleven patients were diagnosed with hematological relapse, and 18 were diagnosed with molecular or cytogenetic relapse. Results The median injection number and median total number of infused CD3+ T cells were 2 and 5.0×107/kg, respectively. The cumulative incidence of acute graft-versus-host disease (aGVHD) of grade ≥II at 4 months after the initiation of DLI was 31.0%. Extensive chronic graft-versus-host disease (cGVHD) occurred in 3 (10.3%) patients. The overall response rate was 51.7%, including 3 cases of hematological complete remission (CR) and 12 cases of molecular/cytogenetic CR. Cumulative relapse rates at 24 and 60 months following DLI in patients who achieved CR were 21.4% and 30.0%, respectively. The overall survival rates at 1, 2 and 3 years after DLI were 41.4%, 37.9% and 30.3%, respectively. Molecular/cytogenetic relapse, a longer interval from HSCT to relapse, and concomitant chemotherapy with 5-azacytidine (Aza) were significantly associated with a relatively long survival following DLI. Conclusion These results indicated that DLI was beneficial for patients with acute leukemia or MDS who relapsed after allo-HSCT and suggested that DLI in combination with Aza for molecular or cytogenetic relapse might result in favorable outcomes.

Genomic and functional impact of Trp53 inactivation in JAK2V617F myeloproliferative neoplasms

Classical myeloproliferative neoplasms (MPNs) are characterized by the proliferation of myeloid cells and the risk of transformation into myelofibrosis or acute myeloid leukemia (AML) and TP53 mutations in MPN patients are linked to AML. However, JAK2V617F has been reported to impact the TP53 response to DNA damage, suggesting potential overlapping role of TP53 inactivation in MPN. We established a mouse model showing that JAK2V617F/Vav-Cre/Trp53−/− mice displayed a similar phenotype to JAK2V617F/Vav-Cre mice, but their proliferation was outcompeted in competitive grafts. RNA-Seq revealed that half of the genes affected by JAK2V617F were affected by p53-inactivation, including the interferon pathway. To validate this finding, mice were repopulated with a mixture of wild-type and JAK2V617F (or JAK2V617F/Vav-Cre/Trp53−/−) cells and treated with pegylated interferonα. JAK2V617F-reconstituted mice entered complete hematological remission, while JAK2V617F/Vav-Cre /Trp53−/−-reconstituted mice did not, confirming that p53 loss induced interferon-α resistance. KEGG and Gene Ontology analyses of common deregulated genes showed that these genes were mainly implicated in cytokine response, proliferation, and leukemia evolution, illustrating that in this mouse model, the development of MPN is not affected by TP53 inactivation. Taken together, our results show that many genetic modifications induced by JAK2V617F are influenced by TP53, the MPN phenotype may not be. Trp53 loss alone is insufficient to induce rapid leukemic transformation in steady-state hematopoiesis in JAK2V617F MPN, and Trp53 loss may contribute to interferon resistance in MPN.

Percutaneous Perirenal Mass Biopsy in a Sitting Position Revealed Extramedullary Relapse of Acute Lymphoblastic Leukemia.

Acute lymphoblastic leukemia (ALL) is a blood malignancy characterized by a rapid proliferation of lymphoid progenitor cells. Extramedullary relapse (EMR) is the recurrence of leukemia that occurs outside the bone marrow. The central nervous system is the most prevalent site of EMR in ALL, whereas other organs, particularly the renal organs, are less commonly involved. A 49-year-old man diagnosed with Philadelphia chromosome-negative ALL (Ph-negative ALL) received a second umbilical cord blood transplant (uCBT) and was confirmed to be in his third hematological complete remission. However, the perirenal mass lesion emerged after two weeks, and was difficult to detect on echography in the prone position. We successfully performed a percutaneous biopsy of the mass in a sitting position and pathologically identified it as EMR. After the diagnosis, chemotherapy was restarted, and the patient was scheduled to receive a third uCBT. This is the first report of EMR in a perirenal lesion of ALL and shows that this novel biopsy can be performed as a renal biopsy, even in a sitting position. This case is the first to describe a biopsy technique in detail and demonstrates the value of collaboration between hematologists and nephrologists in diagnosing EMR of the kidneys.

Acute myeloid leukemia with central nervous system involvement successfully treated with gilteritinib

A 69-year-old woman was referred to our hospital due to hyperleukocytosis. We diagnosed acute myeloid leukemia and started induction therapy with the CAG regimen (aclarubicin, cytarabine and filgrastim). However, the patient was refractory to the initial treatment and developed quadriplegia, and a cerebrospinal fluid (CSF) test showed elevated blasts. We then performed intrathecal chemotherapy, and the number of blasts in CSF gradually decreased. But only two cycles of intrathecal therapy were possible due to severe methotrexate-induced mucositis. The leukemia cells had fms-like kinase 3-internal tandem duplication (FLT3-ITD), so we started treatment with oral gilteritinib. The patient then achieved hematological complete remission. Her paralysis was also resolving, and the CSF was clear of blasts for more than 6 months. Some reports show that gilteritinib may penetrate the CNS, and this case also supports the effectiveness of gilteritinib on CNS leukemia.

Cross-sectional network analysis of plasma proteins/metabolites correlated with pathogenesis and therapeutic response in acute promyelocytic leukemia.

The treatment of PML/RARA+ acute promyelocytic leukemia (APL) with all-trans-retinoic acid and arsenic trioxide (ATRA/ATO) has been recognized as a model for translational medicine research. Though an altered microenvironment is a general cancer hallmark, how APL blasts shape their plasma composition is poorly understood. Here, we reported a cross-sectional correlation network to interpret multilayered datasets on clinical parameters, proteomes, and metabolomes of paired plasma samples from patients with APL before or after ATRA/ATO induction therapy. Our study revealed the two prominent features of the APL plasma, suggesting a possible involvement of APL blasts in modulating plasma composition. One was characterized by altered secretory protein and metabolite profiles correlating with heightened proliferation and energy consumption in APL blasts, and the other featured APL plasma-enriched proteins or enzymes catalyzing plasma-altered metabolites that were potential trans-regulatory targets of PML/RARA. Furthermore, results indicated heightened interferon-gamma signaling characterizing a tumor-suppressing function of the immune system at the first hematological complete remission stage, which likely resulted from therapy-induced cell death or senescence and ensuing supraphysiological levels of intracellular proteins. Overall, our work sheds new light on the pathophysiology and treatment of APL and provides an information-rich reference data cohort for the exploratory and translational study of leukemia microenvironment.

High Mitochondrial Protein Expression as a Potential Predictor of Relapse Risk in Acute Myeloid Leukemia Patients with the Monocytic FAB Subtypes M4 and M5.

AML is a highly aggressive and heterogeneous form of hematological cancer. Proteomics-based stratification of patients into more refined subgroups may contribute to a more precise characterization of the patient-derived AML cells. Here, we reanalyzed liquid chromatography-tandem mass spectrometry (LC-MS/MS) generated proteomic and phosphoproteomic data from 26 FAB-M4/M5 patients. The patients achieved complete hematological remission after induction therapy. Twelve of them later developed chemoresistant relapse (RELAPSE), and 14 patients were relapse-free (REL_FREE) long-term survivors. We considered not only the RELAPSE and REL_FREE characteristics but also integrated the French-American-British (FAB) classification, along with considering the presence of nucleophosmin 1 (NPM1) mutation and cytogenetically normal AML. We found a significant number of differentially enriched proteins (911) and phosphoproteins (257) between the various FAB subtypes in RELAPSE patients. Patients with the myeloblastic M1/M2 subtype showed higher levels of RNA processing-related routes and lower levels of signaling related to terms like translation and degranulation when compared with the M4/M5 subtype. Moreover, we found that a high abundance of proteins associated with mitochondrial translation and oxidative phosphorylation, particularly observed in the RELAPSE M4/M5 NPM1 mutated subgroup, distinguishes relapsing from non-relapsing AML patient cells with the FAB subtype M4/M5. Thus, the discovery of subtype-specific biomarkers through proteomic profiling may complement the existing classification system for AML and potentially aid in selecting personalized treatment strategies for individual patients.

LONG-TERM Results of the Frontline Dasatinib/Blinatumomabprotocol (D-ALBA, GIMEMA LAL2116) for Adult Ph+ Acutelymphoblastic Leukemia

Introduction. The prognosis of Ph+ acute lymphoblastic leukemia (ALL) has changed profoundly following the advent of tyrosine kinase inhibitors (TKIs). Since 2000, the GIMEMA frontline studies for adult Ph+ ALL patients have been based on a TKI plus steroids in induction without systemic chemotherapy. This has allowed complete hematologic remission (CHR) rates of 94-100%, irrespective of age, with virtually no deaths in induction 1-5. We then designed an induction/consolidation chemotherapy-free frontline trial with dasatinib followed by blinatumomab (GIMEMA LAL2116, D-ALBA). The preliminary results 6,7 showed a CHR rate of 98% with 60% of molecular responses at the primary endpoint of the study (after 2 blinatumomab cycles); the OS and DFS were 95% and 88% at 18 months. Here we present the final long-term results of the study. Methods. Post-consolidation treatment was left to the treating physicians and all the information has been collected in the GIMEMA LAL2217 ancillary study. Sixty-three patients were enrolled (median age 54 years, range 24-82); 2 patients withdrew from the trial, 1 died in CHR and 1 relapsed after induction due to a major protocol violation 6,7. Results. After the primary endpoint, molecular responses increased further following additional blinatumomab cycles, being 75, 77, 70, 85, 90 and 93% at 2, 4, 6, 8, 10 and 12 months from the last blinatumomab cycle. At a prolonged follow-up, a persistent molecular negativity was found with 78.3, 73.1, 85, 87.4, 94.2, 90.2, 86.6 and 86.7% of responders at 16, 20, 24, 28, 32, 36, 42 and 48 months in the evaluable population. At a median follow-up of 53 months, DFS and OS are 75.8% and 80.7% (Figure 1). A significantly better DFS and OS was observed in the 17 patients in molecular response at the end of induction (EOI) (100%) vs cases who were not (42) (68.6%) (p=0.016 and 0.036, respectively). These patients have so far not relapsed. After 2 blinatumomab cycles, DFS and OS did not differ between molecular (33) and non-molecular (22) responders: 82.9% and 89.4% vs 75.7% and 84.2%, underlying the effect of blinatumomab. A worse DFS from the EOI was recorded for IKZF1 pluspatients (11; 45.5%) compared to those without IKZF1 deletion (25; 82.3%) or with IKZF1 only deletions (13; 74%) (p=0.029). Similar results were observed also for OS. A similar trend was observed also when DFS was calculated from the primary endpoint of the study (62.5% vs 84.8% vs 74%). The 4 patients with a concomitant IKZF1 plus signature and T315I mutation had the worse outcome. After induction/consolidation, 29 patients continued treatment only with a TKI; 27 (93.1%) had obtained a deep molecular response after dasatinib/blinatumomab. Overall, 28 patients (96.5%) who did not receive systemic chemotherapy/transplant are in persistent CHR at a median follow-up of 48 months. Of the 24 patients transplanted in 1 st CHR, 13 (54.2%) were non-molecular responders at the primary endpoint and only 2 became molecularly negative after further blinatumomab. Twenty patients (83.3%) are alive in CHR at a median follow-up of 49 months, 1 has relapsed 1 month after the transplant and 3 have died of complications. Three/6 patients transplanted in 2 nd CHR are alive at 30, 40 and 52 months. The transplant-related mortality was 12.5% for patients transplanted in 1 st CHR and 13.7% overall. Nine relapses have occurred: 4 hematologic, 4 involving the CNS and 1 nodal. The median time to relapse was 4.4 months (1.9-25.8). A IKZF1 plus signature, evaluated at diagnosis, was present in 4/8 evaluable cases. ABL1 mutations, evaluated on BM samples at relapse or at a concomitant MRD increase in extra-hematologic recurrences, were found in 7 cases. Treatment was well tolerated with no unexpected long-term toxicities. Conclusions. The final analysis of the D-ALBA study shows that a chemotherapy-free induction/consolidation regimen based on a targeted strategy and immunotherapy is feasible and effective in inducing durable long-term hematologic and molecular responses in Ph+ ALL patients of all ages. Half of the patients remained only on a TKI and never underwent systemic chemotherapy or a transplant. These results pave the way for a new era in the treatment of adult Ph+ ALL patients. 1. Vignetti et al, Blood 2007 2.Foà et al, Blood 2011 3. Chiaretti et al, Haematologica 2016 4. Chiaretti et al, Haematologica 2021 5. Martinelli et al, Blood Advances 2022 6. Foà et al, N Engl J Med 2020 7. Foà &amp; Chiaretti, N Engl J Med 2022

Dose Reduced Chemotherapy in Sequence with Blinatumomab for Newly Diagnosed Older Patients with Ph/BCR::ABL Negative B-Precursor Adult Lymphoblastic Leukemia (ALL): Preliminary Results of the GMALL Bold Trial

Older patients (pts) with newly diagnosed ALL are ineligible for unmodified pediatric-based therapies. Although results are improved with age-adapted, dose-reduced regimens including MRD-based treatment modification, there is much space for further improvement.Therefore, the GMALL study group developed a trial to evaluate Blinatumomab, a CD19 directed bi-specific T-cell engager, in sequence with chemotherapy in this patient population with high medical need (NCT 03480438). Importantly, Blinatumomab replaced three cycles of standard consolidation chemotherapy.Pts aged 56 - 76 years (yrs) with CD19-positive, Ph-neg B-precursor ALL wereeligible. The primary endpoint was complete hematologic remission (CR) afterinduction (1 cycle chemo, 1 cycle Blinatumomab) and the key secondary endpoint was molecular response (table 1). The efficacy population included pts treated with dose reduced and shortened induction I (IP1) and Blinatumomab 1 or early death (ED). Induction was followed by 3 further Blinatumomab cycles alternating with age adapted consolidation cycles (HDMTX/ASP, HDAC, reinduction and maintenance) according to GMALL protocols for older pts (Gökbuget et al, ASH 2021). The median age was 66 (56-76) yrs. 21% had pro-B-ALL and 79% c/preB subtype. 40% had comorbidities according to the Charlson Score; most frequent were diabetes (13%) myocardial infarction (10%) or vascular diseases (10%). 50 pts were evaluable for IP1: 76% achieved CR/CRu and 2 pts (4%) died due to infections. 33% (N=11) had a molecular response and 18% MolCR (table 1). 47 pts were evaluable for the primary endpoint after Blinatumomab 1: CR/CRu was observed in 85%; 2 experienced ED (4%; those mentioned above; no additional ED). 88% of the CR pts had a molecular response (82% MolCR). The median follow-up is 757 (61-1584) days. Overall Survival (OS) after 1 and 3 yrs was 80% and 67% for the efficacy population (figure 1). The resp results for the total population were 82% and 65%. The 3y OS was 69% for c/pre-B-ALL and 58% for pro-B-ALL (p&amp;gt;.05). 3y OS was 81% for pts aged 55-65 yrs and 53% for those older than 65 yrs (p=.025). Only three pts received an allogeneic stem cell transplantation in CR1. 6 pts relapsed, 2 pt developed a secondary malignancy (Colon Ca, MDS) and 3 pts died in CR (1 HLH, 1 arterial disease, 1 Covid19). EFS was 60% at 3 yrs. We compared the results with those of the current GMALL standard therapy for older pts with B-precursor ALL (N=186) (Gökbuget et al, ASH 2022). Patient characteristics were similar. CR rates after induction were 85% vs 78% for BOLD vs standard (p&amp;gt;.05). Molecular CR rates in pts with hematologic CR were 82% vs 55% (p=.006). OS at 3 yrs was 67% and 49% (p=0.08) and Remission Duration (RD) was 83% vs 58% (p=0.055). Overall tolerability and efficacy of the regimen was very promising with a high hematologic and molecular response rate; mortality in induction and consolidation was low. In comparison with the current standard therapy the MRD response rates were significantly better. OS and RD was superior despite the omission of several chemotherapy cycles in contrast to other trials with unmodified chemotherapy but additional cycles of Blinatumomab. An ongoing randomized trial (NCT04994717) compares an even more dose reduced combination of Blina and chemotherapy with standard of care. This is an independent academic trial initiated by the GMALL Study Group which received free supply of Blinatumomab and financial support by Amgen.

Long-Term Follow-up of Hypereosinophilic Syndrome Patients Treated with Mepolizumab: A Nationwide Real-Life Study of 59 Patients

Background Mepolizumab, a humanized monoclonal antibody directed against IL-5, has proven efficacious for the treatment of FIP1L1 ∷ PDGFRA ( F/P)-negative Hypereosinophilic Syndrome (HES) in two randomized controlled trials with short term follow-up. However, both its efficacy and safety profiles on the long term are unknown. Methods All F/P-negative HES patient treated with mepolizumab in France from 2003 to 2022 in either GlaxoSmithKline-sponsored randomized trials (MHE100185 and HES200622) or long-term access programs (MHE100901 and MHE10417) were included. For each study visit, we retrospectively collected the following data: drug doses (and spacing), HES-disease status, absolute eosinophil counts (AEC), and doses of oral corticosteroids (OCS). Clinical remission (CR) was defined as the absence of symptoms related to HES. Complete hematological remission (CHR) was defined as an AEC &amp;lt; 0.5 x 10 9/L, and relapse by the occurrence of new or worsening of HES-related symptoms, irrespective of either AEC or increase of HES treatments. Relapse-free survival was modeled using a Kaplan-Meier method. We also assessed the rates of “super responses”, a new outcome measure defined as the combination of both CR, CHR and complete withdrawal of OCS at last follow-up. Results and discussion Data were available for 64 out of the 80 patients identified. All patients ultimately received 300mg subcutaneous mepolizumab, but 27 (45.8%) patients had initially been started on higher doses (700 or 750 mg intravenous). Five patients were excluded because of misdiagnoses despite initially high AEC and HES-mimicking presentation (IgG4-related disease (n=1), Castleman's disease (n=1), lymphoma (n=2) and STAT6 gain-of-function mutation (n=1)). Ultimately, the study population consisted of 59 patients (idiopathic HES, n=51; lymphocytic HES, n=8) with chronic HES sensitive to high-dose OCS yet who remained OCS-dependent on the long run (median [IQR] dose of OCS at baseline: 11 [9-20] mg/d). In median, patients had two organs involved, with gastro-intestinal, respiratory, and cutaneous manifestations being the most frequent symptoms. After a median follow-up of 4.5 [2.5-12.3] years, 11 patients (19%) relapsed, among whom five were clearly related to prior mepolizumab spacing to more than four weeks between injections (Figure 1). In details, most of the patients were in CR (n=55, 93%) and/or in CHR (n=56, 95%) at last follow-up, including 38 (64%) OCS-free patients who fulfilled criteria for super response. No baseline predictive factor for super response was evidenced. When focusing on the 21 (36%) patients with more than eight years of follow-up (median 14.4 [12.2-17.3] years), outcomes tended to be the same as those of the overall population. At last follow-up more than 70% of patients were able to space mepolizumab's infusions for more than four weeks (median time between two injections at last follow-up: 8 [4-11] months). Ultimately, four patients were able to discontinue mepolizumab without subsequent relapse with more than two years of follow-up. There was no new safety signal, and no patient withdrew mepolizumab due to a treatment-related adverse event. Conclusion Mepolizumab remains highly efficacious in the long-term (including in patients with more than 10 years of follow-up), enabling sustained disease remission despite tapering of OCS and spacing of injections. Very few cases of mepolizumab failure were identified, among which the leading cause was HES misdiagnosis.

Comparison between Dasatinib-Blinatumomab Vs Ponatinib-Blinatumomab Chemo-Free Strategy for Newly Diagnosed Ph+ Acute Lymphoblastic Leukemia Patients. Preliminary Results of the Gimema ALLL2820 Trial

Introduction. The outcome of Philadelphia positive acute lymphoblastic leukemia (Ph+ ALL) has dramatically improved in the last decade, due with the introduction in the clinical practice of tyrosine kinase inhibitors (TKIs). A further improvement has been obtained with the use of blinatumomab as a consolidation strategy in newly diagnosed patients. We previously designed an induction/consolidation chemotherapy-free frontline trial with dasatinib followed by blinatumomab (GIMEMA LAL2116, D-ALBA); the preliminary results showed that after 2 cycles of blinatumomab (primary endpoint), molecular responses were achieved in 60% of cases and that, with a median follow-up of 18 months, overall survival (OS) and disease (DFS) were 95% and 88% (Foà et al, NEJM 2020). An updated follow-up at 53 months (Foà et al, under revision and ASH 2023) confirmed the favorable long-term outcomes with OS and DFS of 75.8% and 80.7%, respectively. A total of 9 relapses occurred. The median time to relapse was 4.4 months (1.9-25.8); 4 were at the central nervous system (CNS). To further improve the outcome of these patients, we designed a phase III trial (GIMEMA ALL2820) in which in the experimental arm dasatinib was substituted with ponatinib, followed - in the consolidation phase - by at least 2 cycles of blinatumomab. The trial is currently enrolling. Aims. To compare the efficacy of the combination of ponatinib followed by blinatumomab with that reported with dasatinib followed by blinatumomab for the management of newly diagnosed adult Ph+ ALL patients. Patients and Methods. From September 2021 to July 2023, 74 patients have been enrolled in the experimental arm, based on ponatinib followed by at least 2 cycles of blinatumomab; the induction period has been reduced from 85 to 70 days and the dose of ponatinib was either 45 mg or 30 mg, according to patient's age. A dose reduction to 30 mg was foreseen by day 28 of induction, regardless of age, to avoid unacceptable toxicities. Furthermore, CNS prophylaxis was strengthened with a total of 15 medicated lumbar punctures and triple intrathecal therapy (methotrexate, aracytin and steroids) was administered. Finally, transplant allocation was not left to investigator's choice, but it was established according to biological features (minimal residual disease and presence of the IKZF1 plu s genotype). Results. Median age was 57 years (range 20-80), with 31% of patients being older than 65 years; 51% were males, the median white blood count (WBC) was 12 x10 9/l (1-207 x10 9/l). The p190 fusion protein was detected in 75.6% of cases, the p210 in 21.6% and p190/p210 in 2.7%. The IKZF1 plus genotype was detected in 33% of cases. The median follow-up is 6.1 months (0 - 20.3). Of the 74 patients enrolled, 16 were still receiving induction treatment and have therefore been excluded from the present analysis, and 40 have received ≥2 cycles of blinatumomab. Regarding the induction phase, 55 of 58 patients (95%) achieved a complete hematologic remission (CHR), while 3 patients (5%) died in induction (a 77-year-old woman for unknown causes, a 68-year-old man for an intestinal occlusion and a 52-year-old man due to pneumonia). A molecular response (including both MRD negative and positive non-quantifiable (PNQ) cases) was obtained in 21/55 cases (38.2%). By the end of the consolidation phase, of the 40 evaluable patients 25 (62.5%). achieved a molecular response. So far, a single patient has relapsed (WBC at onset 121 x10 9/l and a IKZF1 plus genotype) after 3 months from CHR: at relapse, this case harbored a T3151 mutation (Sanger sequencing and digital droplet PCR at diagnosis were wild type). At recurrence, CD19 expression was maintained. Conclusions. The preliminary analysis of the GIMEMA ALL2820 trial proved the feasibility of this ponatinib-blinatumomab induction consolidation strategy for newly diagnosed Ph+ ALL of all ages, with a 95% CHR rate. Molecular responses at the end of induction are slightly superior in the current trial (38.2% vs 29% in the D-ALBA study), whereas they are virtually equivalent after 2 cycles of blinatumomab (62.5% vs 60% in in the D-ALBA). So far, the benefit of the current protocol appears to rely on a lower relapse rate, with only 1 relapse being observed to date, while in the same time period 3 relapses were documented with the dasatinib-blinatumomab combination. Further details will be provided.

Outcomes of Antithymocyte Globulin and Cyclosporine for Severe Aplastic Anemia

Background: Aplastic anemia (AA) is mediated by T cell destruction of hematopoietic stem and progenitor cells causing pancytopenia and bone marrow hypoplasia. The current standard of care for severe aplastic anemia (SAA) is hematopoietic stem cell transplantation (HSCT) or immunosuppressive therapy (IST) with antithymocyte globulin (ATG) plus cyclosporine (CsA) with or without eltrombopag (Epag), a thrombopoietin receptor agonist. HSCT is preferred for SAA in young adults as a curative option, but only a small proportion of patients have histocompatible siblings and mortality increases with age. The IST plus CsA combination with or without Epag has led to survival rates comparable with those observed with HSCT recipients. However, complete hematologic remission is rare with IST and there is a considerable risk of clonal complications, including PNH evolution and progression to MDS. The aim of this study was to evaluate outcomes of ATG plus CsA therapy in a large cohort of SAA patients. Methods: We retrospectively analyzed medical records of 156 patients with SAA, aged ≥2 years treated with ATG plus CsA with or without Epag at our institution between July 2000 and January 2023. Hematologic responses were evaluated at 3-, 6- and 12-months post therapy initiation. Super response (SR) was defined as hemoglobin ≥12 g/dL, platelet count ≥150x10 9/L and absolute neutrophil count (ANC) ≥1.0x10 9/L; complete response (CR) was defined as hemoglobin ≥10 g/dL, platelet count ≥100x10 9/L and ANC ≥1.0x10 9/L. Partial response (PR) was defined as not meeting the criteria for CR and SAA. Overall response encompassed SR, CR, and PR. Statistical analyses were performed with the use of Chi-squared test and Kaplan Meier method. Results: The median age at diagnosis was 52 (IQR 30-66) years, 47% were male, and 86% were Caucasian. Twenty three percent of the cohort had coexisting paroxysmal nocturnal hemoglobinuria. Most patients were treated with ATG plus CsA (92%), the remaining 8% additionally received Epag. Overall response rates were 70%, 67%, and 77% at 3-, 6- and 12-months post-treatment initiation, respectively. CR was achieved in 10%, 15%, and 18% at 3-, 6- and 12-months, respectively. SR was achieved in 16.3% of patients at 12 months, as shown in Figure 1. Patients who achieved SR were young with median age at diagnosis of 28 years, while those who achieved PR or no response had a median age of 54 and 56 years, respectively. Patients who responded to the ATG + CsA therapy had significantly higher baseline ANC (p=0.04), absolute reticulocyte count (ARC) (p&amp;lt;0.001) and absolute lymphocyte count (ALC) (p&amp;lt;0.001). Pre-treatment median values of ANC, ARC and ALC were higher for patients who achieved SR compared to the rest of responders. With a median follow up time of 4.5 years, the estimated median relapse free survival was 9.2 years (95% CI, 3.2 - not reached [NR]) (Figure 2). Of the entire cohort, 21 (13%) patients progressed to acute myeloid leukemia or myelodysplastic syndrome. At data cut off, a total of 66 patients had died; the estimated median OS was 11.6 years (95% CI, 8.4 - NR). In particular, 30 patients died within the first 12-months, 13 within 3-months of ATG initiation from treatment-related complications, 6 from pneumonia and the rest from unknown causes. Conclusion: The findings of our study demonstrate that ATG plus CsA is an effective and safe treatment option for patients with SAA, especially in the older patient population where HSCT-related toxicities can lead to high mortality. Those with higher baseline ALC, ANC and ARC were more likely to respond to therapy compared to those with lower counts. A small percentage of patients progressed to myeloid neoplasia. Mortality within the first 12-months was high, indicating the need for close monitoring to avoid treatment-related mortality.

Dasatinib and CAR-T Cell Therapy for Newly Diagnosed Ph-Positive Acute Lymphoblastic Leukemia in Adults

Introduction The use of tyrosine kinase inhibitors has improved outcomes of Ph-positive Acute lymphoblastic leukemia (ALL), but combinations with other agents are needed to achieve molecular response. CAR-T cell therapy has made a breakthrough in refractory or relapsed ALL, but has not yet been applied in newly diagnosed patients. Methods We conducted a phase 2 single-group trial of first-line therapy in adults with newly diagnosed Ph-positive ALL. Dasatinib in combination with a two-week vincristine and glucocorticoids regimen were administered, followed by sequential infusions of CD19 and CD22 CAR-T cells. All patients received single-agent dasatinib maintenance after CAR-T cell therapy. The primary endpoint was complete molecular response (defined as undetectable BCR/ABL1 transcript with a sensitivity of 0.001%) in the bone marrow after this treatment. Here we report initial results from this study. Results At the cut-off date of 31 May 2023, 18 patients have received CD19 CAR-T cell infusions, and 14 of these patients have received subsequent CD22 CAR-T cell infusions. At the end of induction therapy, the complete hematologic remission rate was 100%, and 27.8% (5/18) of the patients had a complete molecular response. The percentage of complete molecular response increased to 72.2% (13/18) after CD19 CAR-T cell therapy, and increased further to 76.9% (10/13) after CD22 CAR-T cell therapy (1 patient has not been evaluated). Notably, of the 5 patients who did not achieve complete molecular response after CD19 CAR-T cell therapy, 4 have received CD22 CAR-T cell therapy, of which 1 eventually achieved complete molecular response and 2 experienced relapses. One patient had a CD19+ CD22+ relapse accompanied by mutations in BCR/ABL1 (F317L and Y253H) and the other patient had a CD19dim CD22+ relapse. After a median follow-up of 13.5 months, 16 patients remained in complete hematologic remission, and 14 patients remained in sustained complete molecular response. No patient received allogeneic stem cell transplantation. No grade 3 or higher cytokine release syndrome or Immune effector cell-associated neurotoxicity syndrome was observed during CAR-T cell therapies. Conclusions Dasatinib in combination with CAR-T cell therapy has enabled chemotherapy-free treatment in newly diagnosed Ph-positive ALL. This treatment is characterized by high complete molecular response, high long-term survival, low toxicity and short treatment cycles.

Venetoclax-Based Therapy before Allogeneic Hematopoietic Cell Transplantation for Acute Myeloid Leukemia

Introduction The BCL-2 inhibitor venetoclax (VEN) is effective in older patients with untreated acute myeloid leukemia (AML). Few reports exist on the use of VEN as a bridging therapy for allogeneic hematopoietic cell transplantation (HCT) for AML. Previous studies have shown that NPM1 and IDH2 gene mutations are associated with high response rates to VEN therapy. We performed a retrospective cohort study to analyze the efficacy of VEN-based bridging therapy before HCT. Methods We included 46 patients who were eligible for HCT and received bridging therapy combined with VEN between April 2021 and June 2023 at our center. We evaluated response rates to VEN and HCT outcomes. None of the patients received VEN prior to the study. The response rate to VEN was evaluated using the 2022 European LeukemiaNet (ELN) criteria. We estimated overall survival (OS) using the Kaplan-Meier method, log-rank test, and Gray's test for univariate analysis of cumulative incidence of relapse (CIR) and non-relapse mortality (NRM). We used the Cox proportional hazards model for a multivariate analysis of OS. We extracted DNA from the bone marrow or peripheral blood, and analyzed gene mutations using next-generation sequencing (NGS), targeting 70 genes known to be recurrently mutated in myeloid malignancies. Results Of the 46 patients, 32 had de novo AML, 7 had de novo MDS/AML, 5 had secondary AML, 1 had secondary MDS/AML, and 1 had myeloid sarcoma. The median age was 59 (21-70) years. Nineteen were women and 7 had a history of HCT. The regimens combined with VEN were azacitidine in 39 cases and low-dose cytarabine in 7. According to the 2022 ELN risk classification by genetics at diagnosis, 7 were favorable, 11 were intermediate, and 27 were at adverse risk. Nine patients were in hematological complete remission (CR) / CR with incomplete count recovery (CRi) while 37 were not, when VEN was initiated. The maximum response rates among the patients who started VEN treatment in the non-CR group were: 18 with CR/CRi (49%) and no response in 19 (51%). The median time from the first dose of VEN to HCT was 70 (27-315) days. Forty-one patients underwent HCT and 19 (43%) were in CR/CRi at HCT. The reasons for discontinuation of VEN were HCT in 34 cases, failure in 9, and adverse events in 4 (hematological toxicity in 3 cases and infection in 1). Sixteen patients died due to primary disease (n=9), infection (n=5), thrombotic microangiopathy (n=1), and multi-organ failure (n=1). The median post-HCT observation period of survivors was 156 (25-775) days, and at 1-year after HCT, OS was 49.6% (95% CI: 28.0-67.9), CIR was 40.6% (95% CI: 24.1-56.6) and NRM was 15.2% (95% CI: 5.5-29.5). At 1-year after HCT, outcomes of the patients who were in CR/CRi at HCT was better than that of those who were not (OS, 80.8% vs. 26.4%, p=0.002; CIR, 13.4% vs. 61.8%, p&amp;lt;0.01; NRM, 0% vs. 26.7%, p&amp;lt;0.05). In 35 of the patients who underwent the first HCT, the 1-year OS was 88.9% in those who were in CR and 36.5% in those who were not (p=0.015). Thirty cases were non-CR at the start of the VEN regimen prior to their first HCT. This group had a 1-year OS of 57.8% (95% CI, 27.4-79.3). In 11 patients who achieved CR before HCT and 18 others who did not, the 1-year OS rates were 83.3% and 39.9%, respectively (p=0.10). Genetic analysis was performed by NGS in 37 patients before starting VEN, revealing mutations in TP53 (n=9), RUNX1 (n=7), IDH1 (n=6), ASXL1 (n=6), and DNMT3A (n=6) (Fig. 1A). Alterations in MDS-related genes (n=20) and kinase-related genes ( KIT, PTPN11, FLT3, KRAS, n=11) were frequent. Among the patients receiving their first HCTs, the 1-year OS was 0% in the group with TP53 mutations, and 63.9% in the wild-type TP53 group (p=0.04). The OS was worse in patients with mutated TP53 or kinase-related genes (n=19) than those without either mutation (n=15) (Fig. 1B, 1-year OS 28.7% vs. 72.9%, p=0.029). A multivariate analysis of OS revealed that patients who were not in CR at HCT (HR, 25.01 [95% CI, 2.406-259.9], p=0.007), those who previously underwent HCT (HR, 36.81 [95% CI, 4.599-294.7], p=0.035), and those with TP53 or kinase-related gene mutations (HR, 6.311 [95% CI, 1.137-350.0], p=0.035) had significantly lower OS rates. There was no significant difference in OS between the different ELN risk categories. Conclusions Non-CR at the time of HCT, a history of HCT, and mutations in TP53 or kinase-related genes were found to be independent poor prognostic factors for OS after VEN-based bridging treatment followed by HCT.

Blinatumomab Therapy for Low Level Minimal Residual Disease Detected By Next-Generation Sequencing in Adult B-Cell Acute Lymphoblastic Leukemia

Introduction: Blinatumomab, a bi-specific T-cell engager, has shown clinical benefit in patients with relapsed-refractory and hematologic complete remission with minimal residual disease (MRD)-positive Acute Lymphoblastic Leukemia (ALL). The BLAST trial (Gökbuget N et al., Blood. 2018) demonstrated improved overall survival (OS) and disease-free survival (DFS) in patients with MRD-positive disease (≥0.1%) who achieved MRD response with Blinatumomab. We sought to evaluate the utility of Blinatumomab in low levels of MRD (&amp;lt;0.1%) using clonoSEQ with a sensitivity of (0.0001%). Methods: Adult (18+) B- ALL patients that underwent treatment for B-cell ALL at Norris Comprehensive Cancer Center (NCCC) between 2016 and 2022 who had residual disease tracked using the Next Generation Sequencing (NGS)-based clonoSEQ assay (Adaptive Biotechnologies, Seattle, WA) were included. Patients who received Blinatumomab for MRD positivity were included only if they had a tracked clonoSEQ sequence within one month before starting treatment. Patients who didn't receive Blinatumomab were included if they had an MRD-positive clonoSEQ report. Those who were relapse/refractory when found to be MRD positive were excluded. Cumulative incidence of relapse (CIR) was evaluated using competing risk regression (Fine-Gray method), with death as a competing outcome. At the same time, OS and DFS were analyzed using Cox proportional hazards model. The start time was set to the date of the MRD report, and patients were censored until the last follow-up. Confounder-adjusted KM curves were calculated using direct standardization. Results: 47 patients were included with a median age at diagnosis of 45 years (range: 21-70). Most were Hispanic (N = 33, 70.2%), and the median follow-up time was 12 months. The 3-year OS, DFS, and CIR were 95.4% (95% CI 89.3-100%), 75.1% (95% CI 60.4-93.5%), and 20.3% (95% CI 7.2-38.0%). Twenty-six patients were treated with Blinatumomab (median two cycles, range 1-9), with most (N= 14, 53.8%) having low levels of MRD (&amp;lt;0.1%). Fourteen patients (53.8%) achieved MRD negativity with a median time to MRD negativity of 3.1 months. There were no relapses or death in patients who achieved MRD negativity in the treated group. However, non-responders with Blinatumomab had one death and two relapses. All patients continued Maintenance therapy after receiving Blinatumomab and did not proceed with the transplant. The patients who received Blinatumomab were more likely to be MRD positive on multiparameter flow cytometry (MFC) (60.0% vs. 28.6%, P = 0.042) but had a similar distribution of patient age, treatment type, and receipt of transplant. Additionally, there was a trend toward increased median percent residual cells on clonoSEQ (0.018% vs. 0.003% P =0.244) and flow (0.02% vs 0% P =0.066) in the Blinatumomab treatment group. On univariate analysis, significant predictors of CIR and DFS were flow percent (DFS: HR = 1.54; 95% CI 1.07-2.23; P = 0.019; CIR: HR = 1.83; 95% CI 1.38-2.41; P&amp;lt;0.001) and clonoSEQ residual cell count(DFS: HR = 1.58; 95% CI 1.04-2.41; P = 0.031, CIR: HR = 1.88; 95% CI 1.18-2.97 P=0.008). When controlling for the number of residual cells on close, patients who received Blinatumomab had significantly better CIR(HR = 0.11; 95% CI 0.02-0.69; P = 0.019) and a trend towards improved DFS(HR = 0.21; 95% CI 0.04-1.28; P = 0.092), but no difference in OS. On subgroup analysis of the 31 patients with low levels of MRD (&amp;lt;0.1%), there was no improvement in DFS for patients who were treated with Blinatumomab (HR = 0.41; 95% CI 0.04-3.91; P = 0.44). Of those with low levels of MRD, only two relapsed, and both did not receive Blinatumomab. Conclusions: In B cell ALL, Blinatumomab may offer a CIR benefit to patients with low levels of MRD as detected on clonoSEQ.

TIM-3 Inhibitor Sabatolimab for Patients with Acute Myeloid Leukemia (AML) with Measurable Residual Disease (MRD) Detected after Allogeneic Stem Cell Transplantation (AlloSCT): Preliminary Findings from the Phase Ib/II Stimulus-AML2 Study

Introduction: AlloSCT is a potentially curative treatment for patients (pts) with AML. However, MRD persistence after transplantation has been identified as a risk factor for relapse. In this regard, the graft-versus-leukemia (GvL) effect is well recognized as one of the leading mechanisms of disease control after transplantation. Sabatolimab is a novel immunotherapy that targets the immuno-myeloid regulator TIM-3 on both immune cells and leukemic blasts, and may have the potential to enhance the GvL effect. STIMULUS-AML2 (NCT04623216) is a Phase Ib/II, open-label, multicenter study of sabatolimab alone or in combination with azacitidine as pre-emptive therapy in pts with AML who are in complete remission (CR) with positive MRD (MRD+) after alloSCT. Here we report preliminary data from the safety run-in of sabatolimab monotherapy at two dose levels (400 mg or 800 mg intravenous [IV] every four weeks [Q4W]). Methods: Eligible pts for the safety run-in were adults (≥18 years [y]) with de novo or secondary AML, who achieved CR post-alloSCT but were MRD+ by local assessment at any time ≥Day (D) 60 after alloSCT (protocol amended from MRD+ D100-365 post alloSCT; March 24, 2022) and ≥2 weeks after immunosuppressive medications had been tapered off. MRD was assessed locally at baseline by polymerase chain reaction (PCR; 12 pts: NPM1 and/or WT1, 8; IDH2, 2; other, 2), multiparameter flow cytometry (MFC; 6 pts), both PCR and MFC (1 pt), and CD34+ chimerism (2 pts). In this safety run-in, adult pts received sabatolimab monotherapy at 400 mg or 800 mg IV on D1 of every 28-day cycle. The primary endpoint was incidence of treatment-emergent dose-limiting toxicity (DLT), including acute graft-vs-host disease (GvHD) and chronic GvHD during the first 2 cycles. Results: A total of21 pts were enrolled in the safety run-in (10 at 400 mg; 11 at 800 mg). Median age was 59 years. At AML diagnosis, across cohorts, 8, 9 and 4 pts had favorable, intermediate, and adverse genetic risk (European LeukemiaNet 2017), respectively. At data cut-off (April 26, 2023), 3 pts were still ongoing in the 400 mg cohort and 7 had discontinued due to disease relapse. At 800 mg, 4 pts were ongoing and 7 had discontinued (5 due to relapse, 1 due to adverse event [AE], 1 due to new therapy) ( Table 1). Across cohorts, there was 1 DLT of grade (G) 3 myocarditis after the first infusion of sabatolimab 800 mg, which recovered/resolved on the same day and sabatolimab was then withdrawn. An overview of safety is shown in Table 2. Any G and G≥3 AEs occurred in 16 (76.2%) and 8 (38.1%) pts, respectively. There were no cases of GvHD or immune-related AEs, 2 cases of G≥3 neutropenia and 1 case of G≥3 thrombocytopenia. G3 neutropenia and G3 thrombocytopenia in the same pt at 400 mg were considered treatment related and the patient later relapsed. At 400 mg, 2 pts experienced serious AEs (SAEs) after the DLT observation period (&amp;gt;3 cycles) and 2 pts at 800 mg had SAEs during the DLT period (G3 myocarditis [1 pt] and disease relapse with central nervous system involvement [1 pt]). There were 5 deaths, all at 400 mg and due to study indication (AML). As a preliminary indicator of efficacy, 7 pts were still on treatment and in CR at data cut-off. At 400 mg, 2 pts and 1 pt had received 14 and 15 cycles of treatment (&amp;gt;1 y), respectively. At 800 mg, 1 pt had received 5, 1 pt 6, and 2 pts 7 cycles. At 400 mg, 7 pts relapsed: 2 pts after cycle 1, 2 pts after cycle 2, 1 pt each after cycles 3, 4 and 7. At 800 mg, 5 pts relapsed: 1 pt after cycle 1, 2 pts after cycle 2, 1 pt after cycle 3 and 1 pt after cycle 5. Conclusions: In adult pts with AML who are in hematological CR with MRD+ after alloSCT, sabatolimab 400 mg and 800 mg monotherapies were well tolerated. Cytopenias occurred at low rates, were generally G1-2 and mostly related to imminent relapse. Importantly, there were no cases of GvHD reported or any immune-related AEs commonly seen with checkpoint inhibitors. Preliminary efficacy was promising with 30% of the pts at 400 mg still in CR after more than 1 y on treatment (available longer-term follow-up &amp;gt;1 y), and data may suggest a delayed onset of relapse. A dose expansion cohort at 800 mg opened for enrollment June 30, 2023. Adults will be randomized to sabatolimab as monotherapy or in combination with azacitidine, and preliminary efficacy on the prevention of hematological relapse will be evaluated. Adolescents (12-17 y) will also be enrolled to evaluate the safety of sabatolimab monotherapy. This study is sponsored by Novartis.

A Completely Oral Regimen Including Oral Etoposide As Cytoreductive Chemotherapy Combined with All Trans Retinoic Acid and Oral Arsenic for Induction Therapy in Patients with High-Risk APL：Comparable to Intravenous Cytoreductive Therapy

Background ：Under the pandemic of coronavirus disease 2019 (COVID-19), in addition to all trans retinoic acid (ATRA) and oral arsenic(RIF), high-risk acute promyelocytic leukemia (APL) patients might lack of the necessity of intravenous cytotoxic chemotherapy infusions timely. Therefore, there is an urgent need for an oral, efficient and safe regimen for high-risk APL. Methods ：We retrospectively analyzed 66 high-risk APL patients from January 2017 to to July 2022, of which 6 (9.1%, 6/66) patients died in the emergency room without treatment within 24 hours of arriving at our hospital (cerebral hemorrhage in 4 cases and multiple organ failure in 2 cases) and were excluded from the final analysis. A total of 60 patients received anti-leukemia treatment: 22 inpatients receiving oral etoposide (VP16) as cytoreductive chemotherapy from February 2020 to July 2022, and 38 inpatients receiving intravenous cytoreductive chemotherapy as historical control group from January 2017 to December 2019. Results ：The median age of oral VP16 group and the control group were 35 years (21-65) and 34.5 years (16-62) (P=0.75). The median dose of oral VP16 was 1000mg (range, 400 to 1550). Differentiation syndrome occurred in 4 patients (18.2%) without severe forms in oral VP16 group and 7 patients (18.4%) in intravenous cytoreductive group(P=0.98). Except for one patient died of early death during induction therapy in the control group, all 59 evaluable patients (100%) achieved complete hematological remission(CHR) after induction therapy and complete molecular remission (CMR) after consolidation therapy. The median time to CHR and CMR was 36 days (range, 28-55) vs. 35 days (range, 28-52) (P=0.75) and 3 months (range, 1.1-5.5) vs. 3.3 months (range, 0.9-5.8) (P=0.58) in oral VP16 group and the control group, respectively. The median follow-up time was 56.6 months (range,10.3-76.4). Two (9.1%) patients in oral VP16 group and 3 (7.9%) patients in the control group experienced molecular relapse. The 2-year estimated OS and EFS was 100% vs. 94.7%(P=0.37) and 90.9% vs. 89.5%(P=0.88), respectively. Conclusions ：A completely oral, efficient and safe induction regimen including oral VP16 as cytoreductive chemotherapy combined with ATRA and RIF is more convenient to administer for patients with high-risk APL.