Central Nervous System Leukemia Research Articles

Older age, CNS leukaemic involvement and induction tumour lysis increases the risk of methotrexate (MTX)-induced neurotoxicity in childhood acute lymphoblastic leukaemia/lymphoma: Experience from a tertiary care centre in South India.

Methotrexate (MTX), although an indispensable part of contemporary treatment protocols for childhood acute lymphoblastic leukaemia (ALL)/lymphomas (LBL) in improving outcomes, can lead to serious neurotoxicity with long-term consequences. The aetiopathogenesis, predisposing factors and treatment for MTX-induced neurotoxicity are not yet well defined. The aim of our study was to detect the incidence, risk factors and to assess the overall outcomes of MTX-induced neurotoxicity among large cohort of paediatric ALL/LBL patients treated on a uniform protocol. We conducted retrospective audit of medical records of 622 consecutive children (≤14 years) diagnosed with ALL and LBL between January 2018 and December 2022 and treated on modified BFM-95 protocol at the Department of Pediatric Oncology, Regional Cancer Centre, Thiruvananthapuram. Risk factors predisposing to MTX-induced neurotoxicity were identified using binary logistic regression analysis. Forty-three children were diagnosed with MTX-induced neurotoxicity with an incidence rate of 6.9%. More than two-thirds of them had high-grade MTX-induced neurotoxicity CTCAE v5.0 with a median age of 9 years (range: 9 months to 14 years). Almost half of them developed MTX neurotoxicity during Protocol M followed by Phase-Ib consolidation (15%). Majority of these patients (84%, 36/43) were challenged again with MTX, with 11% (4/36) developing recurrence. Fifteen per cent had persistent neurological deficits at last follow-up. Univariate analysis found older age (age > 5 years) (p < 0.001), T-cell phenotype (p = 0.040), tumour lysis syndrome during induction (p < 0.001), baseline renal problems prior to MTX exposure (p < 0.001) and CNS leukaemic involvement (p < 0.003) to be significantly associated with MTX neurotoxicity. On multivariate analysis, older age (>5 years), tumour lysis during induction and CNS leukaemia retained statistical significance (p < 0.05). Methotrexate-induced neurotoxicity during paediatric acute lymphoblastic leukaemia/lymphoma therapy is a transient phenomenon in majority and re-challenge with MTX is generally safe. Older age children who develop tumour lysis during induction and CNS leukaemic involvement are at increased risk for MTX-induced neurotoxicity during ALL/LBL treatment.

Abstract LB341: Clinical validation and mechanistic insights of ThisCART: A novel allogeneic platform enhancing CAR-T signaling via intracellular TCRαβ/CD3 retention

Abstract Background: Current allogeneic CAR-T cell therapies face challenges with post-infusion expansion and efficacy. In response, we developed ThisCART, a non-genetic editing, allogeneic platform that significantly enhances CAR-T cell expansion and efficacy. This is achieved through a novel approach of intracellular retention of membrane proteins, reducing surface expression of TCRαβ/CD3 complexes and HLA-I molecules. Our lead product, ThisCART19, has demonstrated superior efficacy compared to conventional AutoCART19 in preclinical and early clinical studies for B-ALL. Methods: In the clinical trial NCT04384393, we assessed the safety and efficacy of ThisCART19 in patients with B-cell malignancies. Post-lymphodepletion, participants received infusions of ThisCART19 and AutoCART19, both personalized from the patient's own T cells, in equal proportions. Safety and efficacy were the primary endpoints, evaluated on Day 28 post-infusion and throughout extended follow-up. Mechanistic insights were gained through comprehensive multi-omics studies, including RNAseq, whole-cell proteomics, and phosphoproteomics. Results: ThisCART19 showed enhanced expansion and an improved safety profile in vivo. As of 01 January 2024, Two patients diagnosed as relapse/refractory acute B cell leukemia (R/R B-ALL) were enrolled in the clinical trial. Pt1 is a 55yo male with Ph-positive B-ALL (36% blasts) who relapsed after multiagent chemotherapy and TKIs. Pt2 is a 16yo male with CNS leukemia (78.5% blasts) after multiagent chemotherapy. No DLTs or ICANS were observed. Pt1 experienced Grade 1 CRS that resolved without treatment, and Pt2 experienced Grade 2 CRS that resolved after tocilizumab and corticosteroids. Complete remission with MRD-negative status was achieved by Day 28. Pharmacodynamic analysis indicated a significant expansion of CAR-T cells, predominantly in the CAR+TCR- subset, highlighting autonomous CAR signaling enhancement. Multi-omics analysis identified upregulation in JAK-STAT, PI3K-Akt, and NFKB pathways, suggesting improved cell proliferation, survival, anti-apoptotic activity, and effector function. This molecular profiling provides a mechanistic understanding of ThisCART19A's therapeutic efficacy. Conclusion: The ThisCART platform marks a transformative advancement in allogeneic CAR-T cell therapy. By enhancing CAR signaling autonomously through a unique intracellular retention of TCRαβ/CD3 complexes, ThisCART has shown promising safety and efficacy in early clinical trials. Its potential in reshaping the treatment landscape for hematological and autoimmune disorders positions ThisCART as a crucial development in cellular therapeutics. Citation Format: Jun Li, Lei Xue, Sujun Li, Ling He, Kaichun Liu, Rong Jin, Tao Wang, Yinhang Zhang, Shanshan Chen, Yulian Gao, Dan Liu, Liyun Yang, Xingbing Wang. Clinical validation and mechanistic insights of ThisCART: A novel allogeneic platform enhancing CAR-T signaling via intracellular TCRαβ/CD3 retention [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB341.

CACA guidelines for holistic integrative management of adult acute myeloid leukemia

The CACA Guidelines was summarized by Hematology Oncology Committee of China Anti- Cancer Association. This portion of the CACA Guidelines for adult acute myeloid leukemia (AML) not only focuses on diagnosis, the treatment options for younger (age < 60 years) and older (age ≥ 60 years) patients (including non-APL, APL, R/R AML), but also pay attention to the treatment of AML complications, including central nervous system leukemia (CNSL), cardiotoxicity, agranulocytosis and fever, hepatitis B virus reactivation, uric acid nephropathy, bleeding and coagulation disorders, and nursing for patients with AML from the perspective of holistic integrative medicine to enhance the quality of life and treatment effects.

Clinical Features and Prognosis of Acute T-cell Lymphoblastic Leukemia in Children--Multi-Center Data Analysis in Fujian

To evaluate the efficacy of acute T-cell lymphoblastic leukemia (T-ALL) in children and explore the prognostic risk factors. The clinical data of 127 newly diagnosed children with T-ALL admitted to five hospitals in Fujian province from April 2011 to December 2020 were retrospectively analyzed, and compared with children with newly diagnosed acute precursor B-cell lymphoblastic leukemia (B-ALL) in the same period. Kaplan-Meier analysis was used to evaluate the overall survival (OS) and event-free survival (EFS), and COX proportional hazard regression model was used to evaluate the prognostic factors. Among 116 children with T-ALL who received standard treatment, 78 cases received the Chinese Childhood Leukemia Collaborative Group (CCLG)-ALL 2008 protocol (CCLG-ALL 2008 group), and 38 cases received the China Childhood Cancer Collaborative Group (CCCG)-ALL 2015 protocol (CCCG-ALL 2015 group). The efficacy and serious adverse event (SAE) incidence of the two groups were compared. Proportion of male, age≥10 years old, white blood cell count (WBC)≥50×109/L, central nervous system leukemia, minimal residual disease (MRD)≥1% during induction therapy, and MRD≥0.01% at the end of induction in T-ALL children were significantly higher than those in B-ALL children (P <0.05). The expected 10-year EFS and OS of T-ALL were 59.7% and 66.0%, respectively, which were significantly lower than those of B-ALL (P <0.001). COX analysis showed that WBC≥100×109/L at initial diagnosis and failure to achieve complete remission (CR) after induction were independent risk factors for poor prognosis. Compared with CCLG-ALL 2008 group, CCCG-ALL 2015 group had lower incidence of infection-related SAE (15.8% vs 34.6%, P =0.042), but higher EFS and OS (73.9% vs 57.2%, P EFS=0.090; 86.5% vs 62.3%, P OS=0.023). The prognosis of children with T-ALL is worse than children with B-ALL. WBC≥100×109 /L at initial diagnosis and non-CR after induction (especially mediastinal mass has not disappeared) are the risk factors for poor prognosis. CCCG-ALL 2015 regimen may reduce infection-related SAE and improve efficacy.

Risk of subsequent gliomas and meningiomas among 69,460 5-year survivors of childhood and adolescent cancer in Europe: the PanCareSurFup study

BackgroundChildhood cancer survivors are at risk of subsequent gliomas and meningiomas, but the risks beyond age 40 years are uncertain. We quantified these risks in the largest ever cohort.MethodsUsing data from 69,460 5-year childhood cancer survivors (diagnosed 1940–2008), across Europe, standardized incidence ratios (SIRs) and cumulative incidence were calculated.ResultsIn total, 279 glioma and 761 meningioma were identified. CNS tumour (SIR: 16.2, 95% CI: 13.7, 19.2) and leukaemia (SIR: 11.2, 95% CI: 8.8, 14.2) survivors were at greatest risk of glioma. The SIR for CNS tumour survivors was still 4.3-fold after age 50 (95% CI: 1.9, 9.6), and for leukaemia survivors still 10.2-fold after age 40 (95% CI: 4.9, 21.4). Following cranial radiotherapy (CRT), the cumulative incidence of a glioma in CNS tumour survivors was 2.7%, 3.7% and 5.0% by ages 40, 50 and 60, respectively, whilst for leukaemia this was 1.2% and 1.7% by ages 40 and 50. The cumulative incidence of a meningioma after CRT in CNS tumour survivors doubled from 5.9% to 12.5% between ages 40 and 60, and in leukaemia survivors increased from 5.8% to 10.2% between ages 40 and 50.DiscussionClinicians following up survivors should be aware that the substantial risks of meningioma and glioma following CRT are sustained beyond age 40 and be vigilant for symptoms.

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.

Craniospinal irradiation for CNS leukemia: rates of response and durability of CNS control.

Management of CNS involvement in leukemia may include craniospinal irradiation (CSI), though data on CSI efficacy are limited. We retrospectively reviewed leukemia patients who underwent CSI at our institution between 2009 and 2021 for CNS involvement. CNS local recurrence (CNS-LR), any recurrence, progression-free survival (PFS), CNS PFS, and overall survival (OS) were estimated. Of thirty-nine eligible patients treated with CSI, most were male (59%) and treated as young adults (median 31 years). The median dose was 18Gy to the brain and 12Gy to the spine. Twenty-five (64%) patients received CSI immediately prior to allogeneic hematopoietic cell transplant, of which 21 (84%) underwent total body irradiation conditioning (median 12Gy). Among 15 patients with CSF-positive disease immediately prior to CSI, all 14 assessed patients had pathologic clearance of blasts (CNS-response rate 100%) at a median of 23 days from CSI start. With a median follow-up of 48 months among survivors, 2-year PFS and OS were 32% (95% CI 18-48%) and 43% (95% CI 27-58%), respectively. Only 5 CNS relapses were noted (2-year CNS-LR 14% (95% CI 5-28%)), which occurred either concurrently or after a systemic relapse. Only systemic relapse after CSI was associated with higher risk of CNS-LR on univariate analysis. No grade 3 or higher acute toxicity was seen during CSI. CSI is a well-tolerated and effective treatment option for patients with CNS leukemia. Control of systemic disease after CSI may be important for CNS local control. CNS recurrence may reflect reseeding from the systemic space.

Clinical significance of flow cytometry in detection of minimal residual disease in cerebrospinal fluid.

Central nervous system leukemia (CNSL) is one of the main causes of recurrence and death in patients with acute leukemia. This study aims to dynamically monitor minimal residual disease (MRD) in cerebrospinal fluid and bone marrow of patients with different types of acute leukemia by flow cytometry (FCM), and to compare the timeliness and consistency of MRD detection between the 2 methods to further explore the application value of monitoring MRD in cerebrospinal fluid. A total of 199 patients with acute leukemia admitted to the Guangdong Provincial people's Hospital between October 2018 and January 2022 were retrospectively analyzed, and multiparametric FCM method was adopted to summarize and analyze MRD in cerebrospinal fluid of patients with different types of leukemia and MRD in cerebrospinal fluid and bone marrow specimens of the same patients, and its role in assessing the prognostic value of patients was discussed. Among the 199 acute leukemia cases, a total of 31 cases (15.58%) were positive MRD in the cerebrospinal fluid, of which 18 cases (58%) were detected earlier than the corresponding bone marrow specimens. Among the 19 patients with acute T lymphoblastic leukemia, 134 patients with acute B lymphoblastic leukemia, and 46 patients with acute myeloid leukemia counted, there were 4, 18, and 9 patients with positive MRD in the cerebrospinal fluid. The Kappa value of the concordance test between the results of cerebrospinal fluid MRD and bone marrow MRD in different types of acute leukemia was only 0.156, demonstrating a low concordance between them. Dynamic monitoring of cerebrospinal fluid MRD by FCM can be used as a monitoring index for central nervous system leukemia, and monitoring cerebrospinal fluid can detect MRD earlier compared with bone marrow, which complements each other as a sensitive index for evaluating prognosis with significant guidance in clinic.

Abstract C156: Dasatinib targets an upregulated SRC family kinase gene in extramedullary leukemia, improving prognosis in these patients

Abstract Purpose: To review outcomes of pts with extramedullary leukemic tumors (EMLT) treated with the second-generation tryrosine kinase inhibitor (TKI) dasatinib. Procedures: Reported cases of extramedullary leukemic tumors in patients treated with TKIs were reviewed and survivals elicited from authors. RNA seq and RT-PCR for lymphocyte-specific kinase (LCK) mRNA were performed on cases of EMLT in breast. Summary: Leukemic cells growing as tumors in any organ lead to treatment failure and death, even if marrow is in remission. Median survival of patients with EMLT is 5 months, unchanged for the last 50 years. Like solid cancers, EMLT are invasive and metastatic, showing desmoplastic fibrosis and invasion of adipose tissue. Traditional anti-leukemia chemo has not reliably cured EMLT in any site, but excision of primary tumors followed by adjuvant chemo has achieved remissions of &amp;gt; 20 yrs. This suggests the benefit of removing tumor microenvironment (TME) containing cytokines and immune cells influencing tumor growth and resistance. TME is a logical target to ablate EMLT; TME is not affected by agents that kill replicating leukemia cells. RNAseq of very long-stored samples of EMLT in breast found upregulation of LCK compared to normal breast, confirmed by LCK RT-PCR analysis in 3 of 5 ALL tumors (2 Ph+ALL, 1 B-ALL) and 1 of 8 AML tumors. LCK is a target of DAS, a second-generation TKI that, like first-generation imatinab (IM), effectively controls BCR-ABL+ (Ph+) chronic myeloid leukemia (CML) marrow. However, IM cannot prevent or treat EM relapse, documented in 90 reported cases, mostly in CNS sites, with or without blastic marrow. CNS leukemia can lead to blindness, deafness, and paralysis. Responses to routine CNS therapy with RT and intrathecal or high-dose chemo +/- transplant, occur but lengthy DFS is rare. Since 2004, DAS +/- routine therapy has cleared CNS sites (meninges, brain, optic nerve) for up to 7+ yrs in Ph+ and T lymphoid leukemias. LCK is expressed diffusely in the CNS within neurons and ependymal cells. Tumors in non-CNS sites have also been cleared by DAS +/- routine therapy in pts with CML, Ph+ALL, T-ALL, and Ph+ B lymphoblastic lymphoma. Sites include skin, pancreas, stomach, testis, and epidural space, with DFS up to 9+ yrs. Among 137 of 153 DAS-treated pts with EMLT with followup after response, 23 have had progression in EM sites, while 47 were disease-free for 1 to 10 yrs (29 pts &amp;gt; 2 yrs). Conclusions: DAS appears to be an effective agent for treatment of EMLT. LCK is a potential DAS target in both Ph+ and non-Ph+ hematologic malignancies (HM), as EM tumors occur in leukemias, lymphomas, and myeloma. DAS combined with other therapies may benefit some HM patients and improve survival. Prospective clinical studies are needed to define which patients might benefit from DAS and the role of LCK. Routine scanning by PET/CT should be conducted in HM to find clinically unrecognized EMLT and to document response. Citation Format: Isabel Cunningham, Jianqi Yang, Herbert B Newton, Rory A Fisher. Dasatinib targets an upregulated SRC family kinase gene in extramedullary leukemia, improving prognosis in these patients [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C156.

Clinical characteristics and prognostic factors analysis of core binding factor acute myeloid leukemia in real world.

Chromosomal translocations involving core binding factor (CBF) genes account for 15% of adult acute myeloid leukemia (AML) cases in China. Despite being classified as favorable-risk by European Leukemia Net (ELN), CBF-AML patients have a 40% relapse rate. This study aims to analyze clinical characteristics and prognosis of CBF-AML, compare its subtypes (inv(16) and t(8;21)), and validate prognostic factors. Retrospective analysis of 149 AML patients (75 CBF-AML, 74 non-CBF) at Peking University First Hospital (March 2012-March 2022). CBF-AML patients have significantly lower disease-free survival (DFS) (p = 0.005) and higher non-relapse mortality (NRM) (p = 0.028) compared to non-CBF AML. inv (16) and t(8;21) show distinct co-occurring gene mutation patterns, with inv(16) being prone to central nervous system (CNS) leukemia. Multivariate analysis identifies age as a risk factor for overall survival (OS) and disease free survival (DFS), kinase mutation as a risk factor for DFS and Recurrence, while WT1 mutation as a risk factor for OS and non relapse mortality (NRM) risk in t(8;21) AML. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) improves prognosis in low-risk t(8;21). Prognosis of CBF-AML is poorer than ELN guidelines suggest. inv(16) and (8;21) are separate entities with relatively poor prognoses, requiring rational risk stratification strategies. Allo-HSCT may benefit low-risk t(8;21), but further research is needed for conclusive evidence.

Treatment of Acute Lymphoblastic Leukemia with PDT Regimen Improves the Prognosis of Newly Diagnosed Central Nervous System Leukemia

Objective To investigate whether pediatric-like regimen can improve the prognosis of newly diagnosed acute lymphoblastic leukemia (ALL) complicated with central nervous system leukemia (CNSL) and reduce the occurrence of CNSL during treatment compared with the adult regimen. Methods We collected the clinical data and survival data of 1023 patients with newly diagnosed ALL in the hematology department of Nanfang Hospital from January 2006 to December 2021. The adult regimen cohort included 612 patients (age≥14 years) diagnosed between January 2006 and December 2015, all of whom were treated with the Hyper-CVAD regimen. The pediatric-like regimen cohort included 411 patients diagnosed between January 2016 and December 2021, all of whom were treated with the PDT-ALL-2016 regimen (a GRAALL2003 backbone, pediatric-inspired regimen therapy). Newly dignosed central nervous system leukemia(Ndx CNSL) is defined as the presence of leukemia cells on cytological examination of the cerebrospinal fluid or significant neurological signs. Differences between OS and EFS in Kaplan-Meier curves were determined using the log-rank test in the R package “survival”. Results Among 1023 patients, a total of 59 patients had Ndx CNSL, including 35 patients (5.72%) in the adult regimen cohort and 24 patients (5.84%) in the PDT-ALL-2016 cohort. There were no statistically significant differences in baseline characteristics between the two groups. In the cohort of Ndx CNSL, after a median follow-up of 42.48 months, overall survival (OS) and event-free survival (EFS) of the adult cohort were significantly inferior than the PDT-ALL-2016 cohort (3-year OS, 14.26%vs38.2%, P=0.044; 3-year EFS, 12.42%vs37.1%, P=0.039). During the chemotherapy treatment, CNSL occurred in 69 patients (11.27%) in the adult regimen cohort and 29 patients (7.06%) in the PDT-ALL-2016 cohort, with a significant difference (P=0.032). Conclusion Compared with the adult regimen, the pediatric-like regimen PDT-ALL-2016 improves the prognosis of ALL patients with newly diagnosed CNSL and reduces the occurrence of CNSL during the chemotherapy treatment. This research was supported by the National Natural Science Foundation of China(NFSC82170163, 81970147), Clinical Study of Nanfang Hospital(LC2016ZD009/2019CR012).

CNS Invasion of TCF3::PBX1+ Leukemia Cells Requires Upregulation of AP-1 Signaling As Revealed By Brain Organoid Model

Introduction: Involvement of the central nervous system (CNS) remains a challenge in childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Currently, the investigation of CNS leukemia mechanisms relies heavily on 2D cell culture and mouse models. However, given the differences between human and murine CNS in cellular identity and architecture, it becomes crucial to explore alternative models to study CNS leukemia. Moreover, novel targets for diagnosis and treatment of CNS ALL are critically needed. Methods: In this study, we established a pioneering 3D co-culture model that combines human induced pluripotent stem cell (iPSC)-derived cerebral organoids with BCP-ALL cells. We developed new methods to extract data from our invasion assays by enhancing the visualization of 3D organoid images, enabling us to accurately measure the invasion depth of leukemia cells compared to healthy controls within the organoids relative to their surface. To gain further insights on leukemia cells invading the organoids compared to those in the non-invaded fraction, we conducted RNA sequencing and immunofluorescence staining. Subsequently, we validated these results in a BCP-ALL in vivo mouse model and in patients initially diagnosed with CNS-positive BCP-ALL compared to CNS-negative cases within a cohort of 100 BCP-ALL patients. Results: Our experiments demonstrated robust and deep engraftment of TCF3::PBX1+ leukemia cell lines and patient-derived xenograft (PDX) cells into cerebral organoids (within a 14-day of co-culture). In contrast, the engraftment of healthy human CD34+ hematopoietic stem and progenitor cells (HSPCs) was limited ( p &amp;lt; 0.05) as compared to leukemia cells. Utilizing the co-culture model, we successfully validated the targeting of CNS leukemia-relevant pathways, such as CD79a/Igα or CXCR4-SDF1, via genetic knockdown or blocking experiments using inhibitor, respectively, which reduced the invasion of BCP-ALL cells into the organoids. Of note, RNA sequencing and immunofluorescence staining analysis revealed a significant upregulation of members of the AP-1 transcription factor complex, namely FOS, FOSB, and JUN, in the organoid-invading cells. Furthermore, we found an enrichment of AP-1 pathway genes in PDX cells recovered from the CNS compared to spleen blasts of mice transplanted with TCF3::PBX1+ PDX BCP-ALL cells (n = 5), thereby supporting the critical role of AP-1 signaling in CNS disease (Figure 1A). In line with these findings, we observed significantly higher levels of the AP-1 gene JUN in patients initially diagnosed with CNS-positive BCP-ALL compared to CNS-negative cases (mean JUN expression: 633.4 ± 78.51 in CNS-negative vs 1142 ± 296.5 in CNS-positive) within a cohort of 100 BCP-ALL patients (Figure 1B). Summary: In summary, we present ALL co-culture systems with iPSC-derived cerebral organoids as a promising complementary model to investigate CNS involvement in BCP-ALL including therapeutic targeting approaches, and identified the AP-1 pathway as a marker of CNS disease in TCF3::PBX1+ BCP-ALL.

Incidence and Risk Factors for Central Nervous System Relapse after Allogeneic Hematopoietic Stem Cell Transplantation in Adult Patients with Acute Lymphoblastic Leukemia

Background Acute lymphoblastic leukemia (ALL) is frequently accompanied with the involvement of the central nervous system (CNS). The clinical prognosis for ALL patients with CNS disease is generally unfavorable, and prophylactic measures such as intrathecal chemotherapy are highly recommended. In adult ALL patients, hematopoietic stem cell transplantation (HSCT) presents a potential curative approach. However, there are currently only a few reports available on the risk factors and epidemiology of CNS relapse after HSCT. Method We conducted a retrospective single-center cohort study involving 1043 patients diagnosed with either acute lymphoblastic leukemia (ALL) or mixed phenotype acute leukemia (MPAL). These patients were treated at our center using the same treatment protocol between 2009 and 2022. During the remission induction phase, we utilized a modified hyper-CVAD regimen, along with six rounds of prophylactic intrathecal (IT) chemotherapy. High-risk patients who had suitable donors underwent allogeneic hematopoietic stem cell transplantation (HSCT) as part of their post-remission therapy. Diagnosis of central nervous system (CNS) leukemia was established when neurologic symptoms were observed in correlation with CNS lesions on imaging studies, or when leukemic blasts were detected in the cerebrospinal fluid (CSF). In our study, we examined the incidence, risk factors, and survival outcomes of patients who experienced CNS relapse after transplantation. Results Among the entire cohort of 1043 patients, CNS involvement was observed in 3 (0.3%) patients at initial diagnosis and 12 (1.2%) during chemotherapy. We proceeded with allogeneic hematopoietic stem cell transplantation (allo-HSCT) in 755 consecutive patients. Among these 755 patients, 3 had CNS leukemia prior to transplantation. Among the group of 755 patients, a total of 224 (29.6%) experienced relapse. Of these relapses, 142 (18.8%) were bone marrow relapses alone, 54 (7.1%) were extramedullary relapses alone (with CNS involvement in 21 [38.8%]), and 28 (3.7%) had both bone marrow and extramedullary relapses (with CNS involvement in 13 [46.4%]). Overall, extramedullary relapse was observed in 82 (10.8%) patients, with CNS involvement in 34 (4.5%) cases, following allo-HSCT. The 5-year cumulative incidence of CNS relapse was 4.6%, which was significantly higher in patients with Philadelphia chromosome-positive (Ph-positive) ALL (9.4% vs. 1.0%, p &amp;lt;0.001), as well as those with a high leukocyte count at diagnosis (8.3% vs. 2.6%, p = 0.001). Among the Ph-positive ALL cases, a high leukocyte count (n=151) was associated with a higher prevalence of pre-HSCT minimal residual disease (MRD) &amp;gt; 0.1% (n=88), which exhibited a significantly increased incidence of CNS relapse (16.6% vs. 6.8%, p = 0.009). Factors such as age, number of intrathecal chemotherapy treatments, conditioning intensity, and dose of anti-thymocyte globulin did not have a significant impact. Among the 34 patients with CNS relapse, 21 (61.7%) had isolated CNS relapse, and 7 of them showed evidence of positive MRD. With the exception of one patient who refused further treatment, the remaining 33 patients received initial CNS local therapy, including intrathecal chemotherapy combined with radiotherapy in 27 (82.0%) cases, intrathecal chemotherapy alone in 6 cases, and radiotherapy alone in 4 cases. Out of these patients, 22 were treated with dasatinib or ponatinib, while 6 received salvage chemotherapy. The median overall survival for patients with CNS relapse was 11.2 months, which was 19.8 months for those with isolated CNS relapse and 10.9 months for those with CNS relapse accompanied by bone marrow relapse (p = 0.077). The subsequent 2-year cumulative incidence of CNS relapse was 30%. Conclusion Based on our findings, the current prophylaxis strategy employed for the prevention of post-HSCT CNS relapse in adult ALL appears to be effective. However, our data indicates that MRD-positive Ph-positive ALL requires distinct management due to its significantly elevated risk of CNS relapse. New strategies including prophylactic radiotherapy for this high-risk subgroup must be considered to prevent post-HSCT CNS disease.

Mini-Hyper-CVD Plus Venetoclax for Treatment of Older Adults with Newly Diagnosed Ph-Negative B-ALL or T-ALL

Introduction Treatment of Philadelphia chromosome (Ph)-negative acute lymphoblastic leukemia (ALL) in older patients (pts) is challenging due to poor tolerance of conventional chemotherapy and chemo-resistant disease. Pre-clinical work demonstrates that lymphoblasts are BCL2-dependent and sensitive to the BCL2 inhibitor venetoclax (VEN). We hypothesized that VEN plus dose-reduced hyper-CVD (cyclophosphamide, vincristine, dexamethasone) chemotherapy would be well tolerated and effective in older pts. We previously reported the safety and tolerability of VEN plus hyper-CVD in newly diagnosed and relapsed/refractory (R/R) pts (Jain ASH 2019), with a maximum tolerated dose of VEN 600 mg daily on days 1-21 per 28-day cycle. Preliminarily efficacy was promising in newly diagnosed pts, which prompted study extension to phase (P) 2, enrolling newly diagnosed older pts with Ph-negative (neg) B-ALL and T-ALL. Methods Pts with Ph-neg B-ALL or T-ALL were enrolled in a multi-center Phase Ib/II study (NCT03319901). In P1, both R/R pts and newly diagnosed pts ≥ 60 years (yrs) were enrolled. In P2, only newly diagnosed pts ≥ 55 yrs old or ≥ 50 yrs old with BMI ≥ 35 kg/m2 were enrolled. Pts began with VEN ramp-up (P1 over 7d; P2 over 3d) to target dose (P1: dose level [DL]1 400 mg/d; DL2 600 mg/d; P2 400 mg/d), Figure 1. Hyper-CVD, including central nervous system (CNS) prophylaxis with intrathecal chemotherapy, was then given with VEN per DL for 21/28 days per cycle, for up to 8 cycles. Following completion of hyper-CVD courses, pts received VEN plus POMP maintenance for up to 2 yrs. Pts were recommended to receive fewer than 8 cycles of hyper-CVD in the setting of toxicity or to proceed to allogeneic hematopoietic stem cell transplant (HSCT) per physician discretion. This report updates follow-up of the newly diagnosed pts enrolled in P1 and the P2 cohort. Complete remission (CR) was defined as &amp;lt;5% marrow blasts, no evidence of extramedullary or CNS leukemia, ANC &amp;gt;1.0 K/uL and platelets &amp;gt;100 K/uL. Measurable residual disease (MRD) was evaluated by multicolor flow cytometry (MFC) and negative defined as &amp;lt;0.01%. Survival outcomes are presented via Kaplan Meier. Results In total, 30 newly diagnosed pts [P1 11 (DL1=3; DL2=8); P2 18] were treated with a median age of 68 yrs (range, 57-81 yrs, n=12 [40%] ≥70 yrs); n=15 (50%) women, n=4 (13%) Hispanic, and n=1 (3%) Black. Twenty-three (77%) pts had B-ALL and 7 (23%) pts had T-ALL (6/7 early T-cell precursor). Two (6%) pts had central nervous system (CNS) involvement at diagnosis (1-CNS3, 1-CNS2). High risk genetics were present in 56% (13/23) of B-ALL pts: TP53 (n=9 associated with complex [n=3] or hypodiploid [n=5] karyotype), KMT2A (n=1), IKZF1 abnormality (n=2), and Ph-like (n=1). Eight B-ALL pts had received prior chemotherapy for multiple myeloma (n=6; n=4 auto HSCT, n=5 lenalidomide), diffuse large B-cell lymphoma (n=1, RCHOP), and breast cancer (n=1, docetaxel, carboplatin, trastuzumab). The median number of hyper-CVD cycles received was 4 (range 1-8) among the 27 pts who have completed the hyper-CVD phase of treatment (3 pts are currently receiving consolidation). Mortality within 30 days was 3% (n=1). One patient died in CR due to sepsis during cycle 4. Venetoclax did not impair count recovery: median time from C1 to C2 was 34 days (range 27-47). Dose adjustments of VEN occurred in 4 pts (15%). An MRD-neg CR was achieved in 25/30 (83%) pts. The median cycles to achieve both CR and MRD negativity by MFC was one (range: CR 1-2 cycles; MRD negativity 1-4 cycles). Remaining pts had refractory disease (n=4, 13%), or were not assessed (n=1, 3%) due to early death. Of the 25 pts who achieved CR, 11/25 (44%) received allogeneic HSCT in CR1 after a median of 200 days (range 138 to 347). With a median follow-up of 16.4 months, the estimated 12- and 24-month OS are 82.1% (95% CI 66, 98) and 74.6% (95% CI 54, 95), Figure 2; and RFS are 82.9% (95% CI 65, 100.0) and 67.8% (95% CI 44, 92), respectively. At data cut-off, 22 pts (73%) are alive. Death events (n=8, 27%) were due to early mortality (n=1, related to both ALL and infection), post HSCT complications (n=3), refractory ALL (n=1), relapsed ALL (n=1), sepsis in CR (n=1), and complications of cardiac surgery in CR (n=1). Conclusion In this ongoing study, the addition of VEN to hyper-CVD in newly diagnosed ALL was well tolerated with encouraging responses. A future amendment will incorporate blinatumomab consolidation for pts with B-ALL.

Cerebral Spinal Fluid Attenuates the Efficacy of Methotrexate Against Acute Lymphoblastic Leukemia Cells

The anti-folate methotrexate is a critical component of acute lymphoblastic leukemia (ALL) therapy. In addition to systemic administration, methotrexate is given intrathecally, or directly into the cerebral spinal fluid (CSF) via lumbar puncture, for central nervous system (CNS) leukemia treatment and prophylaxis. While IT methotrexate played a critical role in improving outcomes for ALL, CNS ALL relapse remains a major cause of treatment failure and therapy related morbidity. However, attempts to develop more efficacious and less toxic CNS ALL therapies have been largely unsuccessful and IT methotrexate has remained the standard of care for 60+ years. Based on our prior work showing that ALL cells are more poised to undergo apoptosis in nutrient poor CSF, we initially hypothesized that ALL chemosensitivity will be increased in CSF (Basile et al., 2020). While this was confirmed for several ALL drugs including cytarabine and anthracyclines, we strikingly found that methotrexate was significantly less efficacious and potent against ALL cells in CSF relative to standard tissue culture media or the more physiologically relevant human plasma-like media (HPLM). CSF also attenuated the sensitivity of ALL cells to other anti-folates including raltitrexed, trimetrexate, and pralatrexate. To define the mechanism(s) underlying this methotrexate resistance induced by CSF, we explored previously well-described mechanisms of methotrexate resistance in leukemia and other cancers. However, to date this work suggests that the molecular etiology of this CSF-induced relative methotrexate resistance is not entirely explained by diminished leukemia proliferation in CSF, altered methotrexate cellular influx/efflux, methotrexate metabolism, folate analog rescue, dysregulated expression of methotrexate target proteins, or compensation by nucleotide salvage pathways. To complement our work examining known mechanisms of methotrexate resistance, we also used a more discovery-based approach and compared the gene expression patterns of leukemia cells in CSF versus tissue culture media. Preliminary bioinformatic analyses identified dysregulation of multiple genes involved in the integrated stress response (ISR) and unfolded protein response (UPR) pathways in leukemia cells in CSF. The ISR/UPR are mechanisms by which cells adapt to diverse stress stimuli in the microenvironment, including potentially nutrient poor CSF which is low in glucose, proteins, and lipids relative to plasma. The hallmark event in this pathway is the phosphorylation of the translation initiation factor eIF2α, which inhibits global protein synthesis and enables the translation of selected genes that together enable cell survival. Supporting our gene expression data, ALL cells in CSF showed increased phosphorylation of eIF2α and a decrease in global protein synthesis. Intriguingly, it has been shown that activation of the UPR can divert metabolites from glycolysis to mitochondrial one-carbon metabolism with resulting resistance to anti-folates such as methotrexate (Reich et al., 2020). Accordingly, we next tested the effect of UPR/ISR activation on leukemia cell sensitivity to methotrexate in tissue culture media. Activation of the UPR with thapsigargin, a sarco/endoplasmic reticulum Ca 2+ ATPase (SERCA) inhibitor that triggers ER stress, increased methotrexate resistance in leukemia cells. Similarly, BtdCPU a small-molecule activator of heme regulated inhibitor (HRI) kinase that phosphorylates eIF2α and activates the ISR, also enhanced leukemia resistance to methotrexate. Building upon these results, current investigations are focused on testing the role of UPR/IST activation in methotrexate resistance in leukemia cells in CSF and modulating this pathway to overcome resistance. While methotrexate is clearly an efficacious and critical component of CNS leukemia treatment and prophylaxis, we have shown that CSF attenuates the overall efficacy of methotrexate in targeting leukemia cells. Moreover, we anticipate that our current work defining the mechanisms driving this resistance may identify novel approaches for maximizing methotrexate efficacy and more completely eradicating leukemia cells in CSF and the CNS. Finally, this work highlights the importance of critically evaluating even long-established standards of care.

The Promising Third-Generation TKI Olverembatinib in Adult BCR::ABL1-Positive Acute Lymphoblastic Leukemia with T315I Mutation and Relapsed/Refractory Disease

Background Olverembatinib (HQP1351) is a novel third-generation tyrosine kinase inhibitor (TKI) that has shown remarkable efficacy and safety in chronic myeloid leukemia (CML). Still, few reports are available on BCR::ABL1-positive acute lymphoblastic leukemia (BCR::ABL1+ ALL). We first reported the early encouraging outcome of olverembatinib in BCR::ABL1+ ALL patients (pts) with T315I mutation or disease progression last year. Here, we enlarged the sample size and included a case of CML in lymphoid blast phase (CML-LBP) who also benefited from olverembatinib to a certain extent. Methods In this observational study, we retrospectively enrolled BCR::ABL1+ ALL or CML-LBP pts with T315I mutation, disease progression, or intolerant to previous TKIs in our institution from Dec. 2021 to May 2023. All pts received olverembatinib monotherapy (40mg qod) or combination therapy. Efficacy was assessed by CR rate, MRD negative (MRD &amp;lt;10 -4) rate by multiparameter flow cytometry (MFC), CMR (BCR-ABL1 transcript&amp;lt;10 -5) rate by RT-qPCR, as well as the survival data. PFS and OS were both calculated from the start of olverembatinib. Adverse events (AEs) were assessed and graded according to CTCAE v5.0. Results Totally, 30 pts with BCR::ABL1+ ALL (n=29) or CML-LBP (n=1) were analyzed. Among 29 BCR::ABL1+ ALL pts (median age of 60 years [range, 23-76]), 14 were in CR with molecular R/R disease, including 1 with MRD only detected by RT-qPCR. While the other 15 had hematological R/R disease, including 4 with central nervous system leukemia. T315I mutation was detected in 23 pts, including 8 with additional mutations. The baseline characteristics are detailed in Table 1. As for the 23-year-old female pt with CML-LBP, dasatinib was switched to olverembatinib when T315I, E255K, and E255V mutations were detected. T315I and E255V were eliminated rapidly after 1-month treatment of olverembatinib, while E255K still existed. At present, the patient maintained in CR, and blinatumomab will be used for MRD clearance before allo-HSCT. She was only included in the safety analysis. Among 14 pts with molecular R/R disease, 61.5% and 50% achieved MRD flow negativity and CMR with a median time of 1.3 months (range, 0.8-4.4) and 1.2 months (range, 0.9-4.4), respectively. Among 15 pts with hematological R/R disease, 80%, 53.3%, and 46.7% achieved CR/CRi, MRD flow negativity, and CMR, with a median time of 1 month (range, 0.2-2.5), 1 month (range, 0.2-3.3) and 2.1 months (range, 0.7-4.6), respectively. Totally, 8 pts underwent allo-HSCT with a median age of 48.5 years (range, 23-60), of which 6 pts achieved CMR before allo-HSCT, and all attained persistent CMR after allo-HSCT. By June 15, 2023, with a median follow-up time of 9.1 months (range, 1.7-16) in BCR::ABL1+ ALL pts, the median PFS was 7.8 months, and the median OS was not reached. For molecular R/R pts, the median PFS and OS were not reached, and for hematological R/R pts, the median PFS and OS were 6.5 and 8.6 months. MRD flow negativity or CMR responders had significantly better PFS and OS (PFS: p&amp;lt;0.001, p&amp;lt;0.001; OS: p&amp;lt;0.001, p&amp;lt;0.001), and bridging allo-HSCT after olverembatinib-based therapy showed a significant survival superiority (PFS: p=0.001; OS: p=0.017). Among the 23 pts with T315I mutation, the MRD flow negativity rate in pts with T315I single mutation was significantly higher than those with additional mutations (p=0.008), and the CMR rate tended to be better (p=0.089). Meanwhile, pts with T315I single mutation showed significant improvements in PFS and OS (Figure 1). As for safety analysis, the olverembatinib-based therapy was well-tolerated. Most non-hematological AEs were G1-2, and most G3-4 AEs were hematological, possibly related to chemotherapy. The incidence of G3-4 cardiovascular AEs was 6.7%. Five elderly pts (median age of 72 years [range, 63-76]) had temporary treatment suspension or dose reduction. No permanent discontinuation or death related to olverembatinib was observed. Conclusion This study further confirmed the efficacy of olverembatinib-based therapy in Chinese adults BCR::ABL1+ ALL pts with T315I mutation or R/R disease, especially in those with T315I single mutation. In addition, bridging allo-HSCT after deeper molecular remission could further improve survival. The safety profiles were manageable, but there is still a need to explore the optimal dose in elderly pts.

Olverembatinib(HQP1351)-Based Therapy in Adults with Relapsed or Refractory Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia or Advanced Chronic Myeloid Leukemia: Results of the Real-Life Study

Background Relapsed or refractory (R/R) Philadelphia chromosome positive acute lymphoid leukemia (ALL) and advanced chronic myeloid leukemia (CML) including accelerated phase (AP) and blast phase (BP) usually result in treatment failure due to therapeutic resistance, intolerance, T315I mutations, or compound mutations, with a poor prognosis. Olverembatinib (HQP1351) is a novel third generation BCR-ABL tyrosine kinase inhibitor (3G-TKI), exhibiting a high potency of inhibition on wild and almost all mutated BCR-ABL1 kinases, including the T315I mutation and exhibiting preliminary favorable efficacy and safety profile in clinical trials. Methods In this open label, single-arm, single-center study, patients with advanced Ph+ leukemia (including CML-BP, CML-AP and R/R Ph+ ALL) were enrolled. Patients with severe cardiovascular diseases, arterial occlusion, hypertension, and pulmonary arterial hypertension were excluded . Eligible patient received olverembatinib monotherapy, combined chemotherapy, or combined immunotherapy. The primary endpoints was overall response rate (ORR) at 28 days, including complete remission (CR) and complete remission with incomplete hematological recovery (CRi), in patients with advanced Ph+ leukemia. Results Between Dec 8, 2021, to Jun 1, 2023, a total of 56 patients (Ph+ALL (n=40), CML-BP (n=13) and CML-AP(n=3)) assessed were included and received olverembatinib-based therapy. 34(60.7%) patients were men and 22 (39.3%) were women. The median age was 38 years old (IQR 29-48) and the median duration of follow-up was 8.3 months (IQR 4.6-11.9). BCR::ABL1 transcript was of p210 type in 29 (51.8%), p190 in 27 (48.2%). 13 (23.2%) and 11 (19.6%) patients had received 2 and ≥ 3 prior TKIs, respectively. 17 (30.4%) patients were pretreated with third-generation TKI (ponatinib). Genetic testing revealed mutations in 48 (85.7%) patients including compound mutation in 11 (19.6%%) patients, of whom 8 (72.3%) patients had the T315I mutation. 11 (19.6%) patients had central nervous system leukemia (CNSL) and 1 (1.8%) had extramedullary disease. Of 56 evaluable patients, 48 (85.7%) patients reached CR/CRi. After achieving CR/CRi, 13/48 (27.1%) patients received allogeneic hematopoietic stem cell transplantation (allo-HSCT), 3/48 (6.3%) patients received donor lymphocyte infusion (DLI), and 3/48 (6.3%) patients received chimeric antigen receptor T-cell immunotherapy (CAR-T therapy). During further follow-up, 24 (42.9%) patients achieved BCR::ABL1&amp;lt; 0.1% and 29 (49.2%) achieved BCR::ABL1 &amp;lt; 1%. In additional, probabilities of DFS, EFS and OS at 12 months were 80.3% (95%CI 61.0%-90.7%), 80.2% (95%CI 61.0%-90.7%), 93.3% (95%CI 75.8%-98.3%) in R/R Ph+ALL and 55.4% (95%CI 18.4%-81.4%), 38.6% (95%CI 9.8%-67.6%), 80.0% (95%CI 37.4%-95.1%) in advanced CML, respectively (Fig. 1). Common treatment-related adverse events (TRAEs) included skin hyperpigmentation, proteinuria, Elevated liver enzyme and hypertriglyceridemia (Table 1). Most nonhematologic TRAEs were grade 1/2. Only one patient died from pulmonary embolism. As of the data cutoff date, 37 (66.1%) patients continued on treatment and 19(33.9%) discontinued because of disease progression, intolerance, loss to follow-up or death. Conclusion Olverembatinib-based therapy showed strong efficacy and tolerable toxicity in advanced Ph+ leukemia.

Olverembatinib (HQP1351) Combined with Chemotherapy Is an Effective and Safe Treatment in Patients with Philadelphia Chromosome-Positive (Ph +) Acute Lymphoblastic Leukemia (ALL) and Chronic Myeloid Leukemia in Lymphoid Blast Phase (CML-LBP) That Failed TKI-Based Regimens

Background The prognosis of relapsed or refractory (R/R) Philadelphia Chromosome-Positive (Ph+) acute lymphoblastic leukemia (ALL) and TKI-resistant chronic myeloid leukemia in lymphoid blast phase (CML-LBP) remains poor, with lower rates of complete remission (CR) and shorter durations of response. Olverembatinib is a novel third-generation tyrosine kinase inhibitor (TKI) that has been demonstrated to effectively target a wide range of BCR::ABL1 kinase mutations, especially T315I, in patients with CML in the chronic or accelerated phase resistant to either imatinib or second-generation TKIs. However, data on olverembatinib-based regimens in R/R Ph+ ALL and CML-LBP are limited. Here, we report the efficacy and safety of olverembatinib, combined with chemotherapy, in patients with Ph+ ALL or CML-LBP that failed prior TKI-based therapies. Methods A retrospective study was conducted in adults with Ph + ALL or CML-LBP who failed imatinib- or second-generation TKI-based chemotherapy and subsequently received olverembatinib-based chemotherapy. Per NCCN 2023 guidelines: refractory disease was defined as CR not achieved at the end of induction; relapsed disease, reappearance of blasts in the blood or bone marrow (&amp;gt; 5%) or any extramedullary site after CR; molecular resistance, persistent or rising BCR::ABL1 transcript (&amp;gt; 1-log) by real-time quantitative polymerase chain reaction (RT-qPCR); and complete molecular response (CMR), BCR::ABL1 transcript &amp;lt; 0.01% by RT-qPCR. The primary endpoints of this study were CR rates in R/R patients and CMR rates in molecular-resistant patients. Results From February 2022 to May 2023, 31 patients were included in this study, including 24 (77%) with TKI-based chemotherapy-failed Ph + ALL; 7 (23%) with TKI-resistant CML-LBP; 15 (48%) with R/R disease; and 16 (52%) with molecular-resistant disease. A total of 17 (57%) patients were male, and the median (range; IQR) age was 46 (20-72; 30-64) years. Among 30 patients screened for BCR::ABL1 kinase domain mutations before administration of olverembatinib, 6 (19%) had no mutations; 15 (48%) had T315I; and 9 (29%) had other mutations, including E255K (n = 2), G250E(n = 2), D241E (n = 1), Y253H (n = 1), F317L (n = 1), F359C(n = 1), and Y253Fplus M351T (n = 1). The 15 R/R patients (11, Ph + ALL; 4, CML-BP) received olverembatinib 30 or 40 mg on alternate days combined with VP (vindesine 4 mg once per week for 4 weeks and prednisone 1 mg/kg for 3 weeks and tapered at the fourth). A total of 13 (86%) patients achieved CR after 4-week induction therapy. At a median (IQR) follow-up of 8 (4-13) months, 5 patients received allogeneic transplantation in CR, and were alive in CMR. A total of 8 patients received olverembatinib-based consolidation chemotherapy of either VP (n = 4) or hyper-CVAD (n = 4) after achieving CR. Six patients relapsed, of whom 4 died, and 1 remained in CMR. The 1-year relapse-free survival (RFS) and 1-year survival rates were 52% (95% CI, 21-83) and 68% (95% CI, 37-98), respectively. Among the 16 patients with molecular resistance to TKI-based chemotherapy (imatinib [n = 4]; dasatinib [n = 9]; flumatinib [n = 3]), 2 received olverembatinib monotherapy, 7 olverembatinib plus VP, and 7 hyper-CVAD, of whom 8 received subsequent allogeneic transplantation. At a median (IQR) follow-up of 9 (5-11) months, 1 of the patients receiving olverembatinib monotherapy progressed to hematologic relapse and was switched to CAR T-cell therapy; the other patient did not achieve CMR and underwent transplantation. Of the 14 patients receiving olverembatinib plus chemotherapy, 7 (50%) achieved CMR and 3 (21.4%) progressed to relapse, of whom 1 had hematological relapse and 2 developed central nervous system leukemia (CNSL) with bone marrow remission. A total of 7 patients received allogeneic transplantation, of whom 3 achieved and 4 did not achieve CMR before transplantation. After transplantation, all the 7 patients were in CMR except one who developed CNSL. The 1-year RFS and survival rates were 67% (95% CI, 42-91) and 93% (95% CI, 79-100), respectively. Among all patients, hematologic adverse events were readily manageable. Treatment-related nonhematologic severe adverse events were observed in 3 patients, including (each) stable angina pectoris, severe pneumonia, and fatal Klebsiella sepsis. Conclusions Olverembatinib-based chemotherapy is effective and safe in patients with R/R and molecular resistant Ph + ALL or CML-LBP.

Azacitidine, Venetoclax and Allogeneic NK Cells in Newly Diagnosed Acute Myeloid Leukemia (ADVENT-AML): An Investigator-Initiated Multicenter Phase Ib Trial

BACKGROUND AND SIGNIFICANCE : Older/unfit patients with acute myeloid leukemia (AML) have limited treatment options. Outcomes in adverse-risk subgroups of AML are modest with CR/CRi rates of 45% to 60% and median overall survival (OS) of 5 to 12 months with current standard frontline therapy of hypomethylating agent with venetoclax (HMA-VEN).While allogeneic stem cell transplantation (allo-SCT) can significantly improve OS in AML, only 10 to 20% of older pts are able to undergo allo-SCT (Pratz et al. Blood 2019, Maiti et al. Blood 2022) Natural killer (NK) cells bridge the innate and adaptive immune system and play a major role in graft-vs-leukemia (GVL) effect responsible for the clinical benefit noted with allo-SCT. NK cell-based adoptive cellular therapies have shown good safety profiles and promising activity in AML with responses noted in 25% to 88% of patients. Furthermore, NK cells are less likely to induce graft-versus-host disease (GVHD), severe cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity syndrome (ICANS). We hypothesize that the combination of azacitidine, venetoclax and allogeneic NK cells will be safe and improve cure rates in AML compared to either Aza/Ven or NK cells alone. Improved clinical activity may be mediated through multiple synergistic mechanisms including reduction of disease burden by Aza/Ven, upregulation of epigenetically silenced NKG2D ligands, dual activation of extrinsic and intrinsic apoptotic cascades, mitochondrial priming of leukemia cells by venetoclax, and bypassing significant morbidity and mortality associated allo-SCT. Significance: This will be the first trial to evaluate 1) cellular therapy in the frontline setting in AML; 2) the synergy of venetoclax with adoptive NK cell therapy; and 3) Aza/Ven as a lymphodepletion strategy. The results will have significant impact on the development of cellular therapies for hematological and solid tumors. STUDY DESIGN AND METHODS: This investigator-initiated, multicenter, open-label, phase Ib study will evaluate the combination of azacitidine, venetoclax and ex vivo-expanded, off-the-shelf cryopreserved allogeneic NK cells in patients with AML (NCT05834244). Eligibility criteria: The dose escalation phase will enroll adults with relapsed or refractory AML or MDS/AML, and the dose expansion phase will enroll older/unfit pts with newly diagnosed adverse-risk AML. Eligible Pts will be ≥ 75 years, or ≥ 18 years with at least one protocol-defined comorbidity. Patients with favorable risk AML, poor end-organ function, needing immunosuppression, uncontrolled infection or CNS leukemia will be excluded. Trial design: The dose escalation phase will enroll a maximum of 12 patients at 2 dose levels to establish a recommended phase 2 dose (RP2D) using a BOIN design. The dose expansion will enroll up to 20 patients at the RP2D ( Fig. 1). Study treatment: Patients will receive Aza/Ven as standard. Two dose levels of NK cells including 0.5 x10 9 and 1 x10 9 flat dose on day 8 and 15 of the first 4 cycles will be evaluated. Subsequently, pts will continue Aza/Ven indefinitely. Objectives: The primary objective is to determine the safety of this novel triplet combination in terms of dose-limiting toxicities including acute GVHD, CRS or ICANS. Secondary objectives include overall response rate, CR/CRi by 4 cycles, rate of negative measurable residual disease, OS and relapse-free survival. Exploratory objectives include additional response and survival endpoints, the persistence of NK cells using SNP-NGS chimerism, kinetics of allorejection, remodeling of host immune microenvironment and impact on AML stem/progenitor cell hierarchies using single cell CyTOF to understand response/resistance mechanisms. Status: Trial approved by the FDA and institutional IRB. Activation planned for 2H 2023. Funding: Gateway for Cancer Research, MDACC PRIME Award, Chimeric Therapeutics, NCI Cancer Center Support Grant.

Measurable Residual Disease Results &amp; Survival with Augmented Early Intensification Therapy in Intermediate-Risk &amp; High-Risk Group Pediatric Acute Lymphoblastic Leukemia Patients Treated with ALL IC-BFM 2009 Protocol: A Single-Center Study from India

Introduction Measurable residual disease (MRD) has proven to be one of the most effective disease monitoring responses in ALL. Multiple treatment groups have demonstrated End-of-Induction (day 33) flow MRD of &amp;lt;0.01% has excellent disease-free survival (DFS). Patients with end-of-consolidation MRD of &amp;lt;0.01% has an overall DFS of 75 % as per COG AALL1131 including the very high-risk B-ALL genotypes. We conducted a study to assess the efficacy &amp; toxicity of augmented early intensification therapy (phase IB) in ALL IC-BFM 2009 protocol for intermediate-risk &amp; high-risk group pediatric ALL patients. Objectives To evaluate efficacy of augmented early intensification therapy (phase IB) in ALL IC-BFM 2009 in terms of achievement of day 78 MRD negative status. To determine the event-free survival in intermediate-risk &amp; high-risk group patients. To appraise the adverse events (AEs) of augmented phase IB Induction. Methodology The study enrolled treatment-naïve ALL patients of 1-25 years' age between April 2021 to February 2023 at AIIMS Rishikesh, India. Patients were risk stratified into Standard (SR), Intermediate (IR) &amp; High risk (HR) groups as per ALL IC BFM 2009 protocol. All patients received Augmented phase IB protocol. The regimen comprised of cyclophosphamide (2 doses), four blocks of cytarabine &amp; 6-mercaptopurine, augmented with vincristine (4 doses), and L-Asparaginase (12 doses). Day 78 bone marrow flowcytometric MRD was performed in all patients irrespective of day 33 marrow morphology &amp; MRD. The study defined complete remission as BM blasts &amp;lt;5% with no extramedullary disease and MRD negativity as &amp;lt;0.01%. The AEs was monitored as per NCI-CTCAE v5. As per the study protocol, patients of B-ALL with day 33 MRD &amp;gt;0.01%, ph-positive ALL, hypodiploidy and T-ALL with day 78 MRD &amp;gt; 0.01% was considered as HR &amp; treated with High-risk blocks consolidation followed by transplant or delayed intensification &amp; maintenance. Results A total of 75 patients enrolled in the study. The M: F ratio was 1.6:1. The median age was 8 years (range 1-25 yrs). B &amp; T-ALL constituted 80% &amp; 20% respectively. ph-positivity accounted 22% of B-ALL. The median Lansky performance was 40 &amp; ECOG was 3 among the participants. The median hb, total white counts, and platelets were 5.9 g/dl, 28 x10 9/L and 30 x10 9/L respectively. At diagnosis, 28% of patients had hyperleukocytosis, 15% with bacterial sepsis, 8% with invasive fungal infections, and 8% with CNS leukemia. At baseline, the distribution of patients in SR, IR &amp; HR was 15%, 68% &amp; 17% respectively. The final risk strata at end-of-induction were 8%, 49% &amp; 43% in SR, IR &amp; HR groups. CNS leukemia accounted for 8% of all patients. Of the total evaluable patients, 86% achieved day 8 good steroid response (absolute blasts count &amp;lt;1000/cu.mm), 73% &amp; 38% achieved day 15 marrow M1 response (&amp;lt;5%blasts) and MRD &amp;lt; 0.1%, 97% &amp; 77% achieved day 33 M1 marrow response and day 33 MRD &amp;lt;0.01% respectively. Among the study participants who were MRD positive on day 15, three-fourths (75%) of them accomplished MRD negativity at day 33. Of the 23% patients with day 33 MRD positivity, 80% achieved day 78 MRD negativity of &amp;lt;0.01% with Augmented phase IB with 3 participants being persistent MRD positive. The median follow-up was 24 months and the overall survival was 74%. The mean survival time was 16.7 months (12.7-20.6) for HR &amp; 21.2 months (18.3-24.1) for IR patients. The subgroup analysis demonstrated an overall survival of 80% for SR, 84% for IR &amp; 64% for HR groups. Nevertheless, the proportion of patients in the SR group (8%) was lower compared to the others. The commonest hematological adverse events were hypofibrinogenemia (22%), followed by febrile neutropenia (19%), anemia (19%), and thrombocytopenia (18%) respectively. The commonest non-hematological AEs were peripheral neuropathy (5%) and typhlitis (5%). Conclusion In our single-center experience, the use of augmented early intensification therapy (phase IB) in ALL IC-BFM 2009 protocol in intermediate-risk &amp; high-risk pediatric ALL patients was associated with achievement of day 78 MRD negative status in 80% patients who had day 33 MRD-positivity without significant treatment-related toxicity, and encouraging event-free survival in this patient population.