Central Nervous System Leukemia Research Articles

Virus-mimicking nanodrug active crossing of the blood-brain barrier via transcytosis against central nervous system leukemia

The poor central nervous system leukemia (CNSL) clinical efficacy of conventional doses of chemotherapy is mainly attributed to the limited permeability of chemotherapy agents caused by the blood-brain barrier (BBB). Effectively enhancing the accumulation of drugs across the BBB in the central nervous system is one of the key challenges in improving patient compliance and clinical efficacy of CNSL. Here, we find that the VP1 protein, the functional module of the John Cunningham (JC) virus, can safely penetrate the BBB through a sialic acid receptor-mediated transcytosis mechanism. Based on this, we develop a JC virus-mimicking nanodrug delivery platform based on VP1 protein-conjugated self-assembled nanoparticles (MFHV), which can active target and cross the BBB via a receptor-mediated transcytosis for safe and effective low-dose chemotherapy against CNSL after systemic administration. The results demonstrate that such a platform can penetrate the BBB through the dual mechanism of clathrin-mediated endocytosis and micropinocytosis pathway. When further synergistic with ferroptosis and histamine metabolism, the long-term survivors of low-dose MTX are significantly enhanced by 83.3 % and 56.7 % in two CNSL mice models. Collectively, this study takes a new perspective on natural living materials and molecule targeting of the BBB to present a promising strategy for low-dose chemotherapy against CNSL with safety and efficacy, which might provide a clinically translatable option for the prevention and treatment of CNSL.

Clinical data and MRI features-based nomogram for differentiation of central nervous system infection and central nervous system involvement in hematological malignancy.

Central nervous system leukemia (CNSL) and central nervous system infection (CNSI) are the most important complications in patients with acute leukemia (AL). However, the differential diagnosis could represent a major challenge since the two disorders are all heterogeneous entities with overlapping clinical characteristics and radiological appearances. In this paper, we conduct a retrospective study to develop a model based on clinical data and magnetic resonance imaging (MRI) to distinguish CNSL from CNSI. A total of 108 patients with AL who underwent cranial MRI between January 2020 and December 2023 in our hospital were included. Univariate and multivariate logistic regression analyses were used to determine the independent predictors. A nomogram was developed based on the predictors, and the performance of the nomogram was evaluated by the area under the receiver operating characteristic (ROC) curve. The validation cohort was used to test the predictive model. Hyperleukocytosis at initial diagnosis, marrow state, fever, conscious disturbance, coinfection in other sites and MRI (parenchyma type) were identified as independent factors. A nomogram was constructed and the discrimination was presented as AUC = 0.947 (95% CI 0.9105-0.984). Calibration of the nomogram showed that the predicted probability matched the actual probability well.

Bayesian identification and estimation of radon-related increased hazard rates of cancer death in the updated French cohort of uranium miners (1946-2014).

A recent update of the French cohort of uranium miners added seven years of follow-up data. We use these new data to look for new possible radon-related increased risks and refine the estimation of the potential association between cumulative radon exposure and four cancer sites: lung cancer, kidney cancer, brain and central nervous system (CNS) cancer and leukemia (excluding chronic lymphocytic leukemia, which is not radiation-induced). Several parametric survival models are proposed, fitted and compared under the Bayesian paradigm, to perform new and original exposure-risk analyses. In line with recent UNSCEAR recommendations, we consider time-related effect modifiers and exposure rate as potential effect modifying factors. We use Bayesian model selection criteria to identify radon-related increased hazard rates. Under the assumption of a linear exposure-risk relationship, we found a substantial evidence for a strictly positive effect of cumulative radon exposure on the hazard rate of death by lung cancer among French uranium miners. Given the current available data under the assumptions of a linear or log-linear exposure-risk relationship, it is not possible to conclude in favour of the absence or the existence of a strictly positive effect of chronic exposure to radon on the hazard rate of death by kidney cancer. Regarding death by brain and CNS cancer, there is a substantial evidence for the absence of radon-related effect. Finally, under the assumption of a log-linear exposure-risk relationship, a small positive radon-related effect appears when looking at the risk of death by leukemia (excluding CLL). This study investigates the existence of radon-related increased risk of death by lung cancer, kidney cancer, brain and CNS cancer and leukemia under a Bayesian framework and assumptions of linear and log-linear exposure-risk relationships. If there is no doubt in the interpretation of the results for lung cancer and brain and CNS cancer, the conclusion is less clear-cut in the case of kidney cancer and leukemia (excluding CLL). A future update of the French cohort, increasing the follow-up time for miners, may help to reach a clearer conclusion for these two cancer sites.

Central nervous system complications during treatment in childhood acute leukemia.

Central nervous system (CNS) complications can be seen in patients with leukemia, depending on the disease itself and the chemotherapeutic agents used. This study focused on CNS complications during treatment in children with acute leukemia in a single pediatric institution. CNS complications were evaluated retrospectively in 115 patients with ALL and AML. Patients with CNS leukemia infiltration at the time of diagnosis or during a neurological event, late-onset encephalopathy, peripheral neuropathy, or a previous history of neurological abnormalities were excluded from the study. A total of 115 children's clinical records with acute leukemia over a four-year period were reviewed. Acute CNS complications developed in 23.1% of acute myeloid leukemia (AML) patients and in 13.5% of acute lymphoblastic leukemia (ALL) patients. CNS complications developed most frequently during the induction phase of the treatment (66.7%). Seizures were the most common symptom (9 patients, 50%), followed by hemiparesis (4 patients, 22.2%) and headache (4 patients, 22.2%). Six patients (33.3%) had chemotherapy-induced toxic leukoencephalopathy, two (11.1%) had Wernicke's encephalopathy, and one patient (5.6%) each had sinus vein thrombosis, posterior reversible encephalopathy syndrome, and CNS infection. Sequelae occurred in three patients (16.7%), and only one patient (5.6%) died due to a CNS complication. Awide variety of symptoms can be observed in childhood leukemia, depending on the disease itself, the chemotherapeutic agents used and a lot of other conditions such as nutritional problems. Our research shows that several CNS complications might manifest with similar symptoms; differentiated diagnosis between the underlying etiological reasons can be made by neuroimaging.

A brain organoid/ALL coculture model reveals the AP-1 pathway as critically associated with CNS involvement of BCP-ALL

AbstractCentral nervous system (CNS) involvement remains a clinical hurdle in treating childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL). The disease mechanisms of CNS leukemia are primarily investigated using 2-dimensional cell culture and mouse models. Given the variations in cellular identity and architecture between the human and murine CNS, it becomes imperative to seek complementary models to study CNS leukemia. Here, we present a first-of-its-kind 3-dimensional coculture model combining human brain organoids and BCP-ALL cells. We noticed significantly higher engraftment of BCP-ALL cell lines and patient-derived xenograft (PDX) cells in cerebral organoids than non-ALL cells. To validate translatability between organoid coculture and in vivo murine models, we confirmed that targeting CNS leukemia–relevant pathways such as CD79a/Igα or C-X-C motif chemokine receptor 4–stromal cell-derived factor 1 reduced the invasion of BCP-ALL cells into organoids. RNA sequencing and functional validations of organoid-invading leukemia cells compared with the noninvaded fraction revealed significant upregulation of activator protein 1 (AP-1) transcription factor–complex members in organoid-invading cells. Moreover, we detected a significant enrichment of AP-1 pathway genes in PDX ALL cells recovered from the CNS compared with spleen blasts of mice that had received transplantation with TCF3::PBX1+ PDX cells, substantiating the role of AP-1 signaling in CNS disease. Accordingly, we found significantly higher levels of the AP-1 gene, jun proto-oncogene, in patients initially diagnosed as CNS-positive BCP-ALL compared with CNS-negative cases as well as CNS-relapse vs non–CNS-relapse cases in a cohort of 100 patients with BCP-ALL. Our results suggest CNS organoids as a novel model to investigate CNS involvement and identify the AP-1 pathway as a critical driver of CNS disease in BCP-ALL.

Cytology or Multiparameter Flow Cytometry Positivity in the Cerebrospinal Fluid Before Transplantation is Predictive of Poor Outcomes After Allotransplantation in Acute Myeloid Leukemia Patients.

Central nervous system leukemia (CNSL) remains a serious complication in patients with acute myeloid leukemia (AML) and an ambiguous prognostic factor for those receiving allo-geneic hematopoiesis stem cell transplantation (allo-HSCT). It is unknown whether using more sensitive tools, such as multiparameter flow cytometry (MFC), to detect blasts in the cerebrospinal fluid (CSF) would have an impact on outcome. We retrospectively analyzed the clinical outcomes of 1472 AML patients with or without cytology or MFC positivity in the CSF before transplantation. Abnormal CSF (CSF+) was detected via conventional cytology and MFC in 44 patients at any time after diagnosis. A control group of 175 CSF-normal (CSF-) patients was generated via propensity score matching (PSM) analyses according to sex, age at transplant, and white blood cell count at diagnosis. Compared to those in the CSF-negative group, the conventional cytology positive and MFC+ groups had comparable 8-year nonrelapse mortality (NRM) (4%, 4%, and 6%, p=0.82), higher cumulative incidence of relapse (CIR) (14%, 31%, and 32%, p=0.007), lower leukemia-free survival (LFS) (79%, 63%, and 64%, p=0.024), and overall survival (OS) (83%, 63%, and 68%, p=0.021), with no significant differences between the conventional cytology positive and MFC+ groups. Furthermore, multivariate analysis confirmed that CSF involvement was an independent factor affecting OS and LFS. Our results indicate that pretransplant CSF abnormalities are adverse factors independently affecting OS and LFS after allotransplantation in AML patients.

A first-in-human, phase 1, dose escalation study of SGR-2921 as monotherapy in patients with relapsed/refractory acute myeloid leukemia or myelodysplastic syndrome.

TPS6590 Background: Cell division cycle 7-related protein kinase (CDC7) is a cell cycle kinase that maintains DNA replication by phosphorylation and activation of the minichromosome maintenance protein 2 and 4 (MCMs), components of the replicative DNA helicase. Due to the CDC7's central role in maintaining replication fork integrity, chemical inhibition of CDC7 can ultimately lead to cancer cell death. SGR-2921 is an oral, small molecule inhibitor of CDC7. Preclinical studies demonstrate that SGR-2921 has potent anti-proliferative activity in AML cell lines representative of difficult to treat patient populations, agnostic of serious mutations (including those with p53 mutations), BTK resistance, and multiple prior lines of treatment. This anti-tumor activity has also been demonstrated in cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) AML models. Methods: This is a phase 1, FIH, open-label, single-agent, two-arm, dose escalation study (NCT#05961839) designed to evaluate safety and tolerability and identify the recommended phase 2 dose (RP2D) of SGR-2921 as monotherapy in subjects with relapsed or refractory (R/R) AML, high risk (HR) MDS, or very high risk (VHR) MDS. The study utilizes an accelerated titration design with single patient cohorts that transitions to a 3+3 design once a single Grade 2 event is observed. This is a multicenter global study (US, Spain and France). SGR-2921 will be administered orally, once daily, utilizing a 5-day on and 9-day off dosing schedule over a 28-day cycle. A maximum of 144 patients will be enrolled into dose escalation and exploratory cohorts. To evaluate the effect of CYP3A4 inhibition on SGR-2921 exposure, subjects will be enrolled into one of two staggered, parallel study treatment arms, according to concomitant administration with (Arm B) or without (Arm A) azole antifungals that are strong CYP3A4 inhibitors. A single dose PK run-in will be required for subjects enrolled into the first 3 cohorts of each treatment arm. Subjects will be treated at increasing doses of SGR-2921 until the maximum tolerated dose (MTD) is exceeded. A RP2D will be selected from one of the tolerable dose levels. Key study inclusion criteria include: Age ≥ 18 years of age; Life expectancy ≥ 8 weeks; Confirmed diagnosis of R/R AML or HR and VHR MDS; Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2. Key study exclusion criteria include: Active malignancies not related to AML or MDS within two years prior to the first dose or requiring ongoing treatment; active CNS leukemia; QTcF ≥470 msec. The primary objectives are to evaluate the safety and tolerability of SGR-2921 as monotherapy and to identify the RP2D. Secondary objectives include evaluating SGR-2921 pharmacokinetics and investigating preliminary antitumor activity. Clinical trial information: NCT05961839 .

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.