MRD-positive Patients Research Articles

Measurable residual disease assessment prior to allogeneic hematopoietic stem cell transplantation in acute myeloid leukemia and myelodysplastic syndromes: a 20-year monocentric study.

Patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) who undergo allogeneic hematopoietic stem-cell transplantation (alloHSCT) can have divergent survival outcomes while all in morphological complete remission (CR). Techniques of measurable residual disease (MRD) have allowed us to refine their prognosis in two categories: MRD-positive and MRD-negative patients. We conducted a monocentric retrospective study (01/2000-12/2020) to assess the prognosis of pretransplant MRD status measured by multiparametric flow cytometry (MFC) and molecular biology assessed by PCR. 192 patients were included. The median follow-up period was 77months. Among patients undergoing alloHSCT in CR, overall survival (median-OS: 130.6 vs. 16.0months, P < 0.001), disease-free survival (median-DFS: 109.6 vs. 7.1months, P < 0.001) and cumulative incidence of relapse (12-month CIR: 7.3% vs. 33.7%, P < 0.0001) were significantly different between MRD-negative and MRD-positive patients. Patients with discordant intermethod results had intermediate DFS. MRD-negative patients according to molecular PCR-based techniques, WT1 overexpression and MFC had longer median-DFS, compared to MRD-positive patients (P = 0.001, P < 0.001, P < 0.001, respectively). Looking into subgroups, MRD-positive patients among the ELN2017 adverse-category (P < 0.0001), myeloablative and reduced-intensity conditioning regimens (P < 0.0001, P = 0.005), < 60-year patients (P < 0.001) and AML patients (P < 0.001) were associated with lower DFS. This difference was not found in ≥ 60-year patients (P = 0.27) and MDS patients (P = 0.70). MRD-positive patients within the favorable/intermediate ELN2017 category trended toward lower DFS (P = 0.05). We confirmed that MRD status prior to alloHSCT is a strong prognostic factor for OS, DFS and CIR. Combining MFC and molecular-PCR techniques to assess MRD seems primordial as inter-method discordance can be consequential.

Efficacy and safety of olverembatinib in adult BCR::ABL1-positive ALL with T315I mutation or relapsed/refractory disease.

Third-generation tyrosine kinase inhibitors (TKIs) have much potential for the treatment of BCR::ABL1-positive leukaemia, particularly that harbouring the ABL1 T315I mutation. Olverembatinib (HQP1351), a novel third-generation TKI, has favourable efficacy and safety profiles in chronic myeloid leukaemia. Here, we present the clinical findings from 31 BCR::ABL1-positive acute lymphoblastic leukaemia (ALL) patients who received olverembatinib. Among the 14 patients with overt relapsed/refractory (R/R) disease (including 10 with the T315I mutation), 71.4% achieved an overall response. Of the other 17 patients with minimal residual disease (MRD)-positive ALL (including 14 with the T315I mutation), 60.0% and 47.1% achieved MRD flow negativity and complete molecular remission, respectively. With a median follow-up time of 16.3 months, the median event-free survival and overall survival were 3.9 and 8.3 months respectively, in overt R/R patients, and 11.5 and 18.4 months in MRD-positive patients. Allogeneic haematopoietic stem cell transplantation further improved outcomes among responders. The safety profile was generally manageable. This study suggests that olverembatinib-based therapy is another promising option for BCR::ABL1-positive ALL in addition to ponatinib, especially for patients with MRD-positive disease and a single T315I mutation.

CtDNA-based molecular residual disease and survival in resectable colorectal cancer.

The interim analysis of the CIRCULATE-Japan GALAXY observational study demonstrated the association of circulating tumor DNA (ctDNA)-based molecular residual disease (MRD) detection with recurrence risk and benefit from adjuvant chemotherapy (ACT) in resectable colorectal cancer (CRC). This updated analysis with a 23-month median follow-up, including 2,240 patients with stage II-III colon cancer or stage IV CRC, reinforces the prognostic value of ctDNA positivity during the MRD window with significantly inferior disease-free survival (DFS; hazard ratio (HR): 11.99, P < 0.0001) and overall survival (OS; HR: 9.68, P < 0.0001). In patients who experienced recurrence, ctDNA positivity correlated with shorter OS (HR: 2.71, P < 0.0001). The significantly shorter DFS in MRD-positive patients was consistent across actionable biomarker subsets. Sustained ctDNA clearance in response to ACT was an indicator of favorable DFS and OS compared to transient clearance (24-month DFS: 89.0% versus 3.3%; 24-month OS: 100.0% versus 82.3%). True spontaneous clearance rate with no clinical recurrence was 1.9% (2/105). Overall, our findings provide evidence for the utility of ctDNA monitoring for post-resection recurrence and mortality risk stratification that could be used for guiding adjuvant therapy.

Are measurable residual disease results after consolidation therapy useful in children with acute lymphoblastic leukemia?

Measurable residual disease (MRD) is regularly tested at later timepoints after the end of first consolidation (EOC) in children with acute lymphoblastic leukemia (ALL). The question remains whether this is useful for detecting (molecular) relapse. We investigated the clinical relevance of MRD after EOC in intermediate risk patients treated on DCOG-ALL-10 (n = 271) and DCOG-ALL-9 (n = 122), with MRD <0.05% at EOC. EOC MRD-negative patients (n = 178) had excellent outcomes, irrespective of MRD results at later timepoints; 6-year cumulative incidence of relapse (6-y CIR) of 7.4% (95% CI, 3.9%–12.3%) for those with MRD negativity at all later timepoints compared to 3.8% (95% CI, 0.3%–16.8%) for those with one or more later timepoints being positive (p = 0.51). Patients with positive EOC MRD (n = 91) of whom the subsequent timepoints were MRD negative (n = 43), had comparable good outcomes, 6-y CIR of 7.0% (95% CI, 1.8%–17.2%). In contrast, patients being MRD positive at EOC and MRD positive at one or more subsequent timepoints (n = 48) had a higher risk of relapse, 6-y CIR 29.4% (95% CI, 17.2%–42.8%), p < 0.001. These findings were confirmed in the validation cohort of ALL-9 as well as using the updated EuroMRD guidelines. In EOC MRD-negative patients, subsequent MRD measurements can be abandoned. For EOC MRD-positive patients the subsequent MRD measurement might be informative for further risk stratification.

Survival benefit of adjuvant chemotherapy based on molecular residual disease detection in resected colorectal liver metastases: subgroup analysis from CIRCULATE-Japan GALAXY

The prognostic role of circulating-tumor DNA (ctDNA)-based molecular residual disease (MRD) detection and its utility for postsurgical risk-stratification has been reported in colorectal cancer. In this study, we explored the use of ctDNA-based MRD detection in patients with colorectal liver metastases (CLM), for whom the survival benefit of adjuvant chemotherapy (ACT) after surgical resection remains unclear. Patients with CLM without extrahepatic disease from GALAXY study (UMIN000039205) were included. The disease-free survival (DFS) benefit of ACT was evaluated in MRD-positive and -negative groups after adjusting for age, gender, number and size of liver metastases, RAS status, and previous history of oxaliplatin for primary cancer. ctDNA was detected using a personalized, tumor-informed 16-plex mPCR-NGS assay. ctDNA-based MRD status was evaluated 2 to 10 weeks after curative surgery, before the start of ACT. Among 6,061 patients registered in GALAXY, 190 surgically resected CLM patients without any preoperative chemotherapy were included with a median follow-up of 24 (1-48) months. ctDNA positivity in the MRD window was 32.1% (61/190). ACT was administered to 25.1% (48/190) of patients. In the MRD-positive group, 24-month DFS was higher for patients treated with ACT (33.3% vs. not reached, adjusted HR: 0.07, P <0.0001); whereas no benefit of ACT was seen in the MRD-negative group (24-month DFS: 72.3% vs. 62.2%, adjusted HR: 0.68, P =0.371). Multivariate analysis showed that the size of liver metastases (HR: 3.94, P =0.031) was prognostic of DFS in the MRD-positive group. However, in the MRD-negative group, none of the clinicopathological factors were prognostic of DFS. Our data suggest that ACT may offer notable clinical benefits in MRD-positive patients with CLM. MRD status-based risk-stratification could be potentially incorporated in future clinical trials for CLM.

Blinatumomab in the Therapy of Acute B-Lymphoid Leukemia.

Blinatumomab, a CD19-CD3 bispecific T cell engager (BiTE), has two recombinant single-chain variable fragments that temporarily link CD3+ T cells and CD19+ B cells, leading to the T cell-mediated lysis of neoplastic B cells. Improved minimal residual disease (MRD)-negative response rates and long-term overall survival have been observed in B-ALL patients who received this drug. These therapeutic successes have led to FDA approval for refractory/relapsed and MRD-positive B-ALL patients. Furthermore, recent studies in newly diagnosed B-ALL patients have led in Philadelphia chromosome-positive patients to the development of chemotherapy-free regimens based on tyrosine kinase inhibitors plus Blinatumomab and in Philadelphia chromosome-negative patients to improvement in outcomes using chemotherapy regimens that have incorporated Blinatumomab in the consolidation phase of treatment.

Outcome of 421 adult patients with Philadelphia-negative acute lymphoblastic leukemia treated under an intensive program inspired by the GIMEMA LAL1913 clinical trial: a Campus ALL study.

The introduction of pediatric-inspired regimens in adult Philadelphia-negative acute lymphoblastic leukemia (Ph-ALL) has significantly improved patients' prognosis. Within the Campus ALL network we analyzed the outcome of adult Ph-ALL patients treated according to the GIMEMA LAL1913 protocol outside the clinical trial, to compare the real-life data with the study results. We included 421 consecutive patients, with a median age of 42 years. The complete remission (CR) rate after the first course of chemotherapy was 94% and a measurable residual disease (MRD) negativity after the third course was achieved in 72% of patients. The 3-year overall survival (OS) and disease-free survival (DFS) were 67% and 57%, respectively. In a multivariate analysis, MRD positivity negatively influenced DFS. In a time-dependent analysis including only very high risk (VHR) and MRD positive cases, transplanted (HSCT) patients had a significantly better DFS than non-HSCT ones (P=0.0017). During induction, grade ≥2 pegaspargase-related hepato-toxicity was observed in 25% of patients (vs 12% in the GIMEMA LAL1913 trial, P=0.0003). In this large real-life cohort of Ph-ALL, we confirmed the very high CR rate and a superimposable OS and DFS compared to the GIMEMA LAL1913 clinical trial: CR rate after C1 94% vs 85%, P=0.0004; 3-year OS 67% vs 67%, P=0.94; 3-year DFS 57% vs 63%, P=0.17. HSCT confirms its important role in VHR and MRD-positive patients. The rate of pegaspargase-related toxicity was significantly higher in the real-life setting, emphasizing the importance of dose adjustment in the presence of risk factors to avoid excessive toxicity.

Circulating tumor DNA kinetics: A future tool for radiation therapy personalization in lung cancer?

Locally advanced non-small cell lung cancer (NSCLC) is a highly diverse disease in terms of its histology, staging and molecular biology, yet chemoradiation treatment paradigms are currently not individualized for these factors. Circulating tumor DNA (ctDNA) in the plasma has clinical utility for several systemic therapies in advanced NSCLC, before, during and after treatment. However, in radiation oncology, the evidence for ctDNA in locally advanced NSCLC is largely limited to minimal residual disease (MRD) detection after treatment. In one study, all post-treatment MRD-positive patients developed disease relapse, compared with just 7% of ctDNA MRD-negative patients. As chemoradiation causes a bolus of tumor cell death with each treatment fraction, it has been posited that ctDNA levels fluctuate as well on a per-fraction basis. Indeed, four preliminary studies reveal a subgroup of patients with a transient elevation of ctDNA levels after the first radiotherapy fraction, followed by an overall ctDNA drop. To follow-up on these data suggesting an early ctDNA spike during chemoradiation, there is a need for larger and more systematic inter-fraction ctDNA studies, which if successful, could form the basis for more personalized and efficacious radiotherapy treatment paradigms.

Use of Circulating Tumor DNA to Guide Decision-making in Adjuvant Colon Cancer.

The use of circulating tumor DNA (ctDNA) assays to guide clinical decision-making in early-stage colon cancer is an area of rapidly advancing active research. With assays clinically available, clinicians must be informed how to best use this novel tool to treat patients. Recent observational and prospective studies have suggested that ctDNA has potential to guide clinical decision-making in early-stage colon cancer by detecting minimal residual disease (MRD) and predicting recurrence risks. MRD-negative patients may be able to de-escalate or forgo adjuvant chemotherapy (ACT) without compromising disease-free survival or overall survival, while MRD-positive patients may benefit significantly from ACT. Recent and ongoing studies have given reason for optimism about the future of ctDNA as a useful biomarker for clinicians treating early-stage colon cancer. Data thus far are mostly limited to observational studies; inconsistent results highlight the need for caution. As more evidence emerges, ctDNA may become standard of care for colon cancer patients.

Utilization of personalized tumor-specific methylation haplotypes of circulating DNA to monitor minimal residual disease in patients with hepatocellular carcinoma undergoing curative resection.

e16245 Background: Minimal residual disease (MRD) is considered an essential factor leading to early relapse after radical surgery, which is challenging to be detected by conventional imaging. The majority of MRD studies in HCC are based on mutation detection. Simultaneously, in certain cancers such as lung and colorectal cancers, the use of methylation detection for MRD has been demonstrated to possess significant detection capabilities. In this study, we present a personalized methylation haplotype (MHP) method for MRD detection in HCC patients underwent curative resection. Methods: Tumor and paracancerous tissue samples were obtained from HCC patients undergoing surgical resections. WBC and plasma samples (T0) were collected before surgery, while plasma samples (T1) were collected in one month after surgery, and subsequent follow-up plasma samples were obtained every three months. All samples were tested using the GutSeer Panel. A personalized tumor-informed MRD detection approach, named TORNADO (Tumor-infORmed DNAm hAplotype DetectiOn), was then developed. Individual seed MHPs were pinpointed based on their presence in cancer tissue or plasma samples collected before surgery (T0 plasma), excluding those in para-cancer tissue and blood cells. The relapse risk score was determined by assessing the proportion of these MHPs detectable in follow-up evaluations. Results: We enrolled 39 early-stage HCC patients who have undergone surgical resections. All the patients have completed at least one year of regular clinical follow-up. Among them, 13 out of 39 patients (33.3%) were identified as MRD-positive based on predictions from T1. Of the MRD-positive patients, 6 experienced tumor relapse. In contrast, only 7.7% relapses were observed among the remaining 26 MRD-negative patients. When considering the T1 and T2 MRD cumulative risk score, 53.8% (21/39) of patients were classified as MRD-positive, and none of the MRD-negative patients experienced relapse. Regardless of whether based on T1 plasma alone or cumulative results, recurrence-free survival (RFS) was significantly correlated with MRD status. Kaplan-Meier analysis demonstrated that MRD-positive patients had significantly poorer RFS (p-value &lt; 0.05). Cox regression analysis further revealed that MRD status was a significant variable for predicting recurrence-free survival (HR=16.00, 95% CI 2-130, P=0.009). Conclusions: The MRD status detected byTORNADOmethod emerged as a significant prognostic indicator for disease relapse in early-stage HCC patients undergoing curative resection, underscoring the clinical relevance of MHP-based MRD detection guided by tumor information. These discoveries pave the way for the development of effective postoperative cancer surveillance strategies specifically tailored for early-stage liver cancer.

Minimal Residual Disease Status in Multiple Myeloma 1 Year After Autologous Hematopoietic Cell Transplantation and Lenalidomide Maintenance Are Associated With Long-Term Overall Survival.

Prognostic Immunophenotyping in Myeloma Response (PRIMeR) is an ancillary study of minimal residual disease (MRD) assessment for multiple myeloma by next-generation multiparameter flow cytometry (MFC). Patients were enrolled on a three-arm randomized control trial (Blood and Marrow Transplants Clinical Trials Network 0702 Stem Cell Transplant for Myeloma in Combination of Novel Agents [STaMINA]; ClinicalTrials.gov identifier: NCT01109004). Four hundred and thirty-five patients consented to the MRD panel, which included 10 monoclonal antibodies measured via six-color MFC. MRD was measured at baseline/preautologous hematopoietic cell transplant (BL/preAutoHCT), premaintenance (PM), and 1 year (Y1) after AutoHCT with a sensitivity of 10-5 to 10-6. The primary objective was to assess MRD-negative (MRDneg) at 1 year after AutoHCT and progression-free survival and overall survival (PFS/OS). Similar to the STaMINA results, at a median follow-up of 70 months, there was no significant difference in PFS/OS by treatment arm in the PRIMeR patients. MRDneg at all three time points was associated with significantly improved PFS, and MRDneg at Y1 had significantly longer OS. Multivariate analysis of PFS, adjusting for disease risk and treatment arm, demonstrated hazard ratios (HRs) in MRD-positive patients compared with MRDneg patients at BL, PM, and Y1 of 1.55 (P = .0074), 1.83 (P = .0007), and 3.61 (P < .0001), respectively. Corresponding HRs for OS were 1.19 (P = .48), 0.88 (P = .68), and 3.36 (P < .001). Patients with sustained MRDneg or who converted to MRDneg by Y1 had similar PFS/OS. To our knowledge, this first, prospective US cooperative group, multicenter study demonstrates that MRDneg at Y1 after AutoHCT with lenalidomide maintenance is prognostic for improved 6-year PFS and OS. Serial MRD measurements may direct trials to test how further therapy may improve long-term PFS and OS.

Increased Th17 and Treg levels in peripheral blood positively correlate with minimal residual disease in acute myeloid leukaemia.

Immune dysregulation plays a key role in acute myeloid leukemia (AML). We aimed to explore the correlation between T helper cell 17 (Th17) and the regulatory cells (Tregs) in the peripheral blood of patients with newly diagnosed (ND) AML and bone marrow blast cells, as well as minimal residual disease (MRD) before and after treatment. Changes in Th17 and Treg cells in the peripheral blood of 32 patients with ND AML were observed before and after induction chemotherapy with cytarabine for seven days and anthracycline for three days. The levels of inflammatory cytokines were measured using an enzyme-linked immunosorbent assay. Correlation analysis between bone marrow blast cells and Th17 and Treg cell frequencies was performed using the Pearson's correlation test. Frequencies of Th17 and Treg cells and MRD were assessed using flow cytometry. IL-6, IL-10, IL-17A, and GM-CSF levels gradually increased in patients with ND AML and CR and NR patients. The percentages of Th17 and Treg cells positively correlated with those of blast cells. In addition, the frequencies of Th17 and Treg cells in MRD-positive patients were higher than those in MRD-negative patients at the initial induction and after three months of chemotherapy. The frequencies of Tregs and Th17 cells positively correlated with MRD onset. Increased Th17 and Treg cell levels were positively correlated with onset of AML, poor remission, and MRD.

Intensified conditioning regimens with total marrow irradiation/etoposide/cyclophosphamide and busulfan/etoposide/cyclophosphamide overcome the impact of pre-transplant minimal residual disease on outcomes in high-risk acute lymphoblastic leukemia patients in complete remission.

Among high-risk acute lymphoblastic leukemia (ALL) patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT), those with positive minimal residual disease (MRD) are susceptible to poor outcomes. Therefore, it is necessary to determine the most suitable preparatory regimen for these patients. Data were analyzed from 141 patients who received allo-HSCT and were diagnosed with high-risk ALL. These patients underwent intensified conditioning regimens, including either total marrow and lymphoid irradiation (TMLI)-etoposide (VP16)-cyclophosphamide (CY) or busulfan (BU)-VP16-CY between October 2016 and November 2022. A total of 141 individuals were in complete remission (CR) before transplantation and, among all patients, 90 individuals exhibited a negative MRD status and 51 patients had a positive MRD status. In patients who tested negative for MRD, the incidence of relapse within a 2-year timeframe was 25.0% (24.8%-25.5%), compared with 32.2% (31.2%-33.2%) in MRD-positive patients; however, this difference was not statistically significant. There were no significant differences in the 2-year disease-free survival (DFS) and 2-year overall survival (OS) rates between the MRD-negative and MRD-positive groups (DFS: 67.2% (57.9%-78.1%) vs. 55.5% (42.6%-72.3%); OS: 69.0% (61.9%-88.2%) vs. 66.7% (53.9%-82.5%)). Furthermore, no notable variations were observed in the occurrence of transplant-related mortality (TRM) and graft-versus-host disease (GVHD) across the two groups. This study reveals the benefits of TMLI-VP16-CY and BU-VP16-CY conditioning regimens in high-risk ALL patients with CR and MRD-positive status. A large-scale prospective clinical trial is warranted in the future.

Dose-Dense Mini-Hyper-CVD, Inotuzumab Ozogamicin and Blinatumomab Achieves Rapid MRD-Negativity in Philadelphia Chromosome-Negative B-cell Acute Lymphoblastic Leukemia

BackgroundThe combination of low-intensity chemotherapy and inotuzumab ozogamicin (INO), with sequential blinatumomab, is highly effective in older adults with newly diagnosed B-cell acute lymphoblastic leukemia (ALL) and in relapsed or refractory B-cell ALL. Earlier, “dose-dense” administration of blinatumomab could lead to earlier and deeper measurable residual disease (MRD) responses and better outcomes. Patients and MethodsWe performed a retrospective analysis of the safety and efficacy of a dose-dense regimen of mini-hyper-CVD (mini-hyperfractionated cyclophosphamide, vincristine, and dexamethasone alternating with mini-methotrexate and cytarabine), INO, and blinatumomab in patients with B-cell ALL. ResultsTwenty-one patients were treated (frontline, n = 9; MRD consolidation, n = 4; relapsed/refractory, n = 8). In the frontline cohort, all patients achieved CR/CRi and MRD negativity by flow cytometry at the end of cycle 1. Across the frontline and MRD consolidation cohorts, 10/11 patients (91%) achieved next-generation sequencing MRD negativity at a sensitivity of 10−6, including 6/10 evaluable patients (60%) who achieved next-generation sequencing MRD negativity after cycle 1. The CR/CRi rate in the relapsed/refractory cohort was 63%, and all responders achieved MRD negativity by flow cytometry at the end of cycle 1. The 1-year overall survival rate for the combined cohort of the frontline and MRD-positive patients was 83%. No new safety signals were observed with the dose-dense mini-hyper-CVD, INO, and blinatumomab regimen. ConclusionDose-dense delivery of mini-hyper-CVD, INO, and blinatumomab was safe and resulted in rapid and deep MRD negativity in patients with B-cell ALL. This regimen is now being prospectively evaluated in both the frontline and relapsed/refractory settings.

Free from Drug Therapy in Multiple Myeloma (FREEDMM): MRD-Based Cessation of Maintenance

Background. Treatment of newly diagnosed multiple myeloma (NDMM) consists of induction therapy followed by autologous stem cell transplant (ASCT) and indefinite maintenance. Continuous lenalidomide carries both significant clinical and financial toxicity. Minimal residual disease (MRD) has proven to be a powerful surrogate for PFS and OS but is not yet used to guide treatment. We hypothesize that MRD could be used to predict a subset of patients who can safely stop maintenance therapy and enter into a disease surveillance phase. Study Design and Methods. This prospective phase 2 study (NCT 05192122) is designed to stop post-ASCT maintenance therapy once sustained MRD negativity is achieved. MM patients are eligible if they have completed ≥2 years of maintenance therapy post-ASCT, and meet IMWG criteria for ≥ PR. Bone marrow (BM) MRD testing is performed twice, one year apart, using NGS. Sustained MRD-negativity is defined at a threshold of 10 -6, with negative MRD sustained between the Year 1 and Year 2 interval. Patients with sustained MRD negativity and absence of new bony lesions on PET then undergo maintenance therapy cessation. MRD-positive patients are removed from study. In patients who discontinue maintenance, BM testing to re-assess for MRD is repeated yearly for 3 years. At the time of MRD testing, peripheral blood (PB) samples are collected for MALDI-TOF mass spectrometry testing and circulating multiple myeloma cell (CMMC) enumeration. These are done in parallel with MRD assessment. Health-related quality of life (HRQoL) using the EORTC QLQ-MY20 questionnaire is measured before and after maintenance cessation. This study plans to enroll 50 patients to meet the primary objective of assessing sustained MRD-negativity 1 year after maintenance cessation. For all patients, 5-mL PB and BM samples are collected, processed, and kept frozen until analysis. Cellular indexing of transcriptomes and epitopes (CITE-seq) to simultaneously quantify cell surface protein and transcriptome data is used to characterize differences in the immune microenvironment between MRD-negative, MRD-positive, as well as between patients with biochemical and/or clinical progression and patients with MRD-resurgence but biochemically and clinically stable. Preliminary Results. FREEDMM enrollment began December 2021, and 31 patients have been enrolled, 29 of whom have undergone Year 1 BM for MRD assessment. Median follow up of our cohort is 414 (0-577) days. The median age is 69.5 (40-78) years, and the majority are either Black (n=9; 29%) or Hispanic (n=11; 35%). 18 (58%) patients had R-ISS 1 or 2, while 2 patients had high risk disease with presence of 17p deletion. The median number of years of maintenance therapy completed prior to Year 1 BM is 3.4 (2-7.9) years. 28 (96.6%) were in CR at time of Year 1 BM. Year 1 MRD results are pending in 13 patients. At Year 1, 11 (68.8 %) of 16 patients were found to be MRD-negative, while 5 (31.3%) patients were found to be MRD-positive with a median of 206 (1-9,748) cells per 10 6 nucleated cells detected. 24 (85%) of 28 patients had a negative MALDI-TOF result at the time of the Year 1 BM. MALDI-TOF results were false negative in 3 MRD-positive patients. PB CMMC samples were concordant with MRD results in all 5 (100%) patients who were tested. There was concordance between MALDI-TOF and CMMC results in 9 (75%) of 12 patients. At year 2, 4 patients continued to be MRD negative, while 1 patient who was previously MRD-negative became MRD positive. At most recent follow-up, 3 (42.9%) of 7 MRD positive patients at Year 1 experienced clinical progression and were removed from the study. 2 (50%) of 4 patients with sustained MRD-negativity have undergone maintenance cessation, with the remaining 2 awaiting confirmation of MRD-negative results. 59 paired PB (n=29) and BM (n=30) samples have been collected for CITE-seq analysis. Pilot CITE-seq experiments captured 10,000-15,000 cells with 33,000-56,000 reads/ cell on one MRD-positive BM and paired PB sample. CITE-seq results for remaining patients will be presented at the conference. Conclusion: This phase 2 trial applies a novel clinical trial design with an adaptive strategy to explore use of MRD testing as a guide to maintenance therapy cessation in MM patients and represents one of the first studies introducing transcriptome analysis of the tumor and immune microenvironment in the maintenance setting. Ongoing results will be reported at the conference.

Cancer Genomic Profiling and Minimal Residual Disease Monitoring By Cell-Free DNA Sequencing in Pediatric Leukemia

Introduction: Cell-free DNA (cfDNA) sequencing has been reported as a promising non-invasive tool for detecting cancer and monitoring treatment response. We sought to evaluate the potential of a cfDNA-based strategy for detecting diverse classes of somatic mutations relevant to pediatric leukemia and cancers. Methods: Plasma samples collected at diagnosis from 135 acute lymphoblastic leukemia (ALL) and 34 acute myeloid leukemia (AML) patients were evaluated, including 114 B-ALL and 21 T-ALL. We also studied diagnostic plasma samples from 38 solid tumor and 19 brain tumor patients, and plasma collected from 12 patients with B-ALL at days 15, 22 and end of induction chemotherapy (EOI). Plasma cfDNA extraction and library preparation were performed with the NucleoSnap cfDNA kit and ThruPLEX Tag-Seq HV kit, respectively. Next-generation sequencing was performed using a capture panel covering 355 pediatric cancer genes (including noncoding regions covering hotspots of structural variation) and 8,103 heterozygous population polymorphisms. We developed analytic approaches for de novo detection of all types of somatic mutations, including focal copy number alterations, rearrangements, and large chromosomal abnormalities. Whole-genome sequencing (WGS) was also performed for 10 cfDNA samples from leukemia. Data were compared with corresponding whole-genome, exome and transcriptome tumor cell sequencing data at diagnosis. Results: At diagnosis, plasma cfDNA yield was higher for leukemias than for solid and brain tumors (median, 142 ng/ml, 7.16 ng/ml, and 7.07 ng/ml, respectively. The average coverages of leukemia cfDNA sequencing were 790X by capture panel post error suppression and 69X by WGS. We found that 100% cases of leukemia at diagnosis had detectable circulating tumor DNA (ctDNA) in plasma cfDNA, and the median ctDNA purity was 77%, comparable to primary tumor purity from diagnostic sequencing. Overall, our panel covered 86% somatic variants present in the tumor samples. Of those covered events, capture-based cfDNA sequencing detected 98% SNVs/indels, 95% focal copy gains/losses, 100% internal tandem duplications, 95% chromosomal translocations, and 99% aneuploidy. In addition, capture-based sequencing identified cfDNA-specific variants such as NRAS/KRAS SNVs and a IKZF1 deletion that were subclonal in plasma cfDNA. Of those uncovered events, 85% were structural variants with their breakpoints in intronic/noncoding regions, and cfDNA WGS identified all somatic events present in the 10 sequenced tumor samples. To detect minimal residual disease (MRD) in B-ALL patients during induction, we increased cfDNA sequencing depth for low VAF events, and the detection limit was 0.4% for SNV/indel and structural variations. Compared to the MRD results from flow cytometry, somatic mutations were detected in 7/8 MRD-positive and 1/4 MRD-negative patients on day 15, 3/4 MRD-positive patients on day 22, and 0/2 MRD-positive patients at EOI. We also sequenced cfDNA from peripheral blood and bone marrow plasma for 2 B-ALL patients on day 0, day 15, and EOI, with comparable ctDNA purity and dynamics observed between the two compartments. In a patient with concurrent ALL and neuroblastoma (NBL) who experienced NBL relapse four months after the primary diagnosis, cfDNA genomic profiling identified ctDNA derived from ALL (52% of total plasma cfDNA), primary NBL (20%), and relapsed NBL (10%), suggesting that genetic variations of multiple tumors could be detected in a single cfDNA sample. Conclusion: Our study has demonstrated the utility of cfDNA sequencing to identify both sequence and structural somatic mutations in childhood acute leukemia. This approach will be useful to monitor disease, as well as providing a non-invasive diagnostic approach.

Decitabine/Cedazuridine (ASTX727) Combined with a Molecularly-Targeted Agent (Venetoclax, Gilteritinib, Ivosidenib, or Enasidenib) As Personalized Maintenance Therapy in Acute Myeloid Leukemia: First Results from a Phase 1b Study

Background: Disease relapse is the major cause of treatment failure and death in acute myeloid leukemia (AML). Currently, oral azacitidine (CC-486) is the only drug approved in the maintenance setting in patients with AML who are unable to complete standard therapy. The ECOG ACRIN E2906 trial suggested an overall survival (OS) benefit with 3-day IV decitabine maintenance. Decitabine/cedazuridine (ASTX727) is an oral formulation of decitabine that achieves systemic exposures as seen with IV decitabine. Multiple small-molecule agents are now available targeting key leukemic drivers (BCL-2, FLT3, and IDH1/IDH2 inhibitors). We developed a multi-arm phase 1b study (NCT05010772) to evaluate an oral maintenance regimen composed of an ASTX727 backbone combined with a molecularly-targeted agent (venetoclax, gilteritinib, ivosidenib, or enasidenib). Methods: Patients ≥ 18 years with AML in first complete remission (CR) or CR with incomplete blood count recovery (CRi) not currently eligible for stem cell transplantation (SCT) and unable/unwilling to complete standard therapy were eligible. Patients having received either intensive induction (at least 2 cycles of therapy based on intermediate to high dose cytarabine) or low-intensity induction (at least 3 cycles based on low-dose cytarabine or a hypomethylating agent) were permitted. Other inclusion criteria were ECOG ≤ 3, adequate hepatic/renal function, absolute neutrophil count &amp;gt; 0.5 x 10 9/L, and platelets &amp;gt; 50 x 10 9/L. Patients were enrolled in one of five arms per physician choice based on molecular profile. Arm A consisted of ASTX727 35/100 mg PO on D1-3. All other arms combined this ASTX727 backbone with either venetoclax 400 mg (adjusted for azoles) PO on D1-5 (arm B), gilteritinib 120 mg PO on D1-28 (arm C), enasidenib 100 mg PO on D1-28 (arm D), or ivosidenib 500 mg PO on D1-28 (arm E). Treatment was administered in 4-week cycles, up to 24 cycles. Each arm initially consisted of a safety lead-in cohort with predetermined dose reductions for dose-limiting toxicity (DLT) per a 3+3 dose de-escalation design. Prophylactic antibiotics, antifungals, and antivirals were encouraged. The primary objective was safety and tolerability. Secondary objectives included relapse-free survival (RFS) and OS. Patients becoming eligible for SCT were taken off study and censored at the time of SCT for time-to-event endpoints. Results: 23 patients, with a median age of 68 years (range 33-83), have been enrolled (3 on arm A, 19 on arm B, and 1 on arm C). 12 (52%) were enrolled following intensive induction and 11 (48%) after low-intensity induction. 16 (70%) had prior venetoclax. Best response at enrollment was CR in 22 (96%) patients and CRi in 1 (4%). 6/22 (27%) patients with available testing were measurable residual disease (MRD)-positive. 2 (9%) patients had antecedent myelodysplastic/myeloproliferative neoplasms and 1 (4%) had therapy-related AML. ELN 2022 risk was favorable in 10 (43%), intermediate in 3 (13%), and adverse in 10 (43%) patients. The most common grade 3/4 adverse events were neutropenia (96%), thrombocytopenia (74%), anemia (39%), lung infection (22%), hypertension (17%), and neutropenic fever (17%). Cycle 2 dose reductions due to myelosuppression occurred in 5/23 (22%) patients. No DLTs were observed. No deaths occurred on protocol. Two patients died in remission from SCT-related complications after going off maintenance. The current median follow-up time is 5.3 months (m). The median number of cycles given is 3 (1-15). Three relapses have occurred to date (1 in arm A, 2 in arm B). The median RFS for the full cohort is not reached (NR, 1-year 71%). The median OS for the full cohort (figure 1A) is NR (1-year 100%). The median RFS for arms A, B, and C are NR (1-year 67%), NR (1-year 84%), and NR, respectively (figure 1B). The median RFS is 14.5 m (1-year 50%) for patients who received intensive induction and NR (1-year 75%) for those who received low-intensity induction. The median RFS for patients who were MRD-negative and MRD-positive at enrollment were NR (6-month 93%) and NR (6-month 75%), respectively (p=0.50). Of the 6 MRD-positive patients, 2 (33%) cleared their MRD while on maintenance (both patients in arm B). Conclusions: A fully oral, targeted maintenance regimen is feasible in AML. Early results show encouraging RFS and OS. Further enrollment and follow-up are required to better assess the safety and efficacy of these regimens.

Dose Escalation of Blinatumomab Is a Better Option for MRD-Positive CR Patients, Results from a Single-Center Real World Study of Blinatumomab for B-Cell Acute Lymphoblastic Leukemia in China

Background：Blinatumomab(Blincyto) is a CD3-CD19 bispecific T-cell engager for treating B-cell acute lymphoblastic leukemia(B-ALL). Blincyto has been available in China since Aug 2021. Standard treatment duration of Blincyto is 28 days(d) per cycle. Due to economic reasons, part of the Chinese patients(pts) received 14d of infusion per cycle. Whether the 14-d regimen impact outcomes remains uncertain. To investigate the efficacy of 14-d regimen, we retrospectively analyzed the data of pts treated with Blincyto in our center. Methods：From Sep 2021 to Jul 2023, all of the B-ALL pts treated with Blincyto in our center were enrolled. Minimal residual disease(MRD) was monitored by 8-color flow cytometry before, d14 and after each cycle of Blincyto. MRDneg was difined as below 10 -4. Different doses of Blincyto were given based on disease burden: relapsed or refractory(R/R) pts were given 9ug, d1-7, 28ug, d8-28/cycle; for complete remission(CR) pts with MRD positive(MRDpos) or MRD negative(MRDneg), the treatment duration varied from 14 to 28d with or without dose escalation per cycle, which was decided by physicians. Ph+ and ph-like pts were recommended to continue tyrosine kinase inhibitors treatment. Intrathecal chemotherapies were given for pts with central nervous system (CNS) involvement. Progression free survival(PFS) was defined as time from treatment initiation until progression, relapse, or death; overall survival(OS) was defined as time from treatment initiation until death. Results: From Sep 2021 to Jul 2023, a total of 45 pts were enrolled(12 R/R, 14 CR MRDpos, 19 CR MRDneg)(Table 1). The median age was 45 year(range, 17~69) and 27(60%) pts were male. In 12 R/R pts(6 ph-, 3 ph-like, 3 ph+), the median disease burden before infusion was 28.9% (range, 6%~92.5%). After 1 cycle of Blincyto, 83.3%(10/12) pts achieved CR/CRi, 90% (9/10) achieved MRDneg. CR rate was 100% in 6 ph- pts, while MRDneg rate was 83.3%(5/6). Among 3 R/R ph-like pts, 2 pts achieved CR(66.7%), both MRDneg(100%). Same results were observed among 3 R/R ph+ pts. The ph+ nonresponder stopped infusion on d9 due to Grade(G) 2 immune effector cell associated neurotoxicity syndrome(ICANS), while the ph-like nonresponder was refractory to induction therapy and failed in subsequent salvages and died. No deaths was observed in other 11 pts. By Jul 2023, the median follow-up time was 8.6 months(m) and the estimated PFS was 13.4m. Among 14 CR MRDpos(5 ph-, 1 ph-like, 8 ph+) pts, the median MRD level was 0.075% (range, 0.01%~3.58%). After 1 cycle of Blincyto infusion, MRDneg was achieved in 92.86% (13/14) pts, except 1 ph+ nonresponder who developed CD19 loss at d14. By Jul 2023, the median follow-up was 6.78m, estimated mPFS was 13.2m. Two pts died(1 Covid-19, 1 CNS involvement). Blincyto was applied in 19 CR MRDneg pts post induction. The median treatment cycle was 1(range, 1-10). With a median follow-up of 4.73 months, PFS and OS were both 100%. In this study, 2 refractory pts and 1 CR MRDpos pt(all ph-) received 14-d regimen. All of them achieved MRDneg(100.0%) after 1 cycle, suggesting that the 14-d cost saving regimen may be feasible. However, MRD-rising was observed just 1 month after response in a refractory pt who developed a CNS relapse after allogeneic transplantation(allo-HSCT). The relatively short MRDneg duration of the pt may due to an insufficient depth of response. Among 14 CR MRDpos pts, the first 4 pts were treated without dose escalation, 75%(3/4) pts achieved MRDneg. The CRS rate was 100%(4/4)(G1-2) and a G3 ICANS(seizure) was observed in the fourth pt. In order to improve tolerance, the regimen was adjusted to apply dose escalation(9μg/d, 3~7d) in all 10 pts afterwards. No more ICANS was observed and the occurrence of CRS decreased to 40%(4/10)(G1-2). The MRDneg rate was 100%. Pts eligible for transplantation all successfully bridged to allo-HSCT after Blincyto treatment(n=24), all of them obtained MRDneg before allo-HSCT. By Jul 2023, the median follow up time was 8.23 months, 3 pts relapsed post allo-HSCT(estimated PFS, 17.3m) and no deaths was observed. Main AEs are listed as Table 1. Conclusion: Blincyto is a safe and effective option for B-ALL pts with different disease burden. For CR MRDpos pts, the 14-d cost saving regimen may be effective but the depth of the response requires further study. Meanwhile, our results suggested that dose escalation may improve tolerance in CR MRDpos pts without impairing efficacy.

A Nationwide Clinical Trial ALL-B12: An Optimized Therapy for Pediatric B-Precursor Acute Lymphoblastic Leukemia with Excellent Overall Survival and Minimal Non-Relapse Mortality: A Report from the Japan Children's Cancer Group

Background: Advancements in treatment have significantly improved therapeutic outcomes for pediatric acute lymphoblastic leukemia (ALL) and relapsed ALL. However, there remains a need for therapies that minimize relapse in high-risk groups and avoid long-term complications. To address this gap. we conducted the nationwide clinical trial ALL-B12, aimed at newly diagnosed B-precursor ALL aged 1-18 years. Methods: ALL-B12 enrolled participants from November 2012 to November 2017. Patients were stratified based on the NCI classification (age and WBC count at diagnosis). Those with NCI-SR and NCI-HR were assigned to the standard risk group (SR) and the intermediate group (IR), respectively. Poor steroid responders and those with high-risk genomic abnormalities were assigned to the high risk group (HR). A treatment regimen, including 4-drug remission induction, early consolidation, HD-MTX-containing intensification, re-induction, and maintenance, was implemented. Anthracycline dose in the induction therapy was reduced in SR patients. In contrast, early consolidation was intensified with L-ASP for a part (randomized) of the IR and the entire HR. Patients classified as CNS3 were treated as high risk, receiving 12 Gy cranial irradiation; prophylactic cranial irradiation was avoided in non-CNS3 groups. Allogeneic hematopoietic cell transplantation (allo-HCT) during the first remission was restricted to those in the very high-risk group with specific genomic abnormalities (e.g., hypodiploid &amp;lt;44 and TCF3-HLF) and residual MRD above 10^-3 at the end of early consolidation. A randomized comparison was carried out within each risk group to identify the optimal treatment. We assessed the effectiveness of intensification with VCR/DEX pulses for the SR, the impact of L-ASP intensification for the IR, and compared block-type treatment and HD-MTX intensified with VCR and L-ASP (HD-MTX/VL) for the HR. The primary outcome measure was the 5-year event-free survival (EFS) rate. Results: In total, 1,936 patients were enrolled, with 1,804 patients receiving protocol treatment after excluding ineligible patients such as those with BCR-ABL1 positivity. The percentage of patients achieving remission at the end of early consolidation was 98.9%. The overall 5-year EFS and OS probability were 85.2% (95%CI 83.5-86.8%) and 94.3% (95%CI 93.1-95.3%), respectively. Only 1.7% of patients underwent allo-HCT during the first remission. The mortality rate during induction was just 0.6%, with non-relapse mortality (NRM) after remission at 0.6%. The overall relapse incidence was 13.2%, and the overall CNS relapse rate was 1.9%. Among patients assigned to risk groups, 1,107 (62.7%) were assigned to the SR, 459 (26.0%) to the IR, and 200 (11.3%) to the HR. The 5yEFS for the SR was 89.9%. The post-randomization EFS rates for those with and without VCR/DEX intensification were 90.7% and 90.1%, respectively, indicating nearly identical survival curves (p = 0.73). The EFS for the IR was 79.7%, but L-ASP intensification was expected to be effective, the EFS for groups with and without ASP intensification was 82.1% and 77.9%, respectively, failing to reach statistical significance (p = 0.31). The EFS for the HR was 75.5%, with overlapping survival curves for block treatment (75.7%) and HD-MTX/VL (74.2%) (p = 0.92). MRD dynamics were associated with prognosis, and early consolidation therapy enhanced by ASP resulted in better MRD clearance. MRD of 10^-4 was associated with poor prognosis at both the end of induction and the end of early consolidation. Conclusion: In our multi-center clinical trial, we observed excellent outcomes in a diverse group of patients nationwide. Using the NCI criteria for stratification, a significant number of patients were categorized into the SR. Additionally, introducing L-ASP during early consolidation decreased the number of MRD-positive patients, which subsequently reduced the subset needing allo-HCT. This strategic adjustment in treatment intensity resulted in both high EFS rates and low NRM. Given the rise of immunotherapy and its promising results for recovery even post-relapse, there's a pressing need to enhance overall outcomes while minimizing non-relapse mortality. We anticipate refining our stratification further and integrating immunotherapy and other innovative treatments into our approach.

Prophylactic or Preemptive Donor-Derived CD19 CAR-T Cell Infusion for Preventing Relapse in High-Risk B-ALL after Allogeneic Hematopoietic Stem Cell Transplantation

Introduction: Relapse remains a significant challenge in the management of high-risk B-cell acute lymphoblastic leukemia (B-ALL) patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Existing post-transplant relapse prevention strategies for high-risk B-ALL patients after transplantation, particularly in cases of Philadelphia chromosome-negative B-ALL, have limitations and suboptimal efficacy. This study aims to evaluate the efficacy and safety profile of prophylactic or preemptive infusion of donor-derived CD19 chimeric antigen receptor T (CAR-T) cells in high-risk B-ALL patients after allo-HSCT. Methods: Between May 2017 and July 2022, high-risk B-ALL patients with minimal residual disease (MRD) positive or MRD negative status after allo-HSCT were enrolled in clinical trials of donor-derived CD19 CAR-T cell therapy (ChiCTR 2000041025 and ChiCTR-ONN-16009862). The primary outcome was the cumulative incidence of relapse (CIR). Secondary outcomes were progression-free survival (PFS), overall survival (OS) and CAR-T cell treatment-related toxicities. Results: A total of 25 high-risk B-ALL patients who received infusion of donor-derived CD19 CAR-T cells after allo-HSCT were enrolled in the CAR-T cell group, including 8 patients with MRD and 17 patients without MRD. A contemporaneous cohort of 43 high-risk B-ALL patients who did not receive CAR-T cell therapy in MRD-positive or MRD-negative status after transplantation was also included as a control group. The median age of patients enrolled in the CAR-T group was 29 years (range: 9-60 years). The median infused CAR-T cell dose was 2.5×10^6/kg (range: 1.0-5.0×10^6/kg), with a median time from transplantation to CAR-T cell treatment of 122 days (range: 45-315 days). The median follow-up duration was 23.6 months (range: 8.3-60.6 months). Of the 25 patients in CAR-T group, eight MRD-positive patients achieved MRD-negative remission after CAR-T cells treatment (Figure1A). The two-year cumulative incidence of relapse in the CAR-T cell group was significantly lower at 4.8% (95% CI: 0.0%-12.6%) compared to the control group's incidence of 26.6% (95% CI: 11.4%-41.8%, P = 0.03，Figure1B). Additionally, the CAR-T cell group exhibited a higher two-year PFS rate [86.3% (95% CI: 71.8%-100%)] compared to the control group [63.5% (95% CI: 48.0%-79.0%), P = 0.04]. However, the two-year OS rates were comparable between the CAR-T cell group [91.0% (95% CI: 79.0%-100%)] and the control group [79.1% (95% CI: 66.0%-92.2%), P = 0.20]. Adverse events were well tolerated, and no patients experienced grade 3-4 cytokine release syndrome or any grade of immune effector cell-associated neurotoxicity syndrome. Hematological cytopenia was the most severe CAR-T cell related toxicity, but the toxicity was manageable, and only three patients experienced acute graft-versus-host disease following CAR-T cell infusion. Conclusions: Prophylactic or preemptive infusion of CAR-T cells after allo-HSCT demonstrated a reduced incidence of relapse and acceptable adverse events in high-risk B-ALL patients. These findings highlight the potential of CAR-T cell therapy as a promising strategy for relapse prevention in high-risk B-ALL patients after allo-HSCT.