High Minimal Residual Disease Research Articles

Limited efficacy of 3 + 7 plus gemtuzumab ozogamycin in newly diagnosed fit intermediate genetic risk acute myeloid leukemia patients.

Gemtuzumab-ozogamycin (GO) is approved in combination with high-dose chemotherapy for treatment-naïve low- and intermediate-risk acute myeloid leukemia (AML). In this retrospective real-life multicenter study, we reported efficacy and safety of GO plus high-dose chemotherapy in newly diagnosed AML patients. A total of 31 fit low- and intermediate-risk AML patients treated with GO-based regimens were retrospectively included in this real-life multicenter study, and results were compared with a control cohort treated with 3 + 7 alone. Complete remission (CR) rate after induction was 77%, and most responders (45%) underwent two GO-based consolidation, and minimal residual disease (MRD) negativity was observed in 17 cases (55%) after the end of consolidation. Low genetic risk was associated with increased CR rate compared with intermediate-risk AML (88% vs. 33%; p < .001), as well as prolonged overall survival (OS; hazard ratio, 0.16; 95% confidential interval, 0.02-0.89; p < .001). GO addition resulted in a survival benefit for low-risk AML (median OS not reached vs. 25 months; p = .19) while not for intermediate-risk subjects (10 vs. 13 months; p = .92), compared with the control group. Moreover, GO-treated patients experienced fever of unknown origin or sepsis in 42% or 36% of cases, respectively, with one death during induction due to septic shock, with similar rates compared with the control group (p = .3480 and p = .5297, respectively). No cases of veno-occlusive disease after allogeneic transplantation were observed. Our real-life multicenter study confirmed GO-based treatment efficacy with high MRD negativity rates in fit newly diagnosed AML patients, especially in those with low genetic risk and core binding factor, while limited benefits were observed in intermediate-risk AML. However, further validation on larger prospective cohorts is required.

Relationship between subtype-specific minimal residual disease level and long-term prognosis in children with acute lymphoblastic leukemia.

Minimal residual disease (MRD) based risk stratification criteria for specific genetic subtypes remained unclear in childhood acute lymphoblastic leukemia (ALL). Among 723 children with newly diagnosed ALL treated with the Chinese Children Leukemia Group CCLG-2008 protocol, MRD was assessed at time point 1 (TP1, at the end of induction) and TP2 (before consolidation treatment) and the MRD levels significantly differed in patients with different fusion genes or immunophenotypes (P all < 0.001). Moreover, the prognostic impact of MRD varied by distinct molecular subtypes. We stratified patients in each molecular subtype into two MRD groups based on the results. For patients carrying BCR::ABL1 or KMT2A rearrangements, we classified patients with MRD < 10-2 at both TP1 and TP2 as the low MRD group and the others as the high MRD group. ETV6::RUNX1+ patients with TP1 MRD < 10-3 and TP2 MRD-negative were classified as the low MRD group and the others as the high MRD group. For T-ALL, We defined children with TP1 MRD ≥ 10-3 as the high MRD group and the others as the low MRD group. The 10-year relapse-free survival of low MRD group was significantly better than that of high MRD group. We verified the prognostic impact of the subtype-specific MRD-based stratification in patients treated with the BCH-ALL2003 protocol. In conclusion, the subtype-specific MRD risk stratification may contribute to the precise treatment of childhood ALL.

Prognostic significance of Wilms' tumor gene 1 expression in children with B-cell precursor acute lymphoblastic leukemia.

The prognostic role of Wilms' tumor 1 (WT1) gene expression at diagnosis in children with B cell precursor acute lymphoblastic leukemia (BCP-ALL) is still controversial. We detected the WT1 transcript levels of 533 de novo pediatric BCP-ALL patients using TaqMan-based real-time quantitative PCR and analyzed their clinical features. The WT1 transcript levels differed among the distinct molecularly defined groups, with the highest levels in the KMT2A rearrangements (KMT2A-r) group. According to the results of the X-tile software, all patients were divided into two groups: WT1/ABL ≥ 0.24% (group A) and <0.24% (group B). The proportions of patients whose age was ≥10 years old, with immunophenotype of Pro-B, belonging in high-risk group, or with minimal residual disease (MRD) ≥ 0.01% at week 12 were significantly higher in group A than in group B. In the B-other group, WT1 overexpression was an independent risk factor of overall survival (OS) rate (P = 0.042), and higher MRD ≥ 0.01% at week 12 was associated with lower OS rate (P<0.001) and event-free survival rate (P<0.001). Moreover, the subgroup analysis revealed that, in patients with initial WBC<50 × 109/L or MRD<0.1% at day 33 or MRD<0.01% at week 12 or in the standard-risk group, WT1 overexpression led to a poorer outcome in comparison with those with WT1 downexpression (P<0.05). Therefore, pediatric BCP-ALL with WT1 overexpression had unique clinico-pathological characteristics and poor treatment response. In B-other patients, WT1 overexpression at diagnosis predicted an inferior prognosis. The WT1 gene may serve as a biomarker for monitoring residual disease in the B-other population, especially in children in the standard-risk group.

Endpoint Surrogacy in Chronic Lymphocytic Leukemia: A Pooled Analysis of the German CLL Study Group

Introduction Overall survival (OS) is generally considered the most patient-relevant endpoint in oncology trials, however, its implementation can entail several challenges in the context of chronic lymphocytic leukemia (CLL): 1) The competing survival risk due to comorbidities in the mostly elderly CLL patient population; 2) the high efficacy of targeted therapies warrant longer observation periods or extensive patient recruitment, which can be operationally challenging; 3) the interference with increasingly potent relapse therapies, which can neutralize differences of efficacy of first line regimen. Hence, surrogate endpoints, such as progression-free survival (PFS), overall response or complete response rate (ORR, CR) or minimal residual disease (MRD), are commonly used in CLL research. However, data supporting a correlation between surrogate endpoints and OS in the treatment for CLL is scarce. Here, we present a large, systematic analysis of over 4000 patients (pts) treated in studies of the German CLL Study Group (GCLLSG) to determine the adequacy of surrogate endpoints in clinical trials for pts with CLL. Methods We analysed twelve phase II and phase III trials of the GCLLSG spanning from 1999 to 2022. Only pts receiving first-line therapy were included in the analysis. To determine correlation, the Kaplan-Meier survival function was estimated for both OS and PFS for each study separately. From these functions, the probability of survival (OS and PFS) was estimated at different time points. These pairs of time points were then correlated across the studies, with each pair of probabilities weighted by the number of pts in each corresponding study using Spearman's correlation coefficients. Additionally, we compared OS according to MRD and iwCLL response status at end-of-treatment (for fixed-duration regimens) or end-of-induction-treatment (for MRD-guided treatments) (EO[I]T) using Kaplan-Meier functions calculated from the time point of MRD assessment in peripheral blood. EO(I)T ranged from month 9 to month 15 after treatment initiation, depending on the study protocol. Results The full analysis set comprised 4237 pts. The median observation time was 67 months. Median age was 64 years (range 27 - 90). 45.1% of pts were older than 65 years. 3159 pts (74.6%) had received chemo/chemoimmunotherapy (C/CIT), whereas 1078 (25.4%) were treated with targeted therapies. There were 2114 progressive disease (PD) events and 1211 deaths captured within the trial data. The Spearman's Rho of the estimated survival probabilities for the time points 12/24, 24/36, 36/48 and 60/72 months (PFS/OS) was 0.95, 0.96, 0.94 and 0.92, respectively ( Panel A). Focussing on pts with confirmed OS event (n=1211), the Spearman's Rho between PFS and OS in months was 0.66 for pts receiving chemo/chemoimmunotherapy and 0.88 for pts receiving targeted treatment. ORR and CR rate was 89.8% and 31.5%, respectively. Pts with a CR had a significantly longer PFS (HR 0.38, 95% CI 0.34-0.42, p &amp;lt;0.001) and OS (HR 0.39, 95% CI 0.33- 0.46, p &amp;lt;0.001) compared to pts with non-CR. MRD measurements at the EO(I)T were available for 2521 pts (59.5%), of which 39% were treated with targeted agents. Rates of undetectable (&amp;lt;10 -4), intermediate (≥10 -4 and &amp;lt;10 -2) and high MRD (≥10 -2) were 59.1%, 21.7%, 19.3%, respectively, across treatment groups. The median OS for undetectable and intermediate MRD was not reached and 60.7 months for high MRD status ( Panel B). The estimated 60-month OS was 84.6%, 71.3% and 51.1%, respectively. Accordingly, median PFS for uMRD was 61.8 months and 60-month PFS was 52.6%. In pts ≤65 years of age, median OS was not reached with undetectable or intermediate MRD and 70.5 months in pts with high MRD status. In pts &amp;gt;65 years, median OS was not reached for uMRD and was 75.2 and 58.8 months, respectively, for pts with intermediate or high MRD. The corresponding hazard ratios for high versus uMRD status at EO(I)T were 3.33 (95% CI 2.57 - 4.3) in older and 5.89 (4.15 - 8.35) in younger pts. Conclusion In this large analysis of 12 prospective CLL trials, we found a robust correlation between PFS and OS, thereby supporting the use of PFS as a surrogate endpoint in clinical studies. More importantly, the MRD status at EO(I)T was associated with OS across all treatment modalities, demonstrating its utility in identifying pts with potentially dismal outcomes and providing a rationale for MRD-guided treatment strategies.

Single-Cell Transcriptomics Points to a Role of Stemness and Bone Marrow Niche Interactions in the Poor Response to Induction Therapy in T-Cell Acute Lymphoblastic Leukemia

T-cell acute lymphoblastic leukemia (T-ALL) has a poor prognosis with a 15-20% relapse rate. The induction therapy response is the strongest predictor of relapse and shows great variation between patients. However, whether intra-patient leukemic cell heterogeneity plays a role for the induction therapy response has not yet been investigated. We studied 13 patients with T-ALL (11 pediatric and 2 young adult, median follow-up 37 months). Of these, three were good responders (end of induction (EOI) minimal residual disease (MRD) undetectable/non-quantifiable by flowcytometry and PCR), while ten had a poor response (EOI MRD&amp;gt;0.01%, (range 0.05-97%). Of the ten poor responders, three experienced relapse and one died from resistant disease. Bone marrow samples from diagnosis (n=13) and paired samples from relapse (n=3) or MRD (n=4, MRD &amp;gt;5%) were subjected to combined single-cell RNA sequencing, single-cell surface marker profiling by antibody-derived tag (ADT)-sequencing, and single-cell TCR sequencing, using the 10X Genomics platform. A published healthy bone marrow dataset was used for cell annotation and clear distinction was observed between healthy cell subsets and leukemic blasts. TCR sequencing data revealed a hyperexpanded clone in six patients, with identical clonal sequences at diagnosis and relapse(n=2)/MRD(n=1). Surface marker profiling using a panel of 134 surface antigens showed good correspondence between leukemia-associated immunophenotypes found by ADT-sequencing and by flow cytometry for 16 common clinically used markers. To examine factors associated with a poor therapy response, we compared average gene expression of leukemic cells in poor and good responders at diagnosis using differential gene expression (DGE) and gene set enrichment analysis (GSEA). At diagnosis, poor responders showed upregulation of genes involved in extracellular matrix (ECM) degradation/organization, including the adhesion molecules ITGA5 and PECAM1, and MMP11, while showing downregulation of cell cycle genes. Accordingly, the fraction of cells predicted to be in G0/G1 phase at diagnosis of poor responders positively correlated with EOI MRD (r=0.52, p=0.07, Spearman's rank correlation). To investigate if this high fraction of quiescent cells in poor responders was associated with a more stem-like cell state, we examined the expression of a published hematopoietic stem cell (HSC) signature (Forsberg et al, 2010) that we previously selected for investigation in BCP-ALL (Modvig et al, Molecular Oncology, 2022). Indeed, patients with a poor response had a higher percentage of leukemic blasts with an HSC signature module score above zero (p=0.028, Kolmogorov-Smirnov, distribution in Figure 1), suggestive of stemness as a contributing factor to therapy resistance. To define molecular changes in leukemic blasts during therapy, we compared the leukemic blast gene expression profiles in matched diagnostic and MRD samples using DGE and GSEA. This revealed that the leukemic blasts within the first month of therapy downregulated cell cycle genes, while upregulating chemokine receptors, such as CXCR4. To identify specific genes associated with high MRD, we combined genes upregulated in poor responders (n=314, p&amp;lt;0.01, DGE) with genes associated with EOI MRD levels (n=98, r&amp;gt;0.8 and p&amp;lt;0.001, rank regression). This resulted in a 30-gene signature, comprising several genes previously associated with cancer stem cells, such as MICAL3, ELF4, and NLRP3, and genes encoding proteins involved in cancer drug resistance. These included sialyl transferases, acid ceramidase ( ASAH1) and zyxin ( ZYX). ZYX silencing was previously shown to downregulate the anti-apoptotic protein BCL-2 in leukemia. Accordingly, the percentage of cells with detectable BCL2 expression at diagnosis correlated with EOI MRD (r=0.58, p=0.04), supporting a role of BCL-2 inhibitor therapy in T-ALL. In conclusion, our data suggest that therapy-resistant cells are more stem-like and quiescent at diagnosis, display upregulation of genes involved in bone marrow niche ECM organization and adhesion, and genes related to drug resistance. Likewise, residual leukemic blast following therapy show less proliferation and CXCR4 upregulation. Thus, single-cell transcriptomics provides important molecular insights into therapy-resistant leukemic cells and could comprise a valuable prognostic tool in T-ALL.

Comparison of Venetoclax Based Treatments for Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia

Background: Venetoclax (Ven) is a BCL-2 inhibitor that produces deep responses with high rates of undetectable minimal residual disease (uMRD) for patients (pts) with chronic lymphocytic leukemia (CLL) (Al-Sawaf et al. 2020). Currently, ven is FDA approved as either monotherapy (mono) or in combination (combo) with rituximab (R) In patients with relapsed/refractory (R/R) CLL (Seymour et al. 2018). However, the optimal ven based treatment (tx) for pts with R/R CLL either as mono, or in combo with anti-CD20 monoclonal antibody (mab), or bruton tyrosine kinase inhibitor (BTKi) is uncertain. We performed a single institution retrospective analysis of pts with R/R CLL treated with ven based regimens evaluating efficacy of different ven based txs. Methods: 98 pts with R/R CLL treated between the years of 2012 and 2023 were evaluated. Ven based treatment consisted of ven mono or in combo with R, obinutuzumab (G), or ibrutinib (BTKi) with standard ven dose ramp up to a maximum dose of 400mg daily. R and G were administered per FDA standard dosing. Ibrutinib was administered as 420mg daily, as either fixed or continuous duration tx. Response assessment was performed using iwCLL criteria. Minimal residual disease (MRD) was assessed by multi-parametric peripheral blood flow cytometry with a sensitivity of 10 -4. Time-to-event analyses were performed with the Kaplan-Meier method, with log-rank test used to assess statistically significant differences between variables. Hazard ratios (HR) were calculated by use of Cox proportional modelling. Results: The pts had a median age of 68 years (range; 46-89). Rai stage at time of tx initiation with ven: I 14.2%; II 36.3%; III 8.8%; Stage IV 40.7%. The median number of previous txs was 4 (range; 1-14). Pts harbored the following cytogenetic abnormalities: del(13q) 50.5%; del(11q) 18.5%; trisomy 12 15.5%; normal 15.5%; del(17p)/TP53 mutation 24.7%; and complex in 33%. Seventy percent of pts harbored an unmutated immunoglobulin heavy chain. 25.5% of pts had genomic complexity, with ≥ 5 gene mutations. 43.9% of pts were treated with ven mono; 19.4% were treated with venR; 25.5% of pts were treated with venG; and 11.2% of pts were treated with ven + BTKi. The median number of months of ven based tx was 16.3 (range; 0.9-118.6). 14.3% of pts currently remain on ven. 60.8% of pts had progression after ven based tx; with 62.2% requiring additional tx. 15.3% of pts developed Richter's Transformation. The best overall response for the cohort was: CR 67%; PR 24.5%; SD 1.1%; and PD 7.4%. The best MRD response for the whole cohort was uMRD 76.8%; low MRD 19.5; and high MRD 3.6%. uMRD as best MRD response occurred in 66.7% of ven mono; 82.4% of venR; 86.4% of venG; and 70% of ven + BTKi treated pts. With a median follow-up of 52 months (mo), the median progression-free survival (PFS) for the whole cohort was 67.8 mo. Ven combo had superior PFS to ven mono; median PFS 76.6 vs 58.9 mo (p = 0.04; HR 0.5037; 95% CI 0.2583 - 0.9635). Among the combination treatment approaches, there was a trend for improved PFS for venG compared to ven mono; median PFS not reached (NR) vs 58.9 mo (p = 0.08; HR 0.4385; 95% CI 0.1608 - 1.0240). Similarly, there was also a trend to improved PFS for ven + BTKi compared to ven mono; median PFS NR vs 58.9 mo (p = 0.07; HR 0.2895; 95% CI 0.0462 - 0.9950). Both the presence of del17p/TP53 mutation; and the presence of MRD (+MRD) 12 months after stopping ven based tx were associated with inferior PFS. The median PFS for pts without del17p/TP53 mutation vs with del17p/TP53 mutation was 118 vs 39.7 mo (p &amp;lt; 0.0001; HR 0.2242; 95% CI 0.0533 - 0.8366). Median PFS for pts with uMRD vs +MRD 12 months after ven was NR vs 42.8 mo (p = 0.0001; HR 0.0689; 95% CI 0.0037 - 0.3810). Conclusions : In a high-risk population of pts with R/R CLL, we found that ven based tx leads to durable remissions, with high rates of uMRD. Combo approaches with the addition of either an anti-CD20mab or BTKi led to improved PFS. While venR is the current FDA approved combo regimen for pts with R/R CLL, we found that there was a trend for improved PFS with either venG or ven + BTKi compared to ven mono. Both the presence of a del17p/TP53 mutation and the presence of MRD 12 months after stopping ven based tx significantly adversely affected PFS. However, pts who maintained uMRD 12 months after completing ven, had exceptionally durable long-term remission. This has possible implications for employing MRD adapted txs for pts with CLL.

Crebbp Mutations Are Associated with Slow Minimal Residual Response to Upfront Induction Chemotherapy in Pediatric High-Hyperdiploid B-Cell Precursor Acute Lymphoblastic Leukemia Treated in the AIEOP-BFM ALL 2009 Protocol

Introduction High-hyperdiploidy (HHD) represents the most common cytogenetic abnormality found in B-cell precursor acute lymphoblastic leukemia (B-ALL). Despite the overall good outcome of this entity, up to 15% of patients suffer from disease relapse. Genome-wide ALL studies with next-generation sequencing (NGS) approaches identified a distinct pattern of somatic mutations in HHD ALL, enriched in mutations occurring in genes activating the RAS pathway and in CREBBP gene, especially in relapsed patients. Although several studies have attempted to explore the prognostic significance of these mutations that are potentially susceptible of targeted therapies, their impact in uniformly treated patients with newly diagnosed B-ALL is not well characterized, and there is no consensus on their clinical significance. In this study, we aimed to investigate the frequency of recurrent mutations and to define their prognostic role in the setting of newly diagnosed HHD B-ALL, by using end of induction minimal residual disease (MRD) and event-free survival (EFS). Methods We included 101 consecutive patients, aged between 1-17 years, with newly diagnosed HHD B-ALL and enrolled in the AIEOP-BFM ALL 2009 protocol (NCT01117441). HHD was defined by the presence of a DNA index ≥1.16 and lack of ETV6::RUNX1, BCR::ABL1, KMT2A::AFF1 translocations. Diagnostic leukemia samples of 89 patients were sequenced using a validated clinical NGS panel profiling 39 genes involved in leukemia pathogenesis. Mutations affecting RAS pathway ( NRAS, KRAS, PTPN11, NF1, BRAF) and mutations affecting CREBBP gene were included. In addition, digital multiplex ligation-dependent probe amplification (digital MLPA) analysis for the identification of IKZF1 deletion and IKZF1plus phenotype was evaluable for 67 patients. A Fisher exact test and Wilcoxon rank sum test were used for categorical and continuous variables. MRD was assessed by an IG/TR PCR assay at day +33 of induction (timepoint 1, TP1) and at day +78 (timepoint 2, TP2). EFS was estimated by using Kaplan and Meier method and differences between groups were tested using the log-rank test. Resistance to treatment, relapse, death or second malignant neoplasm were considered as events, whichever occurred first. Results Patients' characteristics according to the presence of studied mutations are shown in Table 1. Mutations affecting RAS pathway and CREBBP occurred in 57.3% and 12.3% of HHD B-ALL patients, respectively. Clonal RAS pathway mutations, defined by variant allele frequency (VAF) ≥25%, were found in 16.8% of cases. Among the 11 patients with mutations of CREBBP, 7 had also a mutation affecting KRAS and the association was significant (p=0.03). Seven patients (10.4%) had deletion of IKZF1, of whom 5 (7.4%) were IKZF1plus. There was no association between any mutations or IKZF1 status and patient presenting characteristics, as including sex, age and WBC counts. MRD was evaluable in 84 patients at the end of induction (TP1). MRD level ≥5x10 -4 was found in 36.4% of patients with CREBBP mutations and in 9.6% of those without, and this association was statistically significant (p=0.02). Additionally, MRD negativity was found in 9.1% and 38.4%, respectively. At TP2, MRD was still detectable in 45.5% of patients with CREBBP mutations compared to 20.6% of those with CREBBP wildtype (p=0.08). Similarly, we observed an association between RAS pathway mutations and MRD at TP1 (p=0.01) with a marked difference in MRD negative patients (21.3% vs 51.4% in patients with and without mutations). No association was observed between MRD level and clonal RAS pathway mutations or IKZF1 status. Despite the association between CREBBP mutations and high MRD at TP1, no significant difference in final high-risk group was found (27.3% vs 11.5%, p=0.17). A total of 8 events were observed, of which 6 were relapses. No impact of any mutations or IKZF1 status in term of 5-years EFS was found in our cohort. Conclusion Our study shows that CREBBP mutations in HHD B-ALL are associated with inferior early response to treatment in terms of MRD level at the end of induction (TP1) but not with worse EFS with our whole current chemotherapy backbone. Therefore, the inclusion of CREBBP mutated patients in very low risk protocols should be carefully evaluated. The validation of these findings is ongoing through the analysis of patients treated by other international study groups adopting different chemotherapy backbones.

A Real-World Single-Center Report on the Effectiveness and Safety of Blinatumomab Treatment on Pediatric Acute Lymphoblastic Leukemia in China

Background: Studies overseas have demonstrated blinatumomab benefits pediatric acute lymphoblastic leukemia (ALL), but the experience is limited in China. Methods: We retrospectively collected 28 pediatric ALL patients in our center who received blinatumomab treatment since August 2021. All patients were diagnosed with B-ALL with CD19 expression on cell surface. Patients were divided into three groups: clearance of minimal residual disease (MRD) in first complete remission (MC, 18/28), supplement therapy during chemotherapy intolerance (IC, 3/28) and reinduction therapy for refractory or relapsed ALL (RR, 7/28). Results: The age of 28 patients (16 males and 12 females) ranged from 0.6 to 16.4 years (median, 11.0 years). BCR::ABL1 fusion was found in 6 patients in MC group and 1 patient in RR group. The reasons for chemotherapy intolerance included pancreatitis, infection, and endocarditis. The median interphase from diagnosis to blinatumomab was 3.7 (range: 0.7 to 39.8) months, 1.4 (range: 1.1 to 16.8) months and 29.0 (range: 4.9 to 62.1) months in MC, IC and RR groups, respectively. Most patients accepted 14 to 28 days of uninterrupted infusion except 1 patient in MC group received 7 days treatment for economic issue and 2 patients in MC group discontinued therapy for severe reaction in 1 or 2 days. 7 patients received 1 to 3 more cycles of blinatumomab if MRD decreased after the first cycle. In MC group, the median MRD level in bone marrow before blinatumomab, detected by flow cytometry (FC) or by real time PCR (RT-PCR) if recurrent fusion genes were positive, was 0.145% (range: 0.01% to 4.00%). MRDs were turned negative in 13 patients (72.2%) by both FC and RT-PCR, while the MRDs in the other 5 patients with BCR::ABL1 fusion gene, of whom 3 were positive in both FC and RT-PCR and 2 were only positive in RT-PCR, wereturned negative in FC but still positive in RT-PCR. In terms of safety, one patient developed grade 4 immune effector cell associated neurotoxicity syndrome on the second day of infusion. The most common reaction was fever in 9 cases in cycle 1 (9/18). In IC group, all 3 patients with negative MRD before treatment maintained their negative status, with only fever occurring (3/3) during the early stage of infusion. In RR group, the median MRD level before treatment was 8.37% (range: 0.08% to 78.3%). 4 patients (57.1%) with lower MRD (0.08% to 8.37%) by FC before blinatumomab attained MRD negativity, while 3 patients (42.9%) with higher MRD (22.64% to 78.3%) failed. The patient with BCR::ABL1 fusion gene turned MRD negative by FC after blinatumomab, but remained positive by RT-PCR. Two patients (2/7) had cytokine release syndrome of grade 2, and 3 cases only had fever. No other severe or fetal adverse reactions were observed. Conclusions: Blinatumomab is an effective treatment for B-ALL MRD cleanup with a good safety profile. It may, however, not benefit patients with R/R B-ALL with high tumor loads before blinatumomab, and those who carry BCR::ABL1 fusion gene. Studies with a larger sample size are needed to confirm the results.

Frontline Consolidation with Nelarabine for Adults with High-Risk T-Cell Acute Lymphoblastic Leukemia. Results of the Graall-2014/T Atriall Phase 2 Study

Rationale. Acute lymphoblastic leukemia (ALL) with unfavorable biology and/or high minimal residual disease (MRD) levels are at high-risk of disease recurrence. Based on the results of the GRAALL-2005/T study (Trinquand A et al, JCO 2013; Beldjord K et al, Blood 2014), T-ALL patients enrolled in the GRAALL-2014/T trial were classified at high-risk (HR) if presenting an unfavorable 4-gene classifier (absence of NOTCH1/FBXW7 mutations or presence of RAS/PTEN alterations) and/or a post-induction IG/TR MRD1 ≥ 10 -4 (including the need of a salvage course to reach a complete remission [CR]). In the phase 2 ATRIALL sub-study, HR patients were offered to receive nelarabine (NELA) during consolidation and maintenance or as bridge to allogeneic hematopoietic stem cell transplantation (HSCT). The aim of the present report is to compare their outcome to that of similar patients treated in the same GRAALL-2014/T trial but without frontline NELA. Method. Between November 2015 and May 2022, the GRAALL-2014/T included 325 patients with T-ALL. Among these patients, 199 presented with HR features. The ATRIALL sub-study was activated in April 2017. ATRIALL eligibility criteria were defined as HR features, no CNS involvement at baseline, and continuous CR before to start consolidation 2 (first NELA course) at week 12. Based on the results of the COG phase 3 study, the protocol was amended in January 2021 to include patients with CNS involvement at baseline. NELA was given at 1,500 mg/sqm/day at day 1,3 and 5 in combination with etoposide and cyclophosphamide for a maximum of 5 courses during consolidation (2 cycles) and maintenance (3 cycles). Patients with MRD1 ≥ 10 -3 and/or with post-consolidation 1 MRD2 ≥ 10 -4 were eligible for HSCT after one NELA course. A total of 121 patients were included. One patient was excluded due to overt relapse before to start NELA. Eight patients had CNS involvement at baseline. A total of 33 patients included in the GRAALL-2014/T met initial ATRIALL criteria but were not included in the sub-study either before ATRIALL activation (N=21), or during accrual (N=10), or after accrual completion (N=2) and received standard of care (SOC) without NELA. The ATRIALL/CNS- cohort (N=112) was compared to the control cohort (N=33) for MRD response, cumulative incidence of relapse (CIR), disease-free survival (DFS) and overall survival (OS). Results. The median follow-up in the ATRIALL study (n=120) was 2.9 years (95%CI, 2.5-3.5). At 3 years, the CIR, DFS, and OS were 28% (95%CI, 20-37), 67% (95%CI, 55-76), and 71% (95%CI, 61-79), respectively. Patients from the ATRIALL/CNS- (N=112) and control (N=33) cohorts exhibited similar characteristics, except for a longer median follow-up in the control cohort (Figure A). Patients included in the ATRIALL study reached lower post-consolidation MRD3 levels (p=0.05). Among patients with MRD1 ≥10 -4, undetectable MRD3 was achieved in 36/55 (65%) after NELA versus 5/16 (31%) after SOC (p=0.02). When censoring at HSCT time, NELA was associated with a significantly reduced CIR (SHR=0.48; 95%CI, 0.23-0.99; p=0.045) and a trend for a prolonged DFS (HR=0.52; 95%CI, 0.26-1.07; p=0.075) (Figure B,C). This difference did not reach significance when patients were not censored at HSCT time. Indeed, high-risk patients not eligible for HSCT benefited from NELA in terms of CIR (SHR=0.43; 95%CI, 0.20-0.98; p=0.045) and DFS (HR=0.46; 95%CI, 0.21-1.03; p=0.06). Patients with non-ETP ALL had a significantly improved CIR (SHR=0.03; 95%CI, 0.17-0.89; p=0.025) and DFS (HR=0.47; 95%CI, 0.22-0.99; p=0.048), whereas ETP-ALL patients did not benefit from NELA over SOC. There was no benefit of prior NELA in patients who received alloHSCT per protocol. Conclusion. While NELA did not yield an overall improved outcome in the study population, benefits were observed in favorable MRD responders and non-ETP patients. Additional prospective studies are needed to further delineate the specific patient subgroups that might benefit from NELA.

Daratumumab, Bortezomib, Lenalidomide, and Dexamethasone (DVRd) and Daratumumab, Carfilzomib, Lenalidomide and Dexamethasone (DKRd) As Induction Therapy in Newly Diagnosed Multiple Myeloma

Background: Daratumumab, bortezomib, lenalidomide, dexamethasone (DVRd) and daratumumab, carfilzomib, lenalidomide, dexamethasone (DKRd) are promising induction regimens for newly diagnosed multiple myeloma (NDMM), resulting in deep responses and high minimal residual disease (MRD) negativity rates. Our prior work demonstrated progression-free survival (PFS) benefit in patients with high-risk (HR) NDMM receiving KRd versus VRd. Herein, we examined early outcomes associated with DVRd and DKRd induction in the management of patients with NDMM. Methods: We conducted a chart review study with NDMM patients treated with DVRd (N=107) and compared outcomes with patients treated with DKRd (N=82), of which 68 were on study (NCT03290950) at Memorial Sloan Kettering (MSK) from 10/5/2017 to 5/1/23. Cutoff date for analysis was 7/19/23. Patients who received ≤1 prior cycle of another regimen for MM were included (N=29). Patients who have not completed induction and received &amp;lt;4 cycles of a quadruplet regimen or who received the majority of their quadruplet induction outside of MSK were excluded. Bone marrow biopsies (BMBx) were typically performed for MRD evaluation prior to stem cell collection or at the end of cycle 8. MRD negativity was evaluated by flow cytometry at 10 -5 sensitivity threshold. Discrete patient characteristics were summarized by frequency (percentage) and continuous characteristics were summarized by median (Interquartile Range, IQR). PFS and overall survival (OS) were evaluated by Kaplan-Meier method. Logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs). Results: Median age was 66 (IQR, 60-70) for DVRd- and 59 (50-65) for DKRd-treated patients (P&amp;lt;0.001). In the DVRd group, 72% were White and 15% Black while the DKRd group had 79% were White and 9% Black. Most of the patients in both groups had RISS Stage 2 disease (DVRd RISS 1/2/3: 33%/61%/7%; DKRd: 35%/60%/5%). With HR cytogenetic abnormality (HRCA) defined as +1q, del(1p), t(4;14), t(14;16), t(14;20), and/or del(17p), 43/100 (43%) in DVRd group and 46/81 (57%) in the DKRd group had cytogenetic abnormalities that met HR criteria (P=0.065). Among the DVRd patients, 57, 28, and 15 had 0, 1, 2+ HRCA, respectively, while in the DKRd group, 35, 30, and 16 had 0, 1, 2+ HRCA, respectively (P=0.2). Median number of cycles was 6 (IQR, 4-6) for DVRd and 8 (IQR, 6-8) for DKRd (P&amp;lt;0.001). At data cutoff, 72 DVRd and 74 DKRd patients completed stem cell collection; among these patients, 41 (57%) DVRd- and 25 (34%) DKRd-treated patients received upfront ASCT. Best overall response rate (ORR) was 98% and 100% for DVRd and DKRd (P=0.5), respectively. Within 8 cycles of therapy, 21 (20%) and 28 (34%) patients achieved a ≥complete response (CR) in the DVRd and DKRd groups, respectively (P=0.024). Additionally, 83 (78%) patients were in ≥VGPR in the DVRd group and 74 (90%) in the DKRd group (P=0.021). There were 2 pts with best response as stable disease in the DVRd group. 86 DVRd pts and 73 DKRd patients had a BMBx within 8 cycles of induction therapy and were evaluable for MRD. Among these patients, 20 (23%) and 38 (52%) achieved MRD negativity for DVRd and DKRd, respectively. Multivariable analysis with clinical variables including type of quadruplet therapy, age, gender, race, R-ISS stage, cytogenetic risk, and number of cycles, demonstrated no significant association with achievement of CR (DKRd [ref] vs DVRd, OR 0.46, 95%CI 0.19-1.04; P=0.064). After a median follow-up of 13 (95%CI, 11-15) months for DVRd and 53 (48-55) months for DKRd, 1-year estimated PFS was 92% (95%CI, 86%-99%) and 94% (89%-99%) for DVRd and DKRd, respectively (P=0.5). Conclusion: In this single-center chart review study, DVRd was compared to DKRd as induction therapy for patients with NDMM. Importantly, DKRd patients were primarily comprised of patients from a clinical trial (NCT03290950), perhaps affecting demographics of the groups (DVRd group had older patients and more Black patients; DKRd group had more cycles of therapy due to trial design). DVRd and DKRd are both associated with high ORR. Although the ≥CR rate was greater with DKRd, on multivariable analysis there was no statistically significant difference between DKRd and DVRd after adjusting for various clinical variables. Data with follow-up outcomes will be presented at the meeting.

Delayed Intensification Including Venetoclax and Bortezomib Prolongs Survival in Very High Risk Acute Lymphoblastic Leukaemia

Modern multi-drug risk-stratified response-adapted chemotherapy protocols lead to &amp;gt;85% cure rates in childhood acute lymphoblastic leukaemia (ALL). Between 2013-2022, 707 children (0-18 years) with acute lymphoblastic leukaemia (ALL) treated systematically on the ICiCLe-ALL-14 risk-adapted protocol achieved a 3-year event-free survival (EFS) of 73% (95% confidence interval, CI 69-77). A very high risk (VHR) subgroup (N = 107) was identified with poor outcome (3-year EFS, 38% [95% CI 25-51]). This included patients with induction failure, persistent minimal residual disease (MRD) and/or select high risk cytogenetic subtypes ( BCR::ABL1 other ABL-class fusion ALL, TCF3::HLF, low hypodiploidy, IKZF1plus with high end-induction MRD, KMT2A-rearranged infant ALL). Co-culture based high-throughput drug response profiling (DRP) was performed to identify alternate chemotherapeutic drugs for these VHR patients. Primary ALL blasts extracted by density centrifugation, were seeded on immortalized human bone marrow stromal cells and treated with a 14-drug panel: prednisolone; vincristine (VCR), daunorubicin; asparaginase (ASNase), bortezomib (BZM), venetoclax (VEN), panobinostat (PNB), mitoxantrone, cyclophosphamide, cytarabine, selinexor, dasatinib, 6-thioguanine and idarubicin. Seventy-four patients (25 VHR, 37 high-risk, 7 intermediate-risk, and 5 standard-risk,) were analysed. Venetoclax, BZM and PNB were identified as active agents (IC 50 &amp;lt;100nM for VEN and PNB, &amp;lt;10nM for BZM) in 71%, 42% and 75% of VHR samples, respectively. Based on drug-sensitivity patterns of VHR ALL, a pilot study was initiated to prospectively evaluate the addition of VEN and BZM in the frontline delayed intensification (DI) phase of VHR ALL patients (N=24) after informed consent (Figure 1). Response was assessed before and after VHR-DI in 46% (11/24) patients. Good response, i.e. decrease in MRD ≥ 1 log after VHR-DI, was noted in 82% (9/11) patients. Landmark analysis comparing survival of patients (from start of DI) treated on standard DI versus VHR-DI showed significant improvement in 2-year EFS from 54% (95% CI 40-66) to 76% (95% CI 51-89) ( p=0.037, log-rank test). Overall, VHR-DI was tolerated well. No significant difference was noted in grade 4 and 5 toxicities (Common Terminology Criteria for Adverse Events v4.0) between standard DI and VHR-DI ( p= 0.053 &amp; p=0.988 respectively, chi-square test). Fever-neutropenia and sepsis were the most frequent toxicities with VHR-DI. To identify potential mechanisms of resistance in poor-responders, transcriptome analysis was performed on diagnostic blast cells from VHR patients with good (N=5) or poor (N=5) response to VHR-DI and compared with highly sensitive SR patients (N=5). Upregulation of oxidative phosphorylation and ubiquitin-mediated proteolysis were found in good responders while non-responders showed upregulation of amino acid metabolic and RNA splicing pathways. In conclusion, drug response profiling identifies alternative combination therapies for VHR ALL. Our pilot study provides proof-of-concept of effectiveness and tolerability of inclusion of VEN and BZM in the post-induction treatment of patients with poor-response disease.

Mutational Burden in High Risk Genes Do Not Affect Remission Rates and MRD Clearance in Elderly AML Patients Receiving CPX-351 Induction

Background: CPX-351 has recently been approved for the treatment of patients diagnosed with Acute Myeloid Leukemia (AML) arising from a previous myelodisplastic syndrome (s-AML) or secondary to chemotherapy (t-AML) as per former WHO 2016 classification. Minimal residual disease (MRD) assessment is a strong prognostic factor for relapse and shorter survival in AML patients undergoing intensive induction chemotherapy. Recent studies explored the role of genomic profile of AML influencing clinical outcome. In particular, Papaemmanuil et al showed that mutations in critical genes such as TP53, ASXL1, SRSF2 and RUNX1 are independently associated with a worse prognosis; moreover, co-occurrence of different high-risk mutations are predictors of dismal outcome when conventional chemotherapy is administered. Adverse risk mutations are particularly frequent in s-AML and t-AML. As clinical trials evaluating the prognostic relevance of MRD in the context of different molecular subsets mainly involve younger patients affected by de novo AML and receiving conventional 3+7 chemotherapy, there is a lack of data to define the impact of specific mutations on MRD clearance and prognosis in elderly s- AML and t-AML patients receiving CPX-351 induction. Aims: The aim of this study was to evaluate the prognostic impact of recurrent genic mutations and mutational burden at diagnosis on CR probability, MRD clearance and prognosis in a cohort of elderly s-AML or t-AML patients treated with CPX-351 induction chemotherapy. Methods: The study included 67 elderly patients (&amp;gt;60 year, median age 69, range 60-77) with a diagnosis of s-AML or t-AML according to WHO2016 classification, treated in our Center with CPX-351. Next generation sequencing (NGS) was performed using the Myeloid Solution panel by SOPHiA Genetics, encompassing 34 critical genes mutations. Sample have been processed on a Illumina MiSeq platform and the analysis performed with SOPHiA DDM® Software. MRD was analysed in all patients achieving complete remission (CR) with multicolour flow-cytometry, with a threshold of 0.1%. Results: AML patients were re-classified according to ELN 2022 risk score which was adverse, intermediate and favourable in 35, 29 and 3 patients, respectively. Median number of mutations for single patient (mutational burden) by NGS was 4 (range 2-9). Most frequent mutations involved: RUNX1 (44%), ASXL1 (37%), TP53 (33%), IDH1 (18%), IDH2 (14%), DNMT3A (14%), TET2 (8%). Four patients died before response assessment, mainly due to infections. Fifty-four patients (81%) achieved complete remission (CR) after first induction cycle; MRD evaluation was negative in 28/54 responding patients (52%). Univariate and multivariate analysis showed that factors traditionally associated with poor outcome such as ELN risk group, leukocytosis at diagnosis or previous treatment with hypomethylating agents did not affect the probability of CR rate and MRD negativity. Interestingly, having any high risk mutation, the combination of ≥2 high risk mutations or high mutational burden (having ≥ 4) did not affect CR probability and MRD negativity rate both in univariate and multivariate analysis. After cycle 2, the cumulative CR rate was 56/67 (84%), with 33/56 (59%) responding patients obtaining MFC MRD negativity. After a median follow up of 36 months (CI 95%; 22.4 -48.5 months), median OS was 19 months (CI 95% 13-24), whereas 2 year OS was 24%. Multivariate OS analysis revealed that negative MRD was the strongest independent predictor of longer survival (p&amp;lt;0.05). Notably, OS was not affected by mutational burden (29.2% and 27.6% for patients with less or more than 4 mutations, respectively, p=n.s, Fig.1). In landmark analysis, patients achieving CR and proceeding to allogeneic stem cell transplantation consolidation (HSCT) within 3 months from CR (N=13) had a significantly better outcome if compared to CR patients who did not receive HSCT or proceeded to transplant later (N= 41, 2-year OS: 84.6% and 31.7, respectively, p&amp;lt;0.03, Fig. 2). Conclusion : CPX-351 is able to induce good quality remission with high CR rate and MRD negativity, regardless of mutational burden, allowing a high number of elderly AML patients to undergo to HSCT. MRD evaluation has proven to be a strong prognostic tool also in the setting of elderly s-AML and t-AML patients receiving CPX-351. The prognostic value of high risk mutation seems to be less relevant in CPX-351 treated patients.

High Efficacy and Feasibility of a Full Pediatric Induction in Adults Aged up to 55 Years with Philadelphia-Negative Acute Lymphoblastic Leukemia

Background: Treatment of acute lymphoblastic leukemia (ALL) in adults has historically shown unsatisfactory outcomes when compared to the outstanding results obtained in pediatric patients. Pediatric protocols rely on increased drug intensity and on a tighter evaluation of minimal residual disease (MRD) for early intensification. Nowadays, pediatric-inspired protocols have been established as the standard of care for adolescents and young adult patients (AYA) leading to improved results. In the setting of older patients, probably due to the limited data available, the feasibility of such intensive therapies, and in particular the administration of high doses PEG-asparaginase (PEGASP), is still a matter of debate. In this context, the NOPHO group reported that a full-pediatric protocol was feasible and highly effective in adult patients, up to 45 years of age. Aim: The aim of our study was to evaluate the feasibility and efficacy of the entire full pediatric AIEOP-BFM LAL 2009 protocol in an older cohort of adult patients up to 55 years. Methods: Since May 2013, 28 consecutive adults diagnosed with Ph-neg ALL received first line therapy according to AIEOP- BFM-ALL 2009 protocol, which includes high PEG-asparaginase (PEGASP) doses, with an accurate MRD-driven therapeutic strategy. The protocol consists of 2 induction blocks: IA (Vincristine, Daunorubicin, PEGASP, IT methotrexate) and IB (Cytarabine, 6-mercaptopurine, cyclophosphamide, IT methotrexate), I consolidation block (high-dose methotrexate, 6-mercaptopurine, IT methotrexate), maintenance therapy (6-mercaptopurine, weekly MTX, IT Methotrexate). Median age in our study was 45 years (range 17-55), equal to the maximum age allowed in the NOPHO study. Fifteen patients had B-ALL, 13 T-ALL/T including 5 Early-T phenotype. Dose intensification and stem cell transplantation (SCT) were scheduled according to baseline and MRD-driven risk assessment. MRD was evaluated by multicolor-flow cytometry (MFC), with a threshold for positivity of 0.025%, and molecular PCR for JH rearrangement (MOL), with a sensitivity greater or equal to 10-4 in all patients. Patients with MOL MRD &amp;gt;10-4 but &amp;lt;10-3 were defined as low-level positive. MRD time points were day 33 and day 78 (MFC and MOL). Results: All patients achieved complete hematological remission following the first Induction course (100%). One patient died during induction due to infection by multidrug resistant P. aeruginosa. In general, therapy was well tolerated. Remarkably, patients in this study received high dose of PEGASP (median 10000 UI/sqm, equal to 4 administrations at 2500 UI/sqm each) without experimenting life threatening toxicities, which mostly consisted in asymptomatic elevation of transaminase (7 patients G3, 1 G4) and/or bilirubin (9 patients G3, 1 G4) only requiring supportive therapy. No major bleeding or thrombotic events o other &amp;gt;G2 toxicities were observed. All except one patient achieved CR at day 33 and all patients achieved CR at day 78. MFC MRD evaluation at day 33 resulted negative in 24/25 evaluable patients (95%). Day 33 MOL-MRD was evaluated in 22 patients, and resulted negative, low level positive or positive in 14, 5 and 3 patients, respectively. MRD assessment at day 78 showed both MFC and MOL negativity achieved in all 25 and 22 evaluated patients, respectively (Fig. 1). Four very high-risk patients underwent SCT in negative MRD status. After a median follow-up of 59 months (CI 95% 38.45-78.63), median survival was not reached, 5-years OS was 88.7% (Fig. 2). One patient died due to progressive transverse myelitis after isolated CNS relapse and one patient died due to sudden cardiac arrest while in complete MRD negative remission, 6 months after completion of therapy. All other 25 patients are alive and in complete MRD negative remission. Conclusion: The application of a full pediatric induction regimen in a cohort of adult ALL patients with a median age of 45 years proved to be feasible, with tolerable toxicities. In particular, we didn't observe major toxicities during the intensified PEGASP administration and all patients were able to receive the planned PEGASP doses. The possibility to maintain the correct timing translated in a very high MRD negativity rate and promising OS survival.

A phase 1 study of belantamab mafodotin in combination with standard of care in newly diagnosed multiple myeloma: An interim analysis of DREAMM-9.

8018 Background: Belantamab mafodotin (belamaf) is a B-cell maturation antigen-binding antibody-drug conjugate that eliminates myeloma cells via direct cell killing and anti-myeloma immune responses. DREAMM-9 (NCT04091126) is an ongoing Phase 1, randomized, dose and schedule evaluation study. It aims to evaluate belamaf plus bortezomib, lenalidomide, and dexamethasone (VRd) in adult patients (pts) with transplant-ineligible (TI) newly diagnosed MM (NDMM) and to establish the recommended dose for future development of belamaf combination therapies in the 1st-line setting. Herein, we report updated interim-analysis data. Methods: Belamaf dose cohorts (Co1–7) are shown in the Table. VRd was given every 3 weeks (Q3W) until cycle 8, and Rd Q4W thereafter. Following safety data from Co2–5, Co6–7 were opened in parallel (randomized 1:1) and have shorter follow-up (Table). Safety was the primary endpoint; efficacy and tolerability were secondary endpoints. Minimal residual disease (MRD) was assessed by next-generation sequencing (10-5). Results: As of data cutoff (Oct 20, 2022), 93 pts were treated across Co1–7. Median age (range) was 73 (51–88) years, 55% of pts were male, and 84% were white. The most commonly reported non-ocular adverse events (AEs) across all Co were thrombocytopenia (46%), constipation (36%), diarrhea (34%), and peripheral sensory neuropathy (31%). Overall, belamaf-related Grade ≥3 AEs occurred in 35% of pts and led to belamaf dose reductions in 7% and dose delays in 63% of all treated patients. Grade ≥3 ocular AEs (keratopathy and visual acuity [KVA] scale) occurred in 53% of all pts and led to dose reductions in 12% and dose delays in 52% of overall pts. Fatal AEs occurred in 7 pts, all unrelated to study treatment. Efficacy results and ocular AEs are summarized in the Table: 100% of pts responded in Co1 (1.9 mg/kg Q3/4W) and Co3 (1.9 mg/kg Q6/8W). Median time to very good partial response or better (≥VGPR) ranged from 2.1 to 3.1 months (mo) across cohorts. Highest MRD negativity (MRD[-]) rates (≥VGPR) were seen in Co1 (83%) and Co3 (67%). Conclusions: This updated interim analysis demonstrates that belamaf plus VRd has no new safety signals and provides early and deep anti-myeloma responses in pts with TI NDMM, with high MRD[-] rates. Clinical trial information: NCT04091126 . [Table: see text]

Efficacy of Subcutaneous Epcoritamab versus Axi‐cel in R/R DLBCL CAR T‐Naive and CAR T‐eligible patients: An Indirect Comparison

Introduction: Epcoritamab, an off-the-shelf, subcutaneous CD3xCD20 T-cell–engaging bispecific antibody that redirects T cells to eliminate malignant CD20+ B cells, showed single-agent efficacy in patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) with a manageable safety profile. The phase 1/2 EPCORE NHL-1 trial (NCT03625037) of epcoritamab in patients with R/R DLBCL who received ≥2 prior lines of systemic therapy showed high complete response (CR) and minimal residual disease rates. Methods: This matching-adjusted indirect comparison included published data on overall response rate (ORR), CR rate, and overall survival (OS) for axi-cel (ZUMA-1 trial, N = 101) and individual patient-level data (IPD) for epcoritamab (EPCORE NHL-1 trial). Patients in EPCORE NHL-1 with prior CAR T therapy were excluded as ZUMA-1 included only patients without prior CAR T therapy. Analyses were adjusted for imbalances in baseline characteristics between IPD from EPCORE NHL-1 and aggregate data from ZUMA-1. Propensity score weights were applied to estimate risk differences for ORR and CR rate; weighted Cox proportional-hazards models were used to estimate OS hazard ratio (HR). Subgroup analyses of CAR T-eligible patients assessed patients with more similar clinical characteristics. Results: Compared with the ZUMA-1 population, the majority of patients enrolled in EPCORE NHL-1 (N = 86) were men (61.6% vs. 23.8%) with a median age of 69.5 y (vs. 58.0 y), and were refractory to ≥2 consecutive lines of therapy (62.8% vs. 53.5%). Among the CAR T-adjusted matched population, response rates were not statistically different in those treated with epcoritamab versus axi-cel (ORR: 73.4% vs. 74.3%, respectively; difference in ORR: −0.8%; P = 0.927; CR rate: 48.5% vs. 54.5%; difference in CR rate, −6.0%; P = 0.583). In a subgroup of CAR T-naive patients that were CAR T eligible and treated with epcoritamab (n = 50), response rates also did not significantly differ from those in patients treated with axi-cel (ORR 72.7% vs. 74.3%, respectively; difference in ORR: −1.6%; P = 0.873; CR rate: 47.7% vs. 54.5%; difference in CR rate, −6.8%; P = 0.576). In all CAR T-naive patients, OS was not statistically different between those treated with epcoritamab versus axi-cel (HR: 0.695; 95% CI: 0.351, 1.376; P = 0.297). Likewise, the CAR T-eligible subpopulation treated with epcoritamab did not have statistically different OS versus axi-cel (HR: 0.708; 95% CI: 0.309, 1.626; P = 0.416). Conclusions: Findings from this cross-study comparison suggest that epcoritamab is a promising, emerging, novel therapy with no statistically significant difference in efficacy versus axi-cel in patients with highly refractory, hard-to-treat DLBCL. Additional analyses are needed to better understand the therapeutic potential of epcoritamab as an off-the shelf, subcutaneously delivered core therapy for these patients. Encore Abstract - previously submitted to EHA 2023 The research was funded by: Epcoritamab is jointly developed by Genmab A/S and AbbVie Inc.; AbbVie and Genmab are sponsoring this study. Keyword: Aggressive B-cell non-Hodgkin lymphoma Conflicts of interests pertinent to the abstract. C. Thieblemont Consultant or advisory role: AbbVie, BeiGene, BMS/Celgene, Roche, Janssen, Kite/Gilead, Novartis, Regeneron, and Takeda C. P. Fox Consultant or advisory role: GenMab and AbbVie Other remuneration: Steering Committee: GenMab A. Wang Consultant or advisory role: AbbVie, BeiGene, BMS/Celgene, Roche, Janssen, Kite/Gilead, Novartis, Regeneron, and Takeda K. Sail Employment or leadership position: AbbVie Stock ownership: AbbVie A. Alshreef Employment or leadership position: AbbVie Stock ownership: AbbVie M. Moran Employment or leadership position: AbbVie Stock ownership: AbbVie A. Mutebi Employment or leadership position: Genmab Stock ownership: Genmab J. Blaedel Employment or leadership position: Genmab Stock ownership: Genmab V. Chirikov Employment or leadership position: OPEN Health, which received funding support from AbbVie to conduct the research G. Salles Consultant or advisory role: AbbVie, Bayer, BeiGene, BMS/Celgene, Epizyme, Genentech/Roche, Genmab, Incyte, Janssen, Kite/Gilead, Loxo, Miltenyi, MorphoSys, Novartis, Rapt, Regeneron, and Takeda

Abstract 6604: Analytical development and validation of a personalized hybrid capture based assay for high sensitivity monitoring minimal residual disease (MRD)

Abstract Introduction: 5-30% of patients with early-stage cancer relapse, even though most patients had undergone radical surgery. There is increasing evidence that circulating tumor DNA (ctDNA) minimal residual disease (MRD) predicts relapse following treatment for solid tumors. However, liquid biopsy analyses are challenged by the very low concentrations of ctDNA in blood samples. Existing ctDNA methods lack the sensitivity needed for detecting minimal residual disease (MRD) following therapy. Here, we describe a tumor-informed personalized hybrid capture based method using next-generation sequencing (NGS) to highly sensitive and specific detect MRD and predict recurrence in plasma cell-free DNA. To validate the performance of the assay, we present a technical validation study on DNA from cancer cell line material, including lung cancer cell line, reference material, Onco gDNA reference standard and wild type gDNA reference standard. Method: The performance of the assay was assessed using samples from Onco gDNA reference standard and lung cancer cell line. To estimate number of monitoring single nucleotide variants (SNVs) at input volume of 20-80ng, Onco gDNA reference standard was diluted into 8 concentrations (10, 20, 30, 40, 50, 60, 150 and 750 ppm with a variant allele frequency [VAF] range of 0.001% to 0.075%).To estimate limit of detection (LoD) of the assay at input volume of 20ng and 40ng, lung cancer cell line was diluted into 5 concentrations (10, 20, 40, 80 and 160 ppm with a variant allele frequency [VAF] range of 0.001% to 0.016%).10 samples were performed for each concentration, as well as 10 negative reference samples. Personalized panel was performed using ultradeep (100,000X) NGS with customized 55 or 60 SNVs. Result: Validation results of Onco gDNA reference standard: using 40 variants, sensitivity of input volume of 20ng and 40ng are 95% and 98% at 40 ppm, with a specificity of 100%, respectively. Using 40 variants, sensitivity of input volume of 60ng are 95% at 20 ppm, with a specificity of 100%. Using 50 variants, sensitivity of input volume of 60ng are 70% at 10 ppm, with a specificity of 100%. Validation results of lung cancer cell line: using 40 variants, sensitivity of input volume of 20ng and 40ng are 98% and 100% at 50 ppm, with a specificity of 100%, respectively. Conclusion: The assay was validated by sequentially diluting of lung cancer cell line and Onco gDNA reference standard. With input volume of 20ng, sensitivity of the assay is 95% at 40ppm when monitoring 40 variants, while with input volume of 60ng the LoD reached as low as 10 ppm with sensitivity of 70% when monitoring 50 variants. The assay demonstrates high sensitivity, while maintaining specificity above 99%. Citation Format: Xiaoqiang Wang, Lei Ye, Chao Zhang, Wanglong Deng, Yongjie Wei, Jing Chen, Xuan Tang, Xiaoxuan Wang, Chao Song, Qing Xu, Yong Ren. Analytical development and validation of a personalized hybrid capture based assay for high sensitivity monitoring minimal residual disease (MRD) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6604.

Blinatumomab therapy for B cell acute lymphoblastic leukemia accompanied by persistent or relapsed low-level MRD prior to hematopoietic stem cell transplantation in Chinese children: a case series

BackgroundBlinatumomab could be successfully used to reduce minimal residual disease (MRD) prior to hematopoietic stem cell transplantation (HSCT) in pediatric B cell precursor acute lymphoblastic leukemia (BCP-ALL), but sound evidence is lacking in China.Case presentationThis retrospective study assessed the application of blinatumomab in B-ALL accompanied by persistent or relapsed low-level MRD before HSCT from April 2019 to July 2021. Two cases (Cases 1 and 2) initially achieved remission with MRD < 0.01% upon conventional therapy but had MRD relapse with MRD ≥ 0.01% but < 1% during maintenance treatment. Case 3 had no response to routine treatment, with high MRD (9.88% and 1.23% at days 19 and 46, respectively). Nevertheless, all patients had undetectable MRD. Cases 2 and 3 had undetectable fusion gene following blinatumomab therapy. By bone marrow monitoring (bone marrow morphology, bone marrow MRD and fusion gene) post-HSCT, the patients were persistently negative until May 15, 2022. No patient had serious adverse events before or during blinatumomab treatment.ConclusionsBlinatumomab therapy showed a good performance for three pediatric cases with detectable but low MRD before HSCT in China. However, further prospective studies with large sample sizes are still needed for further clarification.

Impact of autologous stem cell transplantation (ASCT) on progression free survival (PFS) in newly diagnosed multiple myeloma patients (NDMM) with high risk cytogenetic abnormalities.

ASCT has been considered the standard of care for younger patients with NDMM, however, not all the studies published so far have uniformly demonstrated the complete superiority of ASCT over chemotherapy at standard doses. A systematic review and meta-analysis of randomized studies has shown a significant benefit with single ASCT in terms of prolonged progression-free survival (PFS), but not of overall survival (OS). In our retrospective analysis we investigated the impact of high dose (HD) chemotherapy followed by ASCT in special population of patients with high risk cytogenetic profile on the PFS and treatment outcome. Retrospective analysis of NDMM patients eligible for HD chemotherapy followed by upfront ASCT in the era of novel agents, who underwent the ASCT in the Department of hematology and oncohematology LF UPJŠ and UNLP Košice in the timeframe of 54 months (from 01/JAN/2019 to 30/JUN/2023). Patients were stratified according to their cytogenetic profile. PFS was defined by the time from ASCT to the disease progression. The OS was defined as the time from the the start of treatment to the death from disease progression. The high risk cytogenetic abnormalities (HRCA) were defined as t(4;14), del(17/17p), t(14;16), t(14;20), nonhyperploidy, gain (1q). Inclusion criteria were met by 65 patients with NDMM who received HD chemotherpy followed by ASCT. We identified 22 (33.8 %) patients with HRCA and 43 (66.2 %) patients with standard cytogenetic risk. During the monitored period we recorded 4 deaths due to disease progression, all of them in the HCRA subgroup. The response was enhanced by the ASCT in both subgroups. The very good partial response (VGPR) increased from 42 % to 46 % and complete remission (CR) increased from 23 % to 45 % after the ASCT. The number of patients achieving only partial response (PR) decreased from 35 % to 9 % after ASCT. In the subgroup of patients with HRCA the median PFS after ASCT was lower compared to the patients with standard cytogenetic risk (17 vs 38 months). The average PFS in both subgroups was 22.9 months. The median OS in both subgroups was not reached, however the only deaths due to disease progression were recorded in the HRCA subgroup. At the time of analysis, 100 % (43) of patients are alive in the standard cytogenetic subgroup versus 72 % (18) of patients in HRCA subgroup. HD chemotherapy followed by ASCT remains the standard of care for NDMM eligible for high dose chemotherapy. Our results confirm the benefit of ASCT even in the presence of HRCA. Lower PFS in the HRCA subgroup might indicate the need for more intensive treatment, which may be achieved by tandem ASCT defined as two ASCT performed within a period of no more than six months. Additionally, as three- and four-drug induction therapies are becoming increasingly available and effective, resulting in high minimal residual disease (MRD) negative rates, it is important to continue discussing and further personalizing upfront ASCT to avoid overtreatment and possible toxicities especially in the non-high-risk patient population (Tab. 5, Fig. 2, Ref. 9).

Comparison of the treatment results in adult patients with acute Ph-negative lymphoblastic leukemia on protocols of the Russian multicenter studies ALL-2009 and ALL-2016

Introduction. Over the past 5 years, signifi cant progress has been achieved in the treatment of patients with Ph-negative acute lymphoblastic leukemia (ALL). Treatment results were compared between two protocols of the Russian multicenter studies «ALL-2009» and «ALL-2016», in which multicomponent high-dose consolidation was not used. The principle of continuity of treatment was observed with modifi cation of doses of cytostatic drugs depending on the depth of cytopenia.Aim – to compare the 5-year results of two studies and to determine the factors of unfavorable prognosis in the treatment of patients with ALL.Materials and methods. The studies were performed from April 2009 to April 2016 (ALL-2009) and from April 2016 to September 2021 (ALL-2016), and 596 patients were included: 330 in ALL-2009 and 266 in ALL-2016. The analysis was performed in March 2022. The median age of patients in ALL-2009 was 28 years (15–55), in ALL-2016 – 32.5 years (18–55). Cytogenetic studies were performed in 242 patients in ALL-2009 (73.3 %) and 236 patients in ALL-2016 (88.7 %). Patients in the ALL-2016 protocol underwent a centralized assessment of minimal residual disease (MRD) by fl ow cytometry on protocol +70 day (after completion of two induction phases), +133 and +190 days. Transplantation of allogeneic stem hematopoietic cells was performed in 7 % of patients in ALL-2009 and in 9 % in ALL-2016.Results. Overall, relapse-free survival (OS, RFS) and the probability of relapse for a period of 3 years from the moment of inclusion of patients in a particular study were 59 %, 63 % and 23 % for ALL-2009, and for ALL-2016 – 64 %, 59 % and 22 %, respectively. For patients with B-cell precursor ALL, two cytogenetic risk groups were formed, in which long-term survival rates differed signifi cantly: the standard group (hyperploid set of chromosomes and normal karyotype) – OS 63 %, RFS 70 %, and high cytogenetic risk (any abnormal karyotype, except for hyperploidy) – OS 49 %, RFS 52 % (р = 0.001, р = 0.0014). In T-ALL, cytogenetic markers had no prognostic value, but the immunophenotype of early T-cell precursor turned out to be an important predictor of poor prognosis (the probability of relapse was 52 % compared with 15 % for all other immunophenotypic variants). According to the results of centralized monitoring of MRD, it was determined that for B-cell precursor ALL, the signifi cant negative factors are the high cytogenetic risk group and positive MRD status at +70 day, and for T-cells, the early immunophenotype and positive MRD status at +133 day.

Experience of Paediatric Acute Lymphoblastic Leukemia Service in A Newly Established Haemato-Oncology Center in Bangladesh: Opportunities and Challenges

Background: Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy and its modern management is complex. We are reporting early experience of establishing a paediatric ALL service in a multidisciplinary paediatric hospital in Bangladesh.&#x0D; Methods: This is a retrospective review of children below 18 years of age with confirmed diagnosis of ALL from July 2020 to June 2021 in Dr. M R Khan Shishu Hospital and ICH, Dhaka, Bangladesh, who received treatment adapted from the standard arm of ICICLE (Indian Childhood Collaborative Leukemia Group) protocol. Data were collected which included demographic, clinical, laboratory features of all patients at the time of presentation and also morbidities and outcome during all phases of chemotherapy. Analysis was done using descriptive statistics.&#x0D; Results: Of 51 patients, 16 were newly diagnosed patients, 32 received continuation care and 3 had relapsed disease. Treatment was initiated in 12 (75%) of 16 patients with newly-diagnosed ALL. Median age was three years, 50% were girls, one had TALL and 5 (42%) had high presentation leucocyte count (³50,000/mm3). Complete cytogenetic testing was available for one patient alone, no patient had Ph+ ALL. Eleven (92%) showed good prednisolone response. All nine patients who completed the induction phase achieved morphological remission, with high minimal residual disease (³0·01%) in two (22%). At last follow-up (30-06-2021), two patients were midway through induction, two died from sepsis (one each in Induction and Consolidation, both high risk ALL) and eight (67%) are alive in remission, on treatment 2-12 months from diagnosis. Continuation care included intrathecal treatments (n=119) and vincristine-corticosteroid pulses (n=53); 94% patient remained in complete remission, while two (6%) relapsed during the course of treatment.&#x0D; Conclusion: Risk-stratified ALL treatment is feasible in a newly established resource limited setting but limited by availability of high-quality diagnostics, specifically cytogenetics. Our study revealed that, during intensive phase approximately two-third children and during maintenance phase majority of children remained in complete remission.&#x0D; DS (Child) H J 2021; 37(2): 116-122