Measurable Residual Disease Status Research Articles

Long-term results of the sequential combination of cladribine and rituximab in Hairy cell leukemia

We report on the long-term efficacy and safety of a phase 2 trial of sequential cladribine and rituximab in hairy cell leukemia (HCL). One-hundred and thirty-nine patients were enrolled: 111 in the frontline setting, 18 in first relapse, and 10 with variant HCL (HCLv). A complete response (CR) was achieved in 133 of 137 evaluable participants (97%) with measurable residual disease (MRD) negativity in 102 (77%). MRD status was not associated with significant differences in event-free survival (EFS) or overall survival (OS). With a median follow-up of 7.8 years (range: 0.40–18.8), eight patients have experienced disease relapse (5.8%), 4/111 with newly diagnosed HCL (3·6%) and 4/10 with HCLv (40%) (p = 0.002). The 10-year EFS and OS rates were 86.7% and 91.1%, respectively. Grade 3 adverse events were observed in 28 participants (20·1%), mostly due to infections. Treatment of HCL with sequential cladribine followed by rituximab is associated with excellent efficacy and safety results both in the frontline and relapsed settings.

Molecular, clinical, and therapeutic determinants of outcome in NPM1 mutated AML

AbstractAlthough NPM1-mutated acute myeloid leukemia (AML) carries a generally favorable prognosis, many patients still relapse and die. Previous studies identified several molecular and clinical features associated with poor outcomes; however, only FLT3-internal tandem duplication (ITD) mutation and adverse karyotype are currently used for risk stratification because of inconsistent results and uncertainty about how other factors should influence treatment, particularly given the strong prognostic effect of postinduction measurable residual disease (MRD). Here, we analyzed a large group of patients with NPM1 mutations (NPM1mut) AML enrolled in prospective trials (NCRI AML17 and AML19, n = 1357) to delineate the impact of baseline molecular and clinical features, postinduction MRD status, and treatment intensity on the outcome. FLT3-ITD (hazard ratio [HR], 1.28; 95% confidence interval [CI], 1.01-1.63), DNMT3A (HR, 1.65; 95% CI, 1.32-2.05), WT1 (HR, 1.74; 95% CI, 1272-2.38), and non-ABD NPM1mut (HR, 1.64; 95% CI, 1.22-2.21) were independently associated with poorer overall survival (OS). These factors were also strongly associated with MRD positivity. For patients who achieved MRD negativity, these mutations (except FLT3-ITD) were associated with an increased cumulative incidence of relapse (CIR) and poorer OS. However, apart from the few patients with adverse cytogenetics, we could not identify any group of MRD-negative patients with a CIR >40% or with benefit from allograft in first remission. Intensified chemotherapy with the FLAG-Ida regimen was associated with improved outcomes in all subgroups, with greater benefits observed in the high-risk molecular subgroups.

Abstract CT150: Trial in progress: A phase 1b single-arm, open-label, study of emavusertib (CA-4948) in combination with azacitidine and venetoclax in acute myeloid leukemia patients in complete response with measurable residual disease

Abstract Background: Emavusertib is a novel potent oral inhibitor of interleukin-1 receptor-associated kinase 4 (IRAK4) with additional inhibitory activity against FMS-like tyrosine kinase 3 (FLT3) and CDC-like kinases (CLK1/2/4). Inhibition of these onco-proteins may induce remission thereby addressing a critical unmet need for novel therapies in acute myeloid leukemia (AML). Clinical studies with emavusertib monotherapy have demonstrated a significant reduction in AML blasts with clinical and molecular responses, including patients with relapsed or refractory AML, previously treated with an HMA and/or FLT3 inhibitors (Metzeler 2022). Azacitidine + venetoclax (aza+ven) has been approved in newly diagnosed, unfit patients with AML. In the VIALE-A study, composite complete response (CRc) (CR, CRh, or CRi) in the absence of measurable residual disease (MRD) of <1 residual blast/1000 leukocytes (MRD negative [MRD−]) resulted in longer duration of response (DOR), event-free survival, and overall survival (OS), and better HSCT outcome compared with patients who achieved CRc but were MRD+ (Pratz, 2022). In pre-clinical studies, emavusertib in combination with aza+ven demonstrated synergistic antileukemic effects in AML cell lines, including azacitidine- or venetoclax-resistant cell lines. Adding emavusertib to aza+ven in MRD+ patients at the time of CR may convert MRD status without adding significant toxicity and confirm that emavusertib can be safely added to aza+ven as a potential new regimen in front-line therapy. Study Design: This is a single-arm, open-label Phase 1b trial evaluating safety and tolerability, PK, and conversion of MRD status with emavusertib as an add-on agent to aza+ven in AML patients who achieved CR or CRh with MRD+ based on local testing (EU CT Number 2023-505828-58-00). The primary objective of the study is to determine a safe and tolerable dosing schedule for the triple combination. Secondary objectives include MRD conversion rate, DOR, OS, and pharmacokinetics. The study will enroll approximately 24 patients at 5 to 10 sites globally. Patients will have received azacitidine and venetoclax as first line therapy and achieved CR or CRh after 1-6 cycles of aza/ven. If MRD status remains positive, emavusertib will be added to the existing well tolerated aza+ven regimen. The starting emavusertib dose is 200 mg BID for 7 days per cycle of 28 days. If well tolerated, duration of emavusertib treatment will be extended to 14 and 21, respectively; no intra-patient change of emavusertib dosing duration is planned. The patients will continue triple treatment (emavusertib+aza+ven) until consent withdrawal, disease progression, intolerable toxicity, or not achieving MRD- within 6 cycles of triple treatment. In this Phase 1b trial, MRD can be evaluated by local testing of bone marrow. Key exclusion criteria include residual toxicities and significant comorbidities. Citation Format: Reinhard von Roemeling, Adolfo De La Fuente, Claudio Cerchione, Sebastian Scholl, Jan Moritz Middeke, Gaurav S. Choudhary, Maria Lamar, Steven Angelides, Uwe Platzbecker. Trial in progress: A phase 1b single-arm, open-label, study of emavusertib (CA-4948) in combination with azacitidine and venetoclax in acute myeloid leukemia patients in complete response with measurable residual disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT150.

Evaluating the safety and efficacy of cryopreserved ovarian tissue transplantation in leukemia patients with different bone marrow remission status using xenotransplantation.

Leukemia patients undergoing cryopreserved ovarian tissue transplantation (OTT) may carry a high risk of disease induction. Measurable residual disease (MRD) in bone marrow is linked to an elevated risk of relapse. It is controversial whether leukemia patients must be allowed to achieve measurable residual disease negative (MRD-negative) status instead of measurable residual disease positive (MRD-positive) status before ovarian tissue cryopreservation (OTC). To explore the safety and efficacy of OTT in acute leukemia patients with different MRD status by using xenotransplantation. Cryopreserved ovarian tissue from 19 leukemia patients was thawed and xenotransplanted to ovariectomized BALB/C nude mice (n=36). The mice were divided into 2 groups based on the patient's MRD status before OTC: MRD-negative group (n=18) and MRD-positive group (n=18), additionally, a control group consisted of ovariectomized mice (n=9). Body weight was measured weekly and mortality, emaciation, and other abnormalities were recorded. Twenty-six weeks post-surgery, livers, spleens, uteruses, and ovarian grafts were removed for macroscopic and histological examinations to evaluate the efficacy of xenotransplantation and assess malignant cell contamination in mice. Follicle growth was visible in the ovarian grafts of the MRD-negative and MRD-positive groups. Compared with the ovariectomized group, a significant decrease in body weight (p<0.01) was noted, the uterine volume was notably larger, estradiol (E2) levels were significantly higher (p<0.01), and follicle-stimulating hormone (FSH) levels were significantly lower (p<0.001) in the other two groups. Mice in the MRD-positive group showed a significantly higher incidence of death (p<0.001) and emaciation (p<0.01), compared to the MRD-negative group. Histological observation revealed the presence of malignant cells in the grafts, livers, and spleens of 3 mice in the MRD-positive group. No abnormalities were observed in the mice from the MRD-negative group in both macroscopic and histological observations except one mouse was sacrificed for ascites unrelated to leukemia relapse. For leukemia patients having ovarian tissue preserved in the first and only centralized human ovarian tissue cryobank in China, immunodeficient mice xenotransplantation can be a method to evaluate the safety and efficacy of OTT; the risk of malignant cell reimplantation due to OTT is higher in leukemia patients with MRD-positive status than those with MRD-negative status before OTC.

Assessment of Measurable Residual Disease on Day 28 of First Induction Chemotherapy in Acute Myeloid Leukaemia Patients

Background: Measurable residual disease (MRD) is an independent, strong, prognostic marker in acute myeloid leukaemia (AML) that is important for risk stratification and treatment planning. This study assessed the MRD on day-28 after first induction chemotherapy in AML patients. Objective: To assess measurable residual disease status on day 28 after the first induction chemotherapy in newly diagnosed acute myeloid leukaemia patients. Methodology: This cross-sectional study was conducted at the Department of Haematology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka from April 2021 to March 2022 among a total of 25 newly diagnosed AML patients who were admitted and received induction chemotherapy with DA (7+3). On Day-28, bone marrow aspiration was done with standard procedure and first pull of 2ml bone marrow sample was sent to a laboratory for MRD evaluation by multiparameter flow cytometry. MRD was considered positive when value was ?0.1%. Results: On day 28 of post induction chemotherapy most of the patients (92%) achieved morphological remission and among them more than half (52.2%) were MRD positive. The presence of CD14 myeloid marker and baseline higher serum uric acid level was significant in MRD positive patients and cytarabine dose 150 mg/m2 was found significant in MRD negative patients. Conclusion: More than half of the Acute Myeloid Leukaemia patients, treated with standard induction chemotherapy and achieved morphological remission on day 28 of chemotherapy, had positive measurable residual disease assessed by multiparameter flow cytometry. Positive MRD indicates relatively poorer prognosis and may necessitate more cycles of induction followed by more intensive consolidation which may include haematopoietic stem cell transplantation.

Postinduction molecular MRD identifies patients with NPM1 AML who benefit from allogeneic transplant in first remission

AbstractSelection of patients with NPM1-mutated acute myeloid leukemia (AML) for allogeneic transplant in first complete remission (CR1-allo) remains controversial because of a lack of robust data. Consequently, some centers consider baseline FLT3–internal tandem duplication (ITD) an indication for transplant, and others rely on measurable residual disease (MRD) status. Using prospective data from the United Kingdom National Cancer Research Institute AML17 and AML19 studies, we examined the impact of CR1-allo according to peripheral blood NPM1 MRD status measured by quantitative reverse transcription polymerase chain reaction after 2 courses of induction chemotherapy. Of 737 patients achieving remission, MRD was positive in 19%. CR1-allo was performed in 46% of MRD+ and 17% of MRD− patients. We observed significant heterogeneity of overall survival (OS) benefit from CR1-allo according to MRD status, with substantial OS advantage for MRD+ patients (3-year OS with CR1-allo vs without: 61% vs 24%; hazard ratio [HR], 0.39; 95% confidence interval [CI], 0.24-0.64; P < .001) but no benefit for MRD− patients (3-year OS with CR1-allo vs without: 79% vs 82%; HR, 0.82; 95% CI, 0.50-1.33; P = .4). Restricting analysis to patients with coexisting FLT3-ITD, again CR1-allo only improved OS for MRD+ patients (3-year OS, 45% vs 18%; compared with 83% vs 76% if MRD-); no interaction with FLT3 allelic ratio was observed. Postinduction molecular MRD reliably identifies those patients who benefit from allogeneic transplant in first remission. The AML17 and AML19 trials were registered at www.isrctn.com as #ISRCTN55675535 and #ISRCTN78449203, respectively.

Flow cytometry-based measurable residual disease (MRD) analysis identifies AML patients who may benefit from allogeneic hematopoietic stem cell transplantation.

Measurable residual disease (MRD) monitoring independently predicts long-term outcomes in patients with acute myeloid leukemia (AML). Of the various modalities available, multiparameter flow cytometry-based MRD analysis is widely used and relevant for patients without molecular targets. In the transplant (HCT) setting, the presence of MRD pre-HCT is associated with adverse outcomes. MRD-negative remission status pre-HCT was also associated with longer overall (OS) and progression-free survival and a lower risk of relapse. We hypothesize that the combination of disease risk and MRD at the time of first complete remission (CR1) could identify patients according to the benefit gained from HCT, especially for intermediate-risk patients. We performed a retrospective analysis comparing the outcomes of HCT versus non-HCT therapies based on MRD status in AML patients who achieved CR1. Time-dependent analysis was applied considering time-to-HCT as a time-dependent covariate and compared HCT versus non-HCT outcomes according to MRD status at CR1. Among 336 patients assessed at CR1, 35.1% were MRD positive (MRDpos) post-induction. MRDpos patients benefitted from HCT with improved OS and relapse-free survival (RFS), while no benefit was observed in MRDneg patients. In adverse-risk patients, HCT improved OS (HR for OS 0.55; p = 0.05). In intermediate-risk patients, HCT benefit was not significant for OS and RFS. Intermediate-risk MRDpos patients were found to have benefit from HCT with improved OS (HR 0.45, p = 0.04), RFS (HR 0.46, p = 0.02), and CIR (HR 0.41, p = 0.02). Our data underscore the benefit of HCT in adverse risk and MRDpos intermediate-risk AML patients.

Clinical significance of monitoring NUP98::NSD1 fusion genes before and after allogeneic hematopoietic stem cell transplantation

Objective: This study aimed to observe the dynamic changes of NUP98::NSD1 expression before and after allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Moreover, the clinical value of measurable residual disease (MRD) was analyzed. Methods: Sixteen AML patients who were diagnosed with the NUP98::NSD1 fusion gene and received allo-HSCT at Peking University People's Hospital were included. The NUP98::NSD1 fusion gene and leukemia-associated immunophenotype (LAIP) were monitored before and after transplantation to evaluate their MRD status. Results: The median follow-up time for all patients was 526 days (139-1136 days) , with four patients (25.0%) experiencing hematological recurrence at a median of 474 days (283-607 days) after transplantation. Three patients (18.8%) died, two of whom (12.5%) died of leukemia recurrence. The median expression level of NUP98::NSD1 in newly diagnosed patients with complete data was 78.5% (18.9%-184.4%) at the time of initial diagnosis. The recurrence rate was higher in NUP98::NSD1-positive patients after transplantation, with 44.4% of patients experiencing recurrence, whereas no recurrence occurred in NUP98::NSD1-negative patients after transplantation. The area under the receiver operating characteristic curve predicted by the NUP98::NSD1 level after transplantation was 1.000 (95% confidence interval: 1.000-1.000, P=0.003) . Among the four patients with recurrence, NUP98::NSD1 was more sensitive than flow cytometry residual (FCM) and Wilms' tumor gene 1 (WT1) . Conclusions: The NUP98::NSD1 fusion gene can be used to evaluate the MRD status of allo-HSCT. NUP98::NSD1-positive patients after transplantation have a high relapse rate and poor prognosis. NUP98::NSD1 was more sensitive than FCM and WT1 in predicting posttransplant relapse.

Quantification of Measurable Residual Disease Detection by Next-Generation Sequencing–Based Clonality Testing in B-Cell and Plasma Cell Neoplasms

Next generation sequencing (NGS)-based measurable residual disease (MRD) monitoring in post-treatment settings can be crucial for relapse risk stratification in patients with B-cell and plasma cell neoplasms. Prior studies have focused on validation of various technical aspects of the MRD assays, but more studies are warranted to establish the performance characteristics and enable standardization and broad utilization in routine clinical practice. Here, we describe our approach and clinical experience with an NGS-based IGH MRD quantification assay, incorporating a spike-in calibrator for monitoring B-cell and plasma cell neoplasms based on their unique IGH rearrangement status. Comparison of MRD status (positive or undetectable) by NGS and flow cytometry (FC) assays showed high concordance (91%, 471/519 cases) and overall good linear correlation in MRD quantitation, particularly for chronic lymphocytic leukemia and B-lymphoblastic leukemia/lymphoma (R=0.85). Quantitative correlation was lower for plasma cell neoplasms, where underestimation by FC is a known limitation. No significant effects on sequencing efficiency by the spike-in calibrator were observed, with excellent inter- and intra-assay reproducibility within our laboratory, and in comparison to an external laboratory, using the same assay and protocols. Assays performed both at internal and external laboratories showed highly concordant MRD detection (100%) and quantitation (R=0.97). Overall, this NGS-based MRD assay showed highly reproducible results with quantitation that correlated well with FC MRD assessment, particularly for B-cell neoplasms.

Updated Results on a Multicenter Phase II Study of a Dose Intensified Pediatric Regimen in Adults with Acute Lymphoblastic Leukemia: The 06-254 DFCI ALL Consortium Trial

Background: Adolescent and young adult (AYA) patients (pts) with acute lymphoblastic leukemia (ALL) have good outcomes when treated with pediatric regimens (DeAngelo Leukemia 2014; Stock Blood 2019). Here we update our multi-center Phase II study (06-254) applying the DFCI pediatric regimen to young adults, as well as our post-trial experience. The 06-254 protocol is based on the very high-risk arm of the DFCI Pediatric Protocol 05-001. This report focuses on Philadelphia negative (Ph-) pts. Methods: Pts between 18-50 years (yrs) with de novo ALL were eligible. The primary objective was to determine the feasibility of a single dose of pegylated-asparaginase (PEG-ASP) during induction followed by a 30 week PEG-ASP consolidation. Induction chemotherapy included doxorubicin, prednisone, vincristine, PEG-ASP, and intra-thecal chemotherapy (IT). Consolidation I consisted of high-dose methotrexate (A), followed by a BFM-like intensification (B), and a course of high-dose cytarabine, etoposide and dexamethasone (C). Central nervous system prophylaxis included intrathecal therapy and cranial radiation. Intensification therapy consisted of eight 3-week courses of doxorubicin, vincristine, dexamethasone, 6-MP and 30 weeks of PEG-ASP. Dosing of PEG-ASP was initially 2500 IU/m2 every 2 weeks but due to toxicity was reduced to 2000 IU/m2 every 3 weeks and given concomitantly with consolidation. Body surface area was capped at 2.3m2 for PEG-ASP dosing. Continuation therapy consisted of 3 week courses of vincristine, dexamethasone, methotrexate, and 6-MP until 2 yrs from complete remission (CR). Additional consecutive Ph- pts treated “as per” 06-254 (2009-2021) were identified; these pts received treatment following 06-254 including PEG-ASP 2000 IU/m2 every 3 weeks in consolidation. Median follow-up was calculated with the reverse Kaplan Meier indicator. The chi square test was used to compare categorical characteristics. Overall survival (OS) and event free survival (EFS) among groups were compared with the log rank test. Results: A total of 152 Ph- pts were treated from 2007 to 2021 (89 pts on protocol and 63 “as per”). Median follow up was 3.5 yrs for pts treated on protocol and 3.8 yrs for pts treated “as per.” Characteristics at diagnosis: Median age 27.9 yrs (82, 54% &amp;lt; 30 yrs); 39.5% female; 31.6% T-lineage; 53.3% overweight/obese BMI per CDC criteria. Older pts (30-50 yrs) were more likely to be overweight/obese than younger (18-29y) pts (71.4% vs. 37.8%, p &amp;lt; 0.001) and were more frequently allografted in CR1 (21.4% vs. 9.8%, p = 0.045). CR was achieved by 142 (92.1%) pts. Among 81 (53.3%) pts with known end-induction measurable residual disease (MRD) status, 68 (84.0%) were MRD negative. In total, 88 (57.9%) pts completed all protocol treatment, 9 (5.9%) had induction failure, 3 (2.0%) died during treatment, 13 (8.6%) relapsed during treatment, 16 (10.5%) exited the protocol for other reasons, and 22 (15.1%) were consolidated with bone marrow transplant (BMT) in CR1. Among the 95 patients who remained on protocol for at least 1 year, 73 (76.8%) had ≥ 26 wks of asparagine depletion. Regarding toxicity: 21 pts (13.8%) had clinical pancreatitis, 98 (64.5%) experienced grade 3-4 laboratory hepatotoxicity, and 20 (13.1%) had allergic reactions to ASP. OS of the entire cohort was 84.4% (95% CI 77.4-89.3) at 3 yrs and 75.8% (95% CI 67.0-82.6) at 5 yrs. Pts aged 18-29 yrs had superior 5-yr OS to those aged 30-50 yrs (82.4% [95% CI 69.4-90.2] vs. 67.1% [95% CI 53.3-77.7], p = 0.004), and pts with a BMI &amp;lt; 25 at diagnosis had superior 5-yr OS than those with BMI ≥ 25 (87.1% [95% CI 73.5-94.0] vs. 66.5% [95% CI 53.9-76.5], p = 0.002). Patients with negative MRD at end of induction had a 5-yr OS of 80.7% (95% CI 66.7-89.3) and those with positive MRD 59.1% (95% CI 21.8-83.4) (p = 0.16). Pts treated “as per” had superior 5-yr OS to those treated on protocol (86.0% [95% CI 71.3-93.5] vs. 68.7% [95% CI 56.5-78.1], p = 0.012). EFS was 77.1% (95% CI 69.0-83.3) at 3 yrs and 70.6% (95% CI 61.4-78.0) at 5 yrs. Pts aged 18-29 yrs had superior 5-yr EFS compared to those aged 30-50 yrs (76.3% [95% CI 63.0-85.3] vs. 62.8% [95% CI 48.8-74.0], p = 0.033). Treatment on trial (compared to “as per”), BMI, and MRD status were not statistically associated with EFS. Conclusions: The administration of a pediatric regimen with dose intensified PEG-ASP to population between 18-50 is feasible and results in a high remission rate with 5-yr OS 75.8%.

Impact of High-Risk Cytogenetics (HR-CTG) on the Outcome of Newly Diagnosed Adult Patients with Philadelphia Negative B-Cell Acute Lymphoblastic Leukemia (B-ALL) Treated with Frontline Blinatumomab (Blina) and/or Inotuzumab Ozogamicin (Ino) Containing Hypercvad (HCVAD) Therapy

Introduction: HR-CTG in B-ALL is considered an adverse prognostic factor along with age and measurable residual disease (MRD) status. The use of potent B-cell targeted drugs like InO and Blina as part of frontline therapy has improved outcomes in adult pts with B-ALL ( Jabbour et al, Lancet Haematology 2022 and 2023) but the impact of baseline HR-CTG needs to be further elucidated . Methods: From Oct 2014-Feb 2023 we identified 71 consecutive patients (pts) with Philadelphia (Ph)-negative B-ALL and adequate CTG data who were treated on frontline therapy that included InO and/or Blina along with HCVAD chemotherapy. The intensive phase of treatment protocol consisted of HCVAD 4 courses followed by 4 courses of blina which could be initiated post HCVAD course 2 for high-risk or MRD positive pts and has been published before (Jabbour et al, Lancet Haematology 2022). The protocol was later amended to include fractionated InO from course 2 of HCVAD at a cumulative dose of 2.4 mg/m 2(Short et al, ASCO 2023). Pts with confirmed Ph-like ALL were excluded. CTG was evaluated and graded as HR based on a combination of conventional karyotyping and fluorescent in situ hybridization data and included low-hypoploidy or near triploidy (Ho-Tr), complex karyotype (CK; ≥5 abnormalities), 14q32 rearrangement ( IGH) and KMT2A re-arrangement as described before (Issa et al, Cancer 2017). Results: 31 of 71 pts (44%) with Ph- B-ALL had HR-CTG; 14 pts (45%) with Ho-Tr, 8 (26%) pts with KMT2A rearrangement, 6 pts (19%) with CK and 3 pts (10%) with IGH rearrangement (Table 1). The median age of the whole cohort was 33 years (range, 18-60 years); median age was 29 yrs in HR-CTG group compared to 34 yrs in non-HR-CTG group. 12 pts (39%) in the HR group compared to 5 pts (12%) in the non-HR group had a TP53 mutation ( p=0.01). 5/12 (42%) pts in the HR group with TP53 mutation had low-hypoploidy. 7 pts (23%) and 13 (32%) pts in the HR-CTG and non-HR-CTG group respectively had RAS mutations, with 1 pt in each group having both TP53 and RAS mutation. 17 pts (55%) received Blina and 14 pts (45%) received both InO and Blina in the HR group compared to 20 pts (50%) each who received Blina and Blina+ InO in the non-HR group. A best response of complete remission (CR)/CR with incomplete count recovery (CRi) was obtained in 100% pts (CR=30, CRi=1) in the HR-CTG group, 17 (55%) of whom had concurrent MRD negativity ; in the non-HR-CTG group 39 pts (98%) attained CR and one pt a partial remission, with concurrent MRD negativity attained in 21/39 (54%) pts with CR. At a median follow-up of 31 months (mos) for the full cohort (43 mos for HR pts and 28 mos for the non-HR group) the median overall survival (OS) was not reached (NR) and 3-yr OS was 85% (95% CI, 78-92%); median OS and 3-yr OS were NR and 89% in the HR-CTG group and 74.7 mos and 82% in the non-HR-CTG group ( p=0.64). The median relapse free survival (RFS) was NR in the HR-CTG group and 74 mos in the non-HR group ( p=0.73) while the 3-yr RFS were 74% and 80% respectively. There was no intergroup difference in RFS and OS based on the MRD status at response assessment. 11 HR-CTG pts (35%) underwent allogeneic stem cell transplantation (SCT) (5 Ho-Tr, 4 KMT2Ar, 1 CK, 1 IGHr) in continued remission at a median of 4.8 mos from therapy initiation (IQR 4.5-8.2 mos), 9 of whom went directly to SCT without introduction of a new therapy between the frontline therapy and SCT. Two pts received additional lines of therapy for MRD relapse/progression without morphological relapse before SCT. The 3-year OS in the HR-CTG pts who underwent SCT was 87% and similar to HR pts who did not undergo SCT (89%, p=0.78). 5 pts (12%) underwent SCT in the non-HR-CTG group, 4 for persistent or recurrent MRD positivity and one with Down's syndrome. No pts in either groups developed hepatic sinusoidal obstruction syndrome or a secondary myeloid neoplasm. Conclusion: In our analysis, in a prospectively maintained dataset where &amp;gt;90% pts were treated on clinical trial, HR-CTG did not have any significant impact on B-ALL survival outcomes when treated with frontline therapy containing B-cell targeted agents. Further analysis is underway.

Association of Measurable Residual Disease with Progression-Free Survival in Patients with Chronic Lymphocytic Leukemia: A Systematic Review and Meta-Analysis in the Era of Novel Agents

Introduction: Achieving undetectable measurable residual disease (uMRD) following treatment has shown significant prognostic value in several hematological malignancies. In chronic lymphocytic leukemia (CLL), uMRD is associated with improved outcomes in the era of chemoimmunotherapy (CIT). However, the role of measurable residual disease (MRD) in the context of novel agents such as Bruton tyrosine kinase inhibitors (BTKi) and/or BCL2 inhibitors (e.g. venetoclax) is uncertain. To address this question, we conducted a systematic review of the literature and performed a comprehensive meta-analysis of trials that included novel agents to evaluate the association between MRD status after treatment and PFS in patients with CLL. Methods: We conducted a comprehensive search of PubMed, EMBASE, Scopus, and Web of Science focusing on CLL trials reporting MRD and its association with PFS. Results were independently screened by two reviewers. Inclusion criteria included prospective phase 3 trials involving a novel agent in one of the treatment arms, while studies with incomplete information on MRD status related to PFS, reviews, abstracts, and retrospective analyses were excluded. The initial search identified 185 studies in PubMed and 402 studies in EMBASE. After applying prespecified criteria, a total of 10 phase 3 trials were included in our analysis. We extracted sample size, patient age, follow-up time, time point and tissue of MRD assessment, MRD cut-off and rate, performance status and molecular status when available. We only considered treatment arms with complete MRD information. The comparison involved patients who achieved uMRD with those exhibiting detectable MRD. When available, hazard ratios (HR) and confidence intervals (CI) were used to evaluate the relationship between MRD status and PFS. If not, we used Kaplan-Meier (KM) curves from both uMRD and MRD subgroups and extracted the coordinates points of the curves using DigitizeIt software (version 2.5.10, I. Bormann) and using the number at risk provided we estimated the HRs and CIs. A meta-analysis was performed using a random effects model from the R package metafor (Viechtbauer, W. (2010). Conducting meta-analyses in R with the metafor package. Journal of Statistical Software, 36(3), 1-48). The pooled hazard ratio estimates, and the corresponding 95% CI and prediction intervals (PI) were reported. Funnel and Baujat plots were generated to assess study heterogeneity and bias. All analysis was performed using R version 4.1.2 (R Foundation for Statistical Computing, Vienna, Austria). Results: A total of 10 phase 3 trials, encompassing 14 treatment arms and involving 3152 patients, met the stringent inclusion criteria. All but one study used a uMRD cut-off of &amp;lt; 0.01%. Detailed information on the treatment arms and key trial characteristics is presented in Table 1. Notably, ten treatment arms were derived from first-line treatment trials, while the remaining arms pertained to the relapsed/refractory population. Only two trials (4 treatment arms) assessed MRD using next generation sequencing (NGS), while the rest used multicolor flow cytometry (MFC) (9 treatment arms) and allele-specific oligonucleotides polymerase chain reaction (ASO-PCR) (2 treatment arms). All but 3 trials assessed MRD in both bone marrow (BM) and peripheral blood (PB). One trial (2 treatment arms) was excluded from the met-analysis due to higher MRD cut-off. All studies included in the meta-analysis measured uMRD (&amp;lt;0.01) versus MRD. The PFS pooled HR estimate for achieving uMRD at 0.01 cut off from the meta-analysis was 0.32 (95% CI [0.22, 0.45]), with minimal bias observed on the Funnel Plot. Conclusions: In this comprehensive meta-analysis, comprising 9 phase 3 trials, achieving uMRD was strongly associated with PFS. These findings further establish the prognostic role of MRD in CLL management and its potential use as a surrogate marker in clinical trials. As the body of evidence on MRD in CLL continues to grow, it becomes imperative to standardize the optimal time point, methodology, and tissue for MRD assessment. Substantial heterogeneity in these aspects underscores the necessity for unified guidelines to ensure the accurate and consistent evaluation of MRD status in clinical practice.

Deep Sequencing Is a Widely Applicable Tool for Relapse Prediction in Acute Myeloid Leukemia with Mutated NPM1

Analysis of measurable residual disease (MRD) is a powerful tool for assessment of treatment response in acute myeloid leukemia (AML). In patients with mutation in NPM1, reverse transcription quantitative polymerase chain reaction (RT-qPCR) is recommended by European Leukemia Net for refinement of risk stratification and monitoring after treatment. However, since RT-qPCR is mutation-specific and requires stringent quality control, many clinical laboratories restrict NPM1 monitoring to the type A mutation (c.860_863dupTCTG) although &amp;gt;50 mutations have been reported in exon 12. Deep sequencing is an alternative method, performed on DNA, that covers all NPM1 exon 12variants in the same assay. Guidelines for its clinical use are however lacking. We here performed a retrospective analysis in a population-based cohort of AML patients to evaluate if deep sequencing MRD analysis of NPM1 during chemotherapy provides prognostic information. Adult patients with AML with mutated NPM1 treated with curative intent in our region during 2006-2016 who achieved complete remission (CR) or CR with incomplete count recovery (CRi) were eligible for the study. This time period was chosen to avoid inclusion of patients treated based on molecular MRD status. Through review of the national AML registry, clinical charts, and screening of diagnostic samples, 99 patients with mutated NPM1 were identified. Of these, 97 patients (60 women and 37 men, median age 64 years, range 19-82) had bone marrow slides for isolation of DNA from at least one time point during treatment. DNA from 257 bone marrow aspirate slides were assessed for MRD using deep sequencing of NPM1. Based on previous comparison with RT-qPCR (Pettersson et al, Int J Lab Hematol 2021;43:664-674), variant allele frequency (VAF) of ≥0.05% was chosen as cut-off to define deep sequencing MRD positivity (MRD pos). For subgroup analyses, patients were divided into groups of treatment intensity; high-dose (cytarabine- and daunorubicin-based, n=67) or low-dose (cytarabine- and daunorubicin-, or azacytidine-based, n=30) treatment regimens. Thirty-one patients underwent allogeneic stem cell transplantation (alloSCT). We first evaluated if deep sequencing MRD status during consolidation (n=70, analyzed after 2 or 3 cycles) had an impact on prognosis. Both 3-year relapse-free survival (RFS) (26.7±11.4% vs 71.6±6.2%, p=&amp;lt;0.001, Figure) and overall survival (OS) (33.3±12.2% vs 72.7±6%, p=0.004) were lower for patients that were MRD pos at any time point during consolidation than for MRD neg patients. Among MRD pos patients, 12/15 (80%) relapsed and 13/15 (87%) died, compared to 19/55 (35%) and 23/55 (42%) MRD neg patients. In univariate analyses, also age and treatment intensity, but not alloSCT or DNMT3A mutation status, predicted RFS and OS. FLT3-ITD predicted OS but not RFS, and there was no effect of FLT3-ITD allelic ratio. In Cox regression multivariate analysis including MRD, age, FLT3-ITD and treatment intensity, MRD pos was the only significant predictor of RFS (Hazard ratio (HR): 2.54, p=0.019). In the multivariate analysis, FLT3-ITD (HR: 2.43, p=0.014) and treatment intensity (HR: 0.43, p=0.035) were significant for OS (MRD pos HR: 1.75, p=0.13). When dividing the cohort based on treatment intensity, the effect of MRD status was most obvious in patients treated with low-dose regimens. When deep sequencing MRD analysis was performed post first cycle (n=96), it had no statistically significant effect on either RFS or OS. At the end of treatment (n=51), deep sequencing MRD status had a strong prognostic value with 3-year RFS and OS for MRD pos patients 30±14.5% and 40±15.5%, compared to 73.2±6.9% and 78±6.5% for MRD neg patients ( p=0.003 and p=0.006, respectively). In summary, this population-based study shows that MRD status by deep sequencing of NPM1 is predictive of both RFS and OS when assessed during or after consolidation. The study confirms the threshold of deep sequencing MRD pos of VAF 0.05% previously obtained by comparison with RT-qPCR. Since deep sequencing can be used for all NPM1 mutations, it is widely applicable and extends the use of molecular MRD analysis and risk refinement to patients with rare mutations in NPM1.

Toward a Measurable Residual Disease-Based Algorithm for Selection of Allogeneic Hematopoietic Stem Cell Transplant in Acute Myeloid Leukemia

Background: The diagnosis and management of acute myeloid leukemia (AML) have transformed in recent years with an improved understanding of leukemogenesis and improved methods of measurable residual disease (MRD) detection. Current treatment algorithms include consideration of allogeneic hematopoietic stem cell transplant (HCT) for intermediate and adverse-risk AML. MRD negativity is widely accepted as a predictive and prognostic marker for disease-free survival and overall survival. However, the clinical use of MRD status in consolidative HCT planning remains unclear. Methods: Two hundred thirty-three consecutive patients achieving complete remission (CR) as defined in ELN 2022 after receiving therapy at Massey Cancer Center were analyzed. MRD status was determined either by multiparameter flow cytometry, PCR-based sequencing, and/or next-generation sequencing. Patients were analyzed via retrospective chart review to obtain baseline characteristics, molecular and cytogenetic profiles, and survival data. Median overall survival (mOS) was calculated and compared using the Kaplan-Meier method. Continuous variables were compared using one-way ANOVA. Categorical variables were analyzed using Fisher's exact test. Results: In total,109 patients achieved MRD-negative CR and 124 patients achieved an MRD-positive CR. Of the MRD-negative patients, 42 went received HCT (39%). In the MRD-positive cohort, 44 underwent HCT (35%). Among the MRD negative group, those receiving HCT tended to be younger (52.1 y. [range: 24.8-71.7] vs 61. 8 y. (range: 27.1-82.9) p = 0.026) with fewer co-morbidities (Charlson comorbidity index [CCI] score: 3 [range: 2-9] vs 4 (range: 0-14), p = 0.322). We observed a similar trend in those who had MRD positivity at best response or at the time of transplant (age 55 y. [range: 24.5-72.2] vs 62 y. [range: 25.1-88], p = 0.142; CCI 4 [range: 2-7] vs 5 (range 2-11], p = 0.014). In the MRD-negative/no HCT group, 49.3% had ELN favorable-risk disease at initial AML diagnosis, 28.4% had intermediate risk, and 22.4% had adverse risk. In the MRD-negative/HCT group, 31% were favorable risk, 33.3% intermediate risk, and 35.7% were adverse risk. In the MRD-positive/HCT group, 46.3% favorable risk, 23.8% intermediate risk, and 29.5% were adverse risk. There were no significant differences in ELN risk between any group. MRD-positive patients who underwent HCT had a mOS of 25.7 m. vs 20.7 m. for no HCT (HR=0.68 [95% CI, 0.41-1.11], p = 0.125). The median OS was not reached for MRD-negative patients, regardless of receipt of HCT (HR=0.61 [95% CI, 0.30-1.23], p = 0.168). Patients undergoing HCT in MRD-negative CR had improved OS compared to those undergoing HCT with persistent MRD positivity (p = 0.006). Discussion: MRD positivity is a known predictor of relapse and decreased survival despite HCT. However, the use of MRD as a decision point predicting which patients will benefit from transplant a priori needs to be better understood. Our data suggest that MRD negativity has a more significant impact on overall prognosis than HCT status.Likewise, the negative impact of MRD positivity was not significantly abrogated by subsequent HCT. This highlights the need for refinement in HCT selection beyond ELN 2022 intermediate/adverse-risk patients, and new validated algorithms incorporating MRD status are warranted.

Clinical Significance of Measurable Residual Disease (MRD) in Relapsed/Refractory Multiple Myeloma (RRMM) Patients (Pts) Treated with Chimeric Antigen Receptor (CAR) T Cells and T-Cell Engagers (TCE)

Clinical Significance of Measurable Residual Disease (MRD) in Relapsed/Refractory Multiple Myeloma (RRMM) Patients (Pts) Treated with Chimeric Antigen Receptor (CAR) T Cells and T-Cell Engagers (TCE)

Trial in Progress: A Phase 1b Single-Arm, Open-Label Study of Emavusertib (CA-4948) in Combination with Azacitidine and Venetoclax in Acute Myeloid Leukemia Patients in Complete Response with Measurable Residual Disease

Background Emavusertib is a novel potent oral inhibitor of interleukin-1 receptor-associated kinase 4 (IRAK4) with additional inhibitory activity against FMS-like tyrosine kinase 3 (FLT3) and CDC-like kinases (CLK1/2/4). Inhibition of these onco-proteins may induce remission thereby addressing a critical unmet need for novel therapies in acute myeloid leukemia (AML). Clinical studies with emavusertib monotherapy have demonstrated a significant reduction in AML blasts with clinical and molecular responses, including patients with relapsed or refractory AML, previously treated with an HMA and/or FLT3 inhibitors (Metzeler 2022). Azacitidine + venetoclax (aza+ven) has been approved in newly diagnosed, unfit patients with AML. In the VIALE-A study, composite complete response (CRc) (CR, CRh, or CRi) in the absence of measurable residual disease (MRD) of &amp;lt;1 residual blast/1000 leukocytes (MRD negative [MRD−]) resulted in longer duration of response (DOR), event-free survival, and overall survival (OS), and better HSCT outcome compared with patients who achieved CRc but were MRD+ (Pratz, 2022). In pre-clinical studies, emavusertib in combination with aza+ven demonstrated synergistic antileukemic effects in AML cell lines, including azacitidine- or venetoclax-resistant cell lines. Adding emavusertib to aza+ven in MRD+ patients at the time of CR may convert MRD status without adding significant toxicity and confirm that emavusertib can be safely added to aza+ven as a potential new regimen in front-line therapy. Study Design: This is a single-arm, open-label Phase 1b trial evaluating safety and tolerability, PK, and conversion of MRD status with emavusertib as an add-on agent to aza+ven in AML patients who achieved CR or CRh with MRD+ based on local testing (EU CT Number 2023-505828-58-00). The primary objective of the study is to determine a safe and tolerable dosing schedule for the triple combination. Secondary objectives include MRD conversion rate, DOR, OS, and pharmacokinetics. The study will enroll approximately 24 patients at 5 to 10 sites globally. Patients will have received azacitidine and venetoclax as first line therapy and achieved CR or CRh after 1-6 cycles of aza/ven. If MRD status remains positive, emavusertib will be added to the existing well tolerated aza+ven regimen. The starting emavusertib dose is 200 mg BID for 7 days per cycle of 28 days. If well tolerated, duration of emavusertib treatment will be extended to 14 and 21, respectively; no intra-patient change of emavusertib dosing duration is planned. The patients will continue triple treatment (emavusertib+aza+ven) until consent withdrawal, disease progression, intolerable toxicity, or not achieving MRD- within 6 cycles of triple treatment. In this Phase 1b trial, MRD can be evaluated by local testing of bone marrow. Key exclusion criteria include residual toxicities and significant comorbidities.

Comparison of Autologous, Matched Sibling, and Alternative Donor Stem Cell Transplant Outcomes for Acute Myeloid Leukemia Patients in First Remission: A Propensity Score Matching Study

Introduction Autologous hematopoietic stem cell transplantation (auto-HSCT), matched sibling donor HSCT (MSD-HSCT), and alternative donor HSCT (AD-HSCT) are viable post-remission treatment options for acute myeloid leukemia (AML). Auto-HSCT is more commonly administered in favorable- and intermediate-risk AML with good remission, while MSD-HSCT and AD-HSCT are suggested for patients with high-risk factors. In the present study, we aim to retrospectively compared auto-HSCT with MSD-HSCT and AD-HSCT in de novo AML patients who are in first complete remission (CR1) with favorable or intermediate risk, according to 2022 ELN criteria. Methods We conducted a single-center retrospective comparative analysis, comparing auto-HSCT and allo-HSCT for favorable and intermediate-risk de novo AML in CR1. Patients with secondary AML, acute promyelocytic leukemia, poor-risk AML, those receiving syngeneic HSCT, those not in CR1 before HSCT, or those who achieved CR1 with ≥ 3 cycles of induction chemotherapy were excluded from the study. A total of 283 de novo favorable- and intermediate-risk AML patients, based on the ELN 2022 criteria, in first complete remission were initially included for propensity score matching. Persistent undetectable MRD (uMRD) was defined as uMRD after one course of chemotherapy without recurrent positive MRD before HSCT, while non-persistent uMRD was characterized by the presence of detectable MRD at least once before HSCT. The variables used for propensity score matching included induction chemotherapy cycles, consolidation chemotherapy cycles, and measurable residual disease (MRD) measurement by flow cytometer before HSCT. A caliper width of 0.2 was used. Following the matching process, 126 patients were selected for further analysis, with 42 patients in each of the auto-HSCT, MSD-HSCT, and AD-HSCT groups. Results After applying propensity score matching, a final cohort of 126 patients was available for analysis. This cohort consisted of 42 patients in each group: auto-HSCT, MSD-HSCT, and AD-HSCT. Among the AD-HSCT group, 38 of 42 (90.5%) patients received haploidentical HSCT (haplo-HSCT). All patients received myeloablative conditioning regimen. There were no significant differences observed in the 3-year overall survival (OS) and disease-free survival (DFS) among the auto-HSCT, MSD-HSCT, and AD-HSCT groups [3-year OS: 79.5% (95% CI, 67.8-93.3%), 83.0% (95% CI, 72.2-95.3%), and 65.7% (95% CI, 50.5-85.5%), respectively; P=0.21. 3-year DFS: 72.6% (95% CI, 59.9-87.9%), 83.0% (95% CI, 72.2-95.3%), and 67.5% (95% CI, 54.2-84.1%), respectively; P=0.32]. The cumulative incidence of 3-year NRM was 2.7% (95% CI, 2.0-12.5%), 7.3% (95% CI, 1.8-17.9%), and 21.9% (95% CI, 10.7-35.6%), respectively (P=0.008). The 1-year probability of OS after relapse was higher in the auto-HSCT group (44.4%; 95% CI, 21.4-92.3%) compared with MSD-HSCT (0.0%) and AD-HSCT (37.5%; 95% CI, 8.4-99.9%) (P=0.0017). The MRD status before HSCT had an impact on DFS (persistent uMRD versus non-persistent uMRD: HR=0.29; 95% CI 0.09-0.94, P=0.04) and relapse (persistent uMRD versus non-persistent uMRD: HR=0.17; 95% CI 0.05-0.66, P=0.01) following auto-HSCT. The subgroup analysis was then performed based on MRD status before HSCT. In patients with uMRD before transplant (n=83), OS was similar across the groups. However, auto-HSCT showed a trend of increased DFS compared to AD-HSCT (HR 2.85, P=0.09), resulting in a 3-year DFS and OS of 79.1% and 82.8%, respectively. In the non-persistent uMRD group (n=38), auto-HSCT exhibited a tendency to increase the risk of relapse, particularly when compared to AD-HSCT (HR 0.24, P=0.07), but this did not result in inferior OS. The monthly direct medical cost per patient within the first two years after HSCT was significantly lower in auto-HSCT compared to MSD-HSCT (P=0.015) and AD-HSCT (P&amp;lt;0.001). Conclusions Our results provide evidence for the use of auto-HSCT as a viable therapeutic option for favorable- and intermediate-risk de novo AML patients in first complete remission with persistent uMRD. Additionally, our findings demonstrated a notable cost advantage associated with auto-HSCT compared to MSD-HSCT and AD-HSCT.

A Novel and Cost-Efficient Measurable Residual Disease (MRD) Detection Assay Using a Single Molecule Molecular Inversion Probe-Based Next Generation Sequencing (NGS) Assay Predicts Overall Survival in Patients with Acute Myeloid Leukemia Undergoing Allogeneic Stem Cell Transplantation

Introduction Relapse remains the main reason for poor outcomes of patients (pts) with acute myeloid leukemia (AML). Allogeneic hematopoietic stem cell transplantation (HSCT) is the preferred post-remission treatment in pts at high risk of relapse. The presence of measurable residual disease (MRD) after intensive frontline treatment or before or after HSCT has emerged as an important predictor of relapse. Various methods are used for MRD detection, including flow cytometry and molecular assays detecting individual gene mutations (mut) such as NPM1mut. Next generation sequencing (NGS)-based assays covering multiple genes commonly mutated in AML may allow sensitive MRD detection in a broad range of pts with diverse genetic characteristics. Methods We established a targeted, error corrected NGS MRD assay utilizing single-molecule molecular inversion probes (smMIPs). The smMIP protocol uses a hybridization-capture approach to selectively enrich and amplify both DNA strands of 92 regions in 32 genes in a single reaction. Unique molecular identifiers (UMIs) facilitate computational correction of sequencing errors to enable reliable detection of variants ≥0.5% variant allele frequency (VAF), with the additional advantage of relatively low reagent and sequencing costs of &amp;lt; $100 per sample. The smMIP assay was used to evaluate MRD status on pre-HSCT bone marrow samples from 98 AML pts who received an HSCT in first (n=83) or second (n=15) complete remission with or without count recovery. Median age at HSCT was 59 (range 20-75) years, 42% were female; 70% had de novo AML, 19% had an antecedent myeloid neoplasm and 11% had AML post cytotoxic therapy. European LeukemiaNet (ELN)-2022 risk groups at diagnosis were favorable in 11%, intermediate in 33%, adverse in 20% and unknown in 22%. All pts had received intensive induction chemotherapy. Twenty-nine percent received a myeloablative conditioning regimen (MAC), while 23% received reduced intensity conditioning (RIC) and 48% a non-myeloablative (NMA) conditioning regimen. Donors were matched related (18%), haploidentical (6%), or matched (55%) or mismatched (21%) unrelated. The median follow-up for pts alive was 34.8 months. Results Overall, we detected 190 variants in 71 (72%) of 98 pre-HSCT remission samples. The most commonly affected genes were DNMT3A (in 37% of pts), TET2 (21%), PPM1D (12%), IDH2 (10%) and TP53 (5%). Twenty-nine percent of pts had only variants affecting the clonal hematopoiesis-related genes DNMT3A, TET2 or ASXL1 (‘DTA‘), while 44% of patients had ≥1 variant involving a non-DTA gene. MRD-positive pts, defined as those with ≥1 non-DTA variant, had similar baseline and HSCT-related characteristics (includingage, sex, ELN risk group, de novo vs. secondary AML) compared to pts without non-DTA variants. Overall survival (OS) was significantly inferior in NGS MRD-positive pts compared to those with no non-DTA variant (Figure A, 5-year OS, 49% vs. 85%, P=.011). MRD-positive pts also had a non-significant higher cumulative incidence of relapse at 5 years (46% vs. 24%, P=.14), while non-relapse mortality was similar in both groups (P=.72). We next performed multivariable analyses, considering variables associated with OS at an univariable P&amp;lt;.10 (MRD status, patient sex, therapy-related AML, conditioning intensity), and using stepwise backward variable selection to identify factors significantly associated with OS (Figure B). In the final multivariable model, pre-HSCT MRD detection remained associated with inferior OS (hazard ratio 2.51; 95% confidence interval, 1.07 - 5.91; P=.035). Female sex associated with favorable OS, while myeloablative conditioning (MAC) showed a borderline significant association with superior OS. Of note, we did not detect an interaction between conditioning intensity and detection of MRD with regard to OS, i.e. the prognostic association of MRD detection was not different between pts receiving myeloablative or less-intensive conditioning. However, this analysis was limited by the small patient number. Conclusion Detection of MRD by targeted NGS using the smMIPs approach provides prognostic information in pts undergoing allogeneic HSCT, including those without established molecular markers such as NPM1mut. This method is applicable to a large proportion of AML pts and is cost-efficient for broad clinical use. S.M.K. and T.H., and M.J. and K.H.M. contributed equally to this abstract.

Subgroup Analyses of Progression-Free Survival from the Phase 3 Octans and Alcyone Studies in Transplant-Ineligible Patients with Newly Diagnosed Multiple Myeloma Treated with Bortezomib, Melphalan, and Prednisone with or without Daratumumab

Introduction:Daratumumab, a human IgGκ monoclonal antibody targeting CD38, has shown clinical efficacy in combination with standard-of-care regimens in patients with newly diagnosed multiple myeloma (NDMM). The addition of daratumumab to bortezomib, melphalan, and prednisone (D-VMP) significantly improved clinical outcomes vs bortezomib, melphalan, and prednisone (VMP) in phase 3 studies in Asian patients (OCTANS) and a global population (ALCYONE) with transplant-ineligible (TIE) NDMM. Here, we present subgroup analyses of progression-free survival (PFS) by measurable residual disease (MRD) and cytogenetic risk status from OCTANS and ALCYONE. Methods: Eligible patients from OCTANS (NCT03217812) and ALCYONE (NCT02195479) had a diagnosis of NDMM and were TIE due to age or comorbidities. Patients were randomized to receive up to nine 42-day cycles of VMP (bortezomib 1.3 mg/m 2 SC twice weekly in Cycle 1 and weekly in Cycles 2-9, and melphalan 9 mg/m 2 and prednisone 60 mg/m 2 orally on Days 1-4 of each cycle) or D-VMP (VMP + daratumumab 16 mg/kg IV weekly in Cycle 1, every 3 wk in Cycles 2-9, and every 4 wk thereafter until disease progression or unacceptable toxicity). MRD negativity (10 -5) was assessed by multi-parameter flow cytometry in OCTANS and next-generation sequencing in ALCYONE. Cytogenetic risk was assessed by FISH or karyotype testing. Results:A total of 220 Asian patients were randomized (D-VMP, n = 146; VMP, n = 74) in OCTANS, and 706 global patients were randomized (D-VMP, n = 350; VMP, n = 356) in ALCYONE. With a median follow-up of 41.2 mo (range, 0.0-59.9) in OCTANS, the median PFS was 38.7 mo with D-VMP and 19.2 mo with VMP (HR, 0.35; 95% CI, 0.23-0.52; P &amp;lt;0.0001). With a median follow-up of 40.1 mo (range, 0.0-52.1) in ALCYONE, the median PFS was 36.4 mo with D-VMP and 19.3 mo with VMP (HR, 0.42; 95% CI, 0.34-0.51; P &amp;lt;0.0001). The rates of overall and sustained MRD negativity were higher with D-VMP vs VMP. In OCTANS, the MRD-negativity rate was 40.4% with D-VMP vs 10.8% with VMP ( P &amp;lt;0.0001), and more patients in the D-VMP group had sustained MRD negativity lasting ≥12 mo (24.7% vs 1.4%; P &amp;lt;0.0001) and ≥18 mo (15.1% vs 1.4%; P = 0.0008). Similarly, in ALCYONE, the MRD-negativity rate was 28.3% with D-VMP vs 7.0% with VMP ( P &amp;lt;0.0001), with more patients in the D-VMP group having sustained MRD negativity lasting ≥12 mo (14.0% vs 2.8%; P &amp;lt;0.0001) and ≥18 mo (8.9% vs 1.7%: P &amp;lt;0.0001). In both studies, longer PFS was observed for patients who achieved MRD negativity vs those who did not within each treatment group; however, the PFS benefit observed for D-VMP vs VMP was maintained irrespective of MRD status ( Figure). In multivariate analyses, achievement of sustained MRD negativity lasting ≥12 mo was associated with longer PFS vs MRD negativity &amp;lt;12 mo in both OCTANS (HR, 0.23; 95% CI, 0.09-0.62; P = 0.004) and ALCYONE (HR, 0.13; 95% CI, 0.06-0.32; P &amp;lt;0.0001). No other factors showed a significant association with PFS in the multivariate analysis for OCTANS; other factors associated with longer PFS in ALCYONE included age &amp;lt;75 vs ≥75 y (HR, 0.38; 95% CI, 0.20-0.75; P = 0.005) and ISS disease stage I vs II (HR, 0.20; 95% CI, 0.05-0.86; P = 0.03). Data from OCTANS and ALCYONE were pooled for an analysis of PFS by cytogenetic risk subgroup (D-VMP, n = 496; VMP, n = 430). D-VMP prolonged median PFS vs VMP in patients with standard cytogenetic risk (not estimable vs 18.9 mo; HR, 0.33; 95% CI, 0.26-0.42) and high cytogenetic risk (25.6 vs 18.9 mo; HR, 0.54; 95% CI, 0.41-0.71), defined by the presence of t(4;14), t(14;16), del(17p), t(14;20), gain(1q21), and/or amp(1q21). Median PFS was also longer with D-VMP vs VMP for patients with gain and/or amp(1q21) (31.9 vs 18.9 mo; HR, 0.45; 95% CI, 0.32-0.63), 1 high-risk cytogenetic abnormality (HRCA; 24.4 vs 19.3 mo; HR, 0.62; 95% CI, 0.44-0.86), and ≥2 HRCA (28.2 vs 17.5 mo; HR, 0.36; 95% CI, 0.20-0.63). Conclusions:In this subgroup analysis of OCTANS and ALCYONE, the prolonged PFS observed with D-VMP vs VMP in the overall study populations was maintained irrespective of the achievement of MRD negativity or the presence of high cytogenetic risk. In addition, the rates of MRD negativity and sustained MRD negativity were higher with D-VMP vs VMP, and achievement of these deep responses translated into longer PFS, consistent with a prior pooled analysis of the MAIA and ALCYONE studies. These results further support the use of daratumumab in combination with VMP in both Asian and global patients with TIE NDMM.

Outcome of Allogeneic Stem Cell Transplantation in FLT3-TKD-Mutated AML - a Study on Behalf of the Acute Leukemia Working Party of the EBMT

Introduction The overall prognostic impact of point mutations in the tyrosine-kinase domain 1 of FLT3 (FLT3-TKD mut) in patients (pts) with acute myelogenous leukemia (AML) remains controversial. Furthermore, co-occurrence of FLT3-TKD mut and mutated nucleophosmin-1 (NPM1 mut) was shown to have a favorable prognostic impact on AML pts receiving conventional chemotherapy. However, little is known about the outcome of AML pts with FLT3-TKD mut with or without co-occurring NPM1 mut treated with allogeneic stem cell transplantation (alloSCT). Patients and Methods This is a retrospective study of the acute leukemia working party (ALWP) of the European Society for Blood and Marrow transplantation (EBMT) investigating the outcome of adult AML pts with FLT3-TKD mut with or without NPM1 mut after first alloSCT using matched sibling (MSD), unrelated (UD) or haploidentical (haplo) donors between 2005 and 2022. All patients were in first or second complete remission (CR1 of CR2). Information on cytogenetic risk was necessary for inclusion. No ex-vivo T-cell depletion (TCD) was allowed. The primary endpoint was leukemia-free survival (LFS) at two years after alloSCT. Secondary endpoints were overall survival (OS), cumulative incidence of relapse (RI), non-relapse mortality (NRM), acute and chronic graft-versus-host disease (GVHD) and GVHD-free, relapse free survival (GRFS). One hundred and eighty-two adult AML pts with FLT3-TKD mut were identified, of which 74 (40.7%) had a co-occurring mutation in NPM1. Median age was 55.1 years (range 18.6-79.1) and 46.7% were male. Median follow-up was 21.4 months [IQR 13.6-28.1]. 78% of the pts were in CR1. Cytogentic risk was favorable, intermediate and adverse in 12.6%, 75.3% and 12.1% of pts, respectively. Additional FLT3 internal tandem duplication (FLT3-ITD) was present in 25.8% of pts. Information on measurable residual disease (MRD) was available for 68.7% of pts, being positive in 48% of these. Karnofsky performance score was &amp;lt; 90% in 21.1%, and hematopoietic cell transplantation-specific comorbidity index (HCT-CI) was &amp;gt;=3 in 28.1% of pts. 69.6% of pts were cytomegalovirus (CMV) positive. Conditioning was myeloablative in 52.8% and reduced intensity in 47.2% of pts. Stem cell donors were MSD, UD and haplo in 25.8%, 55.5% and 18.7% of cases. Stem cell source was bone marrow in 10.4%, peripheral blood in 87.4% and both in 2.2%. In-vivo TCD was performed in 59.2% of pts. GVHD prophylaxis was calcineurin inhibitor-based in 92.2% of pts. Results Engraftment was achieved in 99.4% of pts with a day-60 absolute neutrophil count (ANC) &amp;gt;0.5 x 10 9/L of 97.7% [95% CI: 93.7-99.2]. Day-180 rates of acute GVHD (aGVHD) grade II-IV and grade III-IV were 26.2% (95% CI:19.9-32.9) and 8.1% (95% CI:4.6-12.8), respectively. At two years, rates of total chronic GVHD (cGVHD) and extensive cGVHD were 30% (95% CI: 22.5-38) and 16.6% (95% CI:10.6-23.7), respectively. Two-year LFS and OS were 66.1% (95% CI: 57.6-73.2) and 74% (95% CI: 65.4-80.8), respectively. Two-year RI, NRM and GRFS were 22.5% (95% CI:16-29.8), 11.4% (95% CI: 7-17), and 51.1% (95% CI: 42.4-59.1), respectively. Cause of death was original disease in 47.5%, infection in 27.5%, GVHD in 22.5% and non-SCT related in 2.5% of cases. In univariate analysis the only factor with significant impact on LFS was donor type (haplo [n=34] vs. others, p=0.006). For GRFS, patient CMV negativity (p=0.014) and in-vivo TCD (p=0.01) were significant. Interestingly, co-occurring mutations in FLT3 (FLT3-ITD) or NPM1 were not identified as having a significant impact on LFS or GRFS. Moreover, MRD status before alloSCT was also not shown to have a significant impact on these outcomes. In multivariate analysis of LFS and GRFS, only donor type (haplo [n=34] vs. others) was shown to be significant for both endpoints, hazard ratio (HR) 2.54; 95% CI: 1.4-4.6; p=0.002, and HR 2.01; 95% CI: 1.18-3.41; p=0.01, respectively. Conclusion Acknowledging the limitations of our retrospective study in this rare entity results are encouraging given the high-risk population (median age 55.1 years, CR2 in 22%, co-occurring FLT3-ITD in 25.8%, positive MRD in 48%, HCT CI &amp;gt;=3 in 28.1%). LFS, OS and GRFS rates were 66.1%, 74% and 51.1%, respectively, and both RI and NRM were comparably low with rates of 22.5% and 11.4%, respectively. No positive prognostic impact of co-occurring mutations in FLT3-TKD and NPM1 was detected, unlike what was found for conventional chemotherapy.