Undetectable Measurable Residual Disease Research Articles

Predicting progression-free survival from measurable residual disease in chronic lymphocytic leukemia.

Association between measurable residual disease (MRD) and survival outcomes in chronic lymphocytic leukemia (CLL) has often been reported. However, limited quantitative analyses over large datasets have been undertaken to establish the predictive power of MRD. Here, we provide a comprehensive assessment of published MRD data to explore the utility of MRD in the prediction of progression-free survival (PFS). We undertook two independent analyses, which leveraged available published data to address two complimentary questions. In the first, data from eight clinical trials was modeled via a meta-regression approach, showing that median PFS can be predicted from undetectable MRD rates at 3-6 months of post-treatment. The resulting model can be used to predict the probability of technical success of a planned clinical trial in chemotherapy. In the second, we investigated the evidence for predicting PFS from competing MRD metrics, for example baseline value and instantaneous MRD value, via a joint modeling approach. Using data from four small studies, we found strong evidence that including MRD metrics in joint models improves predictions of PFS compared with not including them. This analysis suggests that incorporating MRD is likely to better inform individual progression predictions. It is therefore proposed that systematic MRD collection should be accompanied by modeling to generate algorithms that inform patients' progression.

Curative Strategy for High-Risk Smoldering Myeloma: Carfilzomib, Lenalidomide, and Dexamethasone (KRd) Followed by Transplant, KRd Consolidation, and Rd Maintenance.

Early treatment of high-risk smoldering myeloma has been shown to delay progression to multiple myeloma (MM). We conducted this trial with curative intention using a treatment approach employed for newly diagnosed patients with MM. Patients with high-risk smoldering myeloma (>50% progression risk at 2 years) and transplant candidates were included and received induction therapy with carfilzomib, lenalidomide, and dexamethasone (KRd), six cycles, followed by high-dose melphalan (200 mg/m2) autologous stem-cell transplantation (HDM-ASCT), two KRd consolidation cycles, and Rd maintenance for 2 years. The primary end point was undetectable measurable residual disease (uMRD) rate by next-generation flow after ASCT. Sustained uMRD 4 years after ASCT was the secondary end point. Between June 2015 and June 2017, 90 patients were included, and 31% met at least one SixtyLightchain MRI (SLiM)-hypercalcemia, renal impairment, anemia, bone disease (CRAB) criterion. After a median follow-up of 70.1 months, 3 months after ASCT, in the intention-to-treat population, 56 (62%) of 90 patients had uMRD, and 4 years later, it was sustained in 29 patients (31%). Five patients progressed to MM, and the 70-month progression rate was 94% (95% CI, 84 to 89). The presence of any SLiM CRAB criteria predicted progression to MM (four of the five patients; hazard ratio, 0.12; 95% CI, 0.14 to 1.13; P = .03). Thirty-six patients showed biochemical progression, and failure to achieve uMRD at the end of treatment predicted it. The 70-month overall survival was 92% (95% CI, 82 to 89). Neutropenia and infections were the most frequent adverse events during treatment, resulting in one treatment-related death. Three second primary malignancies have been reported. Although a longer follow-up is needed, this curative approach is encouraging and more effective than active MM, with 31% of the patients maintaining the uMRD 4 years after HDM-ASCT.

Measurable Residual Disease and Clinical Outcomes in Chronic Lymphocytic Leukemia

Measurable residual disease (MRD) refers to the presence of disease at low levels not detected by conventional pathologic analysis. The association of MRD status as a surrogate end point of clinical outcome in chronic lymphocytic leukemia (CLL) has not been established in the era of targeted agents. Assessing the association of MRD with progression-free survival (PFS) may improve its role as a surrogate marker and allow its use to accelerate drug development. To assess the association between MRD and PFS in CLL using data from prospective clinical trials that studied targeted agents or obinutuzumab-based treatment. Clinical studies on CLL were identified via searches of PubMed, Embase, Scopus, and Web of Science from inception through July 31, 2023. Prospective, single-arm, and randomized clinical trials that assessed targeted agents or obinutuzumab-based treatment and reported PFS by MRD status were included. Studies with insufficient description of MRD information were excluded. Study sample size, median patient age, median follow-up time, line of treatment, MRD detection method and time points, and survival outcomes were extracted. Analyses of survival probabilities and hazard ratios (HRs) were conducted for PFS according to MRD status. Meta-analyses were performed using a random-effects model. A total of 11 prospective clinical trials (9 randomized and 2 nonrandomized) including 2765 patients were analyzed. Achieving undetectable MRD (uMRD) at 0.01% was associated with an HR of 0.28 (95% CI, 0.20-0.39; P < .001) for PFS. Median PFS was not reached in both groups (uMRD vs MRD), but the estimated 24-month PFS was better in the uMRD group (91.9% [95% CI, 88.8%-95.2%] vs 75.3% [95% CI, 64.7%-87.6%]; P < .001). The association of uMRD with PFS was observed in subgroup analyses in the first-line treatment setting (HR, 0.24; 95% CI, 0.18-0.33), relapsed or refractory disease setting (HR, 0.34; 95% CI, 0.16-0.71), and trials using time-limited therapy (HR, 0.28; 95% CI, 0.19-0.40). The findings of this systematic review and meta-analysis suggest that assessing MRD status as an end point in clinical trials and as a surrogate of PFS may improve trial efficiency and potentially allow for accelerated drug registration.

BIOM-02. DISSECTING CDK4/6 INHIBITOR RESISTANCE MECHANISMS IN RECURRENT PEDIATRIC BRAIN TUMORS WITH LONGITUDINAL CSF LIQUID BIOPSIES FROM THE SJDAWN CLINICAL TRIAL

Abstract BACKGROUND SJDAWN (NCT03434262) is a St. Jude Children’s Research Hospital phase 1 trial that assessed the safety and benefit of CDK4/6 inhibitor-based therapy in patients with relapsed CNS tumors. To capture tumor evolution dynamics and arising resistance mechanisms in response to treatment, 143 longitudinal CSF samples were collected from 34/68 (50%) patients for cell-free DNA (cfDNA) analysis. METHODS cfDNA was extracted from CSF liquid biopsies and analyzed using a novel methylation-based platform that integrates copy number, tumor classification, and deconvolution of methylation signatures into normal vs. disease fractions. Samples with measurable residual disease (MRD) were further characterized by deep whole-genome sequencing to discover mutation-driven resistance mechanisms. When available, pre- and post-SJDAWN tumor tissues were processed for single-nucleus multi-omics to track tumor evolution at single-cell resolution. RESULTS In the context of CDK4/6 inhibitor-based therapy, longitudinal cfDNA assessment revealed treatment-induced selection for subclones with focal amplification of positive cell cycle regulators CDK6, CCND2, and MYCN. Emergence of these resistance mechanisms notably preceded disease progression on MRI and CSF cytology by up to 6 months. Of the 68 patients enrolled on SJDAWN, 4 patients (3 Group 3/4, subtype III medulloblastomas and 1 anaplastic ependymoma) achieved &amp;gt;2-year progression-free survival. Interestingly, serial cfDNA profiling of 1 long-term survivor (Group 3/4, subtype III medulloblastoma) exhibited undetectable MRD status for &amp;gt;1.5 years prior to reemergence, suggesting tumor senescence by CDK4/6 inhibition may impede circulating tumor DNA (ctDNA) release kinetics. CSF liquid biopsies were further evaluated in comparison to matched tumor tissues, and changes in CSF-specific subclones were observed in response to treatment. CONCLUSIONS In addition to early MRD detection, liquid biopsies capture tumor evolution dynamics and can inform developing resistance mechanisms. Focal amplification of CDK6, CCND2, and MYCN facilitates CDK4/6 inhibitor resistance. In responders, treatment-induced senescence may inhibit ctDNA release kinetics.

CELESTIAL-TNCLL: An ongoing, open-label, multiregional, phase 3 study of sonrotoclax (BGB-11417) + zanubrutinib vs venetoclax + obinutuzumab for treatment-naïve (TN) CLL.

TPS7087 Background: The combination of venetoclax (ven), the first-generation BCL2 inhibitor, and ibrutinib, a BTK inhibitor, has demonstrated efficacy in patients with CLL (Wierda et al. J Clin Oncol. 2021); however, the toxicity profile of this regimen suggests a need for a more tolerable BTK/BCL2 inhibitor combination. Sonrotoclax, a next generation BCL2 inhibitor, is a more selective and more pharmacologically potent inhibitor of BCL2 than venetoclax. In a phase 1 study in patients with TN CLL treated with sonrotoclax + zanubrutinib, efficacy data was promising with ORR and 1-year progression-free survival (PFS) rates of 100% and deep responses based on undetectable measurable residual disease at &lt;10-4 sensitivity (uMRD4). The most common grade ≥3 TEAE was neutropenia, and no tumor lysis syndrome or cardiac toxicity was observed (Tam et al. Blood. 2023). Zanubrutinib, a next-generation BTK inhibitor, significantly improved PFS and had a more tolerable safety profile, including fewer cardiac adverse events vs ibrutinib in a randomized, head-to-head study of patients with CLL/SLL (Brown et al. N Engl J Med. 2023). Presented here is the design of a phase 3 trial aimed at comparing the efficacy of sonrotoclax + zanubrutinib vs ven + obinutuzumab (obi) in patients with TN CLL. Methods: CELESTIAL-TNCLL (BGB-11417-301; NCT06073821) is a randomized, open-label, phase 3 study. Eligible patients must have previously untreated CLL that requires treatment per 2018 iwCLL criteria, measurable disease by CT/MRI, an ECOG performance score of 0-2, and adequate hematologic and organ function. Approximately 640 patients will be randomized 1:1 to receive either 3 cycles of zanubrutinib monotherapy (320 mg total daily dose, orally), followed by zanubrutinib + sonrotoclax for 12 cycles, or standard ven + obi treatment for 12 cycles. Randomization will be stratified by age (&lt;65 vs ≥65 years) and IGHV and del(17p)/ TP53 mutation status. The primary endpoint is PFS as assessed by independent review committee (IRC) according to 2018 iwCLL guidelines with modifications for treatment-related lymphocytosis for patients with CLL (Cheson et al. 2012). Key secondary endpoints include complete response rate (CRR), defined as CR or CR with incomplete hematopoietic recovery, assessed by IRC; rates of uMRD4 in bone marrow and peripheral blood at the first post-treatment follow-up visit based on next-generation sequencing by clonoSEQ; and overall survival. Other secondary endpoints include PFS as assessed by investigator (INV); CRR by INV; rate of uMRD4 based on flow cytometry; overall response rate by IRC and INV; duration of response by IRC and INV; patient-reported outcomes; and safety and tolerability. Recruitment is ongoing. Clinical trial information: NCT06073821 .

Acalabrutinib, venetoclax, and obinutuzumab in relapsed/refractory CLL: final efficacy and ctDNA analysis of the CLL2-BAAG trial

AbstractThe phase 2 CLL2-BAAG trial tested the measurable residual disease (MRD)–guided triple combination of acalabrutinib, venetoclax, and obinutuzumab after optional bendamustine debulking in 45 patients with relapsed/refractory chronic lymphocytic leukemia (CLL). MRD was measured by flow cytometry (FCM; undetectable MRD <10–4) in peripheral blood (PB) and circulating tumor DNA (ctDNA) using digital droplet polymerase chain reaction of variable-diversity-joining (VDJ) rearrangements and CLL-related mutations in plasma. The median number of previous treatments was 1 (range, 1-4); 18 patients (40%) had received a Bruton tyrosine kinase inhibitor (BTKi) and/or venetoclax before inclusion, 14 of 44 (31.8%) had TP53 aberrations, and 34 (75.6%) had unmutated immunoglobulin heavy-chain variable region genes. With a median observation time of 36.3 months and all patients off-treatment for a median of 21.9 months, uMRD <10–4 in PB was achieved in 42 of the 45 patients (93.3%) at any time point, including 17 of 18 (94.4%) previously exposed to venetoclax/BTKi and 13 of 14 (92.9%) with TP53 aberrations. The estimated 3-year progression-free and overall survival rates were 85.0% and 93.8%, respectively. Overall, 585 paired FCM/ctDNA samples were analyzed and 18 MRD recurrences (5 with and 13 without clinical progression) occurred after the end of treatment. Twelve samples were first detected by ctDNA, 3 by FCM, and 3 synchronously. In conclusion, time-limited MRD-guided acalabrutinib, venetoclax, and obinutuzumab achieved deep remissions in almost all patients with relapsed/refractory CLL. The addition of ctDNA-based analyses to FCM MRD assessment seems to improve early detection of relapses. This trial was registered at www.clinicaltrials.gov as #NCT03787264.

Chronic Lymphocytic Leukemia Therapy Guided by Measurable Residual Disease

BackgroundThe combination of ibrutinib and venetoclax has been shown to improve outcomes in patients with chronic lymphocytic leukemia (CLL) as compared with chemoimmunotherapy. Whether ibrutinib–venetoclax and personalization of treatment duration according to measurable residual disease (MRD) is more effective than fludarabine–cyclophosphamide–rituximab (FCR) is unclear.MethodsIn this phase 3, multicenter, randomized, controlled, open-label platform trial involving patients with untreated CLL, we compared ibrutinib–venetoclax and ibrutinib monotherapy with FCR. In the ibrutinib–venetoclax group, after 2 months of ibrutinib, venetoclax was added for up to 6 years of therapy. The duration of ibrutinib–venetoclax therapy was defined by MRD assessed in peripheral blood and bone marrow and was double the time taken to achieve undetectable MRD. The primary end point was progression-free survival in the ibrutinib–venetoclax group as compared with the FCR group, results that are reported here. Key secondary end points were overall survival, response, MRD, and safety.ResultsA total of 523 patients were randomly assigned to the ibrutinib–venetoclax group or the FCR group. At a median of 43.7 months, disease progression or death had occurred in 12 patients in the ibrutinib–venetoclax group and 75 patients in the FCR group (hazard ratio, 0.13; 95% confidence interval [CI], 0.07 to 0.24; P<0.001). Death occurred in 9 patients in the ibrutinib–venetoclax group and 25 patients in the FCR group (hazard ratio, 0.31; 95% CI, 0.15 to 0.67). At 3 years, 58.0% of the patients in the ibrutinib–venetoclax group had stopped therapy owing to undetectable MRD. After 5 years of ibrutinib–venetoclax therapy, 65.9% of the patients had undetectable MRD in the bone marrow and 92.7% had undetectable MRD in the peripheral blood. The risk of infection was similar in the ibrutinib–venetoclax group and the FCR group. The percentage of patients with cardiac serious adverse events was higher in the ibrutinib–venetoclax group than in the FCR group (10.7% vs. 0.4%).ConclusionsMRD-directed ibrutinib–venetoclax improved progression-free survival as compared with FCR, and results for overall survival also favored ibrutinib–venetoclax. (Funded by Cancer Research UK and others; FLAIR ISRCTN Registry number, ISRCTN01844152; EudraCT number, 2013-001944-76.)

Predictors of unsustained measurable residual disease negativity in transplant-eligible patients with multiple myeloma

AbstractThe role of measurable residual disease (MRD) negativity as a biomarker to stop treatment is being investigated in transplant-eligible patients with multiple myeloma (MM). Thus, it is important to identify risk factors of MRD resurgence and/or progressive disease (PD) among patients achieving undetectable MRD to avoid undertreating them. Here, we studied 267 newly diagnosed transplant-eligible patients with MM enrolled in the GEM2012MENOS65 and GEM2014MAIN clinical trials who achieved MRD negativity by next-generation flow cytometry. After a median follow-up of 73 months since the first MRD negative assessment, 111 of the 267 (42%) patients showed MRD resurgence and/or PD. The only prognostic factors at diagnosis that predicted MRD resurgence and/or PD were an International Staging System (ISS) 3 and the presence of ≥0.01% circulating tumor cells (CTCs). Failure to achieve MRD negativity after induction also predicted higher risk of MRD resurgence and/or PD. Patients having 0 vs 1 vs ≥2 risk factors (ISS 3, ≥0.01% CTCs, and late MRD negativity) showed 5-year rates of MRD resurgence and/or PD of 16%, 33%, and 57%, respectively (P < .001). Thus, these easily measurable risk factors could help refine the selection of patients for whom treatment cessation after MRD negativity is being investigated in clinical trials. This trial was registered at www.clinicaltrials.gov as NCT01916252 and NCT02406144.

Venetoclax and Azacitidine for Molecular Relapse during First Line Intensive Chemotherapy in Patients with NPM1 Mutated or Core Binding Factor (CBF) AML. a Study from the Dataml Registry

Introduction: Molecular follow-up (FU) for AML patients (pts) with NPM1 mutation, RUNX1::RUNX1T1 or CBFB::MYH11 fusion transcripts has been established over the last ten years. Real-time quantitative PCR (qPCR) is the gold standard for the evaluation of measurable residual disease (MRD) in pts undergoing intensive chemotherapy (IC). Failure to achieve a deep molecular response is a strong predictive factor of relapse and survival and may guide post remission therapy (Ivey A, NEJM 2016). Moreover, the ELN MRD working party recommended a schedule for molecular FU and recently established a definition of molecular relapse (Heuser M, Blood 2021). However, there is no therapeutic consensus for pts with molecular relapse before overt clinical relapse. Frontline allogeneic hematopoietic cell transplantation (alloHCT), salvage IC or even waiting for morphological relapse in order to screen molecular characteristics of the relapsing disease or propose a clinical trial, may be discussed with pts. Venetoclax with azacitidine (VEN/AZA) was recently approved in unfit AML pts and demonstrated a particular efficacy in NPM1-mutated AML. In this study, we thought to describe the safety and efficacy of VEN/AZA in pts with NPM1 mutated or CBF AML in molecular relapse after first line IC. Methods: Pts of the DATAML registry with the following criteria were included in this study : AML with NPM1 mutation, RUNX1::RUNX1T1 or CBFB::MYH11 transcripts, first line IC, morphological complete remission (CR), no alloHCT in first line, regular monitoring of MRD by qPCR in bone marrow (BM) and/or blood, molecular relapse defined according to ELN2021 guidelines on two successive samples, at least one cycle of VEN/AZA. Pts with molecular relapse followed by morphological relapse before VEN/AZA or those who relapsed after alloHCT were not included. Treatment: First line IC was cytarabine 200 mg/m² d1-7 with idarubicin 9mg/m²/d1-5 or daunorubicin 90mg/m²/d1-3 in pts 18-60y or cytarabine 100 mg/m² d1-7 with idarubicin 8mg/m²/d1-5 and lomustine 200 mg/m²/d1 in pts &amp;gt; 60y. Post remission therapy was intermediate or high dose cytarabine or mini-consolidations according to age and performance status. Midostaurin was added in FLT3-mutated pts. At time of molecular relapse, pts received off label venetoclax 400 mg/d (d1-14, d1-21 or d1-28 according to centers) with no ramp-up and azacitidine 75 mg/m²/d subcutaneously (d1-5, d8-9). Antifungal/antibiotic prophylaxis and G-CSF use were not systematically recommended. Results: Twenty-two pts treated with VEN/AZAfrom 21/09/2020 to30/03/2023 were included. Their characteristics at diagnosis were: female (n= 14), median age 55y (range 27-71), de novo AML (n=21), median WBC (68 giga/L, range 2.32-339.7), NPM1 mutation (n=20), CBFB::MYH11 (n=2), FLT3 mutation (n=13). All pts achieved first CR after one cycle of induction chemotherapy. Pts received a median of three consolidation cycles. All but three pts had negative MRD or low level MRD (LL-MRD) in blood and/or BM at the end of consolidation. The median time between CR1 and molecular relapse was 9.5 months (range, 1-50). The median time between molecular relapse and first VEN/AZA cycle was 51 days. During first cycle of VEN/AZA, 12, 5 and 5 pts received 14, 21 or 28 days venetoclax, respectively; 19 were treated as out-pts, 4 received posaconazole and GCSF was used in 11 pts. 12 and 3 pts had grade 3-4 neutropenia or febrile neutropenia (FN), respectively. Only 3 pts (14%) were hospitalized for FN. The median number of VEN/AZA cycles was 2 (range 1-12). After C1+/-C2, 10 (45%) and 11 pts (55%) had undetectable or LL MRD in blood, respectively (Fig1). 20 pts were bridged to alloHCT in morphological CR after a median of 2 cycles (range, 1-4). Only one pt had a molecular progression before transplantation after 2 cycles. Two pts died, one had a molecular relapse after 7 cycles and progress rapidly to frank relapse, the other one died of post-transplant complication while in CR with undetectable MRD. All other pts remained in CR at date of last news. With a median FU from D1C1 of 13.5 months, median OS wat not reached and 1y-OS was 86% (Fig2). Conclusion: In the setting of molecular relapse, VEN/AZA is safe, prevent overt relapse, and induce a high rate of molecular response before alloHCT. Molecular relapse becomes a major therapeutic challenge. Clinical trial endpoints should include the treatment of molecular relapse as an event for RFS and EFS estimation.

Quantum-First Trial: FMS-like Tyrosine Kinase 3-Internal Tandem Duplication ( FLT3-ITD)-Specific Measurable Residual Disease (MRD) Clearance Assessed through Induction (IND) and Consolidation (CONS) Is Associated with Improved Overall Survival (OS) in Newly Diagnosed (nd) FLT3-ITD+ AML Patients (pts)

Background Detection of MRD by flow cytometry or gene fusion transcript quantitation increasingly is used to guide treatment decisions in AML. Molecular monitoring of recurrent gene mutations for MRD detection is an alternative strategy but, other than for nucleophosmin 1 ( NPM1) gene quantitation, remains controversial. FLT3-ITD is among the most common recurrent mutations in AML and confers a worse prognosis vs FLT3-wild-type and FLT3-TKD+ AML. Routine use of FLT3-ITD detection in remission as a predictor of relapse risk or OS has been limited by the low sensitivity of both conventional PCR-based detection methods and broad NGS platforms in clinical practice settings. More recently, FLT3-ITD-specific PCR-NGS assays such as getITD (PMID: 31089248) show greater sensitivity and ease of interpretation that point to eventual routine clinical application. However, the clinical value of these measurements has not been evaluated prospectively in large scale randomized controlled trials of FLT3 inhibitors. The phase 3 QuANTUM-First study (NCT02668653) evaluated the novel, potent, and highly selective type II FLT3 inhibitor quizartinib (Quiz) in nd FLT3-ITD+ AML pts and demonstrated that Quiz added to intensive IND and CONS, ± transplant, followed by single-agent continuation (CONT) therapy (Tx) resulted in a significant improvement in OS (PMID: 37116523). We analyzed if FLT3-ITD-specific MRD in QuANTUM-First pts impacted the clinical outcome or the benefits provided by Quiz in nd FLT3-ITD+ AML pts. Methods Genomic DNA, isolated from bone marrow aspirates or peripheral blood from pts after achievement of remission after 1 or 2 courses of IND and at end of CONS (prior to transplant or CONT cycle 1 day 1 [C1D1] for transplant pts and prior to CONT C1D1 for non-transplant pts), was analyzed with a FLT3-ITD PCR-NGS assay specifically developed for this trial (PMID: 31722002). ITD mutations detected after IND were cross-validated against the ITD detected at enrollment for each patient. Using a custom bioinformatics program, ITD mutations were identified, and variant allele frequencies (VAFs) were calculated with a sensitivity of 10 −5. MRD was classified as undetectable (using the 0 cutoff) or detectable above or below a 10 −4 predefined cutoff (based on lower limit of quantification for the assay). Comparisons of complete response (CR), composite complete response (CRc=CR+CRi), and the rate of pts achieving CRc during IND with no MRD between arms were made using a stratified Cochran-Mantel-Haenszel test. Comparison of FLT3-ITD VAF during IND and during CONS between arms was made using Wilcoxon rank sum test. All P-values were not adjusted for multiplicity. Results In QuANTUM-First, 539 nd FLT3-ITD+ AML pts were randomized to Quiz (n=268) or placebo (PBO; n=271). Of the 539 randomized pts, 368 (68.3%) achieved CRc after 1 or 2 courses of IND, and MRD analysis was performed on 321 (87.2%) of these pts (162 pts in Quiz and 159 pts in PBO) using samples collected at the time of response assessment during IND, before further Tx. MRD was also assessed in 337 pts (172 pts in Quiz and 165 pts in PBO) by end of up to 4 cycles of CONS prior to CONT/maintenance Tx. Of these pts, 166 additionally received transplant (87 in Quiz, 79 in PBO). The % of pts in CRc at end of IND with FLT3-ITD MRD of &amp;lt;10 −4 was similar between study arms (25.4% Quiz vs 21.8% PBO, nominal P = 0.3430), however, a greater % of pts in CRc had undetectable MRD with Quiz than PBO (12.3% vs 7.0%, nominal P = 0.0403). Among pts with CRc at end of IND, the median best FLT3-ITD VAF by end of CONS was lower (0% versus 0.0017%; nominal P = 0.0006) with Quiz vs PBO (Fig 1) and, using the 0 cutoff at end of IND, a longer OS was observed with Quiz vs PBO, regardless of MRD status, with a greater effect with Quiz (HR, 0.789 in MRD− pts; HR, 0.749 in MRD+ pts; Fig 2). In MRD+ pts, the median OS was not reached with Quiz and 35.4 months with PBO (Fig 2). Performing this analysis with an MRD cutoff of 10 ‒4 yielded similar findings (HR, 0.696 in MRD− pts; HR, 0.800 in MRD+ pts). Additional data about MRD impact on pts ± transplant in this trial will be presented. Conclusions These findings demonstrate the potential prognostic utility of FLT3-ITD-specific MRD measurements in the clinical management of pts with FLT3-ITD+ AML. Our data suggest that long-term OS benefits conferred by Quiz in part derive from a deep and sustained reduction of the FLT3-ITD+ leukemia burden.

Prospective Evaluation of Measurable Residual Disease (MRD) and Sustainability of the Response in Patients with Systemic AL Amyloidosis Treated with Daratumumab

Background: Daratumumab can provide deep hematologic responses for patients with light chain (AL) amyloidosis, both through its direct anti-clonal activity and immunomodulatory effects on other cell populations in the bone marrow (BM) microenvironment. Promising efficacy in the frontline setting when combined with CyBorD (per the ANDROMEDA trial), as well as in the relapsed/refractory setting as monotherapy, has led to daratumumab becoming the first FDA-approved therapy for AL amyloidosis. Though it is administered for up to 24 cycles, the optimal duration of treatment is unclear. Dynamic monitoring of measurable residual disease (MRD) may provide insights into changes in the aberrant plasma cell (PC) clone and sustainability of the hematologic response in relation to daratumumab therapy. Aims: We sought to evaluate the rates of MRD clearance and resurgence both during and after daratumumab therapy for AL amyloidosis. Methods: MRD status was assessed for patients followed at the Boston University Amyloidosis Center, who were treated with a daratumumab-based regimen and achieved a hematologic very good partial response (hemVGPR) or complete response (hemCR) according to consensus criteria (Palladini, 2012). MRD assessments were performed by multiparametric 10-color flow cytometry of BM aspirates (sensitivity level of ≤10 -5) and repeated at 12-month intervals during follow-up. Clonal progression was defined as growth in the aberrant PC clone size of &amp;gt;1-log. Results: Between 2019 and 2023, a total of 66 patients achieved ≥hemVGPR and were tested for MRD; 43 (65%) received daratumumab monotherapy in the relapsed/refractory setting and 23 (35%) in combination with CyBorD as frontline therapy. Collectively, 48 (73%) achieved a hemCR and 18 (27%) a hemVGPR. The median age at diagnosis was 60 years (range 35-78); 19 (29%) patients were female; and 11 (17%) identified as non-white race. MRD assessment was performed once, twice or ≥3 times for 33, 18 and 15 patients, respectively. The first MRD evaluation occurred while still receiving daratumumab for 33 patients (at median 12 cycles, range 6-23); the remaining patients had their first MRD evaluation after therapy completion (median one month after, range 0-25). Of the entire cohort, 28 (42%) patients achieved MRD negativity and 38 (58%) MRD positivity (median estimated aberrant PC clone size 1.5 x 10 -4, range 1.4 x 10 -5 to 1.1 x 10 -2, representing 46.9% ± 32.8% of total PCs) at first evaluation. All but one patient with a hemVGPR had detectable MRD. Of the 23 patients who received frontline daratumumab-CyBorD (18 hemCR and 5 hemVGPR), 8 (35%) achieved MRD negativity at first evaluation; whereas 20 (47%) of the 43 patients who received daratumumab as monotherapy (30 hemCR and 13 hemVGPR) achieved MRD negativity. We surveyed MRD profiles based on the number of daratumumab treatment cycles received (Table 1) and found no apparent patterns with increasing cycles. Serial MRD monitoring was performed for 33 patients (Figure 1). Of 10 patients who continued to receive daratumumab between MRD assessments (group 1), 6 had sustained MRD negativity; 2 had persistent MRD positivity (of whom one had clonal progression); and 2 had MRD clearance (conversion from positive to negative). Of 23 patients who underwent serial MRD assessments after completing daratumumab (group 2), 9 (39%) had sustained MRD negativity; 10 (43%) had persistent MRD positivity; 2 (9%) had MRD clearance; and 2 (9%) had MRD resurgence (conversion from negative to positive), which occurred 17 and 26 months after daratumumab cessation. Clonal progression was observed in 5 of the 10 patients with persistent positivity, of whom 3 experienced a hematologic relapse. Conclusions: Our findings show that patients with AL amyloidosis can attain deep responses with daratumumab-based treatments, even to the depth of undetectable MRD. Clearance of MRD was frequent not only during treatment with daratumumab but also after completion of therapy, suggesting continuing effects on the plasma cell clone. Clonal progression after daratumumab completion was often associated with hematologic relapse. Prospective studies are needed to investigate whether daratumumab may be stopped early for those with undetectable MRD, or whether those with persistent detectable disease may benefit from extending daratumumab treatment beyond 24 cycles.

Validation of ELN 2022 Risk Classification in Patients Diagnosed with AML Undergoing Allogeneic Hematopoietic Cell Transplantation

Background: In 2022, the European LeukemiaNet (ELN) updated their guidelines (Döhner H et al., Blood 2022) for risk allocation of patients with acute myeloid leukemia (AML) based on essential genetic features at diagnosis as defined in the newest classifications (Arber D et al., Blood 2022, Khoury JD et al., Leukemia 2022). Methods: Retrospective analysis of the 147 consecutive patients diagnosed with AML and available genetic information who underwent alloHCT in a complete morphological response (CR) between 2011 and 2021 in a single institution (HCB). Data was collected retrospectively and updated in July 2023. G-banding karyotype, FISH, qualitative and quantitative PCR and targeted Next Generation Sequencing were assessed at diagnosis to classify patients according to ELN 2022 risk classification. Our primary goal was to validate the ELN 2022 risk classification in patients undergoing alloHCT analyzing overall survival (OS). Secondary objectives were analyzing leukemia-free survival (LFS), 24-month cumulative incidence of relapse (CIR) and in the different molecular subgroups within the ELN2022 risk groups. Results: The main patient, disease-related and transplant characteristics are displayed in Figure 1. Overall, the median age was 52 years (range 18-70), 53.7% of the patients males, with 88% of the patients undergoing alloHCT in CR1. Twenty-two patients could not be classified through NGS assessment between 2011 and 2016 and included in the intermediate risk category due to normal karyotype and wildtype recurrent abnormalities measured by PCR. Patients in the adverse-risk group were older (p &amp;lt;0.001) and underwent alloHCT less often with undetectable measurable residual disease (p = 0.006). Moreover, patients in the favorable or intermediate risk group underwent alloHCT more often in CR2 or CR3 (p = 0.02). In addition, alloHCT characteristics were similar for all the patients included. With a 67-month median follow-up for LFS (95CI: 55-76), the median OS and LFS in patients classified into the favorable and intermediate risk groups were not reached (5-year OS and LFS rate in favorable risk group: 81% (95CI: 73-89) and 72% (95CI: 63-81). 5-year OS and LFS rate in intermediate risk group: 62% (95CI: 56-68) and 64% (95CI: 58-70). Patients included in the adverse risk group had an OS and LFS of 23.7 months (15.3-NR, p &amp;lt;0.001 between intermediate and adverse risk. Figure 1B) and 15.2 months (5.79-NR, p=0.015) respectively, with a significant lower 5-year OS rate (40%, 95CI: 34-46), LFS rate (38%, 95CI: 32-44) and a higher CIR (18% in the favorable risk group (95%CI: 11-26) vs. 20% in the intermediate risk group (95%CI: 18-23) vs. 40% in the adverse risk group (95%CI: 38-44), p = 0.024). Based on these results, a subanalysis was conducted in the patients classified into the adverse group. Those patients diagnosed with complex karyotype, inv(3), t(3;3), del(17p) and/or TP53 mutated were reassessed into a new risk category group called: Adverse-Plus (AdvP).No different baseline characteristics between the AdvP patients and the other subgroups were found. AdvP patients presented a shorter OS (NR in the rest of subgroups vs. 8.73 months in AdvP, p &amp;lt; 0.001 for AdvP vs. adverse risk. Figure 1C), LFS (NR in the rest of subgroups vs. 5.2 months, p &amp;lt; 0.001), and a higher CIR (62.5% in the AdvP group, p &amp;lt;0.001 between adverse risk and AdvP). Interestingly, using this four-group classification including AdvP, the other risk groups presented similar OS, LFS, and CIR without statistical differences in between them Summary/Conclussion: ELN2022 risk classification discriminates properly accurate in patients undergoing alloHCT. Reclassifying AML adverse risk patients diagnosed with complex karyotype, inv(3), t(3;3), del(17p) and/or TP53 mutated in a different subgroup should be considered due to a much worse prognosis after alloHCT, although it remains mandatory in first complete response.

Outcomes of Venetoclax Retreatment after MRD-Guided Venetoclax +/- Ibrutinib: Results of the Improve Study

Data from small cohorts of patients (pts) with chronic lymphocytic leukemia (CLL) relapsing after venetoclax-based fixed-duration regimens suggest that venetoclax retreatment may be a feasible option. Information on the efficacy and tolerability of venetoclax retreatment in this setting is still scanty, making it worth exploring venetoclax retreatment in prospective cohorts of well-characterized pts with CLL. We analyzed the efficacy and safety of venetoclax retreatment in pts with relapsed/refractory CLL enrolled in our clinical trial IMPROVE (NCT04754035). BTK- and BCL2-inhibitor naïve pts enrolled into the study were treated with venetoclax single-agent for 12 months; those with undetectable measurable residual disease (uMRD) discontinued therapy while those with detectable MRD received the combination of ibrutinib and venetoclax until uMRD, toxicity or for up to 12 months. Pts with detectable MRD at the end the combination therapy stopped venetoclax and continued with ibrutinib only. In pts who experienced progressive disease (PD) requiring treatment, venetoclax single-agent was restarted according to the standard schedule and continued until PD or unacceptable toxicity. MRD was tested every 3 months in peripheral blood using the 6-color flow cytometry panel validated by the ERIC (European Research Initiative on CLL). After a median follow-up of 58 months (5-67) from C1D1, 20/38 (52.6%) pts experienced PD requiring treatment after discontinuing therapy, including 19 upon reaching confirmed uMRD (11 treated with venetoclax single-agent, 8 with the combination of venetoclax+ibrutinib), 1 who discontinued both venetoclax and ibrutinib in partial response (PR) with detectable MRD (dMRD) due to an unrelated adverse event. Two out of 20 had Richter transformation (RT), 2 developed autoimmune hemolytic anemia, 2 received other treatments (BTK inhibitors) per investigator's decision and all 6 went off study. The remaining 14 pts (1 with detectable MRD, 7 who previously achieved uMRD with venetoclax monotherapy, 6 who were treated with the combination of venetoclax+ibrutinib) received venetoclax retreatment at a median of 32.5 months (12-44) after the end of initial therapy (Table 1); to note, the pt who stopped treatment in PR with dMRD restarted venetoclax after only 13 months. All 13 uMRD subjects experienced MRD relapse at a median of 5 months (0-41) after stopping treatment, 26 (0-37) months before disease progression requiring therapy. At the time of venetoclax initiation tumor lysis syndrome (TLS) risk was high in 6, medium in 3, low in 5. Best overall response rate was 79% (11/14), all partial responses (PR), 2 pts experienced stable disease (on treatment for 2 and 24 months). With a median time on treatment of 10 months, 2 pts achieved uMRD after 3 and 6 months, the second one maintaining uMRD for 6 months and then becoming MRD positive again (Figure 1). Five out of 14 pts progressed after 2, 7, 9 and 11 (n=2) months on venetoclax retreatment, 3/5 received next-line treatment with ibrutinib, 2/5 received non-covalent BTK inhibitor and all achieved a PR. At last follow-up, 57% of pts remain on venetoclax; 12/14 patients undergoing venetoclax retreatment were alive (1 death due to RT on ibrutinib, 1 due to CLL progression on non-covalent BTK inhibitor). Progression-free survival from venetoclax restart to PD on venetoclax retreatment, last follow-up or death was not reached (0-28 months). Venetoclax retreatment was very well tolerated with no patients experiencing TLS, 6/14 having grade 3-4 neutropenia (only in 1 case leading to treatment discontinuation), 8/14 infections (2 grade 1, 4 grade 2, 2 grade 3). No other grade 3/4 hematologic or non-hematologic toxicities were observed. Venetoclax retreatment was effective and well-tolerated in a cohort of pts with relapsed/refractory CLL who have previously received time limited, MRD-guided treatment with venetoclax+/-ibrutinib. MRD relapse occurred at a median of about 2 years before clinical progression requiring treatment. Venetoclax retreatment was started at a median of 32.5 months after the end of initial therapy. Nearly 80% of patients achieved at least a partial response with venetoclax retreatment, 14% of pts achieved uMRD and 57% remain on venetoclax, with a median time on treatment of 10 months.

Clinical Outcomes with Venetoclax-Based Treatment Regimens in Patients with Chronic Lymphocytic Leukemia (CLL)

INTRODUCTION We aim to identify factors that impact outcomes of venetoclax for patients with CLL treated in routine practice at a tertiary center. We report on the use of venetoclax in the most frequently encountered disease scenarios: first-line, relapsed/Bruton tyrosine kinase inhibitor (BTKi)-naïve, and relapsed/BTKi-exposed. METHODS We identified patients who received venetoclax therapy for CLL (between 4/2012-4/2023) from the Mayo Clinic CLL Database. Undetectable measurable residual disease (uMRD) was defined as &amp;lt;1 CLL cell per 10,000 leukocytes using 8-color flow cytometry on peripheral blood (PB) or bone marrow (BM). Overall survival (OS) was defined as the time from venetoclax start until date of death or last known to be alive. Treatment-free survival (TFS) after venetoclax was defined as the time from venetoclax start until the earliest of date of next treatment, or death. Kaplan-Meier was used to display OS and TFS. Multivariable Cox proportional hazards regression models were used to estimate associations of factors with time-to-event outcomes. RESULTS A total of 155 patients received venetoclax: firstline therapy (in combination with obinutuzumab, n=55) and relapsed CLL (n=100; 17 had relapsed/BTKi-naïve CLL, and 83 had previously received BTKi [55 with progression after BTKi], relapsed/BTKi-exposed). The median follow-up for the cohorts of first-line therapy, relapsed/BTKi-naïve, and relapsed/BTKi-exposed was 12.9 months, 37.0 months, and 27.6 months, respectively. Baseline characteristics at the time of venetoclax initiation for all patients are shown in Table 1. The median TFS for the overall cohort was 39.0 months. The median OS was 54.6 months. Among patients treated with venetoclax as first-line therapy (n=55), the 2-year TFS ( Figure 1) and 2-year OS rates were both 91%. MRD testing was performed in 28 patients and was uMRD in 23 (82%) patients (only PB assessed, n=7; only BM assessed, n=2; PB and BM assessed, n=14). Detectable MRD was identified in 3 patients, and 2 patients had discordant results (PB uMRD and BM detectable disease). Among patients treated with venetoclax in the relapsed/BTKi-naïve setting (n=17), the 2-year TFS rate was 73% ( Figure 1) and the 2-year OS rate was 100%. MRD testing was performed in 7 patients and was uMRD in all 7 (100%) (only PB assessed, n=3; only BM assessed, n=2; PB and BM assessed, n=2). The median time to first uMRD result was 14.1 months. Among relapsed/BTKi-exposed venetoclax-treated patients (n=83), the median TFS was 26.9 months ( Figure 1), and the median OS was 39.4 months.In this subgroup, the median TFS for patients with (n=55) and without (n=28) prior disease progression on prior BTKi were 22.3 and 42.3 months, respectively. Median TFS with venetoclax monotherapy (n=30) was 24.0 months, venetoclax in combination with rituximab (n=37) was 26.9 months, and venetoclax in combination with obinutuzumab (n=16) was 39.0 months. BTKi-exposed patients that were chemotherapy-naïve (n=27) and chemotherapy-exposed (n=56) had median TFS of 29.1 and 24.0 months, respectively. MRD testing was performed in 28 patients and was uMRD in 16 (57%) patients (only PB assessed, n=9; only BM assessed, n=2; PB and BM assessed, n=5). Detectable MRD was identified in 11 patients, and 1 had discordant results (PB uMRD and BM detectable disease). The median time to first uMRD result was 11.5 months. TP53 disruption, unmutated IGHV genes, older age, complex karyotype (CK; defined as more than 3 chromosomal aberrations on CpG stimulated karyotype), and disease progression on prior BTKi were associated with shorter TFS in the overall cohort on univariate analysis. TP53 disruption, older age, CK, and disease progression on prior BTKi were associated with shorter OS in the overall cohort on univariate analysis. Multivariable analysis was performed by including only those patients where all variables significant in univariable analysis were available (OS model n=65, TFS model n=53). In these models, only CK was significantly associated with shorter TFS (HR 8.5; 95%CI 2.5-29.1; P&amp;lt;0.001) and shorter OS (HR 4.1; 95%CI 1.2-14; P=0.03). CONCLUSIONS Patients with BTKi-exposed CLL, particularly those with prior disease progression on BTKi, had worse outcomes. Our study identified CK as one of the most important baseline predictors of adverse TFS and OS in the overall cohort of patients, supporting karyotype assessment for prognostication prior to venetoclax treatment.

A Phase 1 Study of Venetoclax in Combination with a Pediatric-Inspired Regimen for the Treatment of Newly Diagnosed Adults with B-Cell Ph-like ALL

Background: Aberrant overexpression of pro-survival Bcl-2 family proteins is one mechanism by which leukemic cells circumvent apoptosis. BCL-2 overexpression is common in various subtypes of B-acute lymphocytic leukemia (ALL), including Philadelphia (Ph)-like ALL. Ph-like ALL is a chemotherapy-resistant disease associated with higher rates of induction failure and persistent measurable residual disease (MRD), and poor overall survival (OS) outcomes with frontline chemotherapy regimens, compared to other subtypes. Venetoclax (VEN) is a selective BCL2 inhibitor, and its addition to pediatric-type frontline regimens could improve response and long-term outcomes for B-ALL, including Ph-like subtype. Design: This is a phase 1 study with an expansion cohort investigating the safety of combining VEN with induction (IND) and consolidation (CON) cycles of the CALGB 10403 backbone regimen (NCT05157971). Post CONS therapy was per the treating physician discretion. The study enrolled newly diagnosed adults [18-54 years (yrs)] with Ph-negative B-ALL. To enrich the study for Ph-like ALL, we excluded patients (pts) with KMT2A-rearranged, TCF3::PBX1, and ETV6::RUNX1 subtypes at diagnosis. Identification of Ph-like ALL was performed using RNA-sequencing, conventional cytogenetics, fluorescence in situ hybridization, and whole genome array studies. Dose level (DL) 1 of VEN was 400 mg orally daily on days 1-14 of IND and CON, with a ramp-up dosing during IND [Day 1= 100 mg, Day 2= 200 mg, Days 3-14= 400 mg/day]. Results: We enrolled 14 pts as of July 1 st, 2023. The median age was 33 (20-53) yrs, of which 9 pts were males and 13 (93%) were Hispanics. Seven (50%) pts had Ph-like ALL (6 with CRLF2-alterations, 1 JAK2-fusion). Six pts were treated on the phase 1 part, and no dose limiting toxicity was observed during IND. Among 14 pts that completed IND, all achieved complete remission (CR), including 1 pt who required an extended IND phase, and 79% (n= 11) achieved MRD- (&amp;lt;0.01%) by multicolor flow (MCF) on day 28 of IND. Eleven pts completed CONS, and all achieved undetectable MRD CR or CR with incomplete count recovery (CRi) by MCF. Post CONS next-generation sequencing of MRD (clonoSEQ) was available for all 11 pts who completed CONS, and 7 (64%) were undetectable while 4 were detected at very low levels (range: 0.0007-0.0024%). Median time to neutrophil count ≥1000 and platelet count ≥100,000 were 19 (15-26) and 14 (2-27) days from starting IND, respectively. No pt died during IND or CONS cycles. Grade ≥3 adverse events at least possibly related to venetoclax and/or the C10403 regimen that occurred in ≥ 20% of evaluable pts during either IND or CONS cycles were leukopenia (100%), neutropenia (100%), lymphopenia (100%), anemia (70%), thrombocytopenia (50%), hyperbilirubinemia (30%) and hypertriglyceridemia (20%). Only 1 pt underwent consolidation with allogeneic stem cell transplant while in remission. With a median follow up for the entire cohort of 7.2 months (range: 1.9-16.1 months), only 1 pt with Ph-like ALL relapsed and he is currently alive. Conclusion: The addition of 14 days of VEN at 400 mg daily dose to a pediatric-inspired regimen during IND and CONS was safe in adults with newly diagnosed B-ALL and did not delay counts recovery. The addition of VEN led to a promising higher than expected MRD- CR rate in high-risk B-ALL, including for pts with Ph-like subtype. The study is actively enrolling on the expansion cohort, and BH3 profiling on pre-treatment and post relapse samples will be performed to determine BCL-2 dependency and correlates to early MRD- response.

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.

End-of-Treatment Response Assessment after Frontline Therapy for Aggressive B-Cell Lymphoma: Landmark Comparison of a Singular PET/CT Scan Versus Ultrasensitive Circulating Tumor DNA

Background : Lymphoma response criteria rely on PET/CT scans at end of therapy (EOT) to determine complete response (CR), which is necessary for cure. ~25% of patients achieve &amp;lt;CR by response criteria, but PET/CT scans have imperfect specificity and the positive predictive value of a single PET/CT scan at EOT is only ~50% (Kostakoglu 2021). To overcome this limitation, clinicians use additional tests including tissue biopsies or repeat PET/CT scans prior to salvage therapy to adjudicate positive results, but it remains unclear how often this occurs. Circulating tumor DNA (ctDNA) has improved tumor specificity that may reduce reliance on additional tests. We addressed these questions within a clinical trial delivering 1L therapy to pts with aggressive B-cell lymphoma. Methods : Pts were enrolled in a phase 2 study of DA-EPOCH-R or R-CHOP +/- acalabrutinib for treatment naïve DLBCL or high-grade B-cell lymphoma (HGBCL) [NCT04002947]. All pts were &amp;gt;18yrs old, stage II-IV, with adequate organ function. Pts completing induction therapy with available EOT PET/CT scans and EOT plasma samples were studied. PET/CT scans were interpreted by 2 nuclear medicine (NM) radiologists blinded to clinical outcomes using the 5-point Deauville Score (DS) with DS4/5 considered positive. Tissue biopsies and unplanned PET scans after the EOT PET/CT scan to determine remission status were recorded. Measurable residual disease (MRD) in plasma cfDNA was evaluated by Phased Variant Enrichment &amp; Detection Sequencing (PhasED-Seq) at Foresight Diagnostics blinded to clinical outcomes. Tumor derived Phased Variants (PVs) were identified from baseline pretreatment plasma samples or baseline tumor tissue, with matched constitutional DNA from paired PBMCs used to censor germline variants and CHIP. PVs were used to assess EOT MRD. Results were reported as MRD positive when ctDNA levels exceeded an analytical detection threshold (~1:10 6 cfDNA molecules) corresponding to 98% specificity. The prognostic utility of MRD was compared to standardized PET/CT scan at EOT to freedom-from-progression (FFP) and progression-free survival (PFS). Results : 55 enrolled pts completing planned therapy had EOT PET/CT and MRD analyzed. 54 (98%) pts were successfully genotyped and comprised the study population. Median age was 61 (range 26-85), including 22 (41%) female, 44 (81%) with advanced stage, and 26 (48%) with IPI score ³3. Pathologic subtypes included 24 (44%) GCB, 21 (39%) non-GCB, 8 (15%) HGBL-DH, and 1 (2%) THRLBCL. 43 (80%) pts received DA-EPOCH-R and 11 (20%) pts received R-CHOP. Twenty-six (48%) pts received acalabrutinib with R-chemotherapy. After 26 months median follow-up, the 2-year FFP and PFS of the cohort was 89% and 84%. Fourteen (26%) pts had a positive EOT PET/CT scan and 40 (74%) were negative. The concordance rate between the 2 NM radiologists on positive scans was 100%. Only 2 of 14 patients with a positive EOT PET/CT had clinical progression requiring salvage therapy (14% PPV). Nine (64%) of these pts required additional tests to determine remission status including 5 repeat PET/CT scans and 4 tissue biopsies. The 2-year PFS for pts with a positive vs negative EOT PET/CT was 66% vs 90% (p=0.08, Fig.A). Twelve (22%) pts had detectable EOT MRD and 42 (78%) were undetectable. 7 pts with detectable EOT MRD had clinical progression requiring salvage therapy or have died. While no pt with undetectable EOT MRD progressed, 1 (2%) died in remission of sudden cardiac death. Of 14 pts with positive EOT PET/CT, 7 (50%) had undetectable ctDNA and none progressed, suggesting MRD testing could have potentially rendered additional tests unnecessary. Conversely, patients with positive PET/CTs who progressed invariably had detectable ctDNA at EOT, suggesting utility of MRD for adjudicating PET/CT results. The 2-yr PFS for pts with detectable vs undetectable EOT MRD was 33% vs 98% (p&amp;lt;0.0001, Fig.B). At EOT, the PFS hazard ratio for MRD was 35.7, as compared with 3.1 for PET/CT. Conclusions : Response evaluations relying on PET/CT scans often require additional tests and procedures to assess remission status in aggressive B-cell lymphomas. Initiation of salvage therapy without adjudication in patients not achieving CR by EOT PET/CT scans will result in overtreatment. Given the higher specificity and PPV of EOT MRD, we propose an integrated response evaluation strategy combining these methods to reduce unnecessary additional tests and overtreatment.

Chemotherapy-Free Combination of Blinatumomab and Ponatinib in Adults with Newly Diagnosed Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia: Updates from a Phase II Trial

Background Blinatumomab and ponatinib demonstrated efficacy in patients with Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL). A chemotherapy-free regimen combining both drugs in the frontline setting may mitigate the risk of toxicities and the need for hematopoietic stem cell transplantation (HSCT). Methods In this phase II trial, patients ≥18 years of age with newly diagnosed Ph-positive ALL were eligible. They were required to have a performance status of ≤2, total bilirubin ≤2x the upper limit of normal (ULN), and ALT/AST ≤3x the ULN. Patients with uncontrolled cardiovascular disease or clinically significant central nervous system (CNS) comorbidities (except for CNS leukemia) were excluded. Patients received up to 5 cycles of blinatumomab in combination with ponatinib, followed by ponatinib maintenance for ≥5 years. Ponatinib 30mg daily was given during Cycle 1 and decreased to 15mg daily once a complete molecular response (CMR) was achieved. Patients also received 12 doses of prophylactic intrathecal (IT) chemotherapy with alternating cytarabine and methotrexate. The primary endpoint was the CMR rate. Secondary endpoints included response rates, safety measures, event-free survival (EFS), and overall survival (OS). Results Between June 2018 and May 2023, 62 pts with newly diagnosed Ph-positive ALL were treated. Baseline characteristics are shown in Table 1. Twenty-two patients were in complete remission (CR) at the start of therapy. Among 40 patients evaluable for hematologic response, 39 (98%) achieved CR/CRi; 1 patient had early death. Among 55 patients evaluable for molecular response, 37 (67%) achieved CMR after 1 cycle, and 46 (84%) achieved CMR at any time. Forty-seven patients were evaluated for measurable residual disease (MRD) by next-generation sequencing at a sensitivity level of 10 -6, of whom 43 (91%) were found to have negative MRD. Five of these patients with undetectable MRD by NGS had low-level BCR:ABL1 transcripts detected by PCR at the same time (ranging from 0.01% to 1.23% IS). Four of them had p190 transcript and one had p210. The median follow-up was 17 months (range, 2-61 months). Six patients (10%) relapsed after a median of 21 months of remission (range, 8-24 months): two relapsed in the bone marrow (one with acquired E225V mutation), one had an extramedullary-only relapse (Ph-negative and MYC-rearranged relapse), and three had a CNS-only relapse (after 20, 22, and 23 months). Four patients died (one from intracranial hemorrhage, one from post-procedural hemorrhage, one from brain aneurysm, and one following CNS relapse with intracranial edema and septic shock). One leukemia-related death occurred on study; the estimated 2-year EFS and OS rates were 77% and 89%, respectively (Figure 1). Only one patient underwent HSCT in first CR due to persistently low-level BCR:ABL1 positivity. Among the 52 patients in ongoing remission without HSCT, the median duration of response was 16 months (range, 2-61). Most adverse events were grade 1-2 and were consistent with the known toxicity profile of the two agents. Ponatinib was discontinued in two patients due to possibly related adverse events (cerebrovascular accident and coronary artery stenosis in one patient each). Conclusions The chemotherapy-free combination of blinatumomab and ponatinib is safe and effective in newly diagnosed Ph-positive ALL, with high rates of MRD negativity. Encouraging duration of remission and OS has been observed without the need for HSCT.

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)

MRD-Guided Zanubrutinib, Venetoclax and Obinutuzumab after an Optional Debulking with Bendamustine in Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia: Primary Endpoint Analysis of the Phase 2 CLL2-Bzag Study

Background In chronic lymphocytic leukemia (CLL) triple combinations of BTK inhibitors (BTKi), venetoclax (ven) and CD20 antibodies have been tested mostly as first-line treatments and so far sparse data is available on their efficacy in the relapsed/refractory (r/r) setting. In this phase 2 trial, we evaluate the combination of zanubrutinib (zanu), ven and obinutuzumab (obi) in r/r CLL. In order to tailor therapy to the different needs of differently pretreated patients (pts), treatment duration was based on detection of measurable residual disease (MRD). Furthermore, a ctDNA-based MRD monitoring and a ctDNA-based real-time screen of resistance and driver mutations were performed throughout the study. Methods The CLL2-BZAG study evaluated a combination of obi, zanu and ven after an optional debulking with bendamustine in r/r CLL. In the induction, obi was administered 3 times in cycle 1 (days 1/2, 8 &amp; 15) and monthly in cycles 2-6. Zanu was added in cycle 2 and ven in cycle 3 with a dose ramp-up over 5 weeks. Maintenance with continuous zanu and ven and 3-monthly obi was administered either until achievement of a deep remission with undetectable MRD &amp;lt;10 -4 (uMRD) in peripheral blood (PB) or for up to 24 months. The primary endpoint was the uMRD rate by flow cytometry (FCM) in PB at the final restaging (RE, after 6 months of triple therapy). MRD was measured by FCM from PB and by digital droplet PCR (ddPCR) of patient-specific VDJ rearrangements from blood plasma. uMRD was defined as &amp;lt;1 CLL cell/10,000 leukocytes (&amp;lt;10 -4) and no detectable patient-specific VDJ ctDNA. Results Between 11/2020 and 10/2022, 42 pts were enrolled, 2 pts with ≤2 induction cycles were excluded from the analysis population as predefined by the protocol. Median age was 64 years (range 40-82), 32.5% of pts were female. All 40 pts had r/r CLL with a median of 1 prior therapy (range 1-5), 18 pts (45%) had already received a BTKi, 7 pts ven (17.5%), of these 5 pts (12.5%) had received both. Fifteen pts (37.5%) had a del(17p)/ TP53 mutation, 31 (77.5%) had unmutated IGHV and 19 of 38 pts with available information (50%) a complex karyotype. Nineteen pts (47.5%) received bendamustine debulking, 37 pts (92.5%) completed 6 induction cycles and 19 pts (47.5%) have already stopped MRD-guided maintenance treatment with 2 pts who discontinued maintenance early due to adverse events (AEs). With a median observation time of 21.5 months (range 8.0-35.3), 445 AEs were reported, including 90 AEs of CTC grades 3-4. Two pts had fatal AEs (COVID-19, fungal pneumonia secondary to COVID-19). The most common AEs were COVID-19 (n=26 pts), diarrhea (n=15), infusion-related reactions (n=15), thrombocytopenia (n=14), nausea (n=12), fatigue (n=12) and neutropenia (n=12). The most frequent grade ≥3 AEs were neutropenia (n=10 pts), COVID-19 (n=9), thrombocytopenia (n=7) and pneumonia (n=5, Table 1). Two pts had grade ≥3 cardiac AEs (1 pt with grade 3 non-ST-elevation myocardial infarction, 1 pt with 2 AEs of grade 3 atrial fibrillation and a history of atrial fibrillation). At RE all pts responded and 21 (52.5%) showed uMRD in PB ( Figure 1A). In many pts remissions deepened over time, with 34 (85%) achieving uMRD in PB in the course of the study. The proportion of pts with uMRD was similar in pts with TP53 aberrations (80%) and in pts previously exposed to venetoclax and/or BTKi (80%). The estimated PFS and OS rates at 18 months were 96% and 96.8% ( Figure 1B). PFS rates at 18 months were similar for pts with TP53 aberrations (100%) and pts pretreated with BTKi/ven (90%). Two pts had a disease progression per iwCLL criteria, however no pt has yet required a subsequent treatment. Of 22 pts who achieved uMRD and are now off-treatment, only 1 had MRD recurrence (≥10 -4) during follow-up. Serial MRD (FCM) and ctDNA (ddPCR) assessments were done on 281 paired blood/plasma samples throughout the study. At RE, 8 pts who achieved uMRD by FCM still had detectable VDJ ctDNA in blood plasma. Four pts without ctDNA were still MRD positive by FCM at RE. Apart from one PLCG2_S707F mutation that occurred 11 months after the end of treatment, no acquisition of known resistance mutations - in particular in BTK, BCL2 - was observed using ddPCR. Conclusions The time-limited MRD-guided triple combination of zanu, ven and obi induced deep remissions in a r/r CLL population enriched for pts previously treated with BTKi and/or ven. Apart from COVID-19, low rates of infectious AEs were observed and cardiac toxicities were rare.