Blood Minimal Residual Disease Research Articles

Immunoglobulin High Throughput Sequencing (Ig-HTS) Minimal Residual Disease (MRD) Analysis is an Effective Surveillance Tool in Patients With Mantle Cell Lymphoma

IntroductionMantle cell lymphoma (MCL) accounts for 4% to 6% of B-cell non-Hodgkin lymphoma with historically poor outcomes. With the advent of intensive first-line, targeted, and cellular therapies, outcomes have improved, and initial remission can be 8 to 10 years or longer. As patients experience longer remissions, this raises the question of the optimal surveillance modality. Peripheral blood minimal residual disease (MRD) analysis offers a potential alternative to surveillance imaging that is sensitive, less costly, and eliminates the risk of radiation exposure. Materials and MethodsThe clonoSEQ assay (Adaptive Biotechnologies) is an FDA-cleared commercially available Ig-HTS MRD assay with a sensitivity of 1 cell in 1,000,000. We performed a retrospective analysis of 34 patients from 2015 to 2021, who underwent MRD testing after achieving remission with first-line therapy. ResultsWith a median follow-up of 6.5 years, 10-year progression free survival (PFS) was 60% and 10-year overall survival was 92% of the entire cohort. Among 12 patients who sustained a radiographic relapse, peripheral blood became MRD+ either at or prior to the time of relapse in 11 patients (92%). The first MRD+ test had a lead time of 0 to 24 months (median 34 days) prior to radiographic relapse. Only 1 patient had a MRD− result while being found to have progressive disease on imaging. Among 22 patients who sustained continuous clinical remission, 21 have remained MRD−. Several patients were able to enjoy 2 to 4-year intervals without surveillance imaging. ConclusionsOur data suggest that the clonoSEQ MRD assay is an effective surveillance tool for MCL patients following first-line therapy and is predictive of relapse prior to imaging.

A Phase II Study of Zanubrutinib-Based Induction and Maintenance Therapy in Young and Fit Patients with Untreated Mantle Cell Lymphoma (BRIDGE): An Updated Analysis with Long-Term Follow up

Introduction Studies showed that remission after induction therapy is associated with better prognosis in mantle cell lymphoma (MCL) patients, and minimal residual disease (MRD) is also considered as an independent and sensitive factor in MCL patients. As R-CHOP/R-DHAOx is the most common used induction regimen in China, we investigate the benefit of zanubrutinib-based induction (zanubrutinib plus R-CHOP) in untreated young MCL patients. We previously reported a promising result of an ORR of 100% with MRD negative rate of 100% after induction treatment in 2022 PPLC. Here, we reported a long-time (median follow-up: 25.9 months) efficacy and safety in the study. Methods In this prospective, single-center, single-arm, phase II study (NCT04736914), patients aged 18-65 years with previously untreated, Ann Arbor stage II-IV, histologically confirmed MCL will be enrolled to alternately receive R-CHOP + zanubrutinib and R-DHAOx induction for 6 cycles (every 21 days per cycle). Zanubrutinib will be administered in cycle 1, 3, 5 (R-CHOP), 160 mg BID, d1-21, and not in combination with R-DHAOx. Patients who achieve remission (≥PR) will be allowed to proceed to ASCT or maintenance depending on the investigator's evaluation and discretion. In patients who do not achieve a remission at the end of induction (treatment failure), no specific treatment is defined; rather, the further salvage treatment is upon the discretion of investigators. Patients will receive zanubrutinib maintenance for two years in case of remission at ASCT assessment or end of induction assessment. Zanubrutinib is administrated orally at 160 mg BID, continuously for 2 years or until progressive disease, unacceptable toxicity, or death, whichever occurs first. The primary endpoint was bone marrow MRD negative rate after induction therapy (at the completion of cycle 6 or at premature discontinuation). Results A total of 7 patients were enrolled, the median age was 56.3, and bone marrow (BM), peripheral blood (PB) MRD showed positive at baseline. After 6 cycles of R-CHOP + zanubrutinib and R-DHAOx induction treatment, BM and PB MRD negative rate was 100% (7/7). One patient proceeded to ASCT. At the data cut-off date of 30 Jun 2023, one patient has completed the study at week 53 with zanubrutinib maintenance treatment due to the progressive disease, while the other 6 patients remain in the zanubrutinib maintenance treatment and are still under follow-up (Figure). With a median follow-up of 25.9 months, all patients showed good tolerance, with no dose modification and discontinuation during zanubrutinib-based induction therapy, either no BTKi interested AE (includes diarrhea, hypertension, major hemorrhage, and atrial fibrillation/flutter) was observed (Table). Conclusions This prospective, phase II study with a relatively longer follow-up duration estimated the treatment regimen in untreated young MCL patients. At the time of data cut-off, zanubrutinib-based induction therapy was well tolerated in all patients and showed a promising results in response and MRD. With a median treatment duration of 16.6 months, most patients (6/7) did not relapse. The study is ongoing and further results will be continuously released.

Updated Efficacy and Safety Results of Lisaftoclax (APG-2575) in Patients (Pts) with Heavily Pretreated Chronic Lymphocytic Leukemia (CLL): Pooled Analyses of Two Clinical Trials

*Drs. Keshu Zhou, Mingyuan Sun, and Wei Xu are co-first authors; Drs. Jianyong Li, Jianxiang Wang, and Yifan Zhai are co-corresponding authors. Introduction Investigational lisaftoclax is a selective BCL-2 inhibitor that has demonstrated antileukemic activity and favorable tolerability in pts with CLL. We report updated efficacy and safety data of pts with CLL treated with lisaftoclax in phase 1b/2 studies APG-2575-CN001 (NCT03913949) and APG-2575-CC101 (NCT04494503) after a 14-month follow-up. Methods Lisaftoclax (100, 200, 400, 600, and 800 mg) was administered orally once daily to pts with relapsed/refractory (R/R) CLL in repeated 28-day cycles. A daily ramp-up schedule and close monitoring was used for prevention and early detection of tumor lysis syndrome (TLS). Lisaftoclax continued until disease progression, intolerable toxicity, death, or any other reason for termination. Adverse events (AEs) were reported per NCI CTCAE v5.0, and response was evaluated per 2008 iwCLL NCI-WG criteria. Flow cytometry was used to analyze minimal residual disease (MRD) at individual sites in pts who achieved complete response (CR)/CR with incomplete marrow recovery (CRi) and partial response (PR) based on investigator judgement. MRD negativity was defined as a threshold of < 10 -4. Results As of April 27, 2023, a total of 47 pts went through a daily ramp-up of lisaftoclax treatment at an assigned dose, ranging from 100 to 800 mg daily (100 [n = 3], 200 [2], 400 [12], 600 [14], and 800 [16] mg). The median (range) follow-up period was 14.06 (0.70-30.2) months, and the median (range) age was 58 (34-80) years (male, 68.1%), with an ECOG PS of 0-1. At enrollment, 53.2% of pts were in Rai stage III/IV, and 48.9% Binet stage C. A total of 66.0% and 44.7% of pts had been treated with ≥ 2 or 3 lines of systematic treatment, 23.4% > 1 Bruton tyrosine kinase (BTK) inhibitor, and 55.3% a CD20 antibody. A total of 36 (76.6%) pts experienced grade (Gr) 3/4 treatment-emergent AEs (TEAEs), and 13 (27.7%) had serious AEs (SAEs). Incidences of TEAEs were not dose related. Common (> 30%) TEAEs were decreased neutrophil (all Gr, 72.3%; Gr 3/4, 44.7%), platelet (all Gr, 59.6%; Gr 3/4, 31.9%), and leukocyte (all Gr, 51.1%; Gr 3/4, 14.9%) counts; anemia (all Gr, 48.9%; Gr 3/4, 10.6%); hypertriglyceridemia (all Gr, 44.7%; Gr 3/4, 4.3%); hyperuricemia (all Gr, 42.6%); hypokalemia (all Gr, 34.0%); diarrhea (all Gr, 34.0%); and hyperbilirubinemia (all Gr, 31.9%). TRAEs were observed in 45 (95.7%) pts, of whom 32 (68.1%) experienced Gr 3/4 AEs and 7 (14.9%) SAEs. One TLS was reported. Thirty-two (68.1%) pts discontinued the study due to disease progression (51.1%); withdrawal (6.4%); and AEs, investigator decision, poor compliance, protocol deviation, and other reasons (2.1% each). The median (range) time to first response was 2.07 (1.94-3.94) months. The overall response rate (ORR) was 73.3% (33/45), and the CR/CRi rate was 24.4% (11/45). The rate of CR/CRi seemed to be dose-dependent (16.7% at 400, 23.1% at 600, and 33.3% at 800 mg). Furthermore, the pt who achieved a CR in the 200-mg cohort showed systemic exposure (C max and AUC) to lisaftoclax comparable to that observed in the 600-mg cohort. One patient in the 400-mg cohort achieved a CR in response to a dose escalation (per investigator) to 600 mg. MRD negativity was observed in 7 of 18 (38.9%) pts tested with peripheral blood (PB) MRD assessment, and 4 of 6 (66.7%) pts tested negative for MRD with MRD assessment of bone marrow (BM; Table 1). Median progression-free survival (PFS) was 18.53 (95% CI, 9.13-24.05) months, and 12- and 24-month PFS rates were 58.0% (95% CI, 41.9-71.2) and 39.4% (95% CI, 24.4- 54.0), respectively, as shown in Figure 1. The median (range) duration of response was 20.24 (95% CI, 14.75-NR) months. Median overall survival (OS) was NR. OS at 12 and 30 months was 94.8% (95% CI 80.6-98.7) and 86.3% (95% CI 66.1-94.9), respectively. Conclusions Lisaftoclax demonstrated significant efficacy at 400, 600, and 800 mg, and potentially 200 mg, in pts with R/R CLL who were heavily pretreated and had been exposed to BTK inhibitors. CR/CRi exhibited a trend of positive correlation with escalating dose levels. No significant new or unmanageable safety findings were observed.

Early Peripheral Blood Minimal Residual Disease Status By NGS in Patients with Newly Diagnosed Multiple Myeloma (MM) on a Phase 2 Trial Receiving Elotuzumab, Carfilzomib, Lenalidomide, and Dexamethasone (Elo-KRd)

Background: Assaying for minimal residual disease (MRD) in the peripheral blood (PB) of patients with multiple myeloma (MM) could solve issues of patchy and extramedullary disease leading to false-negative MRD tests based on bone marrow (BM) only assessments. However, PB testing is challenging due to limited circulating myeloma cells and/or paraprotein. Further, early PB assessments for MRD by paraprotein are unreliable due to the extended half-lives of immunoglobulins. In this analysis, we investigated the concordance and prognostic significance of early MRD status after 4 cycles of treatment with Elo-KRd by next generation sequencing (NGS) in both the BM and PB and by International Myeloma Working Group (IMWG) response criteria. Methods: All patients received 12 cycles of Elo-KRd in 28-day cycles without intent for stem cell transplant: Elo per standard dosing; K 56/70 mg/m 2 (highest tolerated) days 1, 8 and 15 (20 mg/m 2 on day 1 of cycle 1) ; R 25 mg days 1-21; and dexamethasone 40 mg days 1, 8, 15, 22. An MRD-adapted design was used to determine the duration of carfilzomib as previously reported (Derman et al. JAMA Oncology 2022). MRD by NGS in BM (sensitivity threshold 10 -6,clonoSEQ, Adaptive Biotechnologies) was performed at multiple timepoints per protocol. PB mononuclear cells were evaluated for MRD using the same assay; any quantifiable signal was considered positive in PB. Conventional response was assessed per IMWG response criteria. Paired IMWG response and MRD status in the PB and BM were assessed for concordance and prognostic significance at the end of cycle 4 (C4). The Kaplan-Meier method was used to assess progression free survival (PFS) based on a landmark assessment at C4. Results: A total of 46 patients initiated treatment with Elo-KRd; patient baseline characteristics were reported previously (Derman et al. JAMA Oncology 2022). With a median follow-up of 39 months, estimated 4-year PFS was 75%. Of the 42 patients in response at C4, 39 (93%) achieved >VGPR, and 13 (31%) reached >CR. When stratified by >CR vs <CR at C4, there was no difference in PFS (HR 1.4, 95% CI 0.3-6.9, p=0.7). BM MRD status at C4 was available for 34 patients: 11 (32%) patients were BM MRD(-)and 23 (68%) were MRD(+). Matched PB MRD samples at C4 were available for 31 patients; 22 (69%) patients were PB MRD(-) using the best available threshold based on sample input (16 at 10 -6, 6 at 10 -5). Of the 9 (31%) patients with PB MRD(+), 6 (67%) had at least one high-risk cytogenetic abnormality (del17p in n=4, +1q in n=2, t(4;14) in n=1). Extramedullary disease relapse was a manifestation of progression in 4 (44%) patients. BM MRD(-) at C4 was associated with superior PFS (HR not estimable, p=0.04; Figure 1A). No patient with MRD(-) BM after C4 had disease progression. PB MRD(+) at C4 was also associated with inferior PFS (HR 21, 95% CI 2.3-184, p=0.002; Figure 1B). In comparing BM and PB MRD status, 8/9 (89%) patients with PB MRD(+) at C4 had BM MRD(+), and 14/22 (61%) patients with BM MRD(+) at C4 had PB MRD(-). 3/9 (33%) patients with PB MRD(+) at C4 were in >CR; 16/22 (73%) patients with PB MRD(-) at C4 were in a PR/VGPR. With progression serving as the reference standard, PB MRD(+) carried a sensitivity of 71%, a specificity of 83%, a positive predictive value of 56%, and a negative predictive value of 91%. There were 19 matched BM MRD(+)/PB MRD(+) samples across all timepoints; Pearson's correlation coefficient of detected cells per million between BM and PB MRD was r=0.93. BM MRD detected aberrant cells at higher concentrations, with a median log difference of 1.38 compared to PB MRD (range 0.07-3). Conclusions: MRD by NGS in the PB was less sensitive compared to the same assessment in the BM by 1-2 logs; however, PB MRD status following 4 cycles of induction therapy was strongly prognostic given its association with PFS. PB MRD status early in treatment may represent a leading indicator of early response and/or a marker of high-risk disease features, and validation of these findings may help to eventually guide intensification of therapy.

Minimal Residual Disease (MRD) Testing By Next Generation Sequencing (NGS) after Two Cycles (CY) of Non-Intensive Chemoimmunotherapy Is Predictive of Remission Duration and Need for Maintenance Therapy (MT) in Previously Untreated Mantle Cell Lymphoma (MCL): A Wisconsin Oncology Network Study

Introduction: Despite the variable course of MCL, limited prospective markers exist to identify more indolent disease. MCL is often diagnosed in older patients (pts) less able to tolerate intensive approaches. Bendamustine/rituximab (BR) is a standard non-intensive regimen for MCL, and use of MT remains controversial. Emerging data in MCL suggest a correlation between achieving MRD negativity (MRD-) and progression-free survival (PFS). The GALLIUM study (Marcus R, et al, N Engl J Med 2017) previously showed improved PFS with a bendamustine/obinutuzumab (BO) induction compared with BR in follicular lymphoma, and we postulated this benefit may be observed in MCL. Using MRD testing, we predicted that MT may be omitted in pts achieving MRD- status after induction BO chemoimmunotherapy for MCL. Methods: Adult pts ≥18 years (yrs) with previously untreated MCL who were ineligible for more intensive therapies (including transplant) were enrolled. Pts received 4-6 CY of BO induction intravenously (IV) every 28 days (D) with B 90 mg/m2 IV D1 & 2 every 28D for 6 CY concurrent with O IV (cycle 1 = 100 mg D1, 900 mg D2, and 1000 mg D8 & 15; then 1000 mg D1, CY 2-6). Peripheral blood (PB) MRD was obtained using NGS (ClonoSEQ®) after cycle 2 BO as an exploratory endpoint. Consolidation O (CO) 1000 mg IV weekly for 4 doses was initiated ≤12 weeks after the final dose of BO. Restaging and MRD testing of PB and bone marrow aspirate (BMA) was done ≤30 days after CO completion. For pts with complete response (CR) radiographically and MRD- in PB/BMA, maintenance O (MO) was omitted. For pts without CR or persistent MRD positivity (MRD+) in the PB or BMA, MO was given with 1000 mg IV D1 of a 56-day cycle for 8 CY. Pts were followed for ≥2 years from therapy completion. The primary endpoint is PFS from D1 of BO induction. Secondary endpoints are MRD status, concordance rate of PB/BMA in predicting MRD status, response rates and overall survival (OS). Results: Twenty-one pts (of planned 32) enrolled beginning 2/2018, with follow-up through 6/1/2023. The study closed prematurely due to slow enrollment. Median age is 70 yrs with 3 pts >80 yrs; majority were men (76%). Median MIPI score is 6.11 and median ECOG performance status 0. Twenty pts (95%) have stage IV disease. Twenty pts completed 4 (n=1) or 6 CY BO. Ten pts received MO; 10 did not receive MO per protocol due to radiographic CR and MRD- PB/BMA post-CO. Six pts did not complete MO for reasons of progressive disease (n=4), infection (n=1) and new carcinoma (n=1). After cycle 2 BO, PB analysis was MRD+ in 7 pts and MRD- in 13. Concordance rates between post-CO MRD testing in PB and BMA was 70% (14/20). Of non-concordant values, all had PB MRD- but BMA MRD+. Best responses in 20 assessable pts are: CR 75% (15/20), partial response 20% (4/20), and stable disease 5% (1/20). Most common grade 3/4 toxicities were: neutropenia (10/21), leukopenia (6/21), infections (5/21) and infusion reactions (2/21). One pt had grade 5 cardiac arrest with sepsis during BO. Most common grade 3 infections were abdominal/colitis (n=3) and pneumonia (n=2). Most common grade 1/2 toxicities were nausea (14/21), diarrhea (10/21), constipation (8/21), dysgeusia (6/21), fatigue (8/21) and dry skin/rash (12/21). After a median duration of follow-up of 43.9 months (mos) (95% confidence interval [CI] 28.3-60.1), PFS at 2-yrs and 3-yrs is 66.0% (95% CI 41.6-82.2) and 58.7% (95% CI 33.2-77.3), respectively; and median PFS is 46.5 mos (95% CI 16.4-∞). MRD- status after the exploratory endpoint post-C2 BO was predictive of 2-year PFS (Figure 1a), 83.3% (95% CI 48.2-95.6) for MRD- vs. 42.9% (95% CI 9.78-73.4) for MRD+, with hazard ratio [HR] 0.34 (95% CI 0.09-1.39), p value 0.133. Evaluation of PFS by MRD status post-CO showed similar outcomes regardless of receiving MO (Figure 1b): 2-year PFS is 77.8% (95% CI 36.5-93.9) in MRD- pts post-CO vs 60.0% (95% CI 25.3-82.7) in MRD+ pts; HR 0.45 (95% CI 0.10-1.91, p value 0.278. Median OS is 46.5 mos (95% CI 35.1-∞). Conclusion: Omission of MO in pts achieving MRD- status after induction/CO did not result in worsening PFS. Observed PFS and toxicities with BO induction and CO appears comparable with other data sets utilizing a BR-based induction +/- MT in older, less fit MCL pts. Correlation between PFS and PB MRD testing after C2 induction therapy represents a potential new prognostic marker of MCL behavior, and may be an important early disease indicator in development of risk-adapted therapies.

A Multicenter Phase 2 Trial of Zanubrutinib, Obinutuzumab, and Venetoclax (BOVen) in Patients with Treatment-Naïve, TP53-Mutant Mantle Cell Lymphoma

Background: TP53-mutant mantle cell lymphoma (MCL) is associated with poor survival outcomes with chemoimmunotherapy (Eskelund, Blood 2017) with median progression-free survival (PFS) of 0.9 years and median overall survival (OS) of 1.8 years. There is no standard frontline treatment for this high-risk subset. The combination of Bruton's tyrosine kinase (BTK) inhibition and BCL2 inhibition were synergistic and active in relapsed, refractory MCL, including in patients with TP53 mutation (Tam, NEJM 2018). Obinutuzumab, ibrutinib, and venetoclax were well tolerated and efficacious in relapsed and untreated MCL patients (Le Gouill, Blood 2021). We hypothesized that treatment with zanubrutinib (Zanu), Obinutuzumab (Obin), and venetoclax (Ven) (BOVen) would be well-tolerated and efficacious in untreated TP53-mutant MCL. Methods:In this multicenter, investigator-initiated phase 2 trial (NCT03824483), eligible patients had previously untreated MCL with TP53 mutation (of any variant allele frequency) and ECOG PS ≤2, ANC >1, PLT >75, HGB ≥9 (unless if due to MCL). BOVen is administered in 28-day cycles: Zanu 160 mg PO BID starting D1; Obin 1000 mg IV D1 or split D1-2, 8, 15 of C1, D1 of C2-8; Ven ramp up initiated C3D1 (target 400 mg QD). Treatment duration is 2 years at minimum and the primary endpoint is 2-year PFS. Response was assessed using Lugano criteria (Cheson, JCO 2014). PFS and OS were estimated using the Kaplan-Meier method. Peripheral blood minimal residual disease (PB-MRD) assessment was performed using the Adaptive clonoSEQ ® assay. After 24 cycles, Zanu and Ven can be discontinued if MRD undetectable (<10 -6) complete remission (CR) is achieved. With subsequent PB-MRD monitoring, patients can be retreated if clinical progression or MRD detectability (>10 -6). Adverse events (AE) were assessed per CTCAE v5. Results: All 25 planned patients have been enrolled (May 15, 2023 data cut). The median age on study was 65 years (range 29 - 82); 76% were male (19/25); various histologic subtypes were included (15 conventional MCL, 5 non-nodal leukemic, and 5 blastoid variant); 100% stage IV (25/25); by MIPI: 68% high risk (17/25), 28% intermediate (7/25), and 4% low risk MIPI score (1/25); 67% Ki67 ≥30% (14/21); 33% Ki67≥50% (7/21); 100% TP53 mutation, and 48% 17p deletion (12/25). Treatment was overall well-tolerated. The most common treatment-related AEs (≥20%) were predominantly low-grade and manageable, including diarrhea (52%), neutropenia (28%), infusion-related reaction (24%), bruising (20%), COVID-19 infection (20%), nausea (20%), thrombocytopenia (20%), and rash (20%). The grade 3 or higher treatment-related AEs were neutropenia (12%), infusion-related reaction (8%), COVID-19 (8%), diarrhea (4%), transaminitis (4%), thrombocytopenia without bleeding (4%), and rash (4%). Detailed toxicity data will be presented in future. Median follow-up was 16.1 months. There were 5 progressions and 4 deaths on study (2 COVID-related, 1 post-operative aspiration pneumonia, 1 unknown cause), see Figure 1. All deaths occurred in patients who were in ongoing response at time of death. The best overall response rate was 95% (24/25) with 88% (22/25) achieving a CR. At C3 post Zanu-Obin, 68% (n=17/25) achieved PET-CR and post cycle 3, 5 patients converted to a PET-CR (Figure 1). The 1-year PFS and overall survival (OS) were 84% (95% CI: 71%, 100%) and 96% (95% CI: 89%, 100), respectively. The 16-month PFS and OS were 75% (95% CI: 60%, 95%) and 87% (95% CI: 75%, 100%), respectively. The 16-month PFS and OS for patients less than 65 years of age (n=9) were both 100%. Seven patients completed 24 treatment cycles. Of these, 71% (5/7 pts) were in CR and MRD undetectable (treatment discontinued) and 29% (2/7 pts) were in CR and MRD detectable (continued treatment). Outcomes post C24 will be presented in future. At 10 -6 MRD sensitivity level, 7 (28%) of 23 patients had undetectable MRD at C3 and 16 (100%) of 16 patients at C13. Conclusions:BOVen is a well-tolerated, outpatient regimen associated with high response rates and high rates of undetectable MRD in untreated TP53-mutant MCL. The early PFS and OS estimates with BOVen compare favorably with historical outcomes of chemoimmunotherapy in this high-risk subset of MCL. Based on this data, BOVen emerges as a promising treatment option for TP53-mutant MCL and, therefore, the study was expanded to include an additional 25 (total 50) TP53-mutant MCL patients.

Minimal Residual Disease Detected by the 7NB-mRNAs ddPCR Assay Is Associated with Disease Progression in High-Risk Neuroblastoma Patients: A Prospective Multicenter Observational Study in Japan.

High-risk neuroblastoma (HR-NB) patients remain far from obtaining optimal outcomes, with more than 50% relapse/regrowth rate despite current intensive multimodal therapy. This originated from the activation/proliferation of chemoresistant minimal residual disease (MRD). MRD with a significant prognostic was reported by several quantitative PCR (qPCR) or droplet digital PCR (ddPCR) assays quantitating different sets of NB-associated mRNAs (NB-mRNAs). The 7NB-mRNAs ddPCR assay quantitating CRMP1, DBH, DDC, GAP43, ISL1, PHOX2B, and TH mRNAs was reported to outperform other qPCR assays by a retrospective in-house observational study. In the present study, the Japan Children's Cancer Group (JCCG) Neuroblastoma Committee conducted a prospective multicenter observational study aimed at evaluating a prognostic value of MRD in bone marrow (BM-MRD) and peripheral blood (PB-MRD) detected by 7NB-mRNAs ddPCR assay. Between August 2018 and August 2022, 7 HR-NB patients who registered for JCCG clinical trials (JN-H-11 and JN-H-15) were enrolled. A total of 19 BM and 19 PB samples were collected, and 4/15 BM and 4/15 PB samples were classified as progressive disease (PD)/non-PD samples. BM-MRD and PB-MRD estimated area under curve (AUC) of 0.767 and 0.800 with a significant accuracy (AUC > 0.7). The present study validated a prognostic value of BM-MRD obtained by a previous study (AUC 0.723) and revealed the significant accuracy of PB-MRD as well as BM-MRD.

Clinical impact of minimal residual disease in blood and bone marrow of children with acute myeloid leukemia.

The prognostic significance of bone marrow minimal residual disease (MRD) in pediatric patients with acute myeloid leukemia (AML) is well characterized, but the impact of blood MRD is not known. We, therefore, used flow cytometric assessment of leukemia-specific immunophenotypes to measure levels of MRD in both the blood and bone marrow of patients treated in the AML08 (NCT00703820) clinical trial. Blood samples were obtained on days 8 and 22 of therapy, whereas bone marrow samples were obtained on day 22. Among patients who tested as having MRD-negative bone marrow on day 22, neither day-8 nor day-22 blood MRD was significantly associated with the outcome. However, day-8 blood MRD was highly predictive of the outcome among patients who tested as having MRD-positive bone marrow on day 22. Although the measurement of blood MRD on day 8 cannot be used to identify patients who have day-22 MRD-negative bone marrow who are likely to relapse, our findings suggest that day-8 blood MRD results can identify patients with MRD-positive bone marrow who have a dismal prognosis and may be candidates for the early use of experimental therapy.

A Fixed-Duration Immunochemotherapy Approach Combined with Ibrutinib in CLL Produces Deep and Sustained MRD Responses: 5.5-Year Results from the Icll-07 Filo Trial

Introduction In previously untreated, medically fit patients with chronic lymphocytic leukemia (CLL), the availability of targeted agents has led to research interest in achieving deep, durable remissions and improving survival outcomes. The phase II ICLL-07 (NCT02666898) trial by the French Innovative Leukemia Organization (FILO) evaluated a fixed-duration (15-month) immunochemotherapy approach (no more than 4 fludarabine/cyclophosphamide [FC]-obinutuzumab cycles). Primary analysis showed the approach was safe and 62.2% (84/135) of all patients enrolled achieved complete response (CR) with bone marrow (BM) minimal residual disease (MRD) <0.01% (Michallet et al Lancet Haematol 2019;6:e470-9). Follow-up at median 37 months from treatment start showed a persistent MRD benefit beyond end of treatment, high survival rates, and low long-term toxicity (Michallet et al Blood 2021;137:1019-23). Here we report long-term results at median 64 months from treatment start (data cut-off 20 May 2022). Methods Between 27 October 2015 and 16 May 2017, 135 previously untreated, medically fit patients with CLL were enrolled from 27 FILO centers. All received obinutuzumab 1000 mg (8 infusions over 6 cycles) plus ibrutinib (420 mg/day for 9 months). Following evaluation at D1 M9 (N=130 evaluable), those in CR with BM MRD <0.01% then continued only ibrutinib 420 mg/day for 6 additional months (I arm; n=10); otherwise, patients received 4 cycles of FC-obinutuzumab 1000 mg alongside continuing ibrutinib 420 mg/day for 6 additional months (I-FCG arm; n=115). Beyond end of treatment, patients were followed for peripheral blood (PB) MRD every 6 months, response every 3 months, progression-free/overall survival (PFS/OS), and safety. MRD was assessed by 8-color flow cytometry, using a highly sensitive (10-6) technique developed by the FILO group that enables subdivision of classical MRD <0.01% into low-level positive MRD <0.01% and undetectable MRD. Results At D1 M16, undetectable PB MRD rates were 80.0% (8/10) in the I arm and 92.5% (99/107) in the I-FCG arm. Beyond end of treatment, in the I arm the undetectable PB MRD rate decreased rapidly, and by M40 all patients had PB MRD positivity (≥0.01% or low-level positive <0.01%). In the I-FCG arm, the undetectable PB MRD rate was 76.3% (61/80) at M40, and of patients currently investigated at M64, 50/62 (80%) still had undetectable PB MRD (Figure 1). Four relapses occurred beyond end of treatment, including 2 CLL progressions (both Richter's syndrome). Throughout follow-up, no differences in undetectable PB MRD rates were apparent in the I-FCG arm according to the IGHV -mutated versus unmutated status (currently at M64: 20/27 versus 25/35, P=0.26). Overall 4-year PFS and OS rates (95% confidence intervals) were 95.5% (92% to 99 %) and 96.2% (93% to 99.5%), respectively. Of 12 deaths overall, 7 occurred beyond end of treatment, with 5 since last publication due to Richter's syndrome at M50, COVID at M50, lung cancer at M50, myelodysplastic syndrome at M60, and acute myeloid leukemia at M69. Other serious adverse events since last publication were metastatic prostate adenocarcinoma at M50 and suspicion of cerebrovascular accident at M65. Conclusion Long-term results from the ICLL-07 trial in previously untreated, medically fit patients with CLL demonstrated that that our fixed-duration (15-month) immunochemotherapy approach produced deep and sustained undetectable PB MRD responses that were correlated to PFS, without excess toxicity. These long-term MRD results remain the best to date even compared to the new targeted therapy combinations ie ibrutinib +veneteclax or obinutuzumab + venetoclax A randomized trial is needed to compare our approach with a chemotherapy-free strategy. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Immunoglobulin High Throughput Sequencing (Ig-HTS) Minimal Residual Disease (MRD) Analysis Is an Effective Surveillance Tool in Patients with Mantle Cell Lymphoma

Introduction Mantle cell lymphoma (MCL) accounts for 4-6% of B-cell non-Hodgkin lymphoma (NHL), with historically poor outcomes. With the advent of targeted and cellular therapies, responses and durable remissions have improved although cure remains elusive. As patients experience longer remissions, this raises the question of the optimal surveillance modality. For NHL in general, surveillance imaging surveillance does not improve outcomes and is associated with increased radiation exposure, high costs, and anxiety to patients. Peripheral blood minimal residual disease (MRD) analysis offers a potential alternative to surveillance imaging that is more sensitive, less costly, and eliminates the risk of radiation exposure. The clonoSEQ® assay (Adaptive Biotechnologies) is an FDA-cleared Ig-HTS MRD assay which takes advantage of the fact that B-cell lymphomas nearly always have one or more unique clonal immunoglobulin (Ig) gene rearrangements which can serve as a tumor "marker". These sequences can be detected in the peripheral blood, as circulating tumor DNA (ctDNA), with a sensitivity as low as 1 cell in 1,000,000. Starting in 2015, our group has monitored many of our MCL patients using the clonoSEQ® MRD assay. This has been done in lieu of surveillance imaging, or to minimize its use. We performed a retrospective analysis to summarize our experience with this assay to demonstrate its utility as a surveillance tool for MCL patients. Methods We conducted retrospective data collection and analysis of outcomes in patients who underwent first-line treatment for MCL and were then monitored post-treatment using the clonoSEQ® assay. We captured baseline patient characteristics, as well as every time a surveillance imaging or ctDNA (clonoSEQ®) test was performed. We used swimmer plots to display timelines for individual patients, indicating all ctDNA tests (positive or negative), CT or PET scan results, as well as documented clinical relapse. We used Kaplan-Meier curves to show progression-free survival and overall survival of the entire cohort. We compared ctDNA to radiographic surveillance in terms of ability to detect relapse. Results A total of 31 patients were included. The median age of patients was 59, and the majority had low- or intermediate-risk disease by MIPI score, with 58% having a proliferation index above 30%. The majority (81%) underwent high-dose cytarabine-based induction, 77% underwent autologous transplant in first remission, and 42% received rituximab maintenance (see Table 1). With a median follow up of 5.8 years, overall outcomes with this cohort were excellent, with 69% and 60% progression-free at 5 and 10 years, respectively, and 96% and 92% alive at 5 and 10 years, respectively. Among the 12 patients who ultimately sustained a radiographic relapse, peripheral blood became MRD-positive in 11 patients (92%). The first positive MRD test came with a lead time of between 0-24 months (median 70 days) prior to radiographic relapse. Only one patient had a negative MRD result while being found to have progressive disease on imaging. That patient had a single site of disease at the base of tongue which caused symptoms early, despite a very low overall disease burden. Among the 19 patients who have been in continuous clinical remission, 17 have remained MRD-negative. The other 2 had "molecular relapse” (MRD positive without radiographic relapse), which allowed for pre-emptive rituximab treatment, which converted them back to an MRD-negative state. Several patients were able to enjoy 2-4 year intervals without any surveillance imaging, while still getting reassurance every few months from the negative ctDNA test (see Figure 1). Conclusions Our data suggests that the clonoSEQ® MRD assay is an effective surveillance tool for MCL patients following first-line therapy. In our experience, this MRD assay was predictive of relapse prior to imaging in all but one patient. In addition, the assay allowed for minimization of surveillance imaging, and early detection of MRD allowed for pre-emptive rituximab therapy in select patients. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Abstract 1257: Early blood uMRD correlates with improved PFS in patients with CLL

Abstract The approval of targeted therapies has greatly improved outcomes for patients (pts) with chronic lymphocytic leukemia (CLL) in both 1L and relapsed/refractory (R/R) settings. The use of long-term outcomes such as progression free survival (PFS) and overall survival (OS) to inform early drug development can extend timelines and delay approval of potentially beneficial novel treatments. Establishing correlations between short-term treatment effects and long-term outcomes could shorten development timelines. Minimal residual disease (MRD) is a sensitive indicator of disease burden, with achievement of undetectable MRD (uMRD: &amp;lt; 1 CLL in 10,000 leukocytes [10-4]) either during or at the end of therapy being prognostic of prolonged PFS and OS. Our current work explores correlations between PFS and earlier dynamic changes in lymphocyte counts and peripheral blood (PB) MRD as potential tools for guiding drug development decisions in CLL. Data from five trials (NCT numbers 01328626, 01889186, 02141282, 02756611 (receiving Venetoclax monotherapy and primarily R/R CLL pts) and 01682616 (R/R CLL pts receiving venetoclax + rituximab therapy) were analyzed. PB MRD was quantified by either flow cytometry or next generation sequencing at various timepoints. Many of these pts had high risk features such as 17pDEL or prior BCRi therapy. The relationships between absolute lymphocyte count (ALC) and percent change in lymphocytes at 1, 3, 6, and 9 months (M) of treatment and PB MRD status were explored. Additionally, the relationship between PB MRD levels at 6±2 M and achievement of uMRD was assessed. Lastly, we evaluated the relationship between PB MRD status at different time points (6±2, 9 and 12 M) and PFS using Kaplan Meier plots. Across the trials, 708 CLL pts were treated, with 496 pts having PB MRD assessments at any time on therapy. PB uMRD rate of the evaluable population was 47.6% (236/496). Analysis of pts with PB MRD assessments at ~6 M (6±2 M, n=310) demonstrated that achievement of uMRD correlated with improved PFS (with median PFS of 56 M compared to 26 M in pts who had detectable MRD, p=0.037). Moreover, pts with residual disease in the PB (&amp;gt; 10-4) at ~6 M and achieved uMRD later while on therapy had a significantly lower residual disease at this timepoint than pts who did not achieve uMRD (p&amp;lt;0.001). Pts with residual disease &amp;lt; 10-3 (&amp;lt;1 CLL cell/1,000 leukocytes) at ~6 M were more likely to demonstrate PB uMRD at 12 M (72% vs 6%, p&amp;lt;0.001) compared to pts with residual disease ≥10-3 at this assessment. Neither ALC or percent change in lymphocytes at 1, 3, 6, and 9 M of treatment correlated with PB uMRD. In this R/R CLL population who received continuous dosing of venetoclax, uMRD at ~6 M correlated with PFS outcomes. Additionally, MRD levels at ~6 M of therapy correlated with uMRD at 12 M. These suggest that including PB MRD assessments at early timepoints may be a useful tool in assessing efficacy and informing RP2D decisions during the development of novel agents in this indication. Citation Format: Ibrahim Y. Abdelgawad, Ahmed A. Suleiman, Brenda Chyla, Majd Ghanim, Ahmed H. Salem, Mohamed Badawi. Early blood uMRD correlates with improved PFS in patients with CLL [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1257.

Four-year follow-up from a phase 2 study of obinutuzumab, ibrutinib, and venetoclax in CLL.

7540 Background: Targeted agent combinations for chronic lymphocytic leukemia (CLL) have resulted in safe regimens with improved progression-free survival (PFS) compared to chemoimmunotherapy. The optimal regimen and long-term outcomes remain unknown. We conducted a phase 2 study of obinutuzumab (OBIN), ibrutinib (IBR), and venetoclax (VEN) in relapsed/refractory (RR) and treatment-naïve (TN) CLL patients (pts) and report extended follow up on two previously reported cohorts (RR, TN 1) and a new cohort of identically treated TN pts (TN 2). Methods: Pts with TN or RR (≥1 prior treatment) CLL requiring treatment were eligible. Treatment was given for 14 28-day cycles (C). OBIN was started C1, IBR C2, and VEN C3 with standard dose escalation. Response was assessed 2 months (mos) after C14 (EOT) by iwCLL 2008 criteria. Minimal residual disease (MRD) was measured by 10-color flow cytometry with a cutoff of &lt; 1x10-4. The primary endpoint was complete remission (CR) with undetectable MRD (uMRD) in blood and bone marrow at EOT. A sample size of 25 pts per cohort achieves 90% power to test the null hypothesis of 10% against 30% with 1-sided α of 10%. The Kaplan-Meier method was used to estimate PFS and overall survival (OS). Results: 75 pts were treated in 3 cohorts (Table). Data are as of 1/3/2022. In the TN 2 cohort, the overall response rate (ORR) at EOT was 96% (95% CI: 80-100) and CR with uMRD was 20% (95% CI: 7-41). The ORR for TN 1 and TN 2 combined was 90% (95% CI: 78-97) and CR with uMRD was 24% (95% CI: 13-38). Median follow up was 56 (0-65), 57 (7-63), and 30 (24-35) mos, respectively, for RR, TN 1, and TN 2. There were 3 deaths (RR = 1, TN 1 = 1, TN 2 = 1) and 6 disease progressions (RR = 4, TN 1 = 2, TN 2 = 0). Estimated 48-month PFS for TN 1 and RR cohorts were both 96% (95% CI: 72-99) and OS was 85% (95% CI: 60-95) and 100%, respectively. The estimated 24-month PFS and OS for TN 2 were both 96% (95% CI: 75-99). The most frequent adverse events were neutropenia (95%, 73% grade ≥3), leukopenia (95%, 45% grade ≥3), lymphopenia (93%, 40% grade ≥3), and thrombocytopenia (91%, 28% grade ≥3). The only grade ≥3 non-hematologic toxicity occurring at ≥20% was hypertension (85%, 39% grade ≥3). Atrial fibrillation occurred in 11% of pts. Conclusions: At extended follow-up, remissions remain durable after fixed duration OBIN, IBR, and VEN. The efficacy and acceptable safety justify further study and are being compared to IBR and OBIN in 2 phase 3 US cooperative group trials. Clinical trial information: NCT02427451. [Table: see text]

Sensitive Measurement of Minimal Residual Disease in Blood by HAT-PCR

PCR is widely used to measure minimal residual disease (MRD) in lymphoid neoplasms, but its sensitivity is limited. High Adenine/Thymine PCR and High Annealing Temperature PCR (HAT-PCR) is a modified PCR designed to minimize nonspecificity and hence increase sensitivity. It was evaluated in the laboratory and the clinic, using samples from 58 patients. Of these patients, 57 were adolescents or young adults who were participating in the Australasian Leukemia and Lymphoma Group ALL06 trial in which MRD was measured in blood principally by HAT-PCR and in marrow by conventional PCR. HAT-PCR produced significantly less nonspecificity than conventional PCR, and its limit of detection was <10-6 in 90% of patients. In 196 samples, an excellent correlation was found between blood and marrow MRD. Variable partitioning of leukemic cells between blood and marrow was observed. Measurement of MRD in blood by HAT-PCR was noninferior to measurement of MRD in marrow by conventional PCR, in terms of both detecting disease and predicting clinical outcome. At a median follow-up of 3 years and for MRD levels in blood at the end of consolidation treatment, an MRD level of >10-4 cells/L significantly predicted relapse and mortality, whereas undetectable MRD significantly predicted relapse-free survival and overall survival. HAT-PCR is a simple, quick, cheap and sensitive method for measurement of MRD, and its adoption for MRD in blood may be clinically useful.

Guideline for the treatment of chronic lymphocytic leukaemia

Guideline for the treatment of chronic lymphocytic leukaemia

Zanubrutinib, obinutuzumab, and venetoclax with minimal residual disease-driven discontinuation in previously untreated patients with chronic lymphocytic leukaemia or small lymphocytic lymphoma: a multicentre, single-arm, phase 2 trial

We hypothesised that combining zanubrutinib with obinutuzumab and venetoclax (BOVen) as an initial therapy for chronic lymphocytic leukaemia and small lymphocytic lymphoma would lead to high rates of undetectable minimal residual disease (MRD), and we explored MRD as a biomarker for directing treatment duration. This multicenter, investigator-initiated, single-arm, phase 2 trial took place at two two academic medical centres in the USA. Patients were eligible for the primary cohort if they had treatment-naive chronic lymphocytic leukaemia or small lymphocytic lymphoma, required therapy, and were at least 18 years of age with an Eastern Cooperative Oncology Group performance status up to 2. BOVen was administered in 28 day cycles (oral zanubrutinib at 160 mg twice per day starting in cycle 1 on day 1; intravenous obinutuzumab at 1000 mg on day 1 [split over day 1 with 100 mg and day 2 with 900 mg for an absolute lymphocyte count >25 000 cells per μL or lymph nodes >5 cm in diameter], day 8, and day 15 of cycle 1, and day 1 of cycles 2-8; and oral venetoclax ramp up to 400 mg per day starting in cycle 3 on day 1) and discontinued after 8-24 cycles when prespecified undetectable MRD criteria were met in the peripheral blood and bone marrow. The primary endpoint was the proportion of patients that reached undetectable MRD in both the peripheral blood and bone marrow (flow cytometry cutoff less than one chronic lymphocytic leukaemia cell per 10 000 leukocytes [<10-4]) assessed per protocol. This trial is registered at clinicaltrials.gov (NCT03824483). The primary cohort is closed to recruitment, and recruitment continues in the TP53-mutated mantle cell lymphoma cohort. Between March 14, 2019, and Oct 10, 2019, 47 patients were screened for eligibility, and 39 patients were enrolled and treated. Median age was 62 years (IQR 52-70) with 30 (77%) of 39 male participants and nine (23%) of 39 female participants. 28 (72%) of 39 patients had unmutated immunoglobulin heavy-chain variable-region and five (13%) of 39 had 17p deletion or TP53 mutation. After a median follow-up of 25·8 months (IQR 24·0-27·3), 33 (89%) of 37 patients (95% CI 75-97) had undetectable MRD in both blood and bone marrow, meeting the prespecified undetectable MRD criteria to stop therapy after a median of ten cycles (IQR 8-12), which includes two cycles of zanubrutinib and obinutuzumab before starting venetoclax. After median surveillance after treatment of 15·8 months (IQR 13·0-18·6), 31 (94%) of 33 patients had undetectable MRD. The most common adverse events were thrombocytopenia (23 [59%] of 39), fatigue (21 [54%]), neutropenia (20 [51%]), and bruising (20 [51%]), and the most common adverse event at grade 3 or worse was neutropenia (seven [18%]) in the intention-to-treat population. One death occurred in a patient with intracranial haemorrhage on day 1 of cycle 1 after initiating intravenous heparin for pulmonary emboli. BOVen was well tolerated and met its primary endpoint, with 33 (89%) of 37 previously untreated patients with chronic lymphocytic leukaemia or small lymphocytic lymphoma reaching undetectable MRD in both peripheral blood and bone marrow despite a median treatment duration of only 10 months, owing to our undetectable MRD-driven treatment discontinuation design. These data support further evaluation of the BOVen regimen in chronic lymphocytic leukaemia and small lymphocytic lymphoma with treatment duration guided by early MRD response kinetics. Beigene, Genentech (Roche), Grais-Cutler Fund, Lymphoma Research Fund, Lymphoma Research Foundation, American Cancer Society, Farmer Family Foundation, and the National Instititutes of Health and National Cancer Institute.

Time-Limited Venetoclax and Ibrutinib for Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia (R/R CLL) Who Have Undetectable MRD - Primary Analysis from the Randomized Phase II Vision HO141 Trial

Time-Limited Venetoclax and Ibrutinib for Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia (R/R CLL) Who Have Undetectable MRD - Primary Analysis from the Randomized Phase II Vision HO141 Trial

Phase 1 TRANSCEND CLL 004 study of lisocabtagene maraleucel in patients with relapsed/refractory CLL or SLL

Bruton tyrosine kinase inhibitors (BTKi) and venetoclax are currently used to treat newly diagnosed and relapsed/refractory chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). However, most patients eventually develop resistance to these therapies, underscoring the need for effective new therapies. We report results of the phase 1 dose-escalation portion of the multicenter, open-label, phase 1/2 TRANSCEND CLL 004 (NCT03331198) study of lisocabtagene maraleucel (liso-cel), an autologous CD19-directed chimeric antigen receptor (CAR) T-cell therapy, in patients with relapsed/refractory CLL/SLL. Patients with standard- or high-risk features treated with ≥3 or ≥2 prior therapies, respectively, including a BTKi, received liso-cel at 1 of 2 dose levels (50 × 106 or 100 × 106 CAR+ T cells). Primary objectives included safety and determining recommended dose; antitumor activity by 2018 International Workshop on CLL guidelines was exploratory. Minimal residual disease (MRD) was assessed in blood and marrow. Twenty-three of 25 enrolled patients received liso-cel and were evaluable for safety. Patients had a median of 4 (range, 2-11) prior therapies (100% had ibrutinib; 65% had venetoclax) and 83% had high-risk features including mutated TP53 and del(17p). Seventy-four percent of patients had cytokine release syndrome (9% grade 3) and 39% had neurological events (22% grade 3/4). Of 22 efficacy-evaluable patients, 82% and 45% achieved overall and complete responses, respectively. Of 20 MRD-evaluable patients, 75% and 65% achieved undetectable MRD in blood and marrow, respectively. Safety and efficacy were similar between dose levels. The phase 2 portion of the study is ongoing at 100 × 106 CAR+ T cells. This trial was registered at clinicaltrials.gov as NCT03331198.

Long term follow-up of a phase II study of cladribine with concurrent rituximab with hairy cell leukemia variant

AbstractHairy cell leukemia variant (HCLv) responds poorly to purine analogue monotherapy. Rituximab concurrent with cladribine (CDAR) improves response rates, but long-term outcomes are unknown. We report final results of a phase 2 study of CDAR for patients with HCLv. Twenty patients with 0 to 1 prior courses of cladribine and/or rituximab, including 8 who were previously untreated, received cladribine 0.15 mg/kg on days 1 to 5 with 8 weekly rituximab doses of 375 mg/m2 beginning day 1. Patients received a second rituximab course ≥6 months after cladribine, if and when minimal residual disease (MRD) was detected in blood. The complete remission (CR) rate from CDAR was 95% (95% confidence interval, 75-100). Sixteen (80%) of 20 patients (95% confidence interval, 56-94) became MRD negative according to bone marrow at 6 months. The median duration of MRD-negative CR was 70.1 months, and 7 of 16 are still MRD negative up to 120 months. With a median follow-up of 69.7 months, 11 patients received delayed rituximab, and the 5-year progression-free survival (PFS) and overall survival (OS) were 63.3% and 73.9%, respectively. Five patients with TP53 mutations had shorter PFS (median, 36.4 months vs unreached; P = .0024) and OS (median, 52.4 months vs unreached; P = .032). MRD-negative CR at 6 months was significantly associated with longer PFS (unreached vs 17.4 months; P < .0001) and OS (unreached vs 38.2 months; P < .0001). Lack of MRD in blood at 6 months was also predictive of longer PFS and OS (P < .0001). After progression following CDAR, median OS was 29.7 months. CDAR is effective in HCLv, with better outcomes in patients who achieve MRD-negative CR. This trial is registered at www.clinicaltrials.gov as #NCT00923013.

Abstract CT146: Prognostic and therapeutic significance of leukemia subtypes in the context of risk-directed therapy based on minimal residual disease levels in pediatric acute lymphoblastic leukemia

Abstract Determination of prognostic and therapeutic implications of novel leukemia subtypes in children with acute lymphoblastic leukemia (ALL) treated with contemporary minimal residual disease (MRD)-directed therapy can improve outcome. In this study, we evaluated the clinical impact of identification of the full genomic spectrum of leukemia subtypes and MRD assessment to guide risk-directed therapy. A retrospective cohort study was conducted in 598 consecutive patients enrolled on Total Therapy Study 16 in a single center from October 29, 2007 to March 26, 2017, with a median follow-up of 7 years. High-hyperdiploid and ETV6-RUNX1 ALL were provisionally classified to be low-risk; TCF3-PBX1, hypodiploid&amp;lt;44 chromosomes and T-ALL standard-risk; and BCR-ABL1, infant KMT2A-rearranged and ETP ALL high-risk. Single nucleotide polymorphism arrays, exome and transcriptome sequencing were used to identify novel leukemia subtypes. Final risk assignment was based on MRD levels measured in bone marrow samples on day 15 of induction and day 42 (end of induction). Patients with MRD≥1% on day 15 or 0.01% to &amp;lt;1% on day 42 were assigned to standard-risk and those with MRD≥1% to high-risk group. MRD was determined in blood samples on day 8 for a research aim. The primary outcome was event-free survival. The secondary outcomes were relapse and overall survival. We identified 17 genetic subtypes, 8 of which were novel. Patients with ETV6-RUNX1, high-hyperdiploid and DUX4-rearranged B-ALL had the best 5-year event-free survival: 98.4%, 95.3%, and 95.0%, respectively. Those with TCF3-PBX1, PAX5alt, ETP, iAMP21, hypodiploid and T-ALL had intermediate rates (80.0% to 88.2%), while those with KMT2A-rearranged, BCR-ABL1, BCR-ABL1-like and ETV6-RUNX1-like ALL had the worst rates (64.1% to 76.2%). All but three of the 142 patients with day-8 blood MRD&amp;lt;0.01% remained in continuous remission. Among novel subtypes, intensified therapy based on day-15 MRD≥1% improved outcome of patients with DUX4-rearranged, BCR-ABL1-like, and ZNF384-rearranged ALL, and achievement of day-42 MRD&amp;lt;0.01% did not preclude relapse of those with PAX5alt, MEF2D-rearranged and ETV6-RUNX1-like ALL. Comprehensive genomic analyses identify novel subtypes, such as DUX4-rearranged, PAX5alt, BCR-ABL1-like, ETV6-RUNX1-like, M2F2D-rearranged and ZNF384-rearranged ALL, which have prognostic and therapeutic implications. Citation Format: Sima Jeha, John K. Choi, Deqing Pei, Elaine Coustan-Smith, Hiroto Inaba, Jeffrey E. Rubnitz, Raul C. Ribiero, Tanja A. Gruber, Susana C. Raimondi, Seth E. Karol, Kathryn G. Roberts, Jun J. Yang, Cheng Cheng, James R. Downing, William E. Evans, Mary V. Relling, Dario Campana, Charles G. Mullighan, Ching-Hon Pui. Prognostic and therapeutic significance of leukemia subtypes in the context of risk-directed therapy based on minimal residual disease levels in pediatric acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT146.

RIC Allogeneic Stem Cell Transplantation for High Risk CLL Followed By Preemptive MRD-Based Immunointervention - Final Results from the Phase II ICLL03 Ricac-Pmm Trial (FILO - SFGM-TC French intergroup)

RIC Allogeneic Stem Cell Transplantation for High Risk CLL Followed By Preemptive MRD-Based Immunointervention - Final Results from the Phase II ICLL03 Ricac-Pmm Trial (FILO - SFGM-TC French intergroup)