Minimal Residual Disease In Peripheral Blood 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.

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.

Zanubrutinib and Venetoclax As Initial Therapy for CLL/SLL with Obinutuzumab Triplet Consolidation in Patients with Minimal Residual Disease Positivity (BruVenG)

Background: Bruton's tyrosine kinase inhibitors (BTKi), anti-CD20 antibodies, and B cell lymphoma 2 inhibitors (BCL-2i) are essential therapeutic drug classes in the treatment of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Clinical synergy of BTKi and BCL-2i combinations have been observed, which allow for an oral regimen, that can be safely administered in a clinic setting for most patients (Tam et al., 2022; Wierda et al., 2021). Still, it remains uncertain if anti-CD20 antibodies meaningfully add to the effectiveness of oral combination therapy. Recent reports of triplet regimens demonstrate modest improvement in minimal residual disease (MRD) negativity with similar response rates when compared to oral doublets (Davids et al., 2021; Soumerai et al., 2021; Wierda et al., 2021). Additionally, anti-CD20 antibody use causes significant B cell depletion resulting in prolonged immune suppression. Recent reports suggest BTKi use may in fact impair clinical activity of anti-CD20 antibodies, which can be mitigated by using selective BTKi and incorporating anti-CD20 later in the treatment course when lower disease burden is present (Da Roit et al., 2015; Flinsenberg et al., 2020; Pavlasova et al., 2016; Rawstron et al., 2018). Therefore, anti-CD20 therapy may not be required for all patients and could be optimized within a response-adapted strategy. This trial has been developed to assess efficacy and safety of a response adapted consolidative treatment approach utilizing obinutuzumab triplet consolidation in CLL/SLL patients who remain MRD positive after an oral doublet fixed duration treatment with zanubrutinib and venetoclax. This approach looks to maximize MRD negative remissions, spare toxicity by limiting anti-CD20 exposure, and provide a finite therapy. This study will utilize once daily zanubrutinib for which there is limited data in regard to safety and efficacy particularly in combination with venetoclax. Study Design and Endpoints: This is a single center, open label, phase II, investigator initiated clinical trial enrolling 50 subjects evaluating the efficacy and safety of zanubrutinib and venetoclax with obinutuzumab triplet consolidation in subjects who remain MRD positive (BruVenG). Eligible patients must have treatment naïve CLL/SLL and treatment indications per the International Workshop on CLL 2018 guidelines. Subjects with Richter's transformation are excluded. Treatment will consist of lead-in, combination, and consolidation phases. All subjects will be treated with a 3-cycle lead-in of 320mg oral, once daily zanubrutinib monotherapy. Venetoclax will be incorporated at cycle 4, per the standard prescriber insert ramp-up schedule. A final dose of 400mg oral, once daily venetoclax, in combination with 320mg oral, once daily zanubrutinib will be used in all subsequent cycles after ramp-up. At cycle 16, MRD will be assessed in the peripheral blood (PB) and bone marrow (BM) via clonoSEQ (Adaptive Biotechnologies). Subjects who are MRD negative (<1x10 -4 ) in both compartments will stop therapy. Subjects who are MRD positive in PB or BM will continue zanubrutinib and venetoclax for an additional 6 cycles. Obinutuzumab will be added to the oral doublet starting at cycle 17. Standard intravenous obinutuzumab lead-in will occur during cycle 17, followed by standard monthly intravenous dosing of 1000mg through cycle 22. Depending on MRD status, subjects will be treated for 16 or 22 cycles. All subjects who receive consolidation will stop treatment at cycle 23 regardless of end of treatment MRD status. The primary endpoint is cycle 16 PB and BM MRD negativity rates. A co-primary endpoint will be cycle 23 PB and BM MRD negativity rates in subjects who were MRD positive at C16 and who went on to receive at least 1 dose of obinutuzumab. Key secondary endpoints will include cycle 16 overall response rate, 36-month progression free survival, 36-month overall survival, 36-month time to next treatment, 24- and 36-month PB MRD negativity rates, tumor lysis risk reduction rates, and safety. Exploratory endpoints will assess the positive predicative value of the ∆400 biomarker (Soumerai et al., 2021) on MRD negativity at cycle 16. This biomarker will be assessed between cycle 4 and 6. The MRD negative rates at cycle 16 and cycle 23 will be estimated with a 90% confidence interval using the Clopper-Pearson method based on exact binomial distribution.

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.

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.

Impact of Minimal Residual Disease on Progression-Free Survival Outcomes After Fixed-Duration Ibrutinib-Venetoclax Versus Chlorambucil-Obinutuzumab in the GLOW Study.

In GLOW, fixed-duration ibrutinib + venetoclax showed superior progression-free survival (PFS) versus chlorambucil + obinutuzumab in older/comorbid patients with previously untreated chronic lymphocytic leukemia (CLL). The current analysis describes minimal residual disease (MRD) kinetics and any potential predictive value for PFS, as it has not yet been evaluated for ibrutinib + venetoclax treatment. Undetectable MRD (uMRD) was assessed by next-generation sequencing at <1 CLL cell per 10,000 (<10-4) and <1 CLL cell per 100,000 (<10-5) leukocytes. PFS was analyzed by MRD status at 3 months after treatment (EOT+3). Ibrutinib + venetoclax achieved deeper uMRD (<10-5) rates in bone marrow (BM) and peripheral blood (PB), respectively, in 40.6% and 43.4% of patients at EOT+3 versus 7.6% and 18.1% of patients receiving chlorambucil + obinutuzumab. Of these patients, uMRD (<10-5) in PB was sustained during the first year post-treatment (EOT+12) in 80.4% of patients receiving ibrutinib + venetoclax and 26.3% receiving chlorambucil + obinutuzumab. Patients with detectable MRD (dMRD; ≥10-4) in PB at EOT+3 were more likely to sustain MRD levels through EOT+12 with ibrutinib + venetoclax versus chlorambucil + obinutuzumab. PFS rates at EOT+12 were high among patients treated with ibrutinib + venetoclax regardless of MRD status at EOT+3: 96.3% and 93.3% in patients with uMRD (<10-4) and dMRD (≥10-4) in BM, respectively, versus 83.3% and 58.7% for patients receiving chlorambucil + obinutuzumab. PFS rates at EOT+12 also remained high in patients with unmutated immunoglobulin heavy-chain variable region (IGHV) receiving ibrutinib + venetoclax, independent of MRD status in BM. Molecular and clinical relapses were less frequent during the first year post-treatment with ibrutinib + venetoclax versus chlorambucil + obinutuzumab regardless of MRD status at EOT+3 and IGHV status. Even for patients not achieving uMRD (<10-4), PFS rates remained high with ibrutinib + venetoclax; this is a novel finding and requires additional follow-up to confirm its persistence over time.

CELL‐FREE DNA KINETICS DECIPHER POTENTIAL MECHANISMS OF ACTION OF IBRUTINIB COMBINATION THERAPY IN MANTLE CELL LYMPHOMA (MCL)

Introduction: The European MCL Network trial TRIANGLE (NCT02858258) evaluated the addition of ibrutinib to standard treatment with autologous stem cell transplantation (ASCT) (arm A+I) in comparison to ASCT alone (arm A) and ibrutinib plus chemoimmunotherapy without ASCT (arm I) demonstrating significant and clinically relevant superiority of additional ibrutinib on outcome. Cell-free (cf)DNA captures tumor genetics and can be used to assess disease kinetics and minimal residual disease (MRD). We used capture based targeted sequencing for genotyping and MRD monitoring in cfDNA in the TRIANGLE trial to gain insight into the mechanisms of action of Ibrutinib and to identify patients (pts) with high risk of relapse. Methods: Peripheral blood (PB) and plasma samples from 57 pts with a PB infiltration of ≥10% at baseline (BL) and samples at mid induction (MI, n = 57) and end of induction (EoI, n = 53) were sequenced using the EuroClonality (EC)-NDC assay (Univ8® Genomics UK) to detect immunoglobulin and T-cell receptor (IG/TR) rearrangements, structural- (SV) and single nucleotide variants (SNVs) in 72 genes. Bioinformatics by ARResT/Interrogate with adaptations for cfDNA. Pts were considered MRD+ by detecting ≥1 read of a lymphoma-specific IG, SV or SNV. MRD in PB was analyzed by ASO-qPCR. Results: cfDNA levels were high at BL (mean 93 ng/mL) and MI (124 mg/mL) and decreased at EoI (12 ng/mL). BL cfDNA levels correlated with MIPI scores and identified pts with poor outcome. Genotyping by EC-NDC showed fully concordant IG clonotypes and SVs among 57 paired PB gDNA and cfDNA samples. 126 SNVs were identified (VAF 2.7%–75%, median 30%) in genes described as drivers in MCL, ATM (44%), TP53 (19%), KMT2D (16%), SAMHD1 (8%), CCND1 (8%) and 18 others. On average, 6 MRD markers were identified per patient (range 3-10). Copy number variation analysis revealed deletions in ATM (10%), CDKN2A (16%) and TP53 (5%) pts. TP53 mutations/deletions are a poor prognostic indicator in MCL, but therapy in arms A+I/I (n = 6) overcomes this poor outcome in comparison to arm A (n = 5). At MI, total cfDNA and ctDNA levels were significantly increased in arms A+I/I as compared to arm A (p = 0.049). 20/57 (35%) pts were MRD+ in PB and 35/55 (64%) in cfDNA. ctDNA was detected in 17/21 pts (81%) in Arm A and 18/34 pts (53%) in Arms A+I/I, suggesting effective disease clearance in the lymph nodes by ibrutinib. ctDNA detection at MI predicted outcome only in arm A. At EoI 8/53 (15%) pts were MRD+ in PB and 20/40 (50%) pts were MRD+ in cfDNA. ctDNA was detected in 12/18 pts (66%) in Arm A and 8/22 pts (36%) in Arms A+I/I. Similar to MI, ctDNA at EoI predicted outcome only in arm A. Keywords: combination therapies, liquid biopsy, minimal residual disease Conflicts of interests pertinent to the abstract S. Ferrero Consultant or advisory role: EUSA Pharma, Jannsen Honoraria: Servier Research funding: Gilead, Morphosys, Jannsen V. H. van der Velden Other remuneration: EuroFlow: Patents and Royalties R. García Sanz Honoraria: Janssen, BeiGene, Gilead, Astellas, Amgen, Takeda Research funding: Janssen, Gilead, Astellas, Takeda Educational grants: Janssen M. Dreyling Consultant or advisory role: Novartis, Lilly/Loxo, AstraZeneca, Roche, Janssen, Gilead/Kite, BMS/Celgene, Beigene Honoraria: Novartis, Lilly/Loxo, Amgen, AstraZeneca, Roche, Janssen, Gilead/Kite Research funding: Roche, Janssen, Bayer, AbbVie A. W. Langerak Research funding: Genentech, Roche Other remuneration: Spearkers Bureau: Janssen, Gilead D. Gonzalez de Castro Employment or leadership position: Founder and director of Univ8 Genomics Ltd.

COMBINED USE OF MINIMAL RESIDUAL DISEASE MONITORING AND FDG‐PET FOR OUTCOME PREDICTION IN FOLLICULAR LYMPHOMA: RESULTS FROM THE FONDAZIONE ITALIANA LINFOMI (FIL) FOLL12 TRIAL

Introduction: In follicular lymphoma (FL), FDG-PET is routinely employed to evaluate response at the end of induction (EoI), while minimal residual disease (MRD) analysis is highly reliable in predicting relapse over the entire disease history. Nonetheless, scant data are available describing the integration of these powerful prognostic tools for response evaluation in FL. This issue was investigated in the phase III FIL “FOLL12” trial [Luminari, JCO 2022]. Methods: Only patients with an available molecular marker for MRD and centrally reviewed EoI PET were included. MRD was systematically assessed by RQ-PCR with BCL2::IGH consensus primers in peripheral blood (PB) and bone marrow (BM), as previously reported with inferior follow-up [Ladetto ASH 2021]. PET scans were classified according to Deauville score (DS) criteria: DS1–3 was negative and DS4–5 positive. Results: Overall, 394 patients out of 780 were included (51%), as expected based on the MRD marker availability. These patients had a slightly better outcome than excluded cases (CR rate 82% vs. 73%, p = 0.003, 5y PFS 66% vs. 61%, p = 0.046). At EoI, both BM MRD and PET positivity were independent predictors of poor PFS in multivariate analysis (HR 1.66, CI: 1.01–2.71 and HR 2.03, CI: 1.30–3.18). The 68 discordant cases (i.e., MRD+/PET− or MRD−/PET+) showed an intermediate outcome (PFS HR 1.93, CI: 1.28–2.92) between the 314 double negative (reference) and the 10 double positive ones (HR 6.22, CI: 2.99–12.9), Figure 1A. Moreover, both EoI PET+ and the persistence/reappearance of MRD positivity in BM during the 18 months of rituximab maintenance/observation were independently associated to a higher risk of POD24 (HR 5.61, CI: 2.59–12.1, and HR 2.37, CI: 1.15–4.84, respectively). On the other hand, MRD kinetic analysis by non-invasive PB sampling during the rituximab maintenance/observation period substantially updated the risk status over PET results. Indeed, the marginal PFS HR for an MRD+ after an EoI PET negative result increased from 1.36 (CI: 0.47–3.96) at 6 months, to 2.09 (CI: 1.01–4.18) at 12 months, up to 3.60 (CI: 2.30–5.64) at 24 months (Figure 1B, blue curve). This means that patients scoring PET- at EoI but showing a persistent or reappearing MRD+ signal during the following 24 months had a dismal PFS, superimposable to that of PET+ patients (Figure 1C). Accordingly, in landmark multivariate analysis PB MRD+ either at 12 or 24 months predicted adverse PFS (HR 3.79, CI: 1.60–8.96 and HR 5.21, CI: 1.88–14.4, respectively), independently from EoI PET result. Keywords: indolent non-Hodgkin lymphoma, minimal residual disease, PET-CT Conflicts of interests pertinent to the abstract S. Ferrero Consultant or advisory role: Janssen, EUSA Pharma, Abbvie, Incyte, Clinigen, Sandoz, Italfarmaco Honoraria: Janssen, EUSA Pharma, Servier, Gentili Research funding: Morphosys, Janssen, Gilead, Beigene Educational grants: Takeda, Janssen, EUSA Pharma

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

CLL-106 First Prospective Data on Minimal Residual Disease Outcomes After Fixed-Duration Ibrutinib Plus Venetoclax Versus Chlorambucil Plus Obinutuzumab for First-Line Treatment of CLL in Older Adult or Unfit Patients: The GLOW Study

Minimal residual disease (MRD) is a predictive marker for progression-free survival (PFS) in chronic leukocytic leukemia (CLL) following chemoimmunotherapy and fixed-duration treatment with venetoclax and anti-CD20 antibodies. This has not been explored for ibrutinib+venetoclax (Ibr+Ven), a fixed-duration treatment with mechanisms of action that synergistically eliminate CLL subpopulations in distinct tumor compartments. Investigate MRD outcomes at primary analysis of phase 3 GLOW study (NCT03462719). Randomized, open-label, active-control study. Patients aged ≥65 years or 18-64 years with a CIRS score >6 or creatinine clearance <70 mL/min were randomized 1:1, stratified by IGHV mutational and del11q status, to Ibr+Ven (n=106) or chlorambucil+obinutuzumab (Clb+O) (n=105). Excluded: patients with del17p or known TP53 mutations. Ibr+Ven (3 cycles of ibrutinib lead-in, then 12 cycles of Ibr+Ven) or 6 cycles of Clb+O. Primary endpoint: independent review committee-assessed PFS; secondary endpoint: rate of undetectable MRD (uMRD; <10-4); exploratory endpoints: MRD analyses. MRD results are by next-generation sequencing, reported 3 months after end of treatment (EOT+3) unless otherwise noted. Rates of uMRD<10-4 were higher for Ibr+Ven versus Clb+O in bone marrow (BM) (51.9% vs. 17.1%; P<0.0001) and peripheral blood (PB) (54.7% vs. 39.0%; P=0.0259). For Ibr+Ven, BM uMRD was higher for uIGHV (58.2%) versus mutated IGHV (44.4%). With Ibr+Ven, 84.5% (49/58) of patients maintained PB uMRD from EOT+3 to EOT+12 versus 29.3% (12/41) with Clb+O. Rates of uMRD<10-5 were higher for Ibr+Ven versus Clb+O in BM (40.6% vs. 7.6%), including patients with uIGHV (45.5% vs. 5.6%). uMRD<10-5 in PB was largely sustained from EOT+3 to EOT+12 with Ibr+Ven (80.4% [37/46]) but not Clb+O (26.3% [5/19]). PFS rates for Ibr+Ven during the 12 months after EOT were >90% for patients with uMRD<10-4 and patients with detectable MRD; however, Clb+O arm patients with detectable PB MRD relapsed more quickly than those with uMRD<10-4. All-oral, once-daily, fixed-duration Ibr+Ven demonstrated superior uMRD responses that were deeper and better sustained post-treatment versus Clb+O in older adult or unfit patients with previously untreated CLL.

S146: VENETOCLAX IN PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA WITH 17P DELETION: 6-YEAR FOLLOW-UP AND GENOMIC ANALYSES IN A PIVOTAL PHASE 2 TRIAL

Background: Patients (pts) with chronic lymphocytic leukemia (CLL) with del(17p) and/or mutated TP53 have adverse prognosis and are a population of interest for improving outcomes. In a pivotal Phase 2 study (NCT01889186) evaluating venetoclax (Ven; a selective oral BCL2 inhibitor) monotherapy in del(17p) CLL (N=158), overall response rate (ORR) was 77% (median time on study, 26.6 mo; Stilgenbauer. J Clin Oncol. 2018;17:1973). Aims: To report final analyses after 5 y from last pt enrolled, including post-hoc subgroup analyses of prognostic markers. Methods: Adults with R/R or previously untreated del(17p) CLL received Ven 400 mg (via ramp-up) orally daily until progressive disease (PD) or intolerance. Main cohort comprised pts with R/R CLL; safety expansion cohort included pts with R/R or untreated CLL. Primary endpoints were ORR (main) and safety (safety expansion). Peripheral blood (PB) and bone marrow (BM) were analyzed pre-Ven for somatic mutations via targeted next-generation sequencing (NGS). Minimal residual disease (MRD) was assessed by flow cytometry, ASO-PCR, and/or clonoSEQ NGS; undetectable MRD (uMRD) is reported at <10−4. Results: In all, 158 pts received Ven (main, n=107; safety expansion, n=51). Data cutoff was 15 December 2020. Pts had median 2 (range, 0−10) prior lines of therapy (LOT); 5 had untreated CLL (first-line [1L]). Common mutations (n/N) were TP53 (113/138 [82%]; 35/113 [31%] had >1), SF3B1 (28/137 [20%]) NOTCH1 (22/137 [16%]), ATM (11/120 [9%]), and BIRC3 (6/120 [5%]); 93/115 (81%) had unmutated IGHV and 118/158 (75%) had ≥20% del(17p). Median time on Ven was 27.4 (range, 0–79.3) mo. At study close, 77 pts were alive; 26 remained on Ven. No new safety signals were observed. With 70 mo median follow-up (f/u), investigator-assessed ORR was 77% (95% CI, 70−84); 21% achieved complete remission (CR)/CR with incomplete blood count recovery (CRi). Median duration of response was 39.3 mo (95% CI, 31.1−50.5); 28% had ongoing response at 60 mo. Of 61 evaluable pts with a PB MRD assessment, 25% had uMRD at ~2 y (24−30 mo). Median progression-free survival (mPFS) was 28.2 mo (95% CI, 23.4−37.6; Figure). Median overall survival (mOS) was 62.5 mo (95% CI, 51.7−NR; 5-y PFS and OS rates, 24% and 52%). Of 5 1L pts, 4 were alive and progression-free. In pts with CR/CRi (n=37), mPFS was 62.2 mo (95% CI, 53.1−NR); in pts with partial remission (PR)/nodular PR (n=85), mPFS was 27.6 mo (95% CI, 22.8−38.0). Overall, 98/158 (62%) pts had PD, including 24/158 (15%) with Richter transformation. Of pts with PD (n=98) or whose disease was refractory to Ven (n=11), 73 received another LOT, most commonly ibrutinib (n=41); mOS from ibrutinib initiation was 28.0 mo. In pts with both del(17p) and TP53 mutation (n=111) vs those with either (n=19), ORR was 75% vs 79%; mPFS was 27.4 vs 22.8 mo (P=.8). In pts with mutated (n=22) vs unmutated IGHV (n=93), mPFS was 40.4 vs 26.9 mo (P=.11). No significant difference in ORR, PFS, or OS was observed in pts with vs without ≥20% del(17p), >1 TP53 mutation, NOTCH1, ATM, or BIRC3 mutations; mPFS was shorter in pts with mutated SF3B1 (n=28) vs without (n=109; 16.4 vs 30.2 mo [P=.0071]). Multivariate analysis is ongoing. Image:Summary/Conclusion: At end of study (median f/u, 70 mo), 48% of pts were alive, 24% were progression-free, and 16% remained on Ven, confirming the long-term activity of Ven in this high-risk population with del(17p) CLL and median 2 prior LOT. Except SF3B1 mutation, other adverse features (eg, >1 TP53 mutation, NOTCH1 mutations, unmutated IGHV) did not influence outcomes with Ven treatment in this cohort.

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.

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.

High Resolution Assessment of Minimal Residual Disease (MRD) By Next-Generation Sequencing (NGS) and High-Sensitivity Flow Cytometry (hsFCM) in the Phase 3 GAIA (CLL13) Trial

High Resolution Assessment of Minimal Residual Disease (MRD) By Next-Generation Sequencing (NGS) and High-Sensitivity Flow Cytometry (hsFCM) in the Phase 3 GAIA (CLL13) Trial

Chronic Lymphocytic Leukemia (CLL) Clonal Growth Rate Is Slower Following Venetoclax-Rituximab (VenR): Results from a Minimal Residual Disease (MRD) Model from the Randomized Phase 3 Murano Trial

Chronic Lymphocytic Leukemia (CLL) Clonal Growth Rate Is Slower Following Venetoclax-Rituximab (VenR): Results from a Minimal Residual Disease (MRD) Model from the Randomized Phase 3 Murano Trial