Minimal Residual Disease Positive Patients Research Articles

Biomarkers of minimal residual disease and treatment.

Minimal residual disease (MRD) has been defined as a very small numbers of cancer cells that remain in the body after curative treatment. Its presence or absence will ultimately determine prognosis. With the introduction of new technologies the presence of MRD in patients with solid tumours can be detected and characterized. As MRD predicts future relapse, be it early or late treatment failure, in an otherwise asymptomatic patient its treatment and when to start treatment remains to be determined. Thus the concepts of personalized medicine using different biomarkers to classify the biological properties of MRD maybe come possible. Based on this determinations it may be possible to use targeted therapies rather than all patients with the same type of cancer receiving a standard treatment. However, it is important to understand the limitations of the different technologies, what these techniques are detecting and how they may help in the treatment of patients with cancer. The majority of published studies are in patients with metastatic cancer and there are few reports in patients with MRD. In this chapter the concept of MRD, the methods used to detect it and what treatments may be effective based on the biological characteristics of the tumour cells as determined by different biomarkers is reviewed. MRD depends on the phenotypic properties of the tumour cells to survive in their new environment and the anti-tumour immune response. This is a dynamic process and changes with time in the wake of immunosuppression caused by the tumour cells and/or the effects of treatment to select resistant tumour cells. With the use of biomarkers to typify the characteristics of MRD and the development of new drugs a personalized treatment can be designed rather than all patients given the same treatment. Patients who are initially negative for MRD may not require further treatment with liquid biopsies used to monitor the patients during follow-up in order to detect those patients who may become MRD positive. The liquid biopsy used during the follow up of MRD positive patients can be used to detect changes in the biological properties of the tumour cells and thus may need treatment changes to overcome tumour cell resistance.

Recommendations on Minimal Residual Disease Monitoring in Acute Promyelocytic Leukemia Treated with Combination of All- Trans Retinoic Acid and Arsenic Trioxide

Background All- trans retinoic acid (ATRA)-arsenic trioxide (ATO) combination therapy significantly reduces acute promyelocytic leukemia (APL) relapse compared to ATRA combined with chemotherapy, leading to a cure rate of 80-90% in APL patients. The ideal frequency and duration of minimal residual disease (MRD) monitoring needs to be identified in the era of ATO. Methods A total of 1072 APL patients were enrolled in this study, comprising 855 from the APL2012 trial (NCT01987297) and 217 from our center between January 2018 to June 2022 (APL2018 study). The APL2018 protocol was adjusted for consolidation and maintenance therapy based on APL2012 (Chen et. al. PNAS 2021): In consolidation therapy, low-, intermediate-, and high-risk patients were performed following the ATO-group scheme of corresponding risk stratification in the APL2012 study. From December 2019, chemotherapy was no longer administered to high-risk group during consolidation phase. In maintenance treatment, ATO was replaced with oral arsenic realgar-indigo naturalis formula, and methotrexate was removed. RT-PCR or RQ-PCR was routinely used for MRD monitoring, detecting PML::RARA fusion genes in bone marrow before each consolidation and maintenance therapy. MRD testing was conducted every 3 months within the first year, every 6 months within the second year, and annually from 3 to 5 years after treatment. Results A total of 993 patients achieved complete remission (CR) after induction therapy. The negative MRD rates were observed in 61.7% of patients before 1 st consolidation , 95.4% before 2 nd consolidation, 99.3% before 3 rd consolidation, and 99.5% before maintenance therapy , respectively. The median time to achieve negative MRD was 57 (22-301) days with no significant difference between relapsed and non-relapsed patients (p=0.166). A total of 34 patients (30 in the APL2012 trial and 4 in the APL2018 study) relapsed, including 5 at low risk, 9 at intermediate risk, and 20 at high risk. The median recurrence time was 13.5 (3.5-49.0) months after achieving CR, with 94% (32/34) relapsing within 3 years of achieving CR. After induction remission, the risk of relapse decreased with time (44% occurred within the first year, 29% within the second year, 21% within the third year, and only 6% after three years, Figure 1). The median follow-up for the 179 evaluable patients after achieving CR was 39.7 (3.5 -64.6) months in the APL2018 group. The estimated 5-year disease-free survival (DFS) rates were 95.8% (95% CI 92.8-98.9). Prior to the 1 st, 2 nd, and 3 rd consolidation treatment, and before maintenance therapy, the estimated 5-year DFS rates for MRD positive and negative patients were 92.4% (95% CI 86.1-99.2) versus 97.8% (95% CI 94.8-100), p=0.100; 57.1% (95% CI 30.1-100) versus 97.3% (95% CI 94.7-100), p<0.001; 0 versus 96.5% (95% CI 93.1-100), p<0.001; 0 versus 96.8% (95% CI 94.0-99.6), p<0.001, respectively. The results of the APL2012 study were similar to those of APL2018. In the APL2018 study, the estimated 5-year cumulative incidence of relapse (CIR) was 2.51% (95% CI 2.48-2.54), which was 0%, 1.16% (95% CI 1.13-1.19), and 7.83% (95% CI 7.44-8.22) in the low-risk, intermediate-risk, and high-risk patients, respectively (p=0.057). The estimated 5-year CIR for the low to intermediate risk group was 0.74% (95% CI 0.73-0.75), which was statistically different from high-risk patients (p=0.019). The estimated 5-year CIR for MRD positive and negative patients prior to the 1 st and 2 nd consolidation treatments was 4.92% (95% CI 4.76-5.08) versus 1.10% (95% CI 1.08-1.12), p=0.194; 14.29% (95% CI 10.30-18.28) versus 2.08% (95% CI 2.05-2.11), p=0.010, respectively. Conclusion Our results show that MRD after one course of consolidation treatment, rather than before, is a crucial predictive factor for APL relapse. Patients with positive MRD after 1 st consolidation therapy have a high risk of relapse. ATRA-ATO based treatment has significantly reduced APL relapse, so the value of frequent MRD monitoring may be limited. It is recommended to implement an optimized MRD monitoring for risk stratification. For low to intermediate-risk patients and those with negative MRD after a consolidation treatment, the frequency and duration of MRD testing can be minimized. For high-risk patients with sustained MRD negativity for more than 3 years, MRD testing can be considered for discontinuation.

Free from Drug Therapy in Multiple Myeloma (FREEDMM): MRD-Based Cessation of Maintenance

Background. Treatment of newly diagnosed multiple myeloma (NDMM) consists of induction therapy followed by autologous stem cell transplant (ASCT) and indefinite maintenance. Continuous lenalidomide carries both significant clinical and financial toxicity. Minimal residual disease (MRD) has proven to be a powerful surrogate for PFS and OS but is not yet used to guide treatment. We hypothesize that MRD could be used to predict a subset of patients who can safely stop maintenance therapy and enter into a disease surveillance phase. Study Design and Methods. This prospective phase 2 study (NCT 05192122) is designed to stop post-ASCT maintenance therapy once sustained MRD negativity is achieved. MM patients are eligible if they have completed ≥2 years of maintenance therapy post-ASCT, and meet IMWG criteria for ≥ PR. Bone marrow (BM) MRD testing is performed twice, one year apart, using NGS. Sustained MRD-negativity is defined at a threshold of 10 -6, with negative MRD sustained between the Year 1 and Year 2 interval. Patients with sustained MRD negativity and absence of new bony lesions on PET then undergo maintenance therapy cessation. MRD-positive patients are removed from study. In patients who discontinue maintenance, BM testing to re-assess for MRD is repeated yearly for 3 years. At the time of MRD testing, peripheral blood (PB) samples are collected for MALDI-TOF mass spectrometry testing and circulating multiple myeloma cell (CMMC) enumeration. These are done in parallel with MRD assessment. Health-related quality of life (HRQoL) using the EORTC QLQ-MY20 questionnaire is measured before and after maintenance cessation. This study plans to enroll 50 patients to meet the primary objective of assessing sustained MRD-negativity 1 year after maintenance cessation. For all patients, 5-mL PB and BM samples are collected, processed, and kept frozen until analysis. Cellular indexing of transcriptomes and epitopes (CITE-seq) to simultaneously quantify cell surface protein and transcriptome data is used to characterize differences in the immune microenvironment between MRD-negative, MRD-positive, as well as between patients with biochemical and/or clinical progression and patients with MRD-resurgence but biochemically and clinically stable. Preliminary Results. FREEDMM enrollment began December 2021, and 31 patients have been enrolled, 29 of whom have undergone Year 1 BM for MRD assessment. Median follow up of our cohort is 414 (0-577) days. The median age is 69.5 (40-78) years, and the majority are either Black (n=9; 29%) or Hispanic (n=11; 35%). 18 (58%) patients had R-ISS 1 or 2, while 2 patients had high risk disease with presence of 17p deletion. The median number of years of maintenance therapy completed prior to Year 1 BM is 3.4 (2-7.9) years. 28 (96.6%) were in CR at time of Year 1 BM. Year 1 MRD results are pending in 13 patients. At Year 1, 11 (68.8 %) of 16 patients were found to be MRD-negative, while 5 (31.3%) patients were found to be MRD-positive with a median of 206 (1-9,748) cells per 10 6 nucleated cells detected. 24 (85%) of 28 patients had a negative MALDI-TOF result at the time of the Year 1 BM. MALDI-TOF results were false negative in 3 MRD-positive patients. PB CMMC samples were concordant with MRD results in all 5 (100%) patients who were tested. There was concordance between MALDI-TOF and CMMC results in 9 (75%) of 12 patients. At year 2, 4 patients continued to be MRD negative, while 1 patient who was previously MRD-negative became MRD positive. At most recent follow-up, 3 (42.9%) of 7 MRD positive patients at Year 1 experienced clinical progression and were removed from the study. 2 (50%) of 4 patients with sustained MRD-negativity have undergone maintenance cessation, with the remaining 2 awaiting confirmation of MRD-negative results. 59 paired PB (n=29) and BM (n=30) samples have been collected for CITE-seq analysis. Pilot CITE-seq experiments captured 10,000-15,000 cells with 33,000-56,000 reads/ cell on one MRD-positive BM and paired PB sample. CITE-seq results for remaining patients will be presented at the conference. Conclusion: This phase 2 trial applies a novel clinical trial design with an adaptive strategy to explore use of MRD testing as a guide to maintenance therapy cessation in MM patients and represents one of the first studies introducing transcriptome analysis of the tumor and immune microenvironment in the maintenance setting. Ongoing results will be reported at the conference.

RAMP up: Risk Adapted Post-Autologous Transplant Maintenance Therapy in MRD Positive Myeloma Patients

Background. Post-autologous stem cell transplant (ASCT) maintenance therapy for patients with newly diagnosed multiple myeloma (MM) continues to evolve. Currently, single agent lenalidomide maintenance remains standard of care but outcomes for patients with high-risk cytogenetics are inferior to those with standard risk disease; optimal maintenance strategies for these patients need to be developed. Minimal residual disease (MRD) has proven to be a powerful prognostic factor for PFS and OS but is not yet used to guide treatment. Isatuximab is a cytolytic CD38-directed, immunoglobulin G1 (IgG1) chimeric monoclonal antibody FDA-approved for the treatment of relapsed or refractory MM that is overall well tolerated and efficacious when used in combination regimens. Our upcoming trial, RAMP UP (NCT05344833), investigates the safety and efficacy of isatuximab combined with lenalidomide as a maintenance regimen in patients who are MRD-positive after autologous transplant. Study Design and Methods. This prospective, multicenter single-arm phase 2 (Figure 1) trial will enroll patients that are MRD-positive (10 -5) by Adaptive next generation sequencing within 90 days (+/- 30 days) post-autologous transplant. We plan to enroll: R-ISS stage 1, 2 or 3; <2 lines of induction therapy prior to transplant; > PR per IMWG criteria post-transplant; and ECOG Performance Status <2. Patients will be treated with isatuximab (10 mg/kg weekly for cycle 1 and every other week thereafter) and lenalidomide (10 mg daily on days 1-21) on 28-day cycles for a total of 3 years. Patients will be monitored for disease response every 3 months and for marrow MRD every 12 months. The primary endpoint is the 1-year rate of CR/MRD negativity (10 -5); secondary endpoints include 1-year rate of CR/MRD negativity (10 -6), IMWG-defined response rates, 3-year overall CR/MRD-negativity, PFS, OS, treatment-related adverse events, and health related quality of life (HRQoL) measured by EORTC-QLQ-C30, EQ-5D-5L, EORTC QLQ-MY20. We propose enrollment of 50 patients to allow for approximately 10% dropout rate in order to have 43 patients analyzed for the primary endpoint; for 50 patients to be treated, we estimate that 75-100 patients may have to be enrolled. Correlative objectives include correlation of isatuximab pharmacokinetics and receptor occupancy with MRD-negative response and time to progression, characterization of differences in the BM and peripheral blood T, B, and myeloid cell compartments using cellular indexing of transcriptomes and epitopes (CITE-Seq) between responders and nonresponders, and concurrent assessment of other disease biomarkers, including peripheral blood circulating multiple myeloma cells (CELLSEARCH), with MRD testing. Discussion. Our study started June 2023. One patient has been enrolled, and two have signed informed consent for enrollment. Ultimately, our study aims to inform MRD risk-adapted approaches for maintenance therapy in myeloma.

Outcome of Infants Treated on Total Therapy for Infants with Acute Lymphoblastic Leukemia I: Results from a Non-Randomized Multi-Center Study

Infants with KMT2A rearranged (KMT2Ar) acute lymphoblastic leukemia (ALL) have a poor prognosis with an event-free-survival (EFS) of 33.6-36.9% on recent Children's Oncology Group and Interfant trials. In preclinical studies, we identified bortezomib and vorinostat as novel active agents in primary KMT2Ar infant ALL specimens that have not been included in infant regimens to date. Total therapy for infants with acute lymphoblastic leukemia I (TINI) evaluated this novel combination in a multi-institutional pilot trial for infants with de novo ALL. In this study, bortezomib and vorinostat were incorporated into an ALL chemotherapy backbone containing dexamethasone, mitoxantrone, and pegasparaginase during induction and reinduction chemotherapy cycles. A run-in dose escalation evaluated 3 dose levels of vorinostat which was then followed by a dose expansion phase. The primary endpoint of the study was tolerability; secondary endpoints included minimal residual disease (MRD), 3-year EFS and overall survival (OS). Fifty patients enrolled between 2017-2021. Median follow up was 3.4 years (range 1.6-6.8 years). The six patients in the dose escalation phase had no dose-limiting toxicities. Forty-four patients received vorinostat at the third dose level (DL3) of 180 mg/m 2/dose. 68% of patients treated at DL3 had CNS involvement at diagnosis. 68% of DL3 patients carried a KMT2Ar. The most frequent KMT2A partner genes were AFF1 (40%), MLLT1 (20%), and MLLT3 (13%). The most frequent grade 3-4 non-hematologic adverse events during induction include neutropenic fever (45%), hypertension (43%), infection (40%), anorexia (32%), diarrhea (18%) and perineal skin ulceration (16%). There were 3 episodes of sepsis and 1 induction death due to parainfluenza pneumonia. Fewer events and no deaths or proven sepsis occurred during reinduction, with only grade 3 hypertriglyceridemia exceeding 10% of patients affected (18%). 79% of all patients and 69% of KMT2Ar patients became MRD negative by flow cytometry on day 22 of induction following our investigational block. Following induction intensification with cyclophosphamide, cytarabine, and mercaptopurine, 77% and 66% of all patients and KMT2Ar patients respectively were MRD negative at the time of count recovery. Eight of the forty-four patients, all KMT2Ar, underwent stem cell transplant in first remission due to persistent MRD positivity at the end of consolidation. The 3-year EFS and OS probabilities (SE) of all forty-four DL3 patients were 56.5% (8.0) and 70.5% (7.3), respectively. The 3-year cumulative incidence of relapse (CIR) with death considered a competing event was 29.3% (6.9) and the cumulative incidence of death (CID) as a first event was 8.9% (4.5). Patients lacking a KMT2Ar had superior outcomes with 85.7% (9.4) EFS and 92.9% (6.9) OS. The EFS and OS of KMT2Ar patients were 44.8% (9.5) and 62% (9.1) respectively. CIR and CID for KMT2Ar patients was 43.5% (9.6) and 7.2% (5) respectively. KMT2Ar patients ≥90 days at diagnosis had superior outcomes compared to their younger counterparts with 59.1% (10.5) EFS and 77.3% (8.9) OS. End of induction MRD was predictive of an event in this subgroup, with 85.6% (9.4) EFS for MRD negative patients and 14.3% (13.2) EFS for MRD positive patients. In contrast, KMT2Ar patients < 90 days of age at diagnosis had poor outcomes irrespective of MRD with 12.5% (11.7) EFS and 25% (15.3) OS. Notably KMT2Ar patients < 90 days who were MRD negative at the end of induction had a median time to relapse of 600 days (range 282-969 days), a late time point for this malignancy that typically relapses within a year from initial diagnosis. This suggests the regimen effectively reduced tumor burden leading to an extended duration of remission but failed to sufficiently eradicate disease to prevent relapse. We conclude that the incorporation of bortezomib and vorinostat for treatment of infants with ALL was well tolerated. MRD responses in KMT2Ar patients were robust. Although the study was not powered to evaluate outcomes, EFS and OS in KMT2Ar patients suggest a clinical signal worth pursuing given the low proportion of patients transplanted in first remission. The successor study, TINI 2 (NCT05848687), will build upon the bortezomib/vorinostat backbone by incorporating 2 cycles of blinatumomab and the menin inhibitor ziftomenib in combination with chemotherapy during reinduction.

Response-Adapted Therapy for Newly Diagnosed Multiple Myeloma.

The development of potent novel agents has improved outcomes for patients with multiple myeloma (MM). Heterogeneity of response to therapy, an expanding arsenal of treatment options, and cost are however major challenges for physicians making treatment decisions. Response-adapted therapy is hence an attractive strategy for sequencing of therapy in MM. Despite its successful application in other haematologic malignancies, response-adapted therapy is yet to become a standard of care for MM. We provide our perspective on response-adapted therapeutic strategies evaluated thus far and how they may be implemented and improved on in treatment algorithms of the future. While older studies suggested that early response based on International Myeloma Working Group response criteria could impact long-term outcomes, recent data have contradicted these findings. The advent of minimal residual disease (MRD) as a powerful prognostic factor in MM has raised the promise of MRD-adapted treatment strategies. The development of more sensitive techniques for paraprotein quantification as well as imaging modalities to detect extramedullary disease is likely to change response assessment in MM. These techniques combined with MRD assessment may provide sensitive and holistic response assessments which could be evaluated in clinical trials. Response-adapted treatment algorithms have the potential to allow an individualised treatment strategy, maximising efficacy, while minimising toxicities and cost. Standardisation of MRD methodology, incorporation of imaging into response assessment, and the optimal management of MRD positive patients are key questions to be addressed in future trials.

Abstract 1039: Individualized tumor-informed circulating tumor DNA (ctDNA) analysis for postoperative monitoring of non-small cell lung cancer (NSCLC) - the MEDAL study

Abstract Background: Through parallel testing and comparison of personalized and fixed panel minimal residual disease (MRD) assays, to establish the best technique and application strategy of dynamic MRD detection for prognosis prediction and disease assessment among non-small cell lung cancer (NSCLC) patients. Method: We analyzed 760 plasma samples from prospectively enrolled 181 patients with NSCLC recruited to the MEDAL study (NCT03634826), with disease stage I (63%), II (19%) and III (18%). 80% were adenocarcinomas. Plasma samples were collected at baseline (n=157), landmark 3-day and 1-month (n=334), and longitudinal points (n=248) were analyzed. Additional plasma was collected after relapse for 14 patients (n=21). Median follow-up was 1092 days, and 48 patients progressed. We employed a novel personalized tumor-informed technology named PROPHET using deep sequencing of 50 patient-specific variants. The PROPHET was developed to detect MRD with a limit of detection (LoD) of 0.004% and sample-level specificity of greater than 99% in the analytical validation. Detection and quantification of MRD through tumor-informed (TI) and tumor-agnostic (TA) fixed panel assays in the same samples were conducted for a head-to-head comparison. Results: ctDNA was detected by PROPHET prior to treatment in 45% of samples (83%, 75% and 23% for disease stage III, II and I), and showed a higher positive rate than the TI and TA assays (22% and 19%). PROPHET identified 30 more ctDNA positive patients with a median ctDNA fraction of 0.01% at baseline. From the landmark single test, the sensitivity was 45%; integrating longitudinal time points increased the sensitivity to 85%. Landmark PROPHET status was the only risk factor other than clinical features to predict the clinical relapse (p<0.001, multivariate Cox model). MRD positive patients defined by non-canonical variants (n=8) had similar disease-free survival (DFS) as MRD positive patients defined by canonical variants (n=9). Landmark PROPHET-based MRD status combined with clinical TNM stage outperformed TNM stage for prediction of prognosis (p<0.001). Longitudinal MRD achieved negative predictive value (NPV) of 99% with an interval of 150 days, and demonstrated 299 days of longer lead-time than other state-of-the-art fixed-panel assays. Among 16 patients with equivocal radiological diagnosis, all the MRD positive patients relapsed (n=6). Among relapsed patients received next-line treatments, 7 ctDNA negative patients survived or died other disease, 67% (2/3) ctDNA positive patients died from cancer. Sensitivity for bone and brain metastasis was 100% (11/11) and 50% (2/4), respectively. Conclusion: The sensitive tumor-informed personalized MRD approach could provide advantages in prognosis prediction at landmark and disease assessment during surveillance for NSCLC patients. Citation Format: Kezhong Chen, Chenyang Wang, Haifeng Shen, Xi Li, Yichen Jin, Shuailai Wu, Fujun Qiu, Qiang Lu, Di Peng, Shuai Fang, Bing Li, Juan Lv, Jinlei Song, Yang Wang, Shannon Chuai, Zhihong Zhang. Individualized tumor-informed circulating tumor DNA (ctDNA) analysis for postoperative monitoring of non-small cell lung cancer (NSCLC) - the MEDAL study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1039.

Role of ctDNA for the detection of minimal residual disease in resected non-small cell lung cancer: a systematic review.

Operable stage I-III non-small cell lung cancer (NSCLC) has a high risk of recurrence, mainly due to remnant clones of the disease defined as minimal residual disease (MRD). Adjuvant chemotherapy has a limited efficacy in reducing the risk of relapse, and prognostic as well as predictive biomarkers in this context are currently missing. We performed a systematic review to evaluate the state of the art about the role of circulating tumor DNA detection through liquid biopsy for the assessment of MRD in resected early-stage NSCLC patients. Among the 650 studies identified, 13 were eligible and included. Although highly heterogeneous, all the studies demonstrated a poor prognosis in patients with post-operative MRD, with a detection rate ranging from 6% to 45%. MRD detection preceded radiographic/clinical recurrence by a mean of 5.5 months. MRD positive patients were most likely to benefit from adjuvant treatment in terms of recurrence-free survival (RFS). Consistently, adjuvant therapy did not minimize the risk of relapse in the MRD negative group. Liquid biopsy has a relevant role in assessing post-surgical MRD in resected NSCLC. Since currently there are no criteria other than stage and risk factors for the choice of adjuvant treatment in this setting, post-operative assessment of MRD through liquid biopsy might be a promising approach to guide the decision.

Venetoclax and Hypomethylating Agents Followed By Allogeneic Stem Cell Transplantation in Patients with Acute Myeloid Leukemia

Background So far, it was a treatment paradigm to induce remission in patients with either newly diagnosed (ND) or relapsed/refractory (R/R) acute myeloid leukemia (AML) prior to allogeneic stem cell transplantation (allo-SCT) using intensive therapies with anthracyclins in combination with low- or intermediate to high-dose cytarabine. For AML patients ineligible for intensive therapy, the combination of hypomethylating agents (HMA) and the BCL2 inhibitor Venetoclax (VEN) has become the new treatment standard due to high and rapidly achieved remission rates and a favorable toxicity profile. These properties make this combination also attractive for frontline induction of ND-AML or as salvage therapy in R/R-AML patients with borderline fitness to tolerate and/or limited chance to achieve remission by intensive therapy. Considering the limited evidence from the literature so far, we here report our single-center experience of allo-SCT after HMA/VEN-based therapy. Design/Methods: We retrospectively analyzed all consecutive ND and R/R AML patients, who had received HMA/VEN therapy followed by allo-SCT at our center from 2021 to 2022, regarding outcome after transplant. The study was approved by the ethics committee of the University Duisburg/Essen (approval number: 22-10708-BO) and all patients gave written informed consent for scientific use of their data. Results: Overall, 26 patients (median age 64 years, range 26 to 75) with ND (n=14, 54%) or R/R (n=12, 46%) AML were treated with a median of 2 cycles HMA/VEN (range, 1 to 5; Azacitidine n=10, Decitabine n=16). Overall response rate (CR/CRi, MLFS) in the entire cohort was 58% with no difference between patients with ND and R/R AML (57% vs. 58%, p>0.99). Minimal residual disease (MRD) determined by molecular genetics as part of the clinical routine was not detectable prior transplant in 43% of the responding patients. Allo-SCT using PBSC (n=25, 96%) or BM (n=1, 4%) from a matched sibling (n=4, 15%), unrelated (n=19, 73%) or haploidentical donor (n=3, 12%) was performed in median 98 days (range, 31 to 220) after start of HMA/VEN treatment. Neither the rate of MRD negativity nor time to allo-SCT differed between ND and R/R patients. A reduced-intensity conditioning (RIC) was used in all patients including 11 patients (42%) receiving melphalan- or FLAMSA-based sequential conditioning. Median follow-up from start of HMA/VEN therapy was 10 months (range, 4 to 19 months) and from allo-SCT 6 months (range, 1 to 15 months), respectively. Median overall survival (OS) calculated from start of HMA/VEN therapy and from allo-SCT is both not reached, while the estimated 1-year OS rates were 81% and 80% respectively. OS after transplant was numerically higher in patients with CR at transplant (90% vs. 69%), but did not differ between patients with ND and those with R/R AML (75% vs. 80%) nor between MRD negative and positive CR patients (75% vs. 100%). All patients achieved CR following allo-SCT, but 1 patient had a persistence of his cytogenetic marker and two patients had mixed chimerism. Incidence of acute GvHD was 31% (including 8% with acute GvHD grade III/IV) and of chronic GvHD 4%. A total of 6 patients relapsed after allo-SCT and a total of 4 patients have died due to relapse (n=3) or treatment-related toxicity (n=1). Median relapse-free survival (RFS) after allo-SCT was not reached and the estimated 1-year RFS rate was 67%. Again, RFS numerically differed between in patients in remission and with active disease at transplant (84% vs. 48%), but did not differ between patients with ND and those with R/R AML (70% vs. 64%) nor between MRD negative and positive CR patients (83% vs. 86%). Conclusion: Treatment with HMA/VEN either as induction or salvage therapy in ND or R/R AML leads to reasonable remission rates facilitating subsequent allo-SCT with promising survival rates. This warrants confirmatory analyses in larger patient cohorts with longer follow-up, ideally in a prospective clinical trial.

Predictive Value of Minimal Residual Disease on Efficacy of Rituximab Maintenance in Mantle Cell Lymphoma: Results from the European MCL Elderly Trial

On behalf of the European MCL Network Introduction: Rituximab (R) maintenance after immunochemotherapy represents standard of care in older mantle cell lymphoma (MCL) patients. The European MCL Elderly trial has shown the efficacy of R maintenance after R-CHOP in terms of PFS and OS (Kluin-Nelemans et al., JCO 2020). Induction with R-FC showed similar response rates and failure-free survival but inferior OS as compared to R-CHOP. The assessment of minimal residual disease (MRD) represents a promising tool for individualized treatment decisions. Within the European MCL Elderly trial, we investigated whether MRD status predicts the efficacy of maintenance and aimed to identify MRD-based trigger time points for targeted intervention. Patients and methods: The MCL Elderly trial included patients with previously untreated, advanced stage MCL aged 60 years or older and not suitable for autologous stem cell transplantation. MRD assessment was done at predefined time points during and after treatment until clinical progression for patients recruited in France or Germany with baseline samples and at least one follow-up sample. Three central MRD labs performed marker screening (BCL1-JH t(11;14) translocation or IGH rearrangement) and real-time quantitative PCR (qPCR) following standardized ESG guidelines, as previously reported (Pott et al., Blood 2010). MRD status was pooled from bone marrow and peripheral blood results by classifying a patient as MRD negative if all available samples at the respective time point were negative. Predictive value of MRD status at end of induction for efficacy of maintenance was analysed with Cox regression for PFS including the interaction term of MRD status and treatment group. To assess the prognostic value of MRD status for clinical progression, landmarks were defined at midterm induction (MI), end of induction (EOI), and during four 6-months periods following EOI. Results: A molecular marker for MRD assessment was generated in 85% of 288 screened patients and in 80% a qPCR assay fulfilling standardized criteria could be established. Patients in whom a molecular marker could be identified had more frequently generalized disease compared with those without molecular marker (85% vs. 51% stage IV, 78% vs. 37% with bone marrow involvement, median LDH/ULN quotient: 0.93 vs. 0.81). Among patients without clinical progression during induction, MRD-negativity was achieved more frequently and earlier with R-FC (MI: 63% of 82 patients; EOI: 80% of 82) than with R-CHOP (MI: 26% of 84, p<0.0001; EOI: 53% of 89, p=0.0002). The efficacy of maintenance was clearly seen in patients MRD negative at EOI (PFS-HR 0.38, 95% CI 0.21-0.63, Figure 1A) and was slightly less pronounced in MRD positive patients (HR 0.51, 95% CI 0.26-1.02; interaction p=0.48, Figure 1B). Especially after R-CHOP, the efficacy of R-maintenance was higher among MRD-negative patients (HR 0.23, 95% CI 0.10-0.52) than among MRD-positive patients (HR 0.59, 95% 0.28-1.26, interaction p=0.097). Landmark analyses confirmed the prognostic value of MRD status during and after R-FC and during maintenance/follow-up after R-CHOP. Median time from MRD-positivity 6/12/18/24 months from EOI to clinical progression was consistently short with 2.2/1.2/1.6/1.4 years after R-CHOP and 1.0/1.0/0.7/0.7 years after R-FC. Conclusions: The results confirm the strong efficacy of R-maintenance in MRD-negative patients after induction. Omitting or stopping maintenance based on MRD-negativity is thus discouraged. Considering the short time to progression, more effective treatment strategies should be explored in MRD-positive patients to improve the long-term prognosis of patients with MCL. Figure 1: Progression-free survival (PFS) from end of induction (EOI) by maintenance randomization (R vs. no R) in patients MRD-negative (A) or MRD-positive (B) at EOIFigure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

The Efficacy and Safety of Modified Melphalan and Busulfan-Based Conditioning Regimen for Allogeneic-HSCT in Refractory/Relapsed or Persistent MRD Positive AML Patients

Background: Allogeneic stem cell transplantation (Allo-HSCT) is the only salvage option offering long-term survival opportunity for high-risk AML patients, as those patients respond insufficiently to chemotherapy. However, the overall survival (OS) rate after allo-HSCT is still frustrating. Great efforts have been made in improving the conditioning regimen, such as introducing two alkylating agent, busulfan (Bu) and Melphalan (Mel) to enhance the anti-leukemia efficacy. But high non-relapse mortality (NRM) is reported. In this study, we made refinements in the conditioning regimen with two alkylating agents, namely MCBC (the combination of melphalan, cladribine, busulfan, and cyclophosphamide). We aim to investigate the efficacy and safety of MCBC conditioning regimen for allo-HSCT in refractory/relapsed (R/R) and minimal residual disease (MRD) persistent positive AML patients. Methods: This prospective multi-center clinical trial enrolled R/R AML or AML with MRDpersistentpositivity, who underwent allo-HSCT from July 2020 to May 2022 (ChiCTR Registration ID: ChiCTR2000029936). The MCBC conditioning regimen consists of melphalan 60mg/m2/d, day -9~-8, cladribine 5mg/m2/d, day -7~-5, busulfan 3.2mg/kg/d, day -5~-3, cyclophosphamide 30mg/kg/d, day -2~-1. A post-transplantation maintenance therapy was provided whenever possible, including azacytidine, venetoclax, or FLT3 inhibitors. Results and Discussion: This study included a total 75 AML patients (65 R/R AML and 10 MRD+AML), with median age 37 years (ranged 13-56 years). More than half of patients (40/75) were evaluated as non-remission (NR), including 13 patients with leukemia blast over 20% or active extramedullary disease pre-HSCT. Haplo-identical-donor HSCT (HID-HSCT) was the predominance HSCT type (n=51, 68%). Mucositis was the main reported regimen-related toxicity, mostly were mild and well tolerated. No graft failure was documented. It is inspiring that all patients achieved hematology complete remission (CR) (100%) and 89.3% achieved MRD clearance on reconstitution day, indicating profound anti-leukemia capacity of MCBC regimen. The incidence of severe acute GVHD was 9.3%. With a median follow-up of 232（30-695）days, the estimated one-year overall survival (OS), relapse-free survival (RFS) and NRM of all patients were 72.1±6.3%, 71.4±6.0% and 7.1±3.5% respectively. Notably, patients with persistent MRD positivity obtained 100% OS and RFS. There were 13 patients in R/R AML group relapsed after HSCT, with a median time from HSCT to relapse was 120(75-218) days. The one-year cumulative incidence of relapse was 22.6±5.6%. Univariate analysis using by Kaplan-Meier method was performed. It indicated high blast burden (blast≥20%) pre-HSCT and absence of opportune maintenance therapy post HSCT were two independent risk factors with clinical significance. Competitive risk modal analysis for multivariate analysis also confirms the results. Conclusion: The preliminary data demonstrated profound anti-leukemic capacity and well acceptable toxicity of MCBC regimen for R/R or MRD persistent positive AML. Furthermore, for patients with high leukemia blast burden, opportune maintenance treatment led to significant improved OS and RFS. Figure Legend: Survival outcomes of patients enrolled. Kaplan-Meier curves for Overall survival (A), Disease-free survival (B), Cumulative relapse rate(C) and Non-relapse mortality(D) of patients receiving MCBC conditioning regimen after allo-HSCT. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Combination of Cytogenetic Classification and MRD Status Correlates with Outcomes of Autologous Versus Allogeneic Stem Cell Transplantation in Adults with B Cell-Acute Lymphoblastic Leukemia in First Remission

Objectives: To analyze overall survival (OS), leukemia-free survival (LFS), cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) of patients with B cell-acute lymphoblastic leukemia (B-ALL) who received autologous or allogeneic stem cell transplantation and to provide the basis for the choice of transplantation method. Methods: We retrospectively investigated the outcomes of 388 adult patients with B-ALL in our center. The OS, LFS, CIR and NRM rate and the impact of minimal residual disease (MRD) within 3 chemotherapy cycles along with risk classification were explored. Results: Both univariate and multivariate analysis found that negative MRD within 3 chemotherapy cycles was the important factor associated with the prognosis. As to 355 patients who obtained first complete remission (CR1), we divided patients into 3 groups according to the risk stratification and MRD status within 3 chemotherapy cycles. For patients with negative MRD within 3 chemotherapy cycles and standard-risk group, the 3-year OS (82.5% vs 74.1%, P=0.364), LFS (74.5% vs 74.1%, P=0.904), CIR (25.5% vs 17.6%, P=0.648) and NRM rates(0% vs 8.3%, P=0.234) were not significantly different between autologous hematopoietic stem cell transplantation (auto-HSCT) and allogeneic hematopoietic stem cell transplantation (allo-HSCT) group（Figure 1）. In patients with negative MRD and high-risk factors, although auto-HSCT group and allo-HSCT group had similar 3-year OS(72.7% vs 68.5%, P=0.436) and LFS rate (62.8% vs 56.0%, P=0.375) , the lower NRM (1.5% vs 25.1%, P=0.000) was offset by higher CIR(35.7% vs 18.9%, P=0.018) in auto-HSCT group compared with allo-HSCT group（Figure 2）. As for other patients with high-risk factors and positive MRD after 3 chemotherapy cycles, the prognosis of auto-HSCT group was evidently worse than those of allo-HSCT group as there was a lower trend of 3-year OS (50.0% vs 66.0%, P=0.077), LFS rate (30.8% vs 47.1%, P=0.398) and significantly higher CIR rate(71.4% vs 39.1%, P=0.018) in auto-HSCT group compared to allo-HSCT group（Figure 3）. MRD within 3 chemotherapy cycles was also related to the selection of allogeneic transplantation methods and pretreatment schemes. The 3-year OS (67.4% vs 60.8% vs 65.2%, p=0.735), LFS (56.3% vs 48.3% vs 58.3%, P=0.538), CIR (21.7% vs 23.3% vs 13.3%, P=0.784) and NRM rate (22.1% vs 28.4% vs 28.3%, P=0.672) were similar in matched sibling donor hematopoietic stem cell transplantation (MSD-HSCT), haploid hematopoietic stem cell transplantation (haplo-HSCT) and unrelated donor hematopoietic stem cell transplantation (URD-HSCT) group patients who achieved negative MRD within 3 chemotherapy cycles. While MSD-HSCT group tended to have lower 3-year LFS (33.0% vs 54.1% vs 41.7%, P=0.198) and higher CIR rate (53.2% vs 33.7% vs 46.2%, P=0.233) when comparing with haplo-HSCT and URD-HSCT group patients whose MRD were still positive within 3 chemotherapy cycles. Moreover, in patients who achieved negative MRD within 3 chemotherapy cycles, there was no significant difference in 3-year CIR rate (24.5% vs 23.1%, P=0.784) between TBI group and non-TBI group, but the lower OS (64.2% vs 76.3%, P=0.027) and LFS (54.4% vs 71.3%, P=0.091) was mainly due to the higher NRM rate (17.8% vs 5.6%, P=0.062) in TBI group. For MRD positive patients, TBI group had advantages over non-TBI group, demonstrating a trend of higher 3-year OS (65.0% vs 42.9%, P=0.105), LFS (44.8% vs 27.1%, P=0.138), lower CIR (43.6% vs 63.8%, P=0.106) and similar NRM rate (11.7% vs 9.1%, P=0.671). In addition, we found that 8 most frequently mutated genes were KMT2D、FAT1、NRAS、PAX5、KRAS、SETD2、ASXL1、PTPN11 in 175 patients with preliminary second generation sequencing results（Figure 4）. Mutations in CARD11 and NOTCH signaling pathway were correlated with lower LFS (CARD11: 56.3% vs 16.7%, P=0.002; NOTCH signaling pathway: 59.2% vs 38.8%, P=0.049)（Figure 5）. Conclusions: Auto-HSCT with maintenance therapy after HSCT and non-TBI pretreatment schemes appears to be an attractive treatment option for patients with B-ALL especially for those who achieved negative MRD within 3 chemotherapy cycles. For MRD positive patients, allogeneic transplantation and TBI pretreatment schemes may be more effective. Key words: auto-HSCT, allo-HSCT, acute lymphoblastic leukemia, minimal residual disease Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

MRD Status By Clonoseq ® Is a Poor Predictor of Long-Term Outcomes after Bispecific LV20.19 CAR T-Cell Therapy for Relapsed, Refractory B-Cell NHL

INTRODUCTION: The clonoSEQ® Assay (Adaptive Biotechnologies Corporation, Seattle, USA) uses next-generation sequencing (NGS) based testing to identify disease-specific immunoglobulin sequences and detect evidence of minimal residual disease (MRD). MRD assessments have been shown to predict progression-free survival and overall survival in non-Hodgkin's lymphoma (NHL) patients. We report MRD results via the commercially available clonoSEQ® assay and its association with durability of response in patients treated with bispecific LV20.19 CAR in our phase 1/2 trial (NCT04186520). METHODS: We conducted a phase 1/2 single-center prospective trial (NCT04186520) to evaluate the efficacy and safety of LV20.19 CAR T-cells in patients with NHL at 2.5x106 cells/kg dose. LV20.19 CAR T-cells were manufactured onsite at varying lengths of manufacturing (8 vs 12 days) in the CliniMACS Prodigy device with IL7+15 for cell expansion, with the goal of fresh infusion. The commercial clonoSEQ® assay (by Adaptive Biotechnologies) was used to identify and track tumor clonotypes in responding patients at first assessment performed between Day 28-60. We evaluated associations between MRD status and long-term response post LV20.19 CAR-T cell therapy. Descriptive statistics were utilized for baseline characteristics. Survival analyses were calculated utilizing the Kaplan-Meier method and differences between groups were evaluated via the log-rank test. RESULTS: Among the 32 patients enrolled in the trial, there were 26 responders on Day 28. Of these responders, 23 patients had clonoSEQ® B-cell MRD assay done between Day 28-60 post CAR infusion (Table 1). MRD was performed in 11 patients with Diffuse Large B-cell Lymphoma (DLBCL), 3 patients with Follicular lymphoma (FL), and 9 patients with Mantle Cell Lymphoma (MCL). The median age was 64 years (45-74) and the median lines of prior therapy were 4 (2-11). Of the 23 patients with early MRD status available, the day 28 objective response rate (ORR) was 100% (complete response=57%, n=13 and partial response=43%, n=10). Eighteen patients (78%) were MRD negative at first assessment between days 28-60 and 5 (22%) were MRD positive. Of the 5 patients who were MRD positive, 3 became MRD negative at day 90, 1 patient was non-evaluable due to a non-relapse mortality event, and the remaining patient remains positive but with decreasing MRD status at Day 90. None of the patients with MRD positivity at day 28 have relapsed to date. Among patients who achieved early MRD negativity (n=18), 7 (39%) have relapsed, and all were patients with either DLBCL or FL. No MRD-negative MCL patient has relapsed to date. The duration of response in MRD-negative patients was significantly improved in MCL patients compared to DLBCL/FL patients (Figure 1), p=0.02. Among the 7 MRD negative patients who relapsed, only 1 patient was detected to have disease relapse by MRD positivity, 2 were detected simultaneously on MRD testing and imaging, while 3 were detected by physical exam or imaging findings and did not have MRD testing. Interestingly, 1 patient had a central nervous system relapse while being MRD negative. CONCLUSION: Relapse after CAR T-cell therapy remains a significant clinical challenge. New predictors are indicated to determine which responding patients after CAR-T cell therapy are more likely to relapse. Utilizing the commercially available Adaptive clonoSEQ® assay, early MRD assessment was not predictive of long-term clinical outcomes in DLBCL and FL. MRD positive patients maintained durable remission and converted to MRD negativity, while early MRD negative patients continued to relapse. In contrast, MRD negativity post-CAR-T therapy did appear to predict durable clinical remission in MCL patients. Newer assays, including cell-free technologies, may be more informative for non-MCL histologies. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Efficacy and safety of Venetoclax in the treatment of 25 patients with recurrent hematologic malignancies after an allogeneic hematopoietic stem cell transplantation

目的观察维奈克拉（VEN）治疗异基因造血干细胞移植（allo-HSCT）后复发恶性血液病患者的疗效及安全性。方法回顾性分析2021年2月至2021年11月在中国医学科学院血液病医院接受VEN治疗的25例allo-HSCT后复发患者的临床资料，其中微小残留病（MRD）阳性患者15例（抢先治疗组），形态学复发患者10例（挽救治疗组）。两组VEN剂量均为400 mg/d，联合唑类抗真菌药物时减量至100 mg/d。结果①抢先治疗组男7例，女8例，中位年龄32（18～52）岁；急性髓系白血病（AML）13例，急性淋巴细胞白血病（ALL）1例，原发性骨髓纤维化（PMF）1例；MRD阳性至应用VEN中位时间为2.5（0～12.5）个月。VEN中位疗程数为2（1～4）个。第1疗程治疗第7天VEN中位血药浓度为1 945（688～5 383）µg/L。VEN治疗1疗程后8例患者MRD转为阴性（获得主要反应），4例MRD较治疗前下降50％，3例无效，总体反应率（ORR）为80％（12/15）。9例治疗第7天VEN血药浓度<1 000 µg/L或>3 000 µg/L患者中3例（33.3％）MRD转阴，6例VEN血药浓度1 000～3 000 µg/L患者中5例（83.3％）MRD转阴。5例患者出现3/4级中性粒细胞减少，5例患者出现3/4级血小板减少，无新发严重感染致死病例。②挽救治疗组男7例，女3例，中位年龄44（28～59）岁；AML 6例，ALL 2例，不典型慢性髓性白血病（aCML）1例，骨髓增生异常综合征难治性血细胞减少伴有多系发育异常（MDS-RCMD）1例；复发至应用VEN中位时间为0（0～1）个月；VEN中位疗程数为1（1～2）个；第1疗程治疗第7天VEN中位血药浓度为2 419（1 200～6 155）µg/L。VEN治疗1疗程后3例获得完全缓解（CR）（主要反应），3例获得部分缓解（PR），4例无效，ORR为60％（6/10）。4例治疗第7天VEN血药浓度>3 000 µg/L患者中1例获得CR，6例VEN血药浓度1 000～3 000 µg/L患者中2例获得CR。10例患者均出现3/4级中性粒细胞减少及3/4级血小板减少。1例患者因严重肺感染死亡。③中位随访4.5（1～8.5）个月，抢先治疗组、挽救治疗组总生存（OS）率分别为（70.2±12.7）％、（50.0±15.8）％（χ2＝1.873，P＝0.171）。1疗程VEN治疗获得主要反应、未获得主要反应患者的OS率分别为（90.9±8.7）％、（36.2±14.7）％（χ2＝6.843，P＝0.009）。3例存在TP53突变的患者在VEN治疗后均获得主要反应。结论应用VEN对allo-HSCT后复发的恶性血液病患者进行抢先/挽救治疗有一定疗效且耐受性良好，监测VEN血药浓度有望提高疗效。VEN抢先/挽救治疗1个疗程未获得主要反应的患者预后较差，需尽早转换其他治疗方案。

PB1980: MULTIPLE MYELOMA: ADOPTING MRD BY NEXT GENERATION FLOW CYTOMETRY (NGF) AND FUNCTIONAL IMAGING GUIDED CONSOLIDATION INTO CLINICAL ROUTINE

Background: Minimal residual disease (MRD) detection by NGF and next generation sequencing gains is gaining increasing importance as an endpoint in clinical studies to determine deep responses beyond traditional immunohistochemical complete remission. However, little is known about the value of combining NGF with functional imaging and its role for MRD based consolidation strategies in clinical routine. Aims: The aim of the study was to investigate the role of MRD and functional imaging in clinical routine in MM. In addition, we report our real-world experience with an MRD-guided consolidation strategy. Methods: We included 102 patients with both newly diagnosed (ND) (n=57) and relapsed/refractory (RR) MM (n=45) that achieved serological response of VGPR or better. Among NDMM patients, 92% (n=52) underwent stem cell transplantation (SCT) after induction and 27% of RRMM patients received a salvage transplantation. MRD assessment by NGF was available in all patients. Bone marrow samples were collected between July 2019 and May 2021 and analyzed according to the Euroflow guidelines at a sensitivity level of 10-6. We performed functional imaging in 78 patients with either FDG positron emission tomography or diffusion-weighted magnetic resonance imaging within a median of 1 day after NGF assessment. Results: 51 patients (50%) were negative on MRD assessment by NGF. We observed higher rates of MRD-negativity in subjects with a serological response of CR/sCR or better versus VGPR (59% versus 34%, p=0.01), OR=2.8). Furthermore, we combined NGF results with functional imaging: MRD-negativity on both NGF and functional imaging (double-negativity) was achieved in 45% of patients. 8% and 40% of patients were negative on either NGF or imaging respectively. In some patients, imaging was the only technique applied to detect residual disease. We observed imaging positivity despite negativity on NGF more often in heavily pretreated patients (≥ 4 previous lines) compared to NDMM (p<0.01). In detail, we found a number needed to scan for imaging-only positive patients of 40, 8 and 3 in NDMM, relapsed, and heavily pretreated RRMM, respectively. MRD-triggered consolidation therapy was initiated in 29 patients with 72% responding to treatment and a MRD conversion rate of 51%. Interestingly, MRD-triggered consolidation (mostly after SCT) led to a superior progression free survival (Figure 1) when compared to standard Lenalidomide maintenance on MRD or imaging positive patients (p=0.04). Subjects achieving double-negativity after standard of care treatment were excluded from this analysis. Image:Summary/Conclusion: Our data indicate that combining NGF with functional imaging is beneficial particularly in heavily pretreated MM patients to rule out residual disease. Furthermore, our real-world experience gives evidence that MRD-based consolidation may be used to improve PFS of patients being MRD positive following SCT. Further studies investigating these issues in a randomized prospective fashion are highly warranted.

The association between minimal residual disease status and survival outcomes in transplant-ineligible newly diagnosed multiple myeloma (TIE-NDMM) patients: Systematic review.

e20009 Background: Despite expanding therapeutic armamentarium of multiple myeloma (MM), it remains an incurable disease. Therefore, there is a need to assess the impact of deeper hematological responses to better gauge treatments in clinical trials and routine practice. The presence of minimal residual disease (MRD), is becoming crucial and a new standard in monitoring remission status. Clinical evidence shows that MRD status after treatment is an independent prognostic factor for MM. This review summarizes current data on MRD status and its role in predicting progression-free survival (PFS) and overall survival (OS) outcomes. Methods: We performed a literature search on four databases (PubMed, Embase, Cochrane, and Web of Science) following the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. We screened 1307 studies using the Mesh terms “Multiple Myeloma and Minimal Residual disease.” After excluding review, duplicate, and non-relevant articles, 7 studies were included. Results: The association between MRD status and outcomes, including survival in TIE-NDMM patients was assessed in 7 studies, including 1083 patients. MRD status was determined using different techniques, such as flow cytometry and clonoSEQ. Different regimens were used in all studies. PFS was reported in all studies. Compared with MRD positive status, achieving MRD negativity improved PFS to 58 months versus 28.65 months as per cumulative analysis. The cumulative OS reported in 2 studies (n=196) was 95.85% in MRD-negative patients compared to 55.65% in MRD positive patients. Conclusions: Further clinical data focusing on post-treatment assessment of MRD will be useful in clinical decision-making and could be practice changing. MRD status may serve as surrogate end-points for PFS and OS in ongoing and future clinical trials. Achieving durable MRD negativity with PFS improvement might also increase the time between treatment relapses for MM and might help switch to a lesser aggressive regimen, chemotherapy-free period, avoiding drug toxicity. [Table: see text]

Minimal Residual Disease in Adult Acute Lymphoblastic Leukemia: Egyptian Experience.

Background:Acute lymphoblastic leukemia (ALL) is a clonal disease that affects early lymphoid progenitors in the bone marrow. Minimal residual disease (MRD) is assessed by different methods to monitor disease kinetics after treatment. Aim:to Assess MRD post-induction, at 6 and 12 months after intensive chemotherapy in adult patients with ALL. Patients and Methods: Seventy adult newly diagnosed acute lymphoblastic leukaemia patients were enrolled between July 2018 and July 2019 at the Clinical Hematology Unit, Ain Shams University hospitals, Egypt. MRD was assessed on the bone marrow samples using multi-parameter four color flow cytometry with 0.01% cut-off; below which cases are deemed MRD negative. Results:After the end of induction period, 13 out of 46 patients (28%) had positive MRD. However, MRD positivity is demonstrable in 14/32(43.8%), and 10/28(35.7%) patients at 6 and 12 months; respectively. MRD positivity was significantly associated with older age group (more than 39 years) and high NCCN risk stratum with p-values <0.05. Moreover, most of MRD positive patients at 12 months of therapy were of T-ALL immunophenotype (P value 0.002). Patients with complete remission and negative MRD exhibited significantly higher overall survival when compared to patients having MRD positivity (P value 0.027). Conclusion:MRD is a powerful predictor of outcome in ALL and its positivity at different time points is associated with poor prognostic factors as well as survival outcomes.

Detection of Minimal Residual Disease in Acute Myeloid Leukemia by Multi-color Flow Cytometry

To establish 10-color fluorescent antibody combination panels for the detection of minimal residual disease (MRD) of acute myeloid leukemia (AML) in our laboratory and discuss the value of clinical application. According to the antigen expression characteristics of leukemia cells of incipient AML patients, MRD in bone marrow were detected by multiparameter flow cytometry, and the test results were compared with both bone marrow cell morphology and PCR results, then 10-color fluorescent antibody combination panels in our lab for MRD detection was determined. The immunophenotypic characteristics of 392 incipient patients with AML in the First Affiliated Hospital of Zhengzhou University were analyzed, among them 357 (91.07%) cases showed abnormal immunophenotypes, which mainly included cross-lineage expression, cross-stage expression, deficiency of antigen expression or abnormal antigen intensity and other abnormal expression. The 10-color fluorescent antibody combination panels established according to abnormal immunophenotypic characteristics of leukemia cells were applied for detecting MRD in 156 patients with AML, the positive rate (43.6%) was higher than 26.8% of morphology, and the results were highly consistent with PCR detection results (96.49%), moreover, the recurrence rate of MRD positive patients (86.96%) was significantly higher than 5.75% of MRD negative patients. Therefore, this method could truly reflect the load of leukemia cells and prompt change of disease condition. Multiparameter flow cytometry can detect various abnormal immunophenotypes of AML. The 10-color fluorescent antibody combination panels in our lab based on the characteristics of antigens expression in leukemia cells can well detect MRD of leukemia cells, so as to predict relapse and provide basis for clinical treatment.

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

Post-Transplant MRD Negativity on Day +100 Predicts Outcomes for Pre-Transplant Relapsed/Refractory AML Patients

IntroductionPatients with relapsed/refractory (r/r) AML have in general a dismal prognosis. Allogeneic stem cell transplantation (allo-SCT) provides a curative approach for these patients, however the overall survival (OS) remains still low achieving 20-40%. Though post-transplant minimal residual disease (MRD) monitoring has been shown to be predictive for development of post-transplant relapses and lower survival, data focusing on pre-transplant relapsed/refractory AML patients is scarce. In this study, we investigated the impact of achieving MRD negativity on day +100 for relapses and survival for this high risk patients.Patients and MethodsWe analyzed post-transplant outcomes for pre-transplant r/r AML patients depending on their post-transplant MRD status at day +100. The day +100 was chosen concerning the possibility of early post-transplant interventions (e.g. tapering of immunosuppression or administration of donor lymphocytes).Fifty six consecutive adult patients (≥18 years old) with r/r AML (median age 58, range 20-76; male, n=34, 61%) who underwent allo-SCT (first, n=44, 79%; second, n=12, 21%) between 2015-2020 at the Department for Stem Cell Transplantation at the University Medical Center Hamburg (Germany) were included. The MRD was assessed on day +100 using multiparameter flow cytometry according to “different from normal” strategy.The patients experienced rather primary refractory disease (64%), secondary/therapy-related AML (55%) and abnormal cytogenetics (59%) at diagnosis. The median pre-transplant blast count was 25% (6-91%). A number of 29 patients (52%) showed blasts in peripheral blood. Myeloablative conditioning was used in 31 (55%) patients, whereas 25 (45%) patients received reduced intensity regimens. A number of 29 patients (52%) received a FLAMSA-based conditioning. Post-transplant donor lymphocyte infusions as well as other treatment were given to 13 (23%) and 17 (30%) patients, respectively.ResultsThe median follow up was 20 months (range 4-66). Forty patients (71%) achieved MRD negativity on day +100 and 16 (29%) remained MRD positive. The 2-year OS, LFS, relapses and NRM at 2 years for day +100 MRD negative patients were: 76% (95% CI: 60-87%), 59% (95% CI: 41-75%), 31% (95% CI: 17-50%) and 8% (95% CI: 3-19%), respectively. The 2-year OS, LFS, relapses and NRM at 2 years for day +100 MRD positive patients were: 35% (95% CI: 17-59%, p=p=0.001), 23% (95% CI: 9-46%, p<0.0001), 70% (95% CI: 45-87%, p=0.0002) and 6% (95% CI: 1-28%, p=0.88), respectively.Several factors were evaluated for possible association with day +100 MRD negativity (Table 1). There were no significant associations. Further, the incidence of acute (grade II-IV) GvHD at 100 days was not significantly different between the day 100 MRD positive und negative patients.Following factors had impact on post-transplant outcomes in multivariate analysis: presence (no vs yes) of peripheral blasts prior to allograft (OS: HR 0.3, 95% CI: 0.1-0.9, p=0.03; LFS: HR 0.4, 95% CI: 0.1-0.9, p=0.03; relapses: HR 0.4, 95% CI: 0.1-0.99, p=0.048; NRM: HR 0.5, 95% CI: 0.2-1.3, p=0.17), FLAMSA vs other preparative regimens (OS: HR 0.4, 95% CI: 0.1-0.93, p=0.03; LFS: HR 0.4, 95% CI: 0.2-0.98, p=0.04; relapses: HR 0.4, 95% CI: 0.2-1.0, p=0.05; NRM: HR 0.4, 95% CI: 0.2-1.0, p=0.06), and day +100 MRD (negative vs positive) (OS: HR 0.3, 95% CI: 0.1-0.7, p=0.009; LFS: HR 0.2, 95% CI: 0.1-0.6, p=0.001; relapses: HR 0.2, 95% CI: 0.1-0.4, p=0.0001; NRM: HR 0.2, 95% CI: 0.1-0.5, p=0.0006).ConclusionsPost-transplant MRD detection plays predictive role in pre-transplant r/r AML patients and may help to define possible candidates for early post-transplant interventions. DisclosuresNo relevant conflicts of interest to declare.