Minimal Residual Disease Kinetics Research Articles

Clinical implications of residual normal plasma cells within bone marrow across various disease stages in multiple myeloma.

Residual normal plasma cells (NPCs), which compete with tumor plasma cells, play an important role in multiple myeloma. However, large-scale cohort studies investigating residual NPCs, especially at the minimal residual disease (MRD) phase, are currently lacking. In this study, we conducted a comprehensive investigation into the clinical significance of residual NPCs throughout the entire disease course in 1363 myeloma patients from the NICHE cohort (NCT04645199). Our results revealed that myeloma patients with high baseline NPCs ratio (≥5%) exhibited distinct indolent features, characterized by lower tumor burden, reduced frequencies of cytopenia, immunoparesis, and high-risk cytogenetics. Importantly, high residual NPCs ratio at diagnosis or relapse was independently associated with favorable survival. High absolute percentages of NPCs at undetectable MRD were related with superior clinical benefit and immune reconstitution. At MRD-positive phases, grouping based on NPCs ratio (<50%, 50-90%, ≥90%) demonstrated better risk stratification compared to residual tumor log levels. Based on the time-dependent NPCs ratio trend, we developed a dynamic MRD model that classifies patients into three groups with diverse longitudinal trends, leading to distinct prognoses. Collectively, residual NPCs serves not only as a valuable complementary biomarker for risk stratification but also provides valuable insights on reclassifications and kinetics of MRD.

Ultrasensitive circulating tumor DNA (ctDNA) minimal residual disease (MRD) detection in early stage non-small cell lung cancer (NSCLC).

8078 Background: Translation of ctDNA MRD in NSCLC has been hampered by suboptimal sensitivity of 1st-generation assays. Here, we explore how improvements in analytical sensitivity can drive improved clinical sensitivity for MRD after surgery in NSCLC. Methods: To understand MRD kinetics, we analyzed longitudinal ctDNA in early stage NSCLC using data from the TRACERx study. Patient-specific mathematical models were generated to predict MRD levels at the postsurgical landmark and estimate the impact of an assay’s 95% limit of detection (LOD95) on clinical sensitivity. To test these predictions, tumor-informed ctDNA testing was performed using an SNV-based assay (CAPP-Seq) and a phased variant-based assay (PhasED-Seq, Foresight Diagnostics) on 269 samples from 46 patients. We also assessed MRD performance for predicting 1) patient outcomes at the landmark timepoint and 2) the effect of adjuvant treatment. Results: ctDNA MRD dynamics were assessed in 23 patients from TRACERx with ≥3 consecutive samples with detectable ctDNA without intervening therapy. MRD kinetics strongly correlated with exponential growth, with a median ctDNA doubling time of 51 days. Extrapolating MRD levels to the postsurgical landmark predicted that improving MRD assay LOD95 from 100 ppm (0.01%) to 1 ppm could increase clinical sensitivity by 2.1-fold. We then evaluated 46 NSCLC cases using two assays. The median LOD95 was 1 ppm for PhasED-Seq and 84 ppm for CAPP-Seq. Twelve cases were MRD+ by PhasED-Seq, all of whom recurred (100%), with MRD levels as low as 0.19 ppm. In contrast, 6 cases were MRD+ by the SNV-based approach, of whom 5 (83%) recurred. Accordingly, PhasED-Seq had a higher clinical sensitivity than the SNV-based method (12/18 [67%] vs. 5/18 [28%], P = 0.022). Kaplan Meier analysis for freedom from recurrence revealed significantly worse outcomes for patients with detectable MRD regardless of the method used; however, outcomes were better stratified using PhasED-Seq (HR 3.1 vs. 11.4). Patients who were MRD- after surgery by both assays had similar outcomes regardless of adjuvant therapy (chemotherapy and/or radiotherapy). However, MRD+ patients by PhasED-Seq receiving adjuvant therapy had significantly better outcomes than those who did not (HR 8.2, P = 0.00035). A similar benefit for adjuvant therapy was not observed with the SNV-based assay. Using PhasED-Seq, 80% (4/5) of MRD+ patients receiving adjuvant therapy cleared their MRD, compared to 0% (0/3) without adjuvant treatment. Conclusions: Ultrasensitive ctDNA detection improved the clinical sensitivity of MRD at key landmarks in early stage NSCLC. PhasED-Seq detected MRD at levels below 1 ppm and was associated with significantly better outcomes, revealing potential benefits of adjuvant therapy in MRD+ patients. This suggests that ultrasensitive MRD detection is promising for use in risk-adapted trials in early stage NSCLC.

Molecular Monitoring with Tumor DNA and Nivolumab Maintenance: A Pilot Study in Diffuse Large B-Cell Lymphoma

Introduction Molecular minimal residual disease (MRD) has been shown to correlate with disease relapse in patients (pts) with Diffuse Large B cell Lymphoma (DLBCL)[1-4]. However, the clinical impact of detectable MRD (dMRD) prior to clinical relapse is unknown. Checkpoint inhibitor (CPI) therapy has some activity in certain pts with DLBCL, particularly after CAR-T therapy attributed to effects on T cell activity [5-8]. We hypothesized that early intervention with CPI may lower relapse rate in pts with molecular recurrence only. Patients were monitored for detectable MRD (dMRD) by circulating tumor DNA (ctDNA) using the clonoSEQ assay monthly. We conducted a pilot study in high risk pts in remission after most recent line of therapy (LOT) in which maintenance nivolumab (MN) was offered at time of dMRD to assess effect on MRD clearance and relapse rate. Methods Pts &amp;gt;18 years with high-risk DLBCL (ABC-subtype, high grade B cell lymphoma (HGBCL), MYC translocation, relapsed/refractory disease, or Ki67 &amp;gt;90%) who had achieved CR on most recent LOT. Pts had monthly MRD and every 4 month CT or PET/CT and exam for 2 years. If conversion to dMRD without clinical relapse, pts received MN (240 mg IV q2 weeks) until clinical relapse or toxicity for up to 2 years (26 cycles). Pts with overt relapse at time of dMRD were ineligible for MN and taken off trial. The primary endpoint was rate of conversion from +MRD to undetectable MRD (uMRD) in pts receiving . Results 20 pts were screened and 15 pts were enrolled between June 2018 and March 2022. 5 pts had non-GCB subtype, 2 had GCB subtype, and two had unknown cell of origin. 4 had transformed DLBCL (2 from FL, 1 from MZL, and 1 Richter's), 2 pts had HGBCL (one of which was also transformed). Of the 8 pts who enrolled after 1 prior LOT, none had molecular or clinical relapse (Figure). In 7 pts who enrolled after 2+ prior LOT, 3 had dMRD. 2/3 had clinical relapse at same time as dMRD and were taken off study– one at initial enrollment with dMRD at first ctDNA screening and one converting from uMRD to dMRD after 135 days post enrollment. In the single patient who was eligible for MN, dMRD preceded radiographic relapse by 105 days, 410 days after enrollment. The pt went on to receive 2 cycles of MN before clinical progression and was taken off study. This pt failed to achieve conversion of dMRD to uMRD. Conclusions Due to small sample size and lower than expected relapse rates, we were unable to demonstrate conversion of dMRD to uMRD using MN. Of the 3 pts with dMRD, 2 were not eligible for MN due to clinical relapse at same time as dMRD and both died due to lymphoma progression. In the single pt who received MN, this intervention did not achieve uMRD or prevent relapse. However, this pt went on to achieve CR to subsequent CAR-T and remains in prolonged remission despite multiple relapsed/refractory disease. It is unknown if this patient's positive outcome was impacted by the effect of nivolumab on T cells and/or related to slower disease kinetics as this pt had a 3 month period between dMRD and radiographic detection and long duration of response to prior lines. A larger study is needed to adequately assess impact of early intervention MN using MRD kinetics, particularly in patients receiving CAR-T. All pts with dMRD had radiographic relapse within 4 months of molecular relapse. No pts with uMRD by ctDNA had clinical relapse on study during 2 year follow up, confirming uMRD correlates with disease free survival. If a strong negative predictive value is confirmed in a larger study, ctDNA MRD testing may be used to spare pts from imaging or to guide additional work up in pts with inconclusive findings on scans.

Mosunetuzumab Monotherapy Continues to Demonstrate Durable Responses in Patients with Relapsed and/or Refractory Follicular Lymphoma after ≥2 Prior Therapies: 3-Year Follow-up from a Pivotal Phase II Study

Background: Mosunetuzumab is a CD20xCD3 T-cell engaging bispecific antibody that redirects T cells to eliminate malignant B cells. In a pivotal Phase II study (NCT02500407), mosunetuzumab demonstrated a high complete response (CR) rate with a manageable safety profile in patients with relapsed/refractory (R/R) follicular lymphoma (FL) and ≥2 prior lines of therapy (Budde et al. Lancet Oncol 2022). Mosunetuzumab is a fixed-duration treatment that can be administered in an outpatient setting. Here, we present updated data for patients with R/R FL and ≥2 prior lines of therapy, after 3 years of follow-up. Methods: Eligible patients with R/R FL Grade (Gr) 1-3a and ≥2 prior therapies received intravenous mosunetuzumab in 21-day cycles with step-up dosing in Cycle (C) 1 (C1 Day [D] 1, 1mg; C1D8, 2mg; C1D15/C2D1, 60mg; C3D1 and onwards, 30mg). Hospitalization for treatment was not required. Patients achieving a CR by C8 completed treatment without additional cycles; patients with a partial response or stable disease received a total of 17 cycles. The primary endpoint was CR rate as determined by an Independent Review Committee (as best response; Cheson 2007 criteria). Duration of response (DOR), duration of complete response (DOCR), progression-free survival (PFS), event-free survival (EFS), and safety were secondary endpoints. Time to next treatment (TTNT), response to retreatment, biomarkers of minimal residual disease (MRD), and circulating B-cell counts were exploratory endpoints. Results: Ninety patients with R/R FL were enrolled. As of May 2, 2023, median time on study was 37.4 (range: 2.0-48.0) months. Investigator-assessed best overall response and CR rates were 77.8% (95% CI: 67.8-85.9) and 60.0% (95% CI: 49.1-70.2), respectively. The median DOR was 35.9 months (95% CI: 20.7-not reached [NR]). Median DOCR was NR (95% CI: 33.0-NR); the estimated 30-month DOCR rate was 72.4% (95% CI: 59.2-85.6) ( Table). Three years after the end of treatment, 57.1% of 70 responding patients were alive and disease progression-free. Median PFS was 24.0 months (95% CI: 12.0-NR) ( Figure). The median TTNT was 37.3 months (95% CI: 18.0-NR); estimated EFS at 36 months was 51.8% (95% CI: 40.8-62.8). After initial mosunetuzumab treatment, 34/90 (37.8%) patients had received a new anti-lymphoma therapy, including 33/90 (36.7%) patients who received a new systemic treatment (8/33 [24.2%] of these patients received chimeric antigen receptor T-cell therapy); 8/90 (8.9%) had radiotherapy; 2/90 (2.2%) had excision of tumor; 2/90 (2.2%) had an allogeneic stem cell transplant; and 1/90 (1.1%) had an autologous stem cell transplant. Five patients received retreatment with mosunetuzumab, 3/5 of these patients had a CR. No new cytokine release syndrome (CRS) events, serious, or Gr ≥3 adverse events (AEs) were reported since the previous analysis (median follow-up of 28.3 months; Bartlett et al. ASH 2022). CRS events occurred in 44.4% of patients and 2.2% were Gr 3/4 in severity; all CRS events resolved. Overall AEs and serious AEs were comparable to the previous analysis (Bartlett et al. ASH 2022); febrile neutropenia was not reported. Forty-six (51.1%) patients experienced Gr 3/4 AEs related to mosunetuzumab; the rate of AEs leading to discontinuation was low (4.4%). Peripheral blood B-cell depletion following treatment with mosunetuzumab occurred in all patients, and recovery was observed after a median of 18 months following the end of treatment in patients with a sustained response using follow-up samples. MRD kinetics following mosunetuzumab therapy will be presented. Conclusions: In this updated analysis, with a median follow-up of 37.4 months, durable responses continued to be observed with fixed-duration mosunetuzumab in patients with R/R FL. The manageable safety profile was consistent with previous reports. Evidence of B-cell recovery was observed after a median of 18 months following the end of treatment.

GLOBRYTE: A Phase III, Open-Label, Multicenter, Randomized Trial Evaluating Glofitamab Monotherapy in Patients with Relapsed or Refractory Mantle Cell Lymphoma

Background and Significance: There is currently no standard of care for patients (pts) with relapsed or refractory (R/R) mantle cell lymphoma (MCL). Although Bruton tyrosine kinase inhibitors (BTKi) have improved clinical outcomes in R/R MCL, there is a high unmet need for new treatment options for pts who do not respond to, or progress through, BTKi therapy. Chimeric antigen receptor (CAR) T-cell therapies, such as brexucabtagene autoleucel, have shown promising outcomes, but alternative systemic therapies are still needed in this pt population. Glofitamab is a CD20xCD3 T-cell-engaging bispecific antibody that redirects T cells to eliminate B cells. A Phase I/II trial of glofitamab monotherapy with step-up dosing (SUD) and obinutuzumab pretreatment (Gpt; 1000 or 2000mg) to mitigate the risk of cytokine release syndrome (CRS) showed high and durable complete response (CR) rates (73.0%) and manageable, mostly low-grade CRS in heavily pretreated pts with R/R MCL (n=37), most of whom had failed prior BTKi therapy (Phillips et al. ASH 2021, Phillips et al. ASH 2022). Study Design and Methods : The GLOBRYTE study (GO43878; EU CT: 2023-503206-37-00) is a Phase III, open-label, multicenter, randomized, controlled trial that will evaluate the efficacy, safety, pharmacokinetics (PK), and pharmacodynamics (biomarkers) of glofitamab monotherapy in pts with R/R MCL, in comparison with an investigator's choice of rituximab + bendamustine (BR) or rituximab + lenalidomide (R-Len). Pts with histologically confirmed R/R MCL who have received ≥1 prior line of systemic therapy (including a BTKi) and have an Eastern Cooperative Oncology Group performance status of 0-2 are eligible for enrollment. Exclusion criteria include leukemic, non-nodal MCL; prior CAR T-cell therapy or CD20xCD3 bispecific antibodies; primary or secondary central nervous system (CNS) lymphoma or history of CNS lymphoma; and current or prior CNS disease (including stroke or transient ischemic attack in the past 2 years and residual neurologic deficits, epilepsy, or CNS vasculitis). Eligible pts will be randomly assigned (1:1) to receive glofitamab or investigator's choice of BR or R-Len stratified by line of therapy (1 vs ≥2) and response to last therapy (relapsed vs refractory). Pts will receive intravenous (IV) Gpt (2000mg) on Day (D) 1 of Cycle (C) 1, 7 days prior to the first glofitamab dose (Gpt may be split over 2 days as 1000mg doses if needed: the second 1000mg dose must be administered ≥1 day before initial glofitamab treatment). Pts will receive glofitamab for a fixed duration of 12 cycles, unless progressive disease (PD) or unacceptable toxicity occurs earlier. Glofitamab IV SUD will be given on C1D8 (2.5mg), C1D15 (10mg), and then the target dose (30mg) on D1 of C2-12 (21-day cycles). Pts randomized to the investigator's choice will receive 375mg/m 2 IV rituximab on D1 in combination with either 90mg/m 2 IV bendamustine on D1-2 of each cycle (BR for six cycles) or 20mg/day oral lenalidomide on D1-21 of each cycle (R-Len until PD); the cycle length for BR or R-Len is 28 days. Crossover to glofitamab from the investigator's choice is permitted in pts with radiologic confirmation of PD ( Figure). The primary endpoint is progression-free survival (PFS) determined by independent review committee (IRC). Treatment comparisons will be made with a 2-sided, level 0.05 stratified log-rank test. Secondary endpoints include overall survival (OS); IRC- and investigator-assessed CR rate, objective response rate, duration of response, and duration of CR; PFS (investigator-assessed); safety; health-related quality of life including time to deterioration in physical functioning or fatigue evaluated by the EORTC QLQ-C30; glofitamab PK; and immune response to glofitamab (including presence of anti-drug antibodies). Response will be determined according to Lugano criteria (Cheson et al. J Clin Oncol 2014). Stratified hazard ratios with 95% confidence intervals (95% CI) will be calculated for PFS and OS, and odds ratios (95% CI) will be calculated for the difference in CR rate and overall response rate between treatment arms. Predictive and prognostic biomarkers (to characterize high-risk subgroups and minimal residual disease kinetics) will also be explored. An estimated 80 sites globally will enroll approximately 182 pts with R/R MCL (glofitamab n=91; BR or R-Len n=91 total) starting in Oct-Nov 2023 (APAC, US, and EU regions).

Dissecting MRD Kinetics By Automated Computational Analysis to Improve Outcome Prediction in Mantle Cell Lymphoma: A Bioinformatic Substudy from the Fondazione Italiana Linfomi (FIL) MCL0208 Clinical Trial

Background and Aims. Minimal residual disease (MRD) detection is a validated outcome predictor in mantle cell lymphoma (MCL). Recently, the clinical relevance of repeated MRD monitoring has been described in a prospective clinical trial [Ferrero, Blood 2022]. Nonetheless, complex patterns of MRD kinetics over time and availability of results obtained by heterogeneous tissues (bone marrow, BM, vs peripheral blood, PB) might generate substantial interpretation issues and hamper an easy-to-use application of this predictive biomarker. To overcome the limitation of empirical analysis we tested CONNECTOR, a novel automated computational framework to facilitate the interpretation of MRD kinetics and stratify patients in risk classes based on a solid, algorithm-derived, classification. Patients and methods. ASO RQ-PCR MRD data already generated from BM and PB samples in the FIL MCL0208 trial [Ferrero, Blood 2022], offering first-line high dose chemoimmunotherapy and autologous transplantation (ASCT) to youngers MCL patients, were employed. CONNECTOR (https://qbioturin.github.io/connector/) is a data-driven framework based on Functional Data Analysis for analyzing longitudinal high-dimensional data in a straightforward and revealing way. CONNECTOR allows the aggregation of time-series data through an unsupervised approach in informative clusters. Moreover, we developed a classification approach to predict the risk class for new MRD data. The new MRD curves were allocated to existing risk clusters defined on a training set of MRD data. Results. Without knowledge of any clinical or outcome data, CONNECTOR was run on 117 patients characterized by at least 3 MRD timepoints in BM (median 6, 3-9) and separately on 95 patients with at least 4 MRD timepoints in PB (median 7, 4-9). Starting from BM MRD data, CONNECTOR identified four patient risk Clusters (CrC), based on MRD kinetics, Figure1A. CrC_A comprised 73 patients with an overall quick and stable MRD negativization; CrC_B accounted for 14 patients characterized by later MRD negativization, alternating MRD results, or low-level MRD persistence; the 14 patients in CrC_C were always characterized by early MRD negativization followed by late MRD reappearance; CrC_D was composed of 16 patients with stable MRD positivity or only transient MRD negativization followed by early MRD reappearance. The different trends of MRD kinetics dissected by CONNECTOR fairly predicted patients’ outcomes: median TTP was not reached for CrC_A and B, 36 months for CrC_C and 27 months for CrC_D, respectively (p<0.0001), Figure1B. Similar data were generated when CONNECTOR was run on MRD results from PB samples: CrC allocation of BM vs PB was concordant for 89% of patients and survival analysis on PB results confirmed patients stratification in two groups: favorable MRD kinetics (CrC_A and B, median TTP not reached) vs unfavorable MRD kinetics (CrC_C and D, median TTP 35 months, p<0.0001), as depicted in Figure1B. Finally, we tested the performance of pooling together BM and PB results, to increase the number of evaluable patients (irrespective of eventual missing BM samples). Only the BM point at 12 months after ASCT was considered, together with the PB MRD results of all the available time points. CONNECTOR was used to verify if this mixed MRD pattern was able to correctly reclassify patients in the same CrC. Actually, 89 out of 95 patients (94%) were correctly reclassified (p_mean=0.96, p_sd= 0.07). Discussion. CONNECTOR allowed unsupervised identification of patients clusters with distinct MRD kinetics and highly significant different clinical outcome. Such clusterization proved effective using BM, PB and mixed tissues, as well. Validation of CONNECTOR performance in large, independent prospective trials is currently ongoing. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Minimal residual disease assessment in colorectal cancer (MiRDA-C).

TPS236 Background: Detection of circulating tumor DNA (ctDNA) in the bloodstream is emerging as a novel marker for identifying of radiographically occult microscopic or minimal residual disease (MRD) in colorectal cancer (CRC) patients (pts) after curative intent treatments. Accumulating data suggest that ct-DNA defined MRD is a highly specific prognostic biomarker for future recurrences with a lead time of several months and prospective clinical trials are being conducted using ct-DNA defined MRD as an integral biomarker for improving risk stratification for adjuvant chemotherapy decision making. However, large scale, prospective data regarding kinetics of ctDNA-defined MRD with accurate pre-analytical methodology for plasma isolation and paired clinical data are limited. Methods: In this multi-center, prospective observational study, 1,000 pts with resectable CRC (stages II – IV) without other active malignancies undergoing therapy with curative intent will be enrolled any time from time of diagnosis up to start of adjuvant therapy (or ≤ 3 months post curative surgery, whichever is earlier). All therapeutic and surveillance visits decisions are at the discretion of the treating physicians. Serial biospecimens including blood (in Cell-Free DNA BCT tubes) to be processed to plasma and buffy coat in ≤ 2 days and formalin fixed tumor tissue will be collected at key time points until the time of radiographic recurrence or up to 5 years of surveillance. Blood draws will be at study entry, after each line of neoadjuvant therapy, post-surgery, during and after adjuvant therapy in addition to each surveillance visit. These blood draws will be coordinated with pts’ standard of care visits in order to minimize additional venipunctures. Relevant clinical data including demographics, cancer history, treatment details and outcomes, serum tumor markers and genomic data will be collected at each time point. Samples will be evaluated retrospectively with a primary objective of evaluating sensitivity and specificity of post-operative MRD for radiographic recurrences utilizing Guardant Health’s Reveal assay. Other key objectives include evaluating ctDNA kinetics with neoadjuvant and adjuvant therapies and to correlate with outcomes. The study is active, and enrollment is ongoing. Clinical trial information: NCT04739072.

Minimal Residual Disease Dynamics after Venetoclax-Obinutuzumab Treatment: Extended Off-Treatment Follow-up From the Randomized CLL14 Study.

The CLL14 study has established one-year fixed-duration treatment of venetoclax and obinutuzumab (Ven-Obi) for patients with previously untreated chronic lymphocytic leukemia. With all patients off treatment for at least three years, we report a detailed analysis of minimal residual disease (MRD) kinetics and long-term outcome of patients treated in the CLL14 study. Patients were randomly assigned to receive six cycles of obinutuzumab with 12 cycles of venetoclax or 12 cycles of chlorambucil (Clb-Obi). Progression-free survival (PFS) was the primary end point. Key secondary end points included rates of undetectable MRD and overall survival. To analyze MRD kinetics, a population-based growth model with nonlinear mixed effects approach was developed. Of 432 patients, 216 were assigned to Ven-Obi and 216 to Clb-Obi. Three months after treatment completion, 40% of patients in the Ven-Obi arm (7% in the Clb-Obi arm) had undetectable MRD levels < 10-6 by next-generation sequencing in peripheral blood. Median MRD doubling time was longer after Ven-Obi than Clb-Obi therapy (median 80 v 69 days). At a median follow-up of 52.4 months, a sustained significant PFS improvement was observed in the Ven-Obi arm compared with Clb-Obi (median not reached v 36.4 months; hazard ratio 0.33; 95% CI, 0.25 to 0.45; P < .0001). The estimated 4-year PFS rate was 74.0% in the Ven-Obi and 35.4% in the Clb-Obi arm. No difference in overall survival was observed (hazard ratio 0.85; 95% CI, 0.54 to 1.35; P = .49). No new safety signals occurred. Appearance of MRD after Ven-Obi is significantly slower than that after Clb-Obi with more effective MRD reduction. These findings translate into a superior long-term efficacy with the majority of Ven-Obi-treated patients remaining in remission.

Sustained Minimal Residual Disease Negativity Predicted in Chronic Lymphocytic Leukemia Patients Treated with Venetoclax Combination Therapy for 2 Years: an Integrated Mechanistic Analysis of Multiple Phase I and II Studies

▪Introduction: Minimal residual disease (MRD) is an emerging clinical endpoint in chronic lymphocytic leukemia (CLL). Multiple studies have demonstrated that achieving MRD below 1 in 10,000 (10-4) CLL cells per leukocyte in the blood and/or bone marrow corresponds to longer progression-free survival (PFS) (Owen et al. Leuk Lymphoma . 2017). With the introduction of venetoclax in combination with rituximab high rates (>50%) of MRD negativity (<10-4) may be achieved in relapsed or refractory (R/R) CLL. However, the duration to treat patients to achieve this low level of MRD, and the duration patients should be treated with venetoclax once MRD negativity (<10-4) is achieved, has not been fully elucidated. Therefore, the objective of this research was to develop an integrated semi-mechanistic model of the kinetics of MRD in R/R CLL in response to venetoclax and rituximab therapy in order to evaluate such treatment questions.Methods: Data from 4 phase I and II clinical studies of venetoclax monotherapy and rituximab (6-cycles) combination therapy in R/R CLL were combined for the analysis. An integrated semi-mechanistic pharmacokinetic-pharmacodynamic (PK-PD) MRD model was constructed that accounted for venetoclax PK, rituximab treatment, absolute lymphocyte count (ALC), and blood and BM MRD data. Upon validation of the MRD negativity (<10-4) rates in the blood and BM, the integrated model was used to evaluate the time course of achieving MRD negativity at the 10-4 threshold of venetoclax combined with 6 cycles of rituximab treatment. In addition, the MRD negativity (<10-4) rates were compared between those achieved with continuous venetoclax treatment until progression and those achieved with a defined 24 months of venetoclax treatment.Results: A total of 402 R/R CLL patients, including 49 patients receiving venetoclax and rituximab combination therapy, were incorporated into the dataset. Model predictions of BM MRD negativity (<10-4) in patients administered venetoclax monotherapy and in combination therapy with rituximab were both in good agreement with the observed results. Simulations of venetoclax in combination with rituximab across all R/R CLL patients estimated rates of BM MRD below 10-4 of 48% (90% CI: [43 - 52%]), 60% (90% CI: [53 - 64%]), and 63% (90% CI: [57 - 67%]) at 6, 12, and 24 months of venetoclax treatment, respectively (Figure 1). Continued venetoclax treatment beyond 12 months was predicted to increase the MRD response, even when MRD negativity at 10-4 was reached within 1 year of treatment, with an improved depth of the MRD achieved. Consistent with the observed data, a diversity of responses to treatment were captured in the simulations, with many individual patients predicted to rapidly respond, some predicted to achieve deep responses and then relapse, and a minority of patients predicted to have little-to-no response to the combination therapy. Continued venetoclax treatment beyond 24 months was predicted to result in minimal additional benefit, with comparable rates of MRD below 10-4 to that achieved with stopping therapy. The simulation-based estimated rate of MRD negativity (<10-4) at 48 months with continuous venetoclax treatment was 66% (95% CI: [63 - 70%]) (Figure 1, left panel) compared to an estimated rate of MRD negativity (<10-4) of 64% (95% CI: [61 - 70%]) at 48 months with venetoclax treatment stopping at 24 months (Figure 1, right panel). As additional MRD assessments become available from patients off of venetoclax treatment, these estimates of MRD durability after stopping all therapy may be further refined.Conclusions: The integrated semi-mechanistic model of MRD in R/R CLL patients was able to describe the kinetics of MRD in response to venetoclax monotherapy and combination therapy with rituximab. Simulations indicated that treatment of patients with venetoclax in combination with rituximab beyond 2 years is unlikely to achieve further reductions in the rate of MRD negativity (<10-4), even years after stopping venetoclax. [Display omitted] DisclosuresGopalakrishnan:AbbVie: Employment, Equity Ownership. Chyla:AbbVie: Employment, Equity Ownership. Mensing:AbbVie: Employment, Equity Ownership, Patents & Royalties. Menon:AbbVie: Employment, Equity Ownership. Humerickhouse:AbbVie: Employment, Equity Ownership. Awni:AbbVie: Employment, Equity Ownership. Salem:AbbVie: Employment, Equity Ownership. Freise:AbbVie: Employment, Equity Ownership.

Pharmacogenomics Drives Lenalidomide Efficacy and MRD Kinetics in Mantle Cell Lymphoma after Autologous Transplantation: Results from the MCL0208 Multicenter, Phase III, Randomized Clinical Trial from the Fondazione Italiana Linfomi (FIL)

Pharmacogenomics Drives Lenalidomide Efficacy and MRD Kinetics in Mantle Cell Lymphoma after Autologous Transplantation: Results from the MCL0208 Multicenter, Phase III, Randomized Clinical Trial from the Fondazione Italiana Linfomi (FIL)

Molecular Monitoring in Acute Myeloid Leukemia Patients Undergoing Matched Unrelated Donor – Hematopoietic Stem Cell Transplantation: Single Center Experience

Abstract Introduction: Minimal residual disease (MRD) assessment in acute myeloid leukemia (AML) cases is a complex, multi-modality process and, though much of its clinical implications at different points are extensively studied, it remains even now a challenging area. It is a disease the biology of which governs the modality of MRD assessment; in patients harboring specific molecular targets, high sensitivity techniques can be applied. On the other hand, relapse is considered as the leading cause of treatment failure in AML patients undergoing allogeneic hematopoietic stem cell transplantation (alloHSCT). Materials and methods: Since November 2018 until June 2020, 10 AML patients underwent matched unrelated donor (MUD) HSCT at the University Clinic of Hematology-Skopje, Republic of North Macedonia. Molecular markers were identified in a total of 4 patients; 3 patients expressed chimeric fusion transcripts; two RUNX-RUNX1T1 and one for CBFB-MYH11. One patient harbored mutation in the transcription factor CCAAT/enhancer binding protein α (CEBPA). Post-transplant MRD kinetics was evaluated by using quantitative polymerase chain reaction (RT-qPCR) or multiplex fluorescent-PCR every three months during the first two years after the transplantation. Results: MRD negativity was achieved in three pre-transplant MRD positive patients by the sixth month of HSCT. They sustained hematological and molecular remission for 19, 9 and 7 months, respectively. The fourth patient died due to transplant-related complications. Conclusion: According to our experience, when molecularly-defined AML patients undergo HSCT, regular MRD monitoring helps predict impending relapse and direct future treatment strategies.

Prolonged lenalidomide maintenance therapy improves the depth of response in multiple myeloma

AbstractLenalidomide is an immunomodulatory drug approved for maintenance treatment in newly diagnosed multiple myeloma, and it has been shown to improve progression-free survival (PFS) and, in several studies, overall survival. Nevertheless, the impact of prolonged treatment with lenalidomide on the kinetics of minimal residual disease (MRD) and its prognostic impact have not been studied in depth. To obtain better knowledge in this regard, we retrospectively analyzed 139 patients who received lenalidomide maintenance in real-world clinical practice and whose MRD levels were observed during the treatment period by multiparametric flow cytometry or next-generation sequencing with a sensitivity of at least 10−4. Lenalidomide maintenance correlated with an increased depth of the disease response, with 38.1% of patients achieving maximal response during maintenance. Moreover, 34.3% of patients who were MRD positive after induction treatment achieved MRD-negative status during maintenance and ultimately had improved PFS. Sequential MRD assessments identified patients with progressively decreasing MRD levels who also had better PFS outcomes, compared with patients not showing a decreasing pattern of MRD. These results support the role of maintenance therapy, not only to sustain, but also to increase the depth of disease response with a PFS benefit. In addition, MRD monitoring during maintenance identifies patients with better prognosis and may help in their clinical management.

The prognostic significance of dynamic monitoring of minimal residual disease (MRD) status in patients with newly-diagnosed multiple myeloma

目的探讨多发性骨髓瘤（MM）患者微小残留病（MRD）动态变化及其与临床特征、治疗和预后的关系。方法纳入105例治疗后达到非常好的部分缓解（VGPR）的MM患者，采用多参数流式细胞术（MFC）动态监测MRD状态，结合临床数据和随访，进行Kaplan-Meier曲线及Cox回归等分析。结果①纳入本研究的疗效VGPR患者中，MRD转阴率为72.4%（76/105），中位转阴时间为3个月。②MRD阴性患者2年无进展生存（PFS）率明显高于MRD阳性患者（62.2%对41.3%，P=0.001），持续MRD阳性为PFS独立预后不良因素（HR=3.039，P=0.044）。③失去MRD阴性状态（转阳）患者预后劣于MRD持续阴性患者，二者中位PFS时间分别为18个月和未达到（P<0.001），中位总生存（OS）时间均未达到（P=0.002）。④MRD阴性持续时间≥12个月患者的2年PFS和OS率均显著高于对照组（PFS：77.7%对36.7%，P<0.001；OS：96.4%对57.9%，P<0.001）。随MRD阴性持续时间延长，复发/死亡风险显著降低（PFS：HR=0.865，P<0.001；OS：HR=0.823，P<0.001）。⑤高危细胞遗传学异常（CA）或不适合自体造血干细胞移植（ASCT）患者中，MRD阴性患者PFS延长（高危CA患者中位PFS：未达到对19个月，P=0.006；不适合ASCT患者中位PFS：未达到对25个月，P=0.052）。⑥应用硼替佐米治疗可明显延长MRD阴性持续时间（中位MRD阴性持续时间：25个月对10个月，P=0.034）。结论持续MRD阳性是MM独立的预后不良因素，MRD阴性持续时间是另一重要预后因素，而失去MRD阴性状态可能是复发的早期标志，故动态监测MRD有助于指导复发MM治疗时机的选择。

First Prospective Data on Impact of Minimal Residual Disease on Long-Term Clinical Outcomes after Venetoclax Plus Rituximab Versus Bendamustine Plus Rituximab: Phase III MURANO Study

First Prospective Data on Impact of Minimal Residual Disease on Long-Term Clinical Outcomes after Venetoclax Plus Rituximab Versus Bendamustine Plus Rituximab: Phase III MURANO Study

Minimal Residual Disease Response at End of Induction and during Maintenance Correlates with Updated Outcome in the Phase III GALLIUM Study of Obinutuzumab- or Rituximab-Based Immunochemotherapy in Previously Untreated Follicular Lymphoma Patients

Introduction: Minimal residual disease (MRD) status reflects depth of response and informs prognosis after first-line therapy in patients (pts) with follicular lymphoma (FL). In the GALLIUM study (NCT01332968), the primary endpoint of investigator (INV)-assessed progression-free survival (PFS) in previously untreated FL pts was significantly improved with obinutuzumab (GA101; G)- versus rituximab (R)-based immunochemotherapy treatment. We previously reported consistently higher MRD response rates with G- versus R-based treatment at the end of induction (EOI) (92% vs 85%, respectively; p=0.0041; Pott et al. ASH 2016). Here we report the correlation of MRD response at EOI with updated PFS data and the results of MRD response assessment during maintenance treatment and follow-up. We also assessed MRD responses and outcome in pts who remained MRD-positive at EOI. Methods: Previously untreated pts aged ≥18 years with FL requiring treatment were randomized 1:1 to receive 6-8 cycles of G (1000mg IV on days [D] 1, 8, and 15 of cycle [C] 1 and D1 of C2-6 or 8) or R (375mg/m2 IV on D1) plus standard chemotherapy (CHOP, CVP, or bendamustine). Responding pts received the same antibody as maintenance every 2 months for up to 2 years. MRD status was assessed by real-time quantitative (RQ)-PCR assays at mid-induction (MI) in peripheral blood (PB), at EOI in PB and bone marrow, at 4-monthly intervals during maintenance in PB, and at 6-monthly intervals during follow-up in PB, and was defined as negative (MRD response) if RQ-PCR and subsequent nested PCR were negative in all samples analyzed at the respective time point. INV-assessed PFS was estimated using Kaplan-Meier methods (data cut-off, February 12, 2018). Pts were included in the various analyses if they had evaluable MRD data and achieved a complete or partial response at EOI. Results: After 57 months9 median follow-up, MRD evaluable pts (n=634/1202 randomized FL pts) who had a MRD-negative response at EOI (n=564) continued to have a longer PFS than those who had a MRD-positive response at EOI (n=70; hazard ratio 0.38; 95% confidence interval 0.26, 0.56; p Conclusions: These data confirm the prognostic value of MRD status at EOI in previously untreated FL pts receiving immunochemotherapy. Analysis of MRD kinetics revealed that most of the pts who achieved MRD negativity at EOI sustained their responses during maintenance. The majority of pts who were MRD positive at EOI achieved MRD negativity during the first 4 months of maintenance. While this is likely to be indicative of the efficacy of continued treatment, it also suggests that response kinetics can be slower than in those pts who have an early MRD response at MI, and that responses that are beyond the sensitivity of the MRD assay may be less deep. Importantly, pts who failed to achieve MRD negativity at EOI or during early maintenance had a high chance of experiencing early progression or death. These data demonstrate the prognostic value of MRD response assessments in previously untreated FL pts receiving immunochemotherapy. Disclosures Hoster:F. Hoffman-La Roche: Other: Travel support, Research Funding; Roche Pharma AG: Other: Travel support, Research Funding. Unterhalt:F. Hoffman-La Roche: Other: Travel support. van der Jagt:F. Hoffman-La Roche Ltd: Employment, Honoraria, Research Funding. Janssens:Novartis: Membership on an entity9s Board of Directors or advisory committees; Roche: Consultancy, Membership on an entity9s Board of Directors or advisory committees, Other: Ad board, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Sanofi-Genzyme: Speakers Bureau; Abbvie: Consultancy, Membership on an entity9s Board of Directors or advisory committees, Other: Ad board, Speakers Bureau; Janssen: Consultancy, Speakers Bureau. Kneba:Roche: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. Mayer:Affimed: Research Funding; Roche: Research Funding; Johnson & Johnson: Research Funding; Eisai: Research Funding; Novartis: Research Funding. Pocock:Kent & Canterbury Hospital: Employment. Knapp:Roche: Employment. Danesi:F. Hoffmann-La Roche Ltd: Employment. Nielsen:F. Hoffmann-La Roche Ltd: Employment, Other: Ownership interests PLC. Brown:PAREXEL, external business partner with Roche Products Ltd, Welwyn, UK: Employment. Mundt:Roche: Employment, Other: Ownership interests PLC. Marcus:Gilead: Consultancy; F. Hoffman-La Roche: Other: Travel support and lecture fees; Roche: Consultancy, Other: Travel support and lecture fees . Hiddemann:Celgene: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Bayer: Consultancy, Research Funding; F. Hoffman-La Roche: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding.

Impact of Next-Generation Flow (NGF) Minimal Residual Disease (MRD) Monitoring in Multiple Myeloma (MM): Results from the Pethema/GEM2012 Trial

Background: MRD is an established biomarker to evaluate treatment efficacy, define patients at risk based on persistent MRD, and eventually, act as surrogate for prolonged survival based on sensitive MRD-negative definitions. Accordingly, the IMWG has developed criteria for MRD-negativity defined by next-generation sequencing, NGF or PET/CT, and has recommended their inclusion in clinical trials. Notwithstanding, most flow cytometry results have been obtained using less sensitive methods and in fact, there is no data about the impact of NGF-based MRD assessment in clinical trials. Aim: To define the feasibility, sensitivity and clinical impact of NGF-based MRD assessment in the phase III PETHEMA/GEM2012 trial. Methods: A total of 458 patients were enrolled into the PETHEMA/GEM2012 trial. MRD was predefined to be prospectively assessed at three time-points: after six induction cycles with bortezomib, lenalidomide, and dexamethasone (VRD), after HDT/ASCT, and after two courses of consolidation with VRD. MRD monitoring was performed blinded for clinical outcomes in four PETHEMA/GEM laboratory cores, and data was centralized for MRD analyses. MRD assessment was performed following EuroFlow SOPs in a total of 1,134 bone marrow (BM) samples from 419 patients. The 39 cases without MRD assessment had suboptimal response to induction and were thus considered as MRD+ for intention-to-treat analyses. Noteworthy, in 14 BM samples with undetectable MRD, B-cell precursors, erythroblasts and mast cells represented Results: Overall, 225/458 (49%) patients had undetectable MRD at the latest time-point in which MRD was assessed and were thus classified as MRD-. Conversely, 233/458 (51%) cases remained MRD+: 28% with ≥10-4 MRD, 12% with 10-5 MRD, and 11% with 10-6 MRD. Detailed analyses of MRD kinetics in 320 patients with available MRD results at all three time-points, showed that the percentage of MRD- patients increased from 35% into 54% and 58% after induction, HDT/ASCT and consolidation, respectively. Furthermore, a restricted analysis among MRD+ patients showed that whereas after induction only 8% of them had MRD levels as low as 10-6, subsequent intensification with HDT/ASCT and consolidation could reduce MRD levels down to 10-6 in 32% of MRD+ cases. Progression-free survival (PFS) rates at 3-years were of 92%, 70%, 54% and 44% for patients being MRD-negative, MRD+ 10-6, 10-5 and ≥10-4, respectively (P Conclusions: This is the largest study of MRD monitoring in MM based on the total number of samples analyzed (n=1,134). Our results show that NGF-based MRD assessment is feasible in large multicenter clinical trials, is highly-sensitive, and allows the identification of hemodiluted BM samples inadequate for MRD assessment. Risk of relapse among MRD-negative patients was remarkably reduced (3%), and was particularly related to the reappearance of extramedullary plasmacytomas, which urges the need for combined cellular and imaging MRD monitoring in these patients; by contrast, even MRD levels as low as 10-5 and 10-6 conferred significantly inferior PFS. Overall, this study defines MRD-negativity as the most relevant clinical endpoint for both standard- and high-risk transplant-eligible MM patients. Disclosures Paiva: Sanofi: Consultancy, Honoraria, Research Funding; Janssen: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Amgen: Honoraria; Merck: Honoraria; Novartis: Honoraria; Takeda: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; EngMab: Research Funding. Oriol: Amgen: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Other: sponsored symposia, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Other: sponsored symposia, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Other: sponsored symposia; Celgene: Speakers Bureau. de la Rubia: Janssen: Other: Honoraria; Amgen: Other: Honoraria; Celgene: Other: Honoraria. Rosinol: Celgene: Honoraria; Janssen: Honoraria. Mateos: Amgen: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees. Lahuerta: Amgen: Honoraria; Celgene: Honoraria; Janssen: Honoraria. San Miguel: Roche: Membership on an entity9s Board of Directors or advisory committees; Bristol-Myers Squibb: Consultancy, Membership on an entity9s Board of Directors or advisory committees; MSD: Consultancy, Membership on an entity9s Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity9s Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity9s Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity9s Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity9s Board of Directors or advisory committees; Sanofi: Consultancy, Membership on an entity9s Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity9s Board of Directors or advisory committees.

GvL effects in T-prolymphocytic leukemia: evidence from MRD kinetics and TCR repertoire analyses.

Allogeneic stem cell transplantation (alloSCT) is used for treating patients with T-prolymphocytic leukemia (T-PLL). However, direct evidence of GvL activity in T-PLL is lacking. We correlated minimal residual disease (MRD) kinetics with immune interventions and T-cell receptor (TCR) repertoire diversity alterations in patients after alloSCT for T-PLL. Longitudinal quantitative MRD monitoring was performed by clone-specific real-time PCR of TCR rearrangements (n=7), and TCR repertoire diversity assessment by next-generation sequencing (NGS; n=3) Although post-transplant immunomodulation (immunosuppression tapering or donor lymphocyte infusions) resulted in significant reduction (>1 log) of MRD levels in 7 of 10 occasions, durable MRD clearance was observed in only two patients. In all three patients analyzed by TCR-NGS, MRD responses were reproducibly associated with a shift from a clonal, T-PLL-driven profile to a polyclonal signature. Novel clonotypes that could explain a clonal GvL effect did not emerge. In conclusion, TCR-based MRD quantification appears to be a suitable tool for monitoring and guiding treatment interventions in T-PLL. The MRD responses to immune modulation observed here provide first molecular evidence for GvL activity in T-PLL which, however, may be often only transient and reliant on a poly-/oligoclonal rather than a monoclonal T-cell response.

Comparable Long-Term Outcomes of Reduced-Intensity and Myeloablative Conditioning Allogeneic Hematopoietic Cell Transplantation By Minimal Residual Disease Kinetics during the Tyrosine Kinase Inhibitor-Based Chemotherapy Courses in Adults with Philadelphia-Chromosome Positive Acute Lymphoblastic Leukemia in First Remission

Background: The use of tyrosine kinase inhibitor (TKI)-based chemotherapy has demonstrated improved complete remission (CR) rates and increased applicability to allogeneic hematopoietic cell transplantation (HCT), thus allowing better survival in adults with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-positive ALL). However, the sensitivity of Ph-positive ALL to reduced-intensity conditioning (RIC) versus myeloablative conditioning (MAC) by minimal residual disease (MRD) kinetics is not well established. Previously, we have confirmed that monitoring MRD kinetics is very important to predict long-term outcomes. Here, we examined a cohort of patients with Ph-positive ALL in CR1 and tried to compare the long-term outcomes of RIC-HCT vs MAC-HCT according to pre-HCT MRD kinetics.Methods: During the period between 2000 and 2014, 173 adults (median age, 39 years [range, 16-65 years]) with Ph-positive ALL were included in this analysis. All patients received allogeneic HCT (68 RIC [fludarabine 150mg/m2 + melphalan 140mg/m2] and 105 MAC [total body irradiation 13.2Gy + cyclophosphamide 120mg/kg]) in CR1 following two courses of first-line TKI (138 imatinib and 35 dasatinib)-based chemotherapy and had data on prospectively determined quantitative MRD kinetics. A total of 52 patients were excluded because of >CR1 pre-HCT status (n=26), transplants receiving umbilical cord blood grafts (n=14), and no TKI use before HCT (n=12). All but one RIC transplants received peripheral blood stem cells as a graft source (40 matched sibling donor, 11 matched unrelated donor, 17 mismatched unrelated donor), while MAC transplants used either bone marrow (n=73; 57 matched sibling donor, 8 matched unrelated donor, 6 mismatched unrelated donor) or peripheral blood stem cells (n=32; 2 matched sibling donor, 20 matched unrelated donor, 10 mismatched unrelated donor). The median time to transplant was 154 days (range, 119-291 days) in RIC transplants and 141 days (range, 112-280 days) in MAC transplants, respectively. Calcineurin inhibitors (cyclosporine for sibling donor transplants, tacrolimus for unrelated donor transplants) and methotrexate was used for graft-versus-host disease (GVHD) prophylaxis and antithymocyte globulin was administered to the patients who received mismatched unrelated donor grafts. If residual leukemia was detected in the absence of GVHD at 3 months after transplantation, calcineurin inhibitors were rapidly discontinued. MRD monitoring was centrally evaluated by real-time quantitative PCR (4.5 log sensitivity) through handling of bone marrow samples.Results: After a median follow-up of 70.4 months (range, 16.0-176.8 mo), RIC regimen showed comparable 5-year cumulative incidence of relapse (CIR; 30.2% vs 27.9%, P=0.750), non-relapse mortality (NRM; 20.3% vs 15.5%, P=0.318), disease-free survival (DFS; 49.7% vs 56.6%, P=0.296), and overall survival (OS; 59.3% vs 62.1%, P=0.540) compared to MAC regimen. We further analyzed the impact of conditioning intensity on CIR and DFS according to MRD kinetics. Based on the MRD kinetics during the pre-HCT TKI-based chemotherapy courses, we classified patients into 3 subgroups: early-stable molecular responders (EMR, n=59), late molecular responders (LMR, n=57), and poor molecular responders (PMR, n=53). In all MRD-based subgroups of patients, no significant difference in CIR (EMR: 16.3% vs 6.2%, P=0.280; LMR: 10.5% vs 21.4%, P=0.334; PMR: 63.6% vs 59.4%, P=0.372) or DFS (EMR: 68.1% vs 78.1%, P=0.381; LMR: 49.6% vs 59.5%, P=0.369; PMR: 27.3% vs 34.2%, P=0.250) was observed between RIC and MAC. In multivariate analysis, LMR (HR, 2.36; 95% CI, 0.81-6.86; P=0.114) or PMR (HR, 9.05; 95% CI, 3.40-24.1; P<0.001) had higher relapse risk than EMR. Consequently, compared with EMR, LMR (HR, 2.02; 95% CI, 1.01-4.02; P=0.046) or PMR (HR, 3.79; 95% CI, 1.92-7.50; P<0.001) had poorer DFS. The presence of chronic GVHD, especially mild to moderate grade, was also independently associated with better DFS (HR, 0.28; 95% CI, 0.14-0.53; P<0.001). In addition, patients older than 40 years had higher risk of treatment failure in terms of NRM (HR, 4.25; 95% CI, 1.69-10.6; P=0.002).Conclusion:RIC-HCT showed comparable long-term outcomes to MAC-HCT in all MRD-based subgroups of patients with Ph-positive ALL in CR1. Our data suggest that RIC-HCT is worthy of further investigation in prospective trials of adult Ph-positive ALL. DisclosuresKim:ILYANG: Consultancy, Honoraria, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

Minimal Residual Disease in Patients with Follicular Lymphoma Treated with Obinutuzumab or Rituximab As First-Line Induction Immunochemotherapy and Maintenance in the Phase 3 GALLIUM Study

Minimal Residual Disease in Patients with Follicular Lymphoma Treated with Obinutuzumab or Rituximab As First-Line Induction Immunochemotherapy and Maintenance in the Phase 3 GALLIUM Study

Integrating Genetic Risk Factors with Age, Presenting White Cell Count and MRD Response As Continuous Variables to Predict Relapse in Paediatric Acute Lymphoblastic Leukemia (ALL)

▪Paediatric ALL is heterogeneous in terms of clinical presentation, response to therapy and underlying genetic mechanisms. The application of treatment stratification algorithms has resulted in survival rates exceeding 90%. However, current algorithms apply risk factors as binary variables using arbitrary thresholds and in an independent manner. This approach potentially distorts biological heterogeneity resulting in loss of prediction accuracy. Therefore, we sought to determine whether treating clinical risk factors and MRD response as continuous variables and integrating genetic features can refine prognostication.A total of 2542 patients, aged 1-24 years old, recruited to UKALL2003 were available for analysis. NCI standard/high patients were initially assigned to regimen A/B. Sow early responders and those with HR genetics were transferred to the more intensive regimen C. Minimal residual disease (MRD) was evaluated at the end of induction (EOI) by real-time quantitative PCR analysis of Ig/TCR rearrangements. Patients with EOI MRD >0.01% were randomised to stay on regimen A/B or move to C whereas patients with EOI MRD <0.01% were randomised to receive one or two delayed intensifications. Genetic subtypes were defined as good risk (GRcyto: ETV6-RUNX1, high hyperdiploidy), high risk (HRcyto: KMT2A fusions, near haploidy, low hypodiploidy, iAMP21 and TCF3-HLF), intermediate risk (other B cell precursor cases) and T-ALL.In order to examine MRD as a continuous variable, we log transformed the raw EOI MRD value assuming a minimum detection level of 0.00001 and assigned cases with undetectable MRD a value of one log below this threshold. The transformed MRD variable [t(MRD)] followed a log normal distribution (Figure 1). Importantly, this log normal distribution was distinct across the genetic subtypes (Figure 1, p<0.001); even after accounting for the different induction regimens used. Using the t(MRD) variable, we show that each log reduction in EOI MRD reduces the relapse risk (RR) by 22% (p<0.001). In the current UK paediatric trial (UKALL2011) an MRD threshold of 0.005% is used to assign patients to regimen C. Therefore, we examined the RR by MRD value within each genetic subtype. Table 1 shows that the RR for GRcyto patients remains low (<4%) up to an MRD threshold of 0.1% and treatment intensification did not further reduce this RR. In light of these data, we have changed the MRD threshold for classifying newly diagnosed GRcyto patients as MRD risk from 0.005% to 0.1%. This treatment intervention reduces the proportion of GRcyto patients who receive the most intensive therapy (regimen C) from ~40% to <10% and therefore avoids potential unnecessary toxicity.Next we combined multiple significant risk factors from univariate analysis using forward selection modelling to fit a multivariate prognostic model. The final model included log(WCC) and t(MRD) as continuous variables and two binary genetic variables: GRcyto and HRcyto. Using the coefficients from this model, we constructed a linear model which enabled the calculation of individual risk scores. Figure 2 shows the correlation between an individual’s risk score and their RR. To investigate the clinical relevance of this risk score, we generated five risk groups based on ascending RR (Table 2) which have significant differential outcomes (all p<0.001). Using this classification, 65% patients are very low or low (VLR/LR) risk while 11% are high or very high risk (HR/VHR). Although the HR/VHR groups are small their RR was >25% and together with the standard risk (SR) group capture >70% relapses and, importantly, >80% of HR relapses (very early/early relapses). Among the 136 VLR/LR patients who had MRD >0.01%, there was no difference in EFS between patients randomised to regimen A/B v C (97% v 99%, p=0.5). Equally among 470 VLR/LR patients with MRD <0.01%, there was no difference in EFS between patients randomised to receive 1 or 2 delayed intensifications (96% v 96%, p=0.8).In conclusion, we have showed that EOI MRD is log normally distributed but that the shape of the distribution depends on genetic subtype; suggesting differential MRD kinetics. In addition, we have shown that using a single MRD threshold does not reflect the biological heterogeneity that is a fundamental feature of the disease. Finally, we demonstrate that integrating clinical risk factors as continuous variables with genetics can better define prognostic subgroups. [Display omitted] [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.