Evaluation Of Residual Disease Research Articles

Flow Cytometry Profiling of Plasmacytoid Dendritic Cell Neoplasms.

In this review, we aim to provide a summary of the diverse immunophenotypic presentations of distinct entities associated with plasmacytoid dendritic cell (pDC) proliferation. These entities include the following: (1) blastic plasmacytoid dendritic cell neoplasm (BPDCN); (2) mature pDC proliferation (MPDCP), most commonly seen in chronic myelomonocytic leukemia (CMML); and (3) myeloid neoplasms with pDC differentiation, in which pDCs show a spectrum of maturation from early immature pDCs to mature forms, most commonly seen in acute myeloid leukemia (pDC-AML). Our aim is to provide a flow cytometry diagnostic approach to these distinct and sometimes challenging entities and to clarify the immunophenotypic spectrum of neoplastic pDCs in different disease presentations. In this review, we also cover the strategies in the evaluation of residual disease, as well as the challenges and pitfalls we face in the setting of immune and targeted therapy. The differential diagnosis will also be discussed, as blasts in some AML cases can have a pDC-like immunophenotype, mimicking pDCs.

Molecular analysis of surgical margins with NGS to assess microscopic residual disease in early oral squamous cell carcinomas.

6063 Background: The prognosis of early oral squamous cell carcinomas (OSCC) is strongly correlated with local disease control. However, patients with T1-T2 OSCC operated with clear margins have a 5-year local relapse rate of 10 to 15%. An accurate evaluation of the microscopic residual disease (MRD) is therefore essential. Interestingly, innovative techniques have recently been developed to detect circulating tumor DNA. Methods: A prospective multicenter trial based on patients with T1-T2 OSCC treated surgically with clear margins, was designed to assess the feasibility of a molecular analysis (tetranucleotide instability) of these margins to evaluate a potential MRD while adapting the postoperative strategy (NCT00232960). We, then, evaluate the feasibility of detecting MRD in the margins by identifying specific molecular abnormalities in the primary tumor with Whole Exome Sequencing (WES) and explore them in margins with deep target NGS panel (TGS) and digital PCR (dPCR) for hotspot mutations. Results: 310 patients were included initially with 216 tumor/margins samples available for molecular analysis. After a standard pathologic analysis, all surgical margins were negative.Median follow-up was 58 months [30;83]. Tumor was informative for tetranucleotide instability analysis in 63% of cases. Positive molecular margins were observed in 17.3% of cases, leading to a postoperative treatment (surgery or radiotherapy). In informative tumors, molecularly driven treatment seemed to lower the 5-year local recurrence rate from 14.1% to 6.4% (p=0.15). Among this initial cohort, 108 primary tumors were secondarily screened by WES to find mutations of interest, with an informativity rate of 75%. Positive molecular results (TGS or dPCR), with at least one positive margin, were observed in 19.4% of patients. Then, analyzing retrospectively the oncologic outcomes, we observed a significant benefit for local control at 5 years for patients with TGS-dPCR negative results in all margins compared to pathologic negative margins (91.7% versus 64.1%, p=0.02). Conclusions: To our knowledge, this is the first report of local MRD assessment after surgery using NGS.Molecular analysis of resection margins for early OSCC lead to a better evaluation of MRD and personalized postoperative decision making to improve local control. Clinical trial information: NCT00232960 .

Evaluation of molecular residual disease in operable non-small cell lung cancer with gene fusions, MET exon skipping or de novo MET amplification.

Gene fusions and MET alterations are rare and difficult to detect in plasma samples. The clinical detection efficacy of molecular residual disease (MRD) based on circulating tumor DNA (ctDNA) in patients with non-small cell lung cancer (NSCLC) with these mutations remains unknown. This prospective, non-intervention study recruited 49 patients with operable NSCLC with actionable gene fusions (ALK, ROS1, RET, and FGFR1), MET exon 14 skipping or de novo MET amplification. We analyzed 43 tumor tissues and 111 serial perioperative plasma samples using 1021- and 338-gene panels, respectively. Detectable MRD correlated with a significantly higher recurrence rate (P < 0.001), yielding positive predictive values of 100% and 90.9%, and negative predictive values of 82.4% and 86.4% at landmark and longitudinal time points, respectively. Patients with detectable MRD showed reduced disease-free survival (DFS) compared to those with undetectable MRD (P < 0.001). Patients who harbored tissue-derived fusion/MET alterations in their MRD had reduced DFS compared to those who did not (P = 0.05). To our knowledge, this is the first comprehensive study on ctDNA-MRD clinical detection efficacy in operable NSCLC patients with gene fusions and MET alterations. Patients with detectable tissue-derived fusion/MET alterations in postoperative MRD had worse clinical outcomes.

Evaluation of Molecular Residual Disease by a Fixed Panel in Resectable Colorectal Cancer.

Molecular residual disease (MRD) is a promising biomarker in colorectal cancer (CRC) for prognosis and guiding treatment, while the whole-exome sequencing (WES) based tumor-informed assay is standard for evaluating MRD based on circulating tumor DNA (ctDNA). In this study, we assessed the feasibility of a fixed-panel for evaluating MRD in CRC. 75 patients with resectable stage I-III CRC were enrolled. Tumor tissues obtained by surgery, and pre-operative and post-operative day 7 blood samples were collected. The ctDNA was evaluated using the tumor-agnostic and tumor-informed fixed assays, as well as the WES-based and panel-based personalized assays in randomly selected patients. The tumor-informed fixed assay had a higher pre-operative positive rate than the tumor-agnostic assay (73.3% vs 57.3%). The pre-op ctDNA status failed to predict disease-free survival (DFS) in either of the fixed assays, while the tumor-informed fixed assay-determined post-op ctDNA positivity was significantly associated with worse DFS (HR, 20.74, 95%CI 7.19-59.83; p<0.001), which was an independent predictor by multivariable analysis (HR, 28.57, 95%CI 7.10-114.9; p<0.001). Sub-cohort analysis indicated the WES-based personalized assay had the highest pre-operative positive rate (95.1%). The two personalized assays and the tumor-informed fixed assay demonstrated same results in post-op landmark (HR, 26.34, 95%CI, 6.01-115.57; p<0.001), outperforming the tumor-agnostic fixed panel (HR, 3.04, 95%CI, 0.94-9.89; p=0.052). Our study confirmed the prognostic value of the ctDNA positivity at post-op day 7 by the tumor-informed fixed panel. The tumor-informed fixed panel may be a cost-effective method to evaluate MRD, which warrants further studies in future.

The role of 18F-FDG PET/CT in Neurolymphomatosis: A Comprehensive Imaging Approach.

Neurolymphomatosis (NL) is an uncommon and rare neurologic disorder characterised by extranodal lymphoma, where the tumour cells invade the cranial nerves, nerve plexus, nerve root, spinal nerve roots, trunk nerves or peripheral nerves. MRI is the modality of choice, but is often challenging in detection of early recurrence, assessing residual disease and response evaluation. 18FFDG PET/CT has superior diagnostic performance compared with body CT in the evaluation of NL. 18F-FDG PET-CT is helpful in evaluation of disease extent and potential to guide biopsy. 18F-FDG PETCT is a highly sensitive technique for early localisation of NL than MRI or CT alone. Besides diagnostic and prognostic value in NL, it might be very helpful in response assessment.

NRG-GI008: Colon adjuvant chemotherapy based on evaluation of residual disease (CIRCULATE-NORTH AMERICA).

TPS243 Background: Currently, there are no biomarkers validated prospectively in randomized studies for resected colon cancer (CC) to determine need for adjuvant chemotherapy (AC). However, circulating tumor DNA (ctDNA) represents a highly specific and sensitive approach (especially with serial monitoring) for identifying minimal/molecular residual disease (MRD) post-surgery in CC patients (pts), and may outperform traditional clinical and pathological features in prognosticating risk for recurrence. CC pts who do not have detectable ctDNA (ctDNA-) are at a much lower risk of recurrence and may be spared the toxicities associated with AC. Furthermore, for CC pts with detectable ctDNA (ctDNA+) who are at a very high risk of recurrence, the optimal AC regimen has not been established. We hypothesize that for pts whose CC has been resected, ctDNA status may be used to risk-stratify for making decisions about AC. Methods: In this prospective phase II/III trial, up to 1,912 pts with resected stage IIB, IIC, and III CC will be enrolled. Based on the post-operative ctDNA status using personalized and tumor-informed assay (SignateraÔ, bespoke assay), those who are ctDNA- (Cohort A) will be randomized to immediate AC with fluoropyrimidine (FP)+oxaliplatin (Ox) for 3-6 mos per established guidelines vs. serial ctDNA monitoring. Patients who are ctDNA+ post-operatively or with serial monitoring (Cohort B) will be randomized to FP+Ox vs. more intensive AC with addition of irinotecan (I) for 6 mos. One cycle of chemotherapy is allowed while awaiting ctDNA testing results for cohort assignment. The primary endpoints for Cohort A are time to ctDNA+ status (phase II) and disease-free survival (DFS) (phase III) in the immediate vs. delayed AC arms. The primary endpoint for Cohort B is DFS in the FP+Ox vs FP+Ox+I arms for both phase II and phase III portions of the trial. Secondary endpoints include prevalence of detectable ctDNA post-operatively, time-to-event outcomes (overall survival and time to recurrence) by ctDNA status, and the assessment of compliance to adjuvant therapy. Biospecimens including archival tumor tissue, as well as post-operative plus serial matched/normal blood samples, will be collected for exploratory correlative research. Active enrollment across the NCTN started in June 2022 with CCTG sites joining in August 2023. Support: U10-CA-180868, -180822; UG1CA-189867; Natera, Inc. Clinical trial information: NCT05174169 .

The Clinical Utility of FLT3 Mutation Testing in Acute Leukemia: A Canadian Consensus.

FMS-like tyrosine kinase 3 (FLT3) mutations are detected in approximately 20-30% of patients with acute myeloid leukemia (AML), with the presence of a FLT3 internal tandem duplication (FLT3-ITD) mutation being associated with an inferior outcome. Assessment of FLT3 mutational status is now essential to define optimal upfront treatment in both newly diagnosed and relapsed AML, to support post-induction allogeneic hematopoietic stem cell transplantation (alloSCT) decision-making, and to evaluate treatment response via measurable (minimal) residual disease (MRD) evaluation. In view of its importance in AML diagnosis and management, the Canadian Leukemia Study Group/Groupe canadien d'étude sur la leucémie (CLSG/GCEL) undertook the development of a consensus statement on the clinical utility of FLT3 mutation testing, as members reported considerable inter-center variability across Canada with respect to testing availability and timing of use, methodology, and interpretation. The CLSG/GCEL panel identified key clinical and hematopathological questions, including: (1) which patients should be tested for FLT3 mutations, and when?; (2) which is the preferred method for FLT3 mutation testing?; (3) what is the clinical relevance of FLT3-ITD size, insertion site, and number of distinct FLT3-ITDs?; (4) is there a role for FLT3 analysis in MRD assessment?; (5) what is the clinical relevance of the FLT3-ITD allelic burden?; and (6) how should results of FLT3 mutation testing be reported? The panel followed an evidence-based approach, taken together with Canadian clinical and laboratory experience and expertise, to create a consensus document to facilitate a more uniform approach to AML diagnosis and treatment across Canada.

Leveraging health care technology to improve health outcomes and reduce outcome disparities in AYA leukemia.

Significant improvements have occurred for adolescent and young adult (AYA) B-cell acute lymphoblastic leukemia (B-ALL) patients following the widespread adoption of "pediatric-inspired" treatment regimens for AYA patients cared for in adult oncology settings. However, for AYA patients, aged 15 to 39, an outcomes gap remains in B-ALL, necessitating the incorporation of novel therapies into up-front treatment regimens. As a result, clinical trial enrollment remains the current standard of care for AYA B-ALL across disease subtypes when available and accessible. Currently, several up-front trials are looking to incorporate the use of inotuzumab, blinatumomab, and chimeric antigen receptor T-cell therapy into existing chemotherapy backbones for AYA patients, as well as tyrosine kinase inhibitors for both Philadelphia-positive (Ph+) and Ph-like B-ALL. In addition to ongoing attempts to improve up-front treatments by incorporating immunotherapy and targeted approaches, the increased use of next generation sequencing for measurable residual disease evaluation has led to superior risk-stratification and a decreased need to pursue consolidative hematopoietic stem cell transplantation during the first complete remission for many patients.

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

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

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

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

Rituximab, Bendamustine and Cytarabine Followed By Venetoclax (V-RBAC) in High-Risk Older Patients with Mantle Cell Lymphoma: A Phase 2 Study By the Fondazione Italiana Linfomi (FIL)

Introduction: The R-BAC regimen is considered among standard first-line treatments for elderly fit patients with mantle cell lymphoma (MCL). We previously reported (RBAC500 trial) a significantly inferior progression-free survival (PFS) for patients with high risk (HR) features, namely blastoid morphology and/or elevated Ki67 proliferative index, as compared to other patients, that were defined as low risk (LR). Indeed, when treated with R-BAC, LR patients had excellent outcome, albeit no maintenance therapy was delivered. Methods: We designed a phase 2 prospective multicenter study, which enrolled patients aged ≥65 years and fit according to the geriatric CGA assessment, or age ≤64 years if not eligible to high-dose chemotherapy plus transplantation. Asymptomatic patients with non-nodal disease were excluded. At presentation patients were allocated by central review as LR or HR, depending on tumor morphology (blastoid versus others), Ki67 expression (≥30% versus others), or presence of TP53 mutation and/or deletion. Patients with any of the three risk factors were classified as HR. Patients with LR disease were treated with 6 cycles of R-BAC (rituximab 375 mg/m2 d 1; bendamustine 70 mg/m2 d 1,2; cytarabine 500 mg/m2 d 1,2,3), while HR patients received abbreviated induction with 4 R-BAC followed by consolidation (4 months, 800 mg/d), and maintenance (20 months, 400 mg/d) with venetoclax. The primary endpoint was 2-years PFS for the HR patients. The sample size was calculated with the one arm non parametric survival analysis (alpha-error 0.05, power 90%), assuming that the addition of venetoclax would improve 2-years PFS from 40% (null hypothesis) to 60%. Tumor response was assessed with Lugano criteria. All patients were analyzed by real-time quantitative PCR at baseline on peripheral blood and bone marrow samples for minimal residual disease (MRD) evaluation, and HR patients were followed up at different time points. Results of this specific analysis will be subject of future reports. This trial was registered at ClinicalTrials.gov Identifier: NCT03567876. Results: Overall, 140 patients from 35 centers of the Fondazione Italiana Linfomi (FIL) were prospectively enrolled between 2018 and 2021. Of them, 54 were HR (39%). Median age was 72 (range 57-79), and 44% had elevated MIPI. LR and HR patients had similar clinical characteristics, but differed for LDH, and MIPI, both being significantly higher in the HR group. Overall, 28 (20%) patients had TP53 mutations, 19 (14%) had TP53 deletions, Ki67 was ≥30% in 34 (24%), and blastoid variant was diagnosed in 13 patients (9%, Figure 1A). Toxicity during R-BAC was in line with previous reports, while most frequent grade &amp;gt;=3 adverse events during venetoclax treatment consisted of neutropenia (21%), followed by skin reactions (10%). Of note, there were 5 deaths due to COVID-19 infection in patients in CR (4 LR, 1 HR). Overall response at the end of R-BAC differed between HR and LR patients (85% vs 99%, p=0.001), as was for complete response (61% vs 91%, p=0.0001). Of the 54 HR patients, 43 (80%) started venetoclax consolidation, 37 (69%) started the maintenance phase, with 26 patients (48%) completing the whole treatment per protocol. Of 10 patients that started Venetoclax in partial remission (PR) or stable disease after R-BAC, 3 converted to CR, 1 maintained PR, while 6 patients progressed during maintenance. After a median follow-up of 34 months, the 2-years PFS for the whole population was 74.9% (95% CI 66-82), and OS was 80% (95% CI 72-85). Patients with HR MCL had 2-years PFS and OS of 58% (95% CI 43-70) and 66% (95% CI 50-77), respectively, which were significantly lower than LR patients (85% and 88%, respectively, p=0.0001 for both, see Figure 1B). Predictors of PFS using Cox regression models adjusted for MIPI were blastoid morphology (Hazard Ratio 3.51), and TP53 mutation (Hazard Ratio 4.17), with Ki67, and TP53 deletions that lost their power in multivariate analysis. Conclusions: The VR-BAC trial represents the first prospective study that stratified upfront patients with MCL to different treatments according to the risk profile. In this trial the null hypothesis (2-years PFS 40%) was rejected in HR patients, suggesting that the addition of venetoclax to R-BAC improves the performance of the induction strategy. These results point to the importance of identifying HR patients since initial diagnosis.

Digital Polymerase Chain Reaction (dPCR) Versus Flow Cytometry (FC), a Validation Study for CAR-T Cell Product Optimal Detection

CONCLUSIONS Adoptive immunotherapy with Chimeric Antigen Receptor - T cells (CAR-T), has revolutionized hematological treatment mainly in relapsed/refractory (r/r) B-cell malignancies. CAR-T cells constitute challenging living drugs with heterogeneous in vivo cellular kinetics and adverse side effects that emphasizes the importance of its accurate detection and monitoring. Diagnostic assays are required for precise CAR-T quantification. Digital PCR (dPCR) is characterized by a high specificity, sensitivity and reproducibility, therefore we developed a study to implement this technique for CAR-T detection and compare its efficacy against Flow Cytometry (FC). Duplex dPCR assays were performed to concomitantly amplify CAR and RPP30 (reference gene) sequences using ddPCR Expert Design Assay: CD-19 CAR-T Assay (Bio-Rad, California, USA) with QIAcuity Digital PCR System and data analysis with QIAcuitySoftware Suite (QIAGEN, Germany). To assess sensitivity, a Axicabtagene Ciloleucel (Axi-Cel ®) original product obtained from leftovers's infusion bag patient was employed to perform dPCRs on serial dilutions using genomic DNA(gDNA) from a wild type (WT) patient. Specificity was ensured using WT and no template controls (NTC). Two independent dPCR assays with replicates for each sample were conducted to assess reproducibility. For FC comparative study, CAR-T cells percentage (%CAR-T) was determined by both techniques at variable post-infusion intervals (n=210) in different sample types, peripheral blood (n=205) and cerebrospinal fluid (n=5). Anti-FMC63 scFv Antibody, Mouse IgG1 (Acro biosystems) was employed, using FACSCanto II®, Becton-Dickinson Biosciences with FACSDiva software ® (V8.0; BD) and InfinicytTM software (Cytognos SL, Salamanca, Spain), for data analysis. Correlation coefficients were determined using two-tailed Pearson statistics with a confidence interval of 95%. Statistical analyses were made with SPSS Software (IBM, Germany). The dPCR data collected of 2 independent dPCR assays revealed a good split between the negative and positive partitions for the targets evaluated, showing a progressive decrease of the %CAR-T detected (63,88% - 4,12% - 0,77% - 0,08% - 0,01% - 0,00%). This reduction is correlated with the dilution factor applied to the series with an initial concentration of 50ng/µL both for CAR-T original product and WT gDNA. WT and NTC samples were negative with a SD=0; %CV=0, intra and inter-assays, evidencing thus the specificity of the technique. Positivity of the last (1 pg/µL) samples revealed a maximum sensitivity of 0.009 %CAR-T, threshold below which false positive results would be considered. WT gDNA did not influence the assay's sensitivity. 3 replicates of each sample and 2 independent dPCR assay were performed to study potential variations, exhibiting an excellent intra and inter-assay reproducibility with a minimal SD across dilutions ( Table.1.) Comparative study with FC revealed a light correlation between techniques with a Pearsons's correlation coefficient (R=0,553) ( p&amp;lt;0,001). Differences among both were enhanced for Minimal Residual Disease (MRD) evaluation from 60 days post-infusion monitoring (R=0,58) ( p=0,066) in which CAR-T cells can be detected applying dPCR up to 2 years and 9 months post-infusion, whereas being undetectable by FC. Complex CAR-T in vivo kinetics enhances the need for optimal diagnostic and monitoring techniques. dPCR is an ideal tool for precise CAR-T therapy evaluation with a higher grade of specificity, sensitivity and reproducibility than FC, mainly for MRD assessment. dPCR implementation and the establishment of standardized protocols across centers is required to improve CAR-T biology knowledge with a direct benefit on patient care.

Value of mammographic microcalcifications and MRI-enhanced lesions in the evaluation of residual disease after neoadjuvant therapy for breast cancer.

Microcalcifications persist even if a patient with breast cancer achieves pathologic complete response (pCR) as confirmed by surgery after neoadjuvant treatment (NAT). In practice, surgeons tend to remove all the microcalcifications. This study aimed to explore the correlation between changes in the extent of microcalcification after NAT and pathological tumor response and compare the accuracy of mammography (MG) and magnetic resonance imaging (MRI) in predicting the size of residual tumors. This was a retrospective study which included a consecutive series of patients in Guangdong Provincial People's Hospital. Between January 2010 and January 2020, 127 patients with breast cancer and Breast Imaging Reporting and Data System (BI-RADS) 4-5 microcalcifications were included in this study. The maximum diameter of the microcalcifications on MG and lesion enhancement on MRI pre- and post-NAT were measured. The correlations between the changes in residual microcalcifications on MG and pCR were analyzed. Intraclass correlation coefficients (ICCs) were computed between the extent of the residual microcalcifications, residual enhancement, and residual tumor size. There were no statistically significant differences in the changes in microcalcifications after NAT according to the RECIST criteria on MRI (P=0.09) and Miller-Payne grade (P=0.14). MRI showed a higher agreement than did residual microcalcifications on MG in predicting residual tumor size (ICC: 0.771 vs. 0.097). MRI is more accurate for evaluating residual tumor size in breast cancer. In our study, the extent of microcalcifications on MG after NAT had nearly no correlation with the pathological size of the residual tumor. Therefore, residual tumors with microcalcifications may not necessarily be a contraindication to breast-conserving surgery.

P-083 The role of minimal residual disease evaluation for patients with multiple myeloma

P-083 The role of minimal residual disease evaluation for patients with multiple myeloma

Potential future direction of measurable residual disease evaluation in multiple myeloma

AbstractMultiple myeloma remains an incurable disease plagued by high relapse rates. Deeper and more sustainable responses, however, have been consistently shown to improve outcomes and could eventually pave the way to achieving a cure. Our understanding of disease response has surpassed complete response (CR), because the current definitions are suboptimal, and the treatment goal should aim even beyond stringent CR, toward molecular and flow CR, that is, measurable residual disease (MRD) negativity. It has been more than 20 years since the discrepancy in the outcome between patients in CR with and without MRD has been demonstrated, and the field has come a long way from multiparameter flow cytometry to next-generation flow and next-generation sequencing, able to detect up to a limit of detection of a single myeloma cell from 1 million healthy counterparts. This review aims to summarize the current available data regarding MRD but also its potential future use as a coprimary outcome both in clinical and trial settings as a survival surrogate as well as its use to evaluate treatment efficacy and for adaptive response-based and early-rescue therapy. Furthermore, we discuss whether these concepts are applicable in different settings (eg, newly diagnosed and relapsed/refractory myeloma, patients who are eligible and ineligible for tansplant, and standard- and high-risk disease).

The Role Of 18F-FDG PET/CT In Evaluation Of Primary CNS Lymphoma: The Path Less Travelled.

Primary central nervous system lymphoma (PCNSL) is a rare but highly aggressive lymphoma with increasing incidence in immunocompromised patients. MRI is the modality of choice in evaluating brain lesions. However, MRI is often challenging in the detection of early recurrence, assessing residual disease and response evaluation in PCNSL. 18F-FDG PET/CT has superior diagnostic performance compared with body CT in the evaluation of lymphoma. 18F-FDG PET-CT is helpful in evaluating evaluation of disease extent and differentiating primary CNS lymphoma from systemic lymphoma. Besides diagnostic and prognostic value in primary CNS lymphoma, it might also be helpful in response assessment. The role of FDG-PET in PCNSL is not fully defined. In this article we have reviewed the potential role of 18F-FDG PET/CT in initial diagnosis, baseline staging, restaging, evaluation of treatment response, prognostication, and survival analysis of PCNSL.

Plasmacytoid Dendritic Cell Proliferation Associated with Acute Myeloid Leukemia, Case Report and Review of Literature

We present a typical case of plasmacytoid dendritic cell proliferation associated with acute myeloid leukemia (pDC-AML). The patient was a 65-year-old male admitted for new onset progressive pancytopenia over the course of three weeks. Diagnostic marrow revealed 27% myeloblasts. In addition, flow cytometry and immunohistochemistry studies identified an 18% population of immature plasmacytoid dendritic cells. Baseline next-generation sequencing identified pathogenic mutations in ASXL1, EZH2, FLT3, and RUNX1. The patient underwent induction chemotherapy for a diagnosis of pDC-AML. One month after chemotherapy, evaluation for Measurable Residual Disease (MRD) using multiparameter flow cytometry was interpreted as negative with changes related to treatment. pDC-AML is a newly described rare subtype of acute myeloid leukemia which can impose diagnostic challenges. Clinical, pathologic, and molecular correlation are important to render an accurate final diagnosis. We review the published literature on pDC-AML cases and discuss pDC biology, and the process for differentiating the diagnosis of pDC-AML from those of blastic plasmacytoid dendritic cell neoplasm or mature plasmacytoid dendritic cell proliferations associated with other myeloid neoplasms. The AML MRD evaluation for pDC-AML is a particular challenge. To this end, additional molecular studies, including MRD tests using next-generation sequencing, can be of great help.

Clinical, Radiological and Pathological Evaluation of Residual Disease in Patients Receiving Neoadjuvant Chemotherapy for Locally Advanced Carcinoma Breast

Clinical, Radiological and Pathological Evaluation of Residual Disease in Patients Receiving Neoadjuvant Chemotherapy for Locally Advanced Carcinoma Breast

Liquid Biopsy by ctDNA in Liver Transplantation for Colorectal Cancer Liver Metastasis

IntroductionColorectal cancer is a leading cause of cancer-related death worldwide. Metastatic liver disease develops in 50% of cases and drives patient outcomes. Although the ideal treatment for colorectal cancer liver metastases (CRLM) is resection, only a third of patients are suitable for this approach. Reports of liver transplantation in selected patients with unresectable CRLM have shown encouraging results compared to conventional forms of therapy. No study to date has examined the utility of liquid biopsy circulating tumor DNA (ctDNA) for evaluation of residual disease in this cohort of patients. We report a small series of liver transplantation in patients with CRLM in whom ctDNA was assessed peri-operatively. MethodsFive patients underwent liver transplantation for unresectable CRLM or liver failure following CRLM treatment from 2018 to 2022. Clinical data, cross-sectional imaging, and serum biomarkers including peri-operative ctDNA were reviewed from electronic medical records. ResultsAll patients are alive without radiologic evidence of disease at time of this publication. Median time of follow-up was 32 months (IQR 6.6–40 months). ctDNA was assessed before (4 patients) and after transplant (6 patients). One patient experienced a pulmonary recurrence that was resected, for whom pre-recurrence ctDNA was not available; the remaining patients have not experienced recurrence. Four patients are without evidence of ctDNA following transplant, and two demonstrate persistent ctDNA positivity post-transplant. Three of four patients with positive pre-transplant ctDNA remain ctDNA-negative post-transplant. ConclusionsLiver transplantation for liver-confined unresectable CRLM is emerging as a valid surgical option in selected patients. The significance of liquid biopsy in this population remains elusive due to lack of data. The clearance of ctDNA after transplant in these patients with metastatic disease and despite their immunosuppression is notable. The significance and usefulness of liquid biopsy in patient selection, surveillance, and as an indication for treatment warrant further investigation.

Colon adjuvant chemotherapy based on evaluation of residual disease (CIRCULATE-US): NRG-GI008.

TPS3634 Background: Currently, there are no biomarkers validated prospectively in randomized studies for resected colon cancer (CC) to determine need for adjuvant chemotherapy (AC). However, circulating tumor DNA (ctDNA) represents a highly specific and sensitive approach (especially with serial monitoring) for identifying minimal/molecular residual disease (MRD) post-surgery in CC patients (pts), and may outperform traditional clinical and pathological features in prognosticating risk for recurrence. CC pts who do not have detectable ctDNA (ctDNA-) are at a much lower risk of recurrence and may be spared the toxicities associated with AC. Furthermore, for CC pts with detectable ctDNA (ctDNA+) who are at a very high risk of recurrence, the optimal AC regimen has not been established. We hypothesize that for pts whose CC has been resected, ctDNA status may be used to risk-stratify for making decisions about AC. Methods: In this prospective phase II/III trial, up to 1,912 pts with resected stage III A, B (all pts) and stage II, IIIC (ctDNA+ only) CC will be enrolled. Based on the post-operative ctDNA status using personalized and tumor-informed assay (SignateraTM, bespoke assay), those who are ctDNA- (Cohort A) will be randomized to immediate AC with fluoropyrimidine (FP) + oxaliplatin (Ox) for 3-6 mos per established guidelines vs. serial ctDNA monitoring. Patients who are ctDNA+ post-operatively or with serial monitoring (Cohort B) will be randomized to FP+Ox vs. more intensive AC with addition of irinotecan (I) for 6 mos. The primary endpoints for Cohort A are time to ctDNA+ status (phase II) and disease-free survival (DFS) (phase III) in the immediate vs. delayed AC arms. The primary endpoint for Cohort B is DFS in the FP+Ox vs FP+Ox+I arms for both phase II and phase III portions of the trial. Secondary endpoints include prevalence of detectable ctDNA post-operatively, time-to-event outcomes (overall survival and time to recurrence) by ctDNA status, and the assessment of compliance to adjuvant therapy. Biospecimens including archival tumor tissue, as well as post-operative plus serial matched/normal blood samples, will be collected for exploratory correlative research. Active enrollment across the NCTN started in June 2022. NCT#: NCT05174169. Support: U10-CA-180868, -180822; UG1CA-189867; Natera, Inc. Clinical trial information: NCT05174169 .