Minimal Residual Disease Evaluation Research Articles

Efficacy and Predictive Factors Analysis of Androgen Deprivation Plus Novel Hormone Therapy as Neoadjuvant Treatment for High-Risk Prostate Cancer.

This investigation explored the clinical features, pathological outcomes, and biochemical recurrence (BCR) duration among high-risk prostate cancer (HRPC) patients who have undergone neoadjuvant therapy (NAT) in combination with radical prostatectomy (RP) and pelvic lymph node dissection (PLND). Additionally, we identified prognostic indicators that discern pathological complete response (pCR) or minimal residual disease (MRD) and BCR. In total, we examined 76 HRPC patients, who received NAT with either androgen deprivation therapy (ADT) plus apalutamide or ADT plus abiraterone, with subsequent RP and PLND. We conducted a genetic evaluation of patients receiving neoadjuvant apalutamide. Additionally, patient pathological outcomes, circulating prostate-specific antigen (PSA) response rates, and BCR duration were analyzed. Lastly, we employed uni- and multivariate analyses to screen for prognostic factors that govern pCR or MRD and BCR duration. Patient median age and median PSA at presentation were 69 years (IQR: 66-73), and 47.6 ng/mL (IQR: 24.1-105.75), respectively. We observed marked changes in pCR or MRD rates between the two cohorts. In particular, the ADT plus apalutamide cohort (51.5%) exhibited enhanced rates relative to the ADT plus abiraterone cohort (25.6%) (p = 0.03). The median BCR duration was substantially prolonged among neoadjuvant apalutamide cohort relative to the neoadjuvant abiraterone cohort (261 days vs. 76 days, p = 0.04). Using multivariate analysis, we revealed that the postintervention pre-RP PSA content (≤ 0.1 ng/mL vs. > 0.1 ng/mL) remained a substantial stand-alone indicator of pCR or MRD (odds ratio: 10.712, 95% CI: 2.725-42.105, p < 0.001). Furthermore, supplemental analyses revealed that the ADT plus apalutamide cohort exhibited an augmented serum response rate, which, in turn, reduced the post-intervention pre-RP PSA content. Based on our genetic profiling of the neoadjuvant apalutamide cohort demonstrated high-frequency deleterious changes in the AR axis (30.3%), followed by TP53 mutations (15.15%). Patients with defective AR axis experienced a remarkably shorter median BCR duration relative to patients with other or no genetic alterations (52.5 days vs. 286 and 336 days, respectively, p < 0.0001). Furthermore, using multivariate analysis, we demonstrated that achieving pCR or MRD (hazard ratio [HR]: 0.170, 95% CI: 0.061-0.477, p < 0.001) and presence of defective AR signaling (HR: 11.193, 95% CI: 3.499-35.806, p < 0.001) were strong stand-alone indicators of BCR. Herein, we demonstrated the superior performance of ADT plus apalutamide in achieving pCR or MRD and in extending BCR duration among HRPC patients. Post-intervention pre-RP PSA content as well as genetic shifts, especially in the AR axis, are critical indicators of patient pathological and clinical outcomes. These findings highlight the significance of genetic testing and PSA content monitoring in treating HRPC patients.

Clinical Applications of Circulating Tumor DNA Profiling in GI Cancers.

Over the next few years, the analysis of circulating tumor DNA (ctDNA) through liquid biopsy is expected to enter clinical practice and revolutionize the approach to biomarker testing and treatment selection in GI cancers. In fact, growing evidence support the use of ctDNA testing as a noninvasive, effective, and highly specific tool for molecular profiling in GI cancers. Analysis of blood ctDNA has been investigated in multiple settings including early tumor detection, minimal residual disease evaluation, tumor diagnosis and evaluation of prognostic/predictive biomarkers for targeted treatment selection, longitudinal monitoring of treatment response, and identification of resistance mechanisms. Here, we review the clinical applications, advantages, and limitations of ctDNA profiling for precision oncology in GI cancers.

Prognostic factors in children with acute T-lymphoblastic leukemia: a single-center clinical study of the CCCG-ALL-2015 protocol

To explore the clinical characteristics of children with acute T-lymphoblastic leukemia (T-ALL) and analyze their relationship with prognosis. A retrospective analysis was conducted on the clinical data and follow-up results of 50 children with T-ALL who were treated using the CCCG-ALL-2015 protocol at the Department of Hematology and Oncology, Children's Hospital of Nanjing Medical University from November 2015 to December 2019. Kaplan-Meier survival analysis and Cox regression analysis were employed to identify factors affecting prognosis. Among the 50 T-ALL patients, there were 7 cases of relapse. There was no statistically significant difference in the baseline clinical data between the relapse group and the non-relapse group (P>0.05). However, the positive rate of minimal residual disease (MRD) (≥0.01%) on day 46 after induction remission therapy in the relapse group was significantly higher than that in the non-relapse group (P=0.037). The 5-year overall survival rate for the 50 patients was (87±5)%, and the 5-year event-free survival rate was (86±5)%. Multivariate Cox regression analysis indicated that the MRD level on day 46 after induction remission therapy was an independent prognostic factor (HR=0.104, 95%CI: 0.015-0.740, P=0.024). MRD is of significant importance for the prognosis of T-ALL children. Personalized treatment should be provided based on MRD levels to prevent relapse and improve prognosis in these patients.

NPM1 Minimal Residual Disease Detection at Any Time by Clinical Next Generation Sequencing Predicts Poor Survival in Acute Myeloid Leukemia

Abstract Introduction/Objective Acute Myeloid Leukemia (AML) is a deadly disease that accounts for 80% of adult leukemia cases and carries a 5-year survival rate of only 31.7%. Historically, prognosis hinged heavily on cytogenetic stratification, but more recently minimal residual disease (MRD) has emerged as a crucial prognostic marker. Flow cytometry, PCR, and NGS can all be employed for MRD detection, but each carries its own limitations. Though technically challenging, NGS has the advantage being able to simultaneously assay multiple mutations, thus providing for broader applicability. NPM1 is the most prevalently mutated gene in AML (25-35%). In this study, one of the largest of its kind, we investigate the feasibility and impact of NPM1 MRD detection by clinical NGS. Methods/Case Report IRB approval was obtained. We reviewed the medical record and clinical laboratory data sets from AML patients treated at Moffitt Cancer Center who had NPM1 status assessed by clinical NGS, Testing was performed at LabPMM (San Diego, CA). DNA was extracted, and NPM1 exon 12 was amplified. PCR products were sequenced on an Illumina MiSeq. The clinically reportable assay sensitivity was 5 x 10-5 though lower levels were detected on review of raw data. Kaplan-Meier analysis was conducted for overall survival assessment. Since patients often had multiple tests, we divide patients into those with NPM1+ at any time and NPM1 always negative. Results (if a Case Study enter NA) There was a total of 140 patients. Overall, 346 tests were conducted, with an average of 2.5 tests/patient. There were 85 patients (60%) who underwent serial testing. MRD+ patients (n=80) had a mean age of 66 years, while MRD- patients (n=60) had a mean age of 58 years. MRD+ patients exhibited a mean overall survival of 29.3 months versus 43.6 months for MRD- patients (p=0.005.) Conclusion Through our study encompassing a large patient cohort of 140 patients and nearly 350 testing data points, we confirm the feasibility and clinical utility of NPM1 MRD evaluation by NGS. The significantly poorer survival in patients who were MRD+ at any time during their disease provides a scientific rationale for serial NGS testing to enable risk stratification of NPM1+ AML patients.

Real-World Evidence on Prognostic Value of MRD in Multiple Myeloma Using Flow Cytometry.

Minimal residual disease (MRD) is one of the most important prognostic factors in multiple myeloma (MM) and a valid surrogate for progression-free survival (PFS) and overall survival (OS). Recently, MRD negativity was approved as an early clinical endpoint for accelerated drug approval in MM. Nevertheless, there is limited evidence of MRD utility in real-world setting. In this retrospective multicenter study, we report outcomes of 331 newly diagnosed MM patients with MRD evaluation at Day+100 after autologous stem cell transplantation using flow cytometry with a median limit of detection of 0.001%. MRD negativity was reached in 47% of patients and was associated with significantly prolonged median PFS (49.2 months vs. 18.4 months; hazard ratios (HR) = 0.37; p < 0.001) and OS (not reached vs. 74.9 months; HR = 0.50; p = 0.007). Achieving MRD negativity was associated with PFS improvements regardless of age, International Staging System (ISS) stage, lactate dedydrogenase (LDH) level, or cytogenetic risk. Importantly, MRD positive patients benefited from lenalidomide maintenance versus no maintenance (18-months PFS: 81% vs. 46%; HR = 0.24; p = 0.002) while in MRD negative patients such benefit was not observed (p = 0.747). The outcomes of our real-world study recapitulate results from clinical trials including meta-analyses and support the idea that MRD positive patients profit more from lenalidomide maintenance than MRD negative ones.

Evaluation of Minimal Residual Disease Using Next Generation Flow Cytometry in Patients With AL Amyloidosis

Evaluation of Minimal Residual Disease Using Next Generation Flow Cytometry in Patients With AL Amyloidosis

Clinical Efficacy and Safety of CD7-Targeted CAR T Cell Therapy for T-cell Malignancies: A Systematic Review and Meta-analysis.

Although T-cell malignancies are relatively less prevalent compared to B-cell malignancies, they are highly malignant, and patients usually have poor prognoses. Employing CD7-targeted chimeric antigen receptor (CAR) T cell therapy as a novel immunotherapy to treat malignant T cells faces numerous challenges and is in its early phase. To evaluate this possibility, we aimed to review and meta-analyze the related clinical trials systematically. On October 9, 2023, the online databases of PubMed, Scopus, Embase, and Web of Science were systematically searched for pertinent studies. After completing a two-step title/abstract and full-text screening process, the eligible studies were included. We observed a pooled overall response rate (ORR) of 100%. Partial response (PR), stringent and/or complete response (sCR/CR), and relapse rate were 6%, 85%, and 18%, respectively. Additionally, the pooled rate of minimal residual disease (MRD) negativity was 85%. The most common grade ≥3 adverse events were related to hematological toxicities, including neutropenia (100%), thrombocytopenia (79%), and anemia (57%). Cytokine release syndrome (CRS) was also a frequent complication with a 100% rate; however, 81% of CRS events were low grades. No grade ≥3 GVHD was reported, and the immune effector cell-associated neurotoxicity syndrome (ICANS grade ≥3) was rare (4%). CD7 is an active and safe target that shows promising results in the treatment of relapsed and/or refractory (r/r) T-cell malignancies.

Tailored Digital PCR Follow-Up of Rare Fusion Transcripts after Initial Detection through RNA Sequencing in Hematological Malignancies

The management of hematologic malignancies has entered a new era in which minimal residual disease (MRD) monitoring plays a pivotal role. Well-established molecular targets such as PML::RARA, CBFB::MYH11 or RUNX1::RUNX1T1 are conventionally tracked by quantitative reverse-transcription PCR. Recently, a broader landscape of fusion transcripts has been unveiled through transcriptomic analysis. These newly discovered fusion transcripts may emerge as novel molecular markers for MRD quantification. In this study, we compared a targeted RNA-seq approach (FusionPlex) with a whole transcriptomic strategy (Advanta RNA-seq XT) for fusion detection in a training set of 21 samples. We evidenced a concordance of 100% for the detection of known fusions, and showed a good correlation for gene expression quantification between the two techniques (Spearman r=0.77). Additionally, we prospectively evaluated the identification of fusions by targeted RNA-seq in a real-life series of 126 patients with hematological malignancy. At least one fusion transcript was detected for 60 patients (48%). We designed tailored digital PCR assays for 11 rare fusions, and validated this technique for MRD quantification with a limit of detection below 0.01%. The combination of RNA-seq and tailored digital PCR may become a new standard for MRD evaluation in patients lacking conventional molecular targets.

Overview of the Role of Liquid Biopsy in Non-small Cell Lung Cancer (NSCLC)

Solid tumour tissue has traditionally been used for cancer molecular diagnostics. Recently, biomarker assessment in blood or liquid biopsies has become relevant because it allows genotyping in a less invasive and costly manner. In addition, it is a very useful technique in cases with insufficient tumour samples.Recent data have shown that this method can provide the baseline molecular characteristics of the tumour and resistance changes that emerge during cancer treatment. In terms of diagnostic application, the platforms available for clinical use in lung cancer focus on the isolation and detection of circulating DNA (ctDNA) and generally cover a limited number of mutations in genes such as epidermal growth factor receptor (EGFR), Kirsten rat sarcoma viral oncogene homolog (KRAS) and BRAF, as well as anaplastic lymphoma kinase (ALK) rearrangements. In parallel, there are plasma genotyping platforms based on next-generation sequencing (NGS) techniques, which are much broader in scope, allowing multiple genes to be studied simultaneously in a more efficient manner.More recently, promising research scenarios for liquid biopsy have emerged, such as its utility for early diagnosis and evaluation of minimal residual disease after oncological treatment.In light of these advances, knowledge of the benefits and limitations of liquid biopsy, as well as awareness of emerging information on new indications for this technique in non-small cell lung cancer (NSCLC), are of paramount importance in developing more effective management strategies for patients with this neoplasm.

A phase II study evaluating the effect of IMNN-001 on second-look laparoscopy (SLL) when administered in combination with bevacizumab (BEV) and neoadjuvant chemotherapy (NACT) in patients newly diagnosed with advanced epithelial ovarian cancer (EOC).

TPS5633 Background: IMNN-001, an interleukin-12 (IL-12) DNA plasmid formulated with a DNA carrier, polyethyleneglycol-polyethyleneimine cholesterol lipopolymer, has been shown to exhibit a favorable benefit/risk ratio when administered intraperitoneally (IP), in combination with intravenous platinum-taxane chemotherapy, up to doses of 100 mg/m2 in women with advanced EOC in earlier Phase I &amp; II studies. The 201-21-202 study (NCT05739981) is a multi-center, randomized, open-label phase I/II study which hypothesizes the addition of IMNN-001 to neoadjuvant &amp; adjuvant carboplatin-paclitaxel and bevacizumab (chemo + BEV) reduces the risk of histologically documented minimal residual disease (MRD) as determined by SLL by 50%. Methods: Patients with newly diagnosed stage III and IV high grade serous EOC who are candidates for NACT will be enrolled into the trial. Initial safety lead-in will evaluate at least 6 patients randomized to the experimental arm. Upon confirmation of safety by the DSMB, a target of ~50 patients will be randomized 1:1 to receive either chemo + BEV with or without IMNN-001. Patients receive at least 4 cycles of NACT followed by interval cytoreductive surgery (ICS), and 3 additional adjuvant cycles of study treatments will be administered. BEV will be included with each cycle except cycle 1, the last cycle of NACT immediately preceding ICS, and the first cycle of adjuvant chemotherapy. In the experimental arm, IMNN-001 will be administered on C1D15 and continue weekly though the last cycle of adjuvant therapy. Following adjuvant therapy, all patients will undergo SLL with peritoneal washing and multiple biopsies. Pathologic detection of residual tumor in any biopsies or peritoneal cytology constitutes presence of MRD. All patients will receive maintenance therapy with Olaparib + BEV, IMNN-001 + BEV, or BEV alone based on their homologous recombination deficiency status and treatment randomization. Translational:All subjects will undergo biospecimen collection and organoid preparation prior to treatment, at the time of ICS and SLL for comprehensive longitudinal genomic, circulating tumor DNA, immune, and microbiome profiling. Subjects in the experimental arm will also undergo peritoneal lavage and collection of fluid and cells for assessment of the peritoneal tumor environment. Endpoints: The primary endpoint is the rate of MRD at SLL. Secondary endpoints include progression-free survival, overall survival, objective response rate, chemotherapy response score, surgical response, and serologic response. All patients will be evaluated for safety. Status: The study is actively enrolling and is in the safety lead-in portion. We plan to enlist approximately 4 sites in USA. Clinical trial information: NCT05739981 .

Analytical and clinical validation of a personalized, tumor-informed circulating tumor DNA assay for minimal residual disease detection.

e14545 Background: The detection of minimal residual disease (MRD) through circulating tumor DNA (ctDNA) analysis provides an advanced molecular method for early identification of surgical patients at high risk of recurrence. In this study, we present the development of mClear, a personalized, tumor-informed next-generation sequencing (NGS) assay for MRD detection. Furthermore, we report the analytical and clinical validation processes conducted to evaluate the performance of the MRD assay. Methods: mClear is designed to assess MRD in patients with solid tumors. Whole exome sequencing (WES) was performed on tumor tissues and matched peripheral blood samples to detect somatic variants comprehensively. Personalized MRD assays were carefully designed by selecting up to 40 prioritized variants, including single nucleotide variants (SNVs), small insertions and deletions (InDels), and fusions while ensuring coverage of 21 additional key driver genes. For analytical validation, we utilized a pan-cancer MRD ctDNA quality control product (LDT-999, LDT Bioscience), characterized by known variant allele frequency (VAF) gradients of 0%, 0.005%, 0.05%, and 0.5%, confirmed through droplet digital PCR (ddPCR). We conducted 18 replicate tests at VAF gradients of 0.5% and 0.05%, 23 replicates at the 0.005% VAF gradient, and 16 replicates at the 0% VAF gradient. For clinical validation, preoperative and postoperative blood samples from a cohort of 264 pan-cancer patients were analyzed. ctDNA collected for MRD detection underwent ultra-deep next-generation sequencing (100,000× average depth of coverage). The library preparation process commenced with an input of 30ng DNA. Results: At VAF gradients of 0.5% and 0.05%, the assay achieved an excellent sensitivity of 100%, and at VAF gradients of 0.005% and 0%, it demonstrated a sensitivity of 95.7% and a specificity of 100%. Preoperative ctDNA was detected in 86.7% (72/83) of the pan-cancer patients with 71.4% (5/7), 90.9% (10/11), 85.5% (47/55), and 100.0% (10/10) in pathological stage (pStage)I, pStage II, pStage III, and pStage IV, respectively. In the pan-cancer cohort, the positive rate of longitudinal MRD was 35.7% (75/210) with 17.8% (21/118), 50.0% (13/26), 55.1% (27/49), and 82.4% (14/17) in pStage I, II, III, and IV, respectively. In four patients who relapsed, MRD detection during surveillance preceded radiological recurrence by a lead time of 1-8 months. Conclusions: Our personalized MRD assay demonstrated excellent analytical sensitivity and specificity with a limit of detection (LoD) of 0.005% VAF at the sample level. Furthermore, it displayed high clinical sensitivity for the detection of ctDNA in the pan-cancer cohort, highlighting its potential for monitoring of recurrence.

Indirect comparison of linvoseltamab versus teclistamab for triple-class exposed (TCE) relapsed/refractory multiple myeloma (RRMM).

7560 Background: No head-to-head clinical trials have compared effectiveness of anti-BCMA×CD3 bispecific antibodies for TCE RRMM. This analysis compared efficacy of linvoseltamab vs teclistamab via an unanchored matching-adjusted indirect comparison (MAIC). Methods: A MAIC was deemed feasible after excluding 10 patients (pts) with prior BCMA antibody–drug conjugate exposure from LINKER-MM1 (linvoseltamab) to match MajesTEC-1 (teclistamab) criteria. Pt-level data from LINKER-MM1 (107 pts receiving 200 mg in Phase 1/2, data cut-off [DCO] 9/2023, median follow-up 11.1 months [mos]) and published data from MajesTEC-1’s efficacy population (150 pts, DCO 11/2021, median follow-up 9.8 mos) were analyzed. LINKER-MM1 pts were weighted to match key baseline characteristics in MajesTEC-1 (cytogenetic risk, age, refractory status, ISS stage, ECOG score, extramedullary disease/plasmacytoma status) selected via a prespecified algorithm (Kumar et al., 2023). Objective response rate (ORR), very good partial response or better (≥VGPR), complete response or better (≥CR), and minimal residual disease (MRD) negativity (- [at 10-5 threshold]) rates, duration of response (DOR), progression-free survival (PFS), and overall survival (OS) were compared. Odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs) were reported before and after matching; a sensitivity analysis included all LINKER-MM1 200 mg pts (n=117). Results: Effective sample size for linvoseltamab was 82 after matching and baseline characteristics were balanced with MajesTEC-1. Before and after matching, linvoseltamab exhibited higher ORR, ≥VGPR, ≥CR, and MRD(-) rates, with significant differences in ≥CR. Linvoseltamab had significantly longer PFS and a trend toward longer OS and DOR (Table). Sensitivity analysis results were similar. Conclusions: The results suggest potentially greater efficacy for linvoseltamab vs teclistamab for all outcomes, highlighting its potential as a highly effective treatment option for TCE RRMM. [Table: see text]

Abstract PO5-16-04: Tissue-informed personalized MRD detection assay may outperform tumor-informed fixed panel strategy in Triple Negative Breast Cancer (TNBC)

Abstract Background: Minimal residual disease (MRD) detection by ctDNA analysis enables identifying patients with high recurrence risk and refining risk stratification to guide treatment selection precisely, which may improve patient survival or avoid overtreatment. We previously developed a 1021-gene fixed panel MRD detection assay, MNavigator V1, demonstrating high prognostic evaluation value in various solid tumors, including lung cancer, colorectal cancer, and esophageal carcinoma, and relevant research results have been published. Recently, the assay upgraded to MNavigator V2, a customized patient-specific panel strategy to ultra-deep sequencing, with higher clinical performance and more economical. Here, we head-to-head compared the performance of MNavigator V1 with V2, using the same collection of blood samples from TNBC patients. Methods: The retrospective study recruited 48 patients diagnosed with stage II~III TNBC with adequate samples (NCT04501523/NCT04803539). Five patients in the cohort received neoadjuvant therapy (Neoad-group), and the standard treatment regimen of the remaining 43 patients was adjuvant therapy (ad-group) after surgery. The surgical tumor tissue of all these patients was collected. Peripheral blood samples were collected at various time points, baseline samples before neoadjuvant therapy, 7-day after neoadjuvant therapy, 1-month postoperative, 7-day after adjuvant therapy, and subsequent every 3~6 months follow-up. The personalized, tumor-informed MRD detection approach MNavigator V2 started by identifying somatic mutation of the resected tumor with a 1021-gene panel covering 1.6Mb of the human genome. Then, a customized panel consisting of up to 20 top-ranked patient-specific somatic variants was designed. After that, unique molecular identifiers (UMI) based 100,000X ultra-deep next-generation sequencing on plasma samples was conducted by adopting the mix panel of the patient-specific panel and a 5kb breast cancer universal core panel. MNavigator V1 assay, a fixed panel assay also applied the same off-the-shelf 1021-genes panel with a sequencing depth of 10,000X to detect MRD of blood samples. Results: Until May 2023, the median follow-up time of 660 days, and 8 patients were recurrence confirmed by CT imaging. The median tracked tissue-informed mutations was 7 (2~18). In this study, the screening time point was defined as the combined MRD status of the blood samples collected before and after neoadjuvant therapy, and 1-month post-surgery for the Neoad-group, as for the ad-group, the time point referred to 1-month post-surgery and post-adjuvant therapy. If any one of these time nodes' MRD was positive, the screening period MRD was positive. During the screening period, MNavigator V1 and V2 accurately predicted 6/8 (75.0%) recurrence. MRD-positive status was associated with a worse prognosis, compared to the MRD-negative population, with hazard ratios of 9.0 and 19.9 for V1 and V2 assay, respectively. The longitudinal MRD evaluation yield a higher sensitivity of 7/8 (87.5%) for recurrence prediction with MNavigator V2 at a median lead time of 104 days, whereas the V1 assay predicted 6/8 (75.0%) at 94 days, and the hazard ratio was 40.4 vs 8.5. In one brain-only metastasis patient, MRD was undetectable, which may be due to the limitation of the blood-brain barrier. For recurrence-free patients with 1 year of follow-up, 92.5% (37/40) were MRD-negative with MNavigator V2 assay. These three patients who detected MRD-positive after surgery, ctDNA cleared after adjuvant therapy, and persistently negative during follow-up, may benefit from treatment. Conclusion: Based on the patient-specific tumor mutation profile, the personalized MRD detection assay achieved better clinical performance than the fixed panel strategy. Citation Format: Shunying Li, Wei Gao, Ning Fu, Wuqiang Cao, Xiaoling Zeng, Xinhua Du, Qiang Liu. Tissue-informed personalized MRD detection assay may outperform tumor-informed fixed panel strategy in Triple Negative Breast Cancer (TNBC) [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-16-04.

Application and prognostic relevance of CD34 detection in immunophenotyping of pediatric acute B lymphoblastic leukemia.

We aimed to investigate the application of CD34 detection in immunophenotypic discrimination and its prognostic relevance in children with acute B-lymphoblastic leukemia (B-ALL). A retrospective analysis was conducted on clinical follow-up data of 105 children with newly diagnosed B-ALL treated at our hospital from January 2022 to December 2023. Based on the expression of CD34 in the bone marrow, patients were divided into a CD34 positive group (positive cells ≥10%) and a CD34 negative group (positive cells <10%). The study compared the positive rates of common leukemia cell antigens, clinical characteristics, initial treatment responses, and long-term follow-up outcomes between the two groups. Among all 105 B-ALL cases, 87 children (82.9%) had bone marrow CD34 positive cells ≥10%, classified into the CD34 positive group, while the remaining 18 children (17.1%) had bone marrow CD34 positive cells <10%, classified into the CD34 negative group. The CD34 positive group exhibited significantly higher positive rates of CD13 expression, standard-risk B-ALL, and risk stratification than the CD34 negative group. In contrast, the proportions of early pre-B-ALL, E2A-PBX1 fusion gene, and MLL-AF4 fusion gene were significantly lower in the CD34 negative group, with statistically significant differences (p<0.05). No significant differences were found in the positive rates of leukemia cell antigens such as CD10, CD19, CD20, CD22, CD79a, CD13, CD33, and CD38 between the two groups (p>0.05). The occurrence rates of minimal residual disease (MRD) and relapse after induction chemotherapy in the CD34 positive group were significantly lower than those in the CD34 negative group (p<0.05). However, the sensitivity to the first prednisone treatment and bone marrow treatment efficacy on the 19th and 33rd days after chemotherapy showed no significant differences between the groups (p>0.05). A higher positive rate of bone marrow CD34 expression in children with B-ALL is associated with a favorable prognosis. Children with negative CD34 expression are relatively more prone to MRD and tumor relapse after chemotherapy.

Droplet digital PCR: An effective method for monitoring and prognostic evaluation of minimal residual disease in JMML.

Juvenile myelomonocytic leukaemia (JMML) is a rare myeloproliferative neoplasm requiring haematopoietic stem cell transplantation (HSCT) for potential cure. Relapse poses a significant obstacle to JMML HSCT treatment, as the lack of effective minimal residual disease (MRD)-monitoring methods leads to delayed interventions. This retrospective study utilized the droplet digital PCR (ddPCR) technique, a highly sensitive nucleic acid detection and quantification technique, to monitor MRD in 32 JMML patients. The results demonstrated that ddPCR detected relapse manifestations earlier than traditional methods and uncovered molecular insights into JMML MRD dynamics. The findings emphasized a critical 1- to 3-month window post-HSCT for detecting molecular relapse, with 66.7% (8/12) of relapses occurring within this period. Slow MRD clearance post-HSCT was observed, as 65% (13/20) of non-relapse patients took over 6 months to achieve ddPCR-MRD negativity. Furthermore, bone marrow ddPCR-MRD levels at 1-month post-HSCT proved to be prognostically significant. Relapsed patients exhibited significantly elevated ddPCR-MRD levels at this time point (p = 0.026), with a cut-off of 0.465% effectively stratifying overall survival (p = 0.007), event-free survival (p = 0.035) and cumulative incidence of relapse (p = 0.035). In conclusion, this study underscored ddPCR's superiority in JMML MRD monitoring post-HSCT. It provided valuable insights into JMML MRD dynamics, offering guidance for the effective management of JMML.

The Role of Autologous Stem Cell Transplantation in the Treatment of Newly Diagnosed Multiple Myeloma: Is It Time to Rethink the Paradigm in the Era of Targeted Therapy?

High-dose melphalan (HDM) plus autologous stem cell transplant (ASCT) remains a standard-of-care treatment approach for eligible patients with newly diagnosed multiple myeloma (NDMM) based on demonstrated superiority in terms of progression-free survival (PFS) versus nontransplant approaches. Very high rates of minimal residual disease (MRD)-negative responses are also being seen with novel triplet and quadruplet induction regimens plus HDM-ASCT. However, recent clinical trials have shown no overall survival benefit with transplant versus nontransplant approaches. Furthermore, HDM is associated with several important downsides, including acute and long-term toxicities, transient decreases in quality of life, the need for hospitalization, an increased mutational burden at relapse, and an elevated risk of second primary malignancies. In this context, given the highly heterogeneous nature of MM in the NDMM patient population, as well as the continued emergence of novel agents and treatment approaches, there is an increasing rationale for considering deferred HDM-ASCT approaches in selected patients. Approaches under investigation include MRD-adapted therapy and the use of novel immune-based therapies as alternatives to HDM-ASCT. Ongoing developments in understanding the pathobiology and prognostic factors in NDMM, plus immune profiling and routine MRD evaluation, will result in novel, HDM-sparing treatment paradigms, enabling further improvement in patient outcomes.

Clinical Analysis of Mitoxantrone Liposome in the Treatment of Children with High-Risk Acute Myeloid Leukemia

To investigate the safety and efficacy of mitoxantrone liposome in the treatment of children with high-risk acute myeloid leukemia (AML). The children with high-risk AML who received the mitoxantrone liposome regimen at Wuhan Children's Hospital from January 2022 to February 2023 were collected as the observation group, and the children with high-risk AML who received idarubicin regimen were enrolled as controls, and their clinical data were analyzed. Time to bone marrow recovery, the complete remission rate of bone marrow cytology, the clearance rate of minimal residual disease, and treatment-related adverse reactions were compared between the two groups. The patients treated with mitoxantrone liposome showed shorter time to recovery of leukocytes(17 vs 21 day), granulocytes(18 vs 24 day), platelets(17 vs 24 day), and hemoglobin(20 vs 26 day) compared with those treated with idarubicin, there were statistical differences (P <0.05). The effective rate and MRD turning negative rate in the observation group were 90.9% and 72.7%, respectively, while those in the control group were 94.1% and 76.4%, with no statistical difference (P >0.05). The overall response rate of the two groups of patients was similar. The efficacy of mitoxantrone liposome is not inferior to that of idarubicin in children with high-risk AML, but mitoxantrone liposome allows a significantly shorter duration of bone marrow suppression and the safety is better.

Abstract 3659: Development of customized circulating tumor DNA panel for minimal residual disease detection in biliary tract cancer

Abstract Biliary tract cancer (BTC) is a rare type of abdominal cancer and is more frequent in Asian countries than in Western. The 5-year survival rate for BTC is very low 7 to 20% and only 20% of BTC patients could undergo curative-intent surgery. BTC diagnosis based on biopsy and cytology are low in sensitivity that prompted the necessity to identify alternative biopsy. Liquid biopsy, specifically circulating tumor DNA (ctDNA) is known for the accessibility and low invasiveness received great interest for their potential uses in various clinical applications for patients with insufficient tumor tissue, including mutation profiling, treatment monitoring, and cancer detection. However, the panel available in the market up-to-date focused mainly targeted, actionable alterations and thus not suitable for minimal residual disease (MRD) monitoring. In this study, we aimed to develop a customized ctDNA panel for MRD monitoring in BTC. In this study, 124 BTC patients undergone curative resections were enrolled at Hokkaido University and Sapporo Medical University from May 2019 to April 22. All enrolled patients have BTC diagnosis confirmed by pathological diagnosis after surgery, and without other malignant tumors. Genomic profiles of FFPE tissue were conducted using Ampliseq CCP. 13 patients were excluded for high fragmentation. Referring to the genomic profiles of 111 patients in our study and 1924 patients in TCGA established a customized panel using Ion Ampliseq HD technology. The Ampliseq HD panel claims to detect variants at 0.1% LOD for ctDNA detection. It also integrates molecular barcodes to reduce NGS-related errors. The designed panel was 258 Amplicons and 20 genes including eleven therapeutically targetable genes. Clinical characteristics of ctDNA detection were also assessed. Results:The panel validation: concordance of the mutation allele frequency (MAF) between the NGS standard control and Ampliseq HD panel showed a coefficient of determination (R2) of 0.96. Also, concordance of MAF Ampliseq CCP and Ampliseq HD panel on FFPE tumor profiling showed R2 of 0.78. When assessing 70% of BTC patients were covered to have at least one tumor-derived Ampliseq HD panel. When assessing using plasma cell-free DNA, 55% of BTC patients were detected to have at least one tumor-derived ctDNA. Distribution of detected altered top4 genes using Ampliseq HD panels shows TP53 35%, KRAS 10%, SMAD4 5%, ARID1A 2.5%. Clinical characteristics may affected the concordance of plasma and FFPE tumor tissue; stage (P=0.035), size of tumors (P=0.0088), subtype (P=0.013), LN metastasis (P=0.11). Conclusions: A highly sensitive ctDNA customized panel for BTC was established. We also found that clinical characteristics of the BTC affects the detection of ctDNA from blood liquid biopsy. Future study: MRD evaluation using this customized panel. Citation Format: Yoshihito Shinohara, Siew-Kee Low, Toru Nakamura, Yasutoshi Kimura, Takeshi Murakami, Kazuma Kiyotani, Satoshi Hirano. Development of customized circulating tumor DNA panel for minimal residual disease detection in biliary tract cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3659.

Mutations of epigenetic modifier genes predict poor outcome in adult acute lymphoblastic leukemia.

Epigenetic modifier (EM) genes play important roles in the occurrence and progression of acute lymphoblastic leukemia (ALL). However, the prognostic significance of EM mutations in ALL has not yet been thoroughly investigated. This retrospective study included 205 adult patients with ALL engaged in a pediatric-type regimen. Based on targeted next-generation sequencing, they were divided into EM mutation group (EM-mut, n = 75) and EM wild-type group (EM-wt, n = 130). The EM-mut group showed a higher positive rate of minimal residual disease (MRD) on treatment day24 and before consolidation therapy (P = 0.026, 0.020). Multivariate Cox regression analysis showed that EM-mut was an independent adverse factor for overall survival (OS) and event-free survival (EFS) (HR = 2.123, 1.742; P = 0.009, 0.007). Survival analysis revealed that the OS and EFS rates were significantly lower in the EM-mut group than in the EM-wt group (3-year OS rate, 45.8% vs. 65.0%, P = 0.0041; 3-year EFS rate, 36.7% vs. 53.2%, P = 0.011). In conclusion, EM was frequently mutated in adult ALL and was characterized by poor response to induction therapy and inferior clinical outcomes.

Abstract A077: The utility of surgical minimal residual disease after frontline treatment for prognostic and investigational opportunities in advanced ovarian cancer

Abstract Cure rates for patients with advanced stage ovarian cancer have not changed significantly over the last four decades likely due to inability to eradicate residual cancer cells after frontline therapy. Identifying clinically undetectable minimal residual disease (MRD) after frontline therapy by second look laparoscopy (SLL) has potential to a) uncover mechanisms of chemoresistance and tumor dormancy, b) identify MRD-specific therapeutic targets, and c) allow for earlier intervention with investigational therapies. The objective of this study is to describe the initial safety and feasibility of SLL and illustrate clinical and pathological correlates. Methods: This IRB-approved observational, single-center study includes patients with epithelial high-grade ovarian cancer with complete CA-125 and radiologic response after frontline treatment (combination of surgery and platinum-taxane chemotherapy) who underwent SLL from 4/2017-6/2023. Patients were subsequently offered standard of care or investigational maintenance therapy options based on homologous recombination deficiency (HRD) and MRD status. Summary statistics described the study population, chi-square tests compared categorical variables, and progression free survival (PFS) based on MRD status was estimated using Kaplan-Meier method and compared using log rank test. Results: 70 patients underwent SLL with a median of 8.5 biopsies (range 3-16). The majority of patients had stage III-IV disease (90%), and high-grade serous histology (90%). Approximately half (51.4%) of patients underwent neoadjuvant chemotherapy (NACT) with interval tumor reductive surgery (TRS). MRD was present in 32 patients (45.7%), and the presence of MRD was associated with a worse PFS (HR 3.0, 95% CI 1.5-5.8; 12.5 vs. 24.8 months; p=0.001). MRD was more frequent among NACT recipients compared to those who underwent primary TRS (63% vs 26%, P=0.002), those with HRD negative tumors (58% vs 24%, P=0.025), and those with R1 versus R0 resections (71% vs 39%, P=0.024). Of patients with MRD, 22 patients (71%) received bevacizumab until progression as part of a clinical trial (NCT02884648), 3 (10%) received bevacizumab off trial, 5 (16%) received a PARP inhibitor (all HRD positive), and 1 received other therapy. There were two (2.9%) intraoperative complications (both enterotomies) requiring conversion to laparotomy. Conclusions: SLL is feasible, overall safe, and detected MRD in 46% of ovarian cancer patients who were in radiologic and CA-125 remission after frontline therapy. PFS was significantly shorter for patients with residual disease, despite those patients all receiving additional therapy. Knowledge of MRD status in this patient population enables interventional, observational, and translational opportunities, as well as personalized prognostic counseling. MRD rate may also have utility as an early surrogate for efficacy in trials evaluating novel frontline investigational therapies. Future studies will compare the performance of circulating tumor DNA (ctDNA) versus surgical MRD. Citation Format: Anne Knisely, Roni Nitecki, J. Alejandro Rauh-Hain, R. Tyler Hillman, Jolyn S. Taylor, Lois M. Ramondetta, Michaela O. Grinsfelder, Lauren P. Cobb, David M. Boruta, Gwyn Richardson, Pamela T. Soliman, Aaron Shafer, Shannon N. Westin, Nicole D. Fleming, Travis T. Sims, Anil K. Sood, Pedro T. Ramirez, Karen H. Lu, Amir A. Jazaeri. The utility of surgical minimal residual disease after frontline treatment for prognostic and investigational opportunities in advanced ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A077.