Circulating tumor DNA adds specificity to PET after axicabtagene ciloleucel in large B-cell lymphoma

Circulating tumor DNA as a powerful tool in diagnostics and treatment outcome prediction - focus on large B-cell lymphomas and follicular lymphomas

INTRODUCTION

Pathogenesis of large B-cell lymphomas (LBCL) and follicular lymphomas (FL) is a multistep process associated with development of diverse DNA alterations and consequent deregulation of critical cellular processes. Detection of tumor-associated mutations within non-tumor compartments (mainly plasma) is the basis of the 'liquid biopsy' concept. Apart from tumor mutational profiling, quantitative analysis of circulating tumor DNA (ctDNA) allows longitudinal assessment of tumor burden. ctDNA-based technologies provide a new tool for tumor diagnostics and treatment personalization.

AREAS COVERED

Our review provides a comprehensive overview and summary of available ctDNA studies in LBCL and FL. The accuracy of ctDNA based detection of lymphoma associated DNA alterations is correlated to the known LBCL and FL molecular landscape. Additionally, we summarized available evidence that supports and justifies the clinical use of ctDNA for lymphoma risk stratification, treatment response evaluation, and treatment response-adapted therapy. Lastly, we discuss other clinically important ctDNA applications: monitoring of lymphoma clonal evolution within resistance and/or relapse development and utilization of ctDNA for diagnostics in non-blood fluids and compartments (e.g. cerebrospinal fluid in primary CNS lymphomas).

EXPERT OPINION

Despite certain challenges including methodological standardization, ctDNA holds promise to soon become an integral part of lymphoma diagnostics and treatment management.

Understandings 18 FDG PET radiomics and its application to lymphoma

The early identification of lymphoma patients who fail front-line treatment is crucial for optimizing disease management. Positron emission tomography, a well-established tool for staging and response evaluation in lymphoma, is typically assessed visually or semiquantitatively, leaving much of its latent information unexploited. Radiomic analysis, which employs mathematical descriptors, can enable the extraction of quantitative features from baseline images that correlate with the disease's biological characteristics. Emerging radiomic features such as metabolic tumour volume, total lesion glycolysis and markers of disease dissemination and metabolic heterogeneity are proving to be powerful prognostic biomarkers in lymphoma. Texture analysis, the most advanced area of radiomics, offers highly complex features that require further standardization and validation before being adopted as reliable biomarkers. Combining radiomic features with clinical risk factors and genomic data holds promising potential for improving clinical risk prediction. This review explores the current state of radiomic analysis, progress towards its standardization and its incorporation into clinical practice and trial designs. The integration of radiomic markers with circulating tumour DNA may provide a comprehensive approach to developing baseline and dynamic risk scores, facilitating the testing of novel treatments and advancing personalized treatment of aggressive lymphomas.

Measurable Residual Disease Testing During Treatment with Bispecific Antibodies for Lymphoma

The introduction of bispecific antibodies (BsAbs) has led to significant improvements in survival for patients with relapsed and refractory B-cell lymphomas. Despite these advances, there remains a significant number of patients who experience disease progression after these novel therapies. Predicting which patients may respond to certain treatments and the durability of their responses remains challenging. Measurable residual disease (MRD) has become easier to detect and quantify through the use of genomic next-generation sequencing tools and has been studied as a possible biomarker to predict long-term outcomes and risk-stratify patients after BsAb therapy in several lymphoma subtypes. Here, we review recent data demonstrating that MRD negativity is associated with radiographic response and improved progression-free survival. Because of heterogeneity in assay choice, assessment timing, and technical parameters, further work is needed before MRD testing is ready to be incorporated into clinical practice in the context of BsAb treatment for B-cell lymphomas.

Reduced Chimeric Antigen Receptor T Cell Expansion Postinfusion Is Associated with Poor Survival in Patients with Large B Cell Lymphoma after Two or More Therapies

CD19-directed chimeric antigen receptor T cell (CAR-T) therapy is now standard of care for relapsed/refractory large B cell non-Hodgkin lymphoma. Despite good overall response rates, many patients still experience disease progression and therefore it is important to predict those at risk of relapse following CAR-T therapy. We performed a prospective study using a flow cytometry assay at a single treatment center to assess early CAR T cell expansion in vivo 6 to 9 days after CAR T cell infusion. Early CAR T cell expansion was used in conjunction with additional clinical risk factors to identify those at greater risk of relapse or treatment failure. Forty-four patients treated with commercial CD19-directed CAR-T therapy were included in the study, with a median follow-up of 306 days. CAR T cell expansion of >30 cells/μL was associated with a lower risk of disease progression or death (hazard ratio, 0.34; P = .048), but did not correlate with the risk of death alone. Patients who had poor early CAR T cell expansion (<30 cells/μL) in addition to high lactate dehydrogenase (LDH) had significantly lower median progression-free survival and overall survival. High LDH level alone was not a statistically significant risk factor for death or disease progression, and thus the interaction between CAR T cell expansion and this clinical risk factor may be important in predicting response. The mean CAR T cell count was higher in patients with grade 2 to 4 cytokine release syndrome (CRS) compared to those with grade 0 to 1 CRS (54.9 cells/μL versus 25.5 cells/μL; P = .01). The methodology of this assay is easily reproducible outside of a clinical trial, allowing for real-life implementation in clinical settings. This study suggests that early assessment of CAR T cell expansion can assist in identifying patients with poor overall survival who may benefit from early intervention or more intensive monitoring.

Circulating tumor DNA in diffuse large B-cell lymphoma: analysis of response assessment, correlation with PET/CT and clone evolution

INTRODUCTION

Circulating tumor DNA (ctDNA) can be obtained from cell-free DNA (cfDNA) andis a new technique for genotyping, response assessment and prognosis in lymphoma.

METHODS

Eighteen patients with samples at diagnosis (ctDNA1), after treatment (ctDNA2) and extracted from diagnostic tissue (FFPE) were evaluated.

RESULTS

In all patients, at least one mutation in cfDNA was detected at diagnosis. CREBBP was the most frequent mutated gene (67 %). In 12 of the 15 patients with complete remission, the mutation attributed to the disease found at diagnosis cleared with treatment. A reduction in the ctDNA was observed after treatment in 14 patients, 12 of whom achieved complete remission. Correlations were found between the ctDNA at diagnosis and total metabolic tumor volume (r = 0.51; p-value = 0.014) and total lesion glycolysis 2.5 (r = 0.47; p-value = 0.024) by PET at diagnosis and between ctDNA at diagnosis and radiomic features of the lesions with the largest standardized uptake value. There was a strong inverse correlation between ΔctDNA1 and ΔSUVmax by PET/CT (r = -0.8788; p-value = 0.002).

CONCLUSION

Analysis of ctDNA and PET/CT in large B-cell lymphoma are complementary data for evaluating tumor burden and tumor clearance after treatment. Analysis of radiomic data might help to identify tumor characteristics and their changes after treatment.

Prospects for liquid biopsy approaches in lymphomas

Analytes within liquid biopsies have emerged as promising alternatives to traditional tissue biopsies for various malignancies, including lymphomas. This review explores the clinical applications of one such liquid biopsy analyte, circulating tumor DNA (ctDNA) in different types of lymphoma, focusing on its role in diagnosis, disease monitoring, and relapse detection. Advancements in next-generation sequencing (NGS) and machine learning have enhanced ctDNA analysis, offering a multi-omic approach to understanding tumor genetics. In lymphoma, ctDNA provides insights into tumor heterogeneity, aids in genetic profiling, and predicts treatment response. Recent studies demonstrate the prognostic value of ctDNA and its potential to improve patient outcomes by facilitating early disease detection and personalized treatment strategies Despite these advancements, challenges remain in optimizing sample collection, processing, assay sensitivity, and overall consensus workflows in order to facilitate integration into routine clinical practice.

Clinical applications of circulating tumor DNA in hematological malignancies: From past to the future

Liquid biopsy, particularly circulating tumor DNA (ctDNA), has drawn a lot of attention as a non- or minimal-invasive detection approach for clinical applications in patients with cancer. Many hematological malignancies are well suited for serial and repeated ctDNA surveillance due to relatively high ctDNA concentrations and high loads of tumor-specific genetic and epigenetic abnormalities. Progress of detecting technology in recent years has improved sensitivity and specificity significantly, thus broadening and strengthening the potential utilities of ctDNA including early diagnosis, prognosis estimation, treatment response evaluation, minimal residual disease monitoring, targeted therapy selection, and immunotherapy surveillance. This manuscript reviews the detection methodologies, clinical application and future challenges of ctDNA in hematological malignancies, especially for lymphomas, myeloma and leukemias.

Five-Year Follow-Up of Standard-of-Care Axicabtagene Ciloleucel for Large B-Cell Lymphoma: Results From the US Lymphoma CAR T Consortium

PURPOSE

Axicabtagene ciloleucel (axi-cel) is an autologous CD19 chimeric antigen receptor (CAR) T-cell therapy that is approved for the treatment of relapsed or refractory large B-cell lymphoma. Little is known about the long-term survivorship after CAR T-cell therapy.

METHODS

We previously reported the results of 298 patients who were leukapheresed with the intent to receive standard-of-care axi-cel (n = 275 infused) after two or more previous lines of therapy at a median follow-up of 12.9 months. Here, we report extended follow-up of this cohort to a median of 58 months, with a focus on late survivorship events.

RESULTS

Among axi-cel-infused patients, progression-free survival at 5 years was 29% and overall survival (OS) at 5 years was 40%. The 5-year lymphoma-specific survival was 53% with infrequent late relapses. However, the 5-year nonrelapse mortality (NRM) was 16.2%, with over half of NRM events occurring beyond 2 years. Patients who were 60 years and older had a lower risk of relapse (P = .02), but a higher risk of NRM compared with patients younger than 60 years (NRM odds ratio, 4.5 [95% CI, 2.1 to 10.8]; P < .001). Late NRM was mainly due to infections and subsequent malignant neoplasms (SMNs). In total, SMNs occurred in 24 patients (9%), including therapy-related myeloid neoplasms (n = 15), solid tumors (n = 7), and unrelated lymphoid malignancies (n = 2).

CONCLUSION

In the standard-of-care setting, axi-cel exhibits outcomes consistent with those reported in clinical trials, with sustained, durable responses observed at the 5-year time point. However, late infections and the development of SMN are key survivorship issues that reduce long-term survival after CAR T-cell therapy, particularly in the elderly.

[Progression and application of circulating tumor DNA in lymphoma]

Lymphomas are a highly heterogeneous group of tumors that are classified into several subtypes. The gold standard method for the molecular profiling of lymphoma is based on invasive lymph node or tissue biopsy. However, this method cannot accurately capture spatial tumor heterogeneity in each patient as well as systemic tumor invasion and tumor burden. Circulating tumor DNA (ctDNA) is an emerging and highly versatile biomarker that overcomes the basic limitations of imaging scanning and tissue biopsy; has the characteristics of being simple, rapid, and non-invasive; and has good specificity and high sensitivity. ctDNA testing has been applied to a variety of subtypes of lymphoma and has been used for somatic mutation genotyping, efficacy monitoring during treatment, detection of minimal residual disease, and the prediction of survival, which may help clinicians make better clinical decisions in the diagnosis and treatment of lymphoma patients. Furthermore, this study also aims to review the different methods of ctDNA analysis and describe the specific applications of ctDNA in different lymphoma subtypes.

The prognostic utility of 18F-FDG PET parameters in lymphoma patients under CAR-T-cell therapy: a systematic review and meta-analysis

BACKGROUND

Chimeric antigen receptor (CAR) T-cell therapy has attracted considerable attention since its recent endorsement by the Food and Drug Administration, as it has emerged as a promising immunotherapeutic modality within the landscape of oncology. This study explores the prognostic utility of [18F]Fluorodeoxyglucose positron emission tomography ([18F]FDG PET) in lymphoma patients undergoing CAR T-cell therapy. Through meta-analysis, pooled hazard ratio (HR) values were calculated for specific PET metrics in this context.

METHODS

PubMed, Scopus, and Ovid databases were explored to search for relevant topics. Dataset retrieval from inception until March 12, 2024, was carried out. The primary endpoints were impact of specific PET metrics on overall survival (OS) and progression-free survival (PFS) before and after treatment. Data from the studies were extracted for a meta-analysis using Stata 17.0.

RESULTS

Out of 27 studies identified for systematic review, 15 met the criteria for meta-analysis. Baseline OS analysis showed that total metabolic tumor volume (TMTV) had the highest HR of 2.66 (95% CI: 1.52-4.66), followed by Total-body total lesion glycolysis (TTLG) at 2.45 (95% CI: 0.98-6.08), and maximum standardized uptake values (SUVmax) at 1.30 (95% CI: 0.77-2.19). TMTV and TTLG were statistically significant (p < 0.0001), whereas SUVmax was not (p = 0.33). For PFS, TMTV again showed the highest HR at 2.65 (95% CI: 1.63-4.30), with TTLG at 2.35 (95% CI: 1.40-3.93), and SUVmax at 1.48 (95% CI: 1.08-2.04), all statistically significant (p ≤ 0.01). The ΔSUVmax was a significant predictor for PFS with an HR of 2.05 (95% CI: 1.13-3.69, p = 0.015).

CONCLUSION

[18F]FDG PET parameters are valuable prognostic tools for predicting outcome of lymphoma patients undergoing CAR T-cell therapy.

Minimal residual disease detection in lymphoma: methods, procedures and clinical significance

Lymphoma is a highly heterogeneous lymphohematopoietic tumor. As our understanding of the biological and pathological characteristics of lymphoma improves, we are identifying an increasing number of lymphoma subtypes. Genotyping has enhanced our ability to diagnose, treat, and monitor the prognosis of lymphoma. Despite significant improvements in treatment effectiveness, traditional methods for assessing disease response and monitoring prognosis are imperfect, and there is no significant improvement in overall remission rates for lymphoma patients. Minimal Residual Disease (MRD) is often indicative of refractory disease or early relapse. For lymphoma patients, personalized MRD monitoring techniques offer an efficient means to estimate disease remission levels, predict early relapse risk, and assess the effectiveness of new drug regimens. In this review, we delve into the MRD procedures in lymphoma, including sample selection and requirements, detection methods and their limitations and advantages, result interpretation. Besides, we also introduce the clinical applications of MRD detection in lymphoma.

Biomarkers of outcome in patients undergoing CD19 CAR-T therapy for large B cell lymphoma

CD19-directed autologous chimeric antigen receptor T cell (CAR-T) therapy has transformed the management of relapsed/refractory (R/R) large B cell lymphoma (LBCL). Initially approved in the third line and beyond setting, CAR-T is now standard of care (SOC) for second-line treatment in patients with refractory disease or early relapse (progression within 12 months) following primary chemoimmunotherapy. Despite becoming SOC, most patients do not achieve complete response, and long-term cure is only observed in approximately 40% of patients. Accordingly, there is an urgent need to better understand the mechanisms of treatment failure and to identify patients that are unlikely to benefit from SOC CAR-T. The field needs robust biomarkers to predict treatment outcome, as better understanding of prognostic factors and mechanisms of resistance can inform on the design of novel treatment approaches for patients predicted to respond poorly to SOC CAR-T. This review aims to provide a comprehensive overview of clinical, molecular, imaging, and cellular features that have been shown to influence outcomes of CAR-T therapy in patients with R/R LBCL.

Circulating Tumor DNA as a Complementary Prognostic Biomarker during CAR-T Therapy in B-Cell Non-Hodgkin Lymphomas

The emergence of CD19-directed chimeric antigen receptor T-cell (CAR-T) therapy has revolutionized the treatment paradigm for R/R B-cell NHLs. However, challenges persist in accurately evaluating treatment response and detecting early relapse, necessitating the exploration of novel biomarkers. Circulating tumor DNA (ctDNA) via liquid biopsy is a non-invasive tool for monitoring therapy efficacy and predicting treatment outcomes in B-NHL following CAR-T therapy. By overcoming the limitations of conventional imaging modalities, ctDNA assessments offer valuable insights into response dynamics, molecular mechanisms of resistance, and early detection of molecular relapse. Integration of ctDNA monitoring into clinical practice holds promise for personalized therapeutic strategies, guiding the development of novel targeted therapies, and enhancing patient outcomes. However, standardization of assay methodologies and consensus on clinical response metrics are imperative to unlock the full potential of ctDNA in the management of B-NHL. Prospective validation of ctDNA in clinical trials is necessary to establish its role as a complementary decision aid.

Circulating Tumor DNA in Diffuse Large B-Cell Lymphoma: from Bench to Bedside?

OPINION STATEMENT

Diffuse large B-cell lymphoma (DLBCL) is a curable disease with variable outcomes due to underlying heterogeneous clinical and molecular features-features that are insufficiently characterized with our current tools. Due to these limitations, treatment largely remains a "one-size-fits-all" approach. Circulating tumor DNA (ctDNA) is a novel biomarker in cancers that is increasingly utilized for risk stratification and response assessment. ctDNA is readily detectable from the plasma of patients with DLBCL but has not yet been incorporated into clinical care to guide treatment. Here, we describe how ctDNA sequencing represents a promising technology in development to personalize the care of patients with DLBCL. We will review the different types of ctDNA assays being studied and the rapidly growing body of evidence supporting the utility of ctDNA in different treatment settings in DLBCL. Risk stratification by estimation of tumor burden and liquid genotyping, molecular response assessment during treatment, and monitoring for measurable residual disease (MRD) to identify therapy resistance and predict clinical relapse are all potential applications of ctDNA. It is time for clinical trials in DLBCL to utilize ctDNA as an integral biomarker for patient selection, response-adapted designs, and surrogate endpoints. As more ctDNA assays become commercially available for routine use, clinicians should consider liquid biopsy when treatment response is equivocal on imaging. Incorporating MRD may also guide decision-making if patients experience severe treatment toxicities. Though important barriers remain, we believe that ctDNA will soon be ready to transition from bench to bedside to individualize treatment for our patients with DLBCL.

Dynamic monitoring of circulating tumor DNA reveals outcomes and genomic alterations in patients with relapsed or refractory large B-cell lymphoma undergoing CAR T-cell therapy

BACKGROUND

Over 50% of patients with relapsed or refractory large B-cell lymphoma (r/r LBCL) receiving CD19-targeted chimeric antigen receptor (CAR19) T-cell therapy fail to achieve durable remission. Early identification of relapse or progression remains a significant challenge. In this study, we prospectively investigate the prognostic value of dynamic circulating tumor DNA (ctDNA) and track genetic evolution non-invasively, for the first time in an Asian population of r/r patients undergoing CAR19 T-cell therapy.

METHODS

Longitudinal plasma samples were prospectively collected both before lymphodepletion and at multiple timepoints after CAR19 T-cell infusion. ctDNA was detected using a capture-based next-generation sequencing which has been validated in untreated LBCL.

RESULTS

The study enrolled 23 patients with r/r LBCL and collected a total of 101 ctDNA samples. Higher pretreatment ctDNA levels were associated with inferior progression-free survival (PFS) (p=0.031) and overall survival (OS) (p=0.023). Patients with undetectable ctDNA negative (ctDNA-) at day 14 (D14) achieved an impressive 3-month complete response rate of 77.8% vs 22.2% (p=0.015) in patients with detectable ctDNA positive (ctDNA+), similar results observed for D28. CtDNA- at D28 predicted significantly longer 1-year PFS (90.9% vs 27.3%; p=0.004) and OS (90.9% vs 49.1%; p=0.003) compared with patients who remained ctDNA+. Notably, it is the first time to report that shorter ctDNA fragments (<170 base pairs) were significantly associated with poorer PFS (p=0.031 for D14; p=0.002 for D28) and OS (p=0.013 for D14; p=0.008 for D28) in patients with LBCL receiving CAR T-cell therapy. Multiple mutated genes exhibited an elevated prevalence among patients with progressive disease, including TP53, IGLL5, PIM1, BTG1, CD79B, GNA13, and P2RY8. Notably, we observed a significant correlation between IGLL5 mutation and inferior PFS (p=0.008) and OS (p=0.014).

CONCLUSIONS

Our study highlights that dynamic ctDNA monitoring during CAR T-cell therapy can be a promising non-invasive method for early predicting treatment response and survival outcomes. Additionally, the ctDNA mutational profile provides novel insights into the mechanisms of tumor-intrinsic resistance to CAR19 T-cell therapy.