Real-world evaluation of ctdna for risk stratification across the spectrum of both aggressive and indolent lymphomas Free

Introduction: Circulating tumor DNA (ctDNA) has emerged as a promising biomarker for treatment response monitoring, risk stratification, and early recurrence detection for patients with lymphoma. Tumor-informed ctDNA testing for detecting molecular residual disease (MRD) is seeing early adoption in this setting, demonstrating technical feasibility and clinical need for personalized monitoring tools. However, the prognostic utility of ctDNA across indolent and aggressive subtypes of lymphoma remains poorly understood. Here, we present real-world data on ctDNA detection and clearance dynamics in patients with various lymphoma subtypes, including patients who are newly diagnosed and those in the relapsed/refractory setting receiving chimeric antigen receptor (CAR)-T therapy.

Methods: We performed a retrospective, real-world analysis of ctDNA testing in 148 patients with either B-cell (n=129) or T-cell lymphoma (n=19). Among the 129 patients with B-cell lymphoma, 113 patients had aggressive subtypes (n=84 with DLBCL; n=29 with other), and 16 had indolent lymphoma subtypes. ctDNA was analyzed using a tumor-informed 16-plex mPCR-NGS assay (Signatera^TM, Natera, Inc.) from September 2020 - May 2025. Plasma samples (n=1,122; median: 7 per patient, range: 1-31) were collected at baseline, during therapy, at end-of-treatment (EOT), and during follow-up per physician's discretion. ctDNA status at baseline and EOT, and clearance kinetics during first-line (1L) induction therapy were correlated with clinical outcomes.

Results: The median patient age was 61 years (range: 18.3–84), and median follow-up was 18.7 months (range: 0.6–54.4 months). Disease stage at diagnosis was available for 139 patients: stage I (n=15, 11%), stage II (n=31, 22%), stage III (n=16, 12%), and stage IV (n=77, 55%). Stage was unknown in 9 patients. Overall, ctDNA detection at baseline was 95.7% (90/94), including 100% in patients with indolent B-cell (11/11), and T-cell lymphomas (6/6), and 94.8% (73/77) in patients with aggressive B-cell lymphomas. Across all subtypes, EOT ctDNA status was strongly prognostic for event-free survival (EFS). Patients with ctDNA-positivity at EOT had significantly worse EFS (HR: 7.33, 95%CI: 2.8-19.18, p<0.0001). In aggressive lymphomas, particularly in DLBCL, ctDNA positivity at EOT was associated with a markedly worse prognosis (Aggressive: HR: 7.69, 95%CI: 2.62-22.56, p=0.0002; DLBCL only: HR: 5.74, 95%CI: 1.71-19.23, p<0.01). Among patients with evaluable ctDNA time points relative to 1L therapy (N=60), ctDNA clearance at any time point during treatment correlated with improved EFS. (HR: 18.55, 95%CI: 4.82-71.32, p<0.0001). All patients who did not clear ctDNA relapsed, yielding a positive predictive value of 100% (11/11); the negative predictive value for those who did clear was 88% (43/49). The remaining six patients turned positive during surveillance prior to relapse. Of 15 patients treated with CAR-T cell therapy, 11 had pre- and post-infusion timepoints for ctDNA analysis. Of these, 82% (9/11) were ctDNA-positive prior to CAR-T, and 55% (5/9) achieved post-infusion ctDNA clearance and a complete clinical response, though one became ctDNA-positive and relapsed (13.3 months post-CAR-T), and another suffered non-disease mortality (22.3 months post-CAR-T). In contrast, all 4 patients remaining ctDNA-positive post-CAR-T relapsed or died within a median of 3.3 months (range: 1.3–6.4 months). Two patients persistently ctDNA-negative remain disease-free. Taken together, the PPV and NPV for 12-month EFS following CAR-T therapy using a single ctDNA timepoint were both 100%.

Conclusions: This is the first report of the largest, real-world study evaluating the utility of ctDNA across a broad spectrum of heterogeneous lymphoma subtypes in patients receiving various standard of care therapies. ctDNA status at EOT and on-treatment clearance were strong predictors of clinical outcomes across multiple histological subtypes of lymphoma treated with standard-of-care agents including CAR-T cell therapy. The robustness of these findings across biologically distinct subgroups highlight the broad applicability of ctDNA testing for risk stratification and recurrence monitoring for both aggressive and indolent disease. Further prospective studies are needed to validate these findings.