Abstract 252: A single-tube approach for detection of circulating tumor DNA using customized panels

Abstract

Abstract Circulating tumor DNA (ctDNA) is a promising biomarker for cancer. Applications of ctDNA analysis include screening, diagnosis, treatment selection, minimal residual disease (MRD) detection and recurrence monitoring. While some applications are best served by tumor-agnostic panels covering large regions of the genome, such large panels are not universally appropriate due to limitations in sensitivity, user-friendliness, turn-around time (TAT), and sequencing cost. One application where customized, tumor-informed panels can be preferable is detection of MRD and cancer recurrence, and multiple studies have shown that ctDNA can detect residual/recurrent disease several months earlier than routine clinical imaging. This application requires high sensitivity and in most cases will involve repeat testing of longitudinal samples collected over several months or years. In this scenario, the ideal assay characteristics include tumor-informed, personalized assay panels, with a simple, rapid workflow, and with minimal cost per assay. We have developed the Fluent LBx assay to meet these requirements. Fluent LBx analysis can be performed on-site in any appropriately equipped research or clinical laboratory, avoiding the extra cost and delay associated with external testing. Fluent LBx is a variation on SiMSen-Seq (PMID 27060140) that uses modified target and adapter primer sequences to facilitate barcoding and uniform amplification of multiple targets in a single-tube library construction protocol. Library preparation can be completed in under 1.5 hours with approximately 20 minutes of hands-on time. Using this approach, target DNA molecules are first barcoded and then amplified with indexed adaptors compatible with Illumina sequencers, in a single PCR reaction. After clean-up and sequencing, barcode information is used to compile reads from individual DNA molecules and minimize base calling errors introduced during PCR and sequencing. Here we present data demonstrating uniformity, sensitivity and specificity of Fluent LBx assays using LGC SeraCare quality control standards. Additionally, we present longitudinal clinical demonstration of residual disease detection from ctDNA collected from multiple head and neck and gastrointestinal cancer patients through longitudinal monitoring post therapeutic intervention. The Fluent LBx workflow allows rapid, inexpensive, patient-specific monitoring of MRD and recurrence in multiple cancer indications. Citation Format: Robert Meltzer, Jessalyn Kaur, Ekaterina Kintsurashvili, Christopher D'Amato, Tony Godfrey. A single-tube approach for detection of circulating tumor DNA using customized panels [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 252.