Abstract 5877: Feasibility of ctDNA detection with a low-volume blood collection device

Abstract Patient-centric technology for personalized healthcare can transform medical research and disease management by addressing logistical hurdles, and enabling flexible, ongoing patient monitoring with reduced blood volumes. The Tasso+ low blood volume collection device allows a shift from traditional in-clinic blood collection to patient-centric, home, blood collection for volumes up to 1 mL of capillary blood. To demonstrate the utility of low blood volume collection and subsequent molecular residual disease surveillance, we evaluated the capability of the Signatera™ RUO tissue-informed assay (Natera, Inc.) to detect single nucleotide variants (SNVs) using whole blood samples collected by a microsampling device that can collect up to 500 µL, the Tasso+, as compared to traditional venipuncture. We first tested the technical feasibility of the Signatera assay to detect SNVs using a commercial circulating tumor DNA (ctDNA) reference standard (Seraseq ctDNA mutation mix v2, 0.625-5ng) spiked into low blood volumes that are representative of those obtainable from routine Tasso+ collection. Next, we tested the clinical utility of low blood volume collection using commercially obtained traditional venipuncture and Tasso+ samples from 7 cancer patients (pt) with advanced relapsed/refractory solid tumors (bladder n=1, colorectal cancer n=3, lung n=1, melanoma n=2). Venipuncture plasma samples (4 mL, 1mL, 2⨉ 500µL) and 1 in the Tasso+ device (250-500µL) were extracted per patient and assessed for ctDNA detection using the patient-informed 16-plex Signatera mPCR-NGS-based RUO ctDNA assay. The feasibility study demonstrated the ability to detect ctDNA at the single variant molecule level down to the lowest quantity of reference standard in the 250µL plasma sample. In the clinical setting, ctDNA was consistently detected among 6 of 7 pts (86%) at the 4 mL plasma volume and in 5 of 7 pts (71.4%) at all other volumes, including the 250µL volume of plasma from Tasso+ samples. The levels of ctDNA detected were generally consistent for most patients across all sample volumes, including that from the Tasso+ device. These results demonstrate that ctDNA can reliably be detected down to the single variant molecule level using the Signatera RUO assay on small plasma volumes collected with the novel Tasso+ microsampling technology. Additional evaluation using larger patient numbers would further validate this technique. Citation Format: Brad Evans, Jordan Feeney, Derrick Renner, Alexey Aleshin, Matthew Rabinowitz, Steven Townson, Himanshu Sethi. Feasibility of ctDNA detection with a low-volume blood collection device [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5877.