LAUSR

The non-invasive detection of circulating tumor DNA (ctDNA) from plasma has been shown to have clinical value for detection of minimal residual disease (MRD), identification of emerging resistance to treatment, and predicting treatment response. The ability to detect MRD following curative treatment allows for the stratification of patients with higher risk of disease recurrence. Multiple studies, across hundreds of patients in different indications, including lung and colon cancer, have shown that tumor-informed personalized assays have high sensitivity to detect recurrence. The tumor-informed bespoke panels utilize sequencing of the tumor tissue to identify clonal somatic variants, which are then used to generate a personalized panel to track the variants in patient plasma. Next-generation MRD technologies are aiming to provide greater sensitivity by expanding methods beyond the small, personalized panels. Utilization of increased numbers of somatic variants is predicted to achieve a greater level of sensitivity for detection of MRD. Here we describe, C2I Genomics which provides a novel platform that exploits whole genome sequencing of the tumor tissue and plasma to define a somatic variant signature. An important difference of this method is that it develops a personalized bioinformatic signature rather than a personalized NGS panel. To understand the potential of this novel methodology, we utilized a set of 54 contrived clinical sample dilutions from three indications, with an expected (or engineered) VAF range of 0.2-0.002%, that have commutability to the intended use population. We found that C2I Genomics technology is highly sensitive, where for all returned samples, the assay routinely achieved detection down to the lowest dilution of 0.002% allelic frequency. Overall, the assay resulted in an average detection rate of 93% across all dilutions (n = 54). The aggregate detection rate of several tumor-informed assays, examining the same dilutions, yielded a detection rate of 68%. In summary, the C2I Genomics assay showed robust detection from contrived samples which are representative of clinical trial samples in both cfDNA yields and allele frequency. Citation Format: Paul Labrousse, Daniel Stetson, James Hadfield, Chris Abbosh, Ahmet Zehir, Carl Barrett, Brian Dougherty, Darren Hodgson. The evolution of MRD assays: Moving beyond the tumor-Informed bespoke NGS panel [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB293.