Abstract

Early Assessment of Treatment Response in Solid Tumors via Quantitating Circulating Tumor DNA

Xiaoju Max Ma, Director, Medical Affairs, Roche Sequencing Solutions, Inc.

Thanks to the advancement of modern medicine, multiple therapeutic options often exist for the treatment of various cancers. Lessons learned from managing blood cancers under therapy have taught us the importance of early response. Longitudinal monitoring of circulating tumor DNA (ctDNA) is an emerging method for disease management in solid tumors. We employed a 197-gene NGS assay, the AVENIO ctDNA Surveillance Kit, which allowed us to perform longitudinal ctDNA analysis and measure changes in ctDNA levels in plasma. Specifically, we evaluated the association between change in ctDNA levels within first two cycles of treatment and survival data from a cohort of 106 advanced lung adenocarcinoma subjects treated with first-line chemo or chemoradiation therapies. Our data show that a decrease in post-treatment ctDNA level measured by the Surveillance Kit was associated with better outcome (both PFS and OS) in advanced lung adenocarcinoma. Thus, an early assessment of treatment effect can be measured using ctDNA in plasma within 1 or 2 treatment cycles.