626P - Percentage of cancer patients undergoing adjusted targeted therapy after ctDNA testing: Insights from a tertiary hospital experience

Background

Circulating tumor DNA (ctDNA) analysis with comprehensive panels is now integral to cancer genomic profiling, advancing precision medicine in clinical practice. Yet, the practicality of treatment post ctDNA testing remains uncertain. This study aims to estimate treatment application post ctDNA analysis and its clinical utility.

Methods

Over a 7-month period, from January to July 2023, we retrospectively evaluated 102 patients with solid tumors who underwent ctDNA using the next generation sequencing method at a university-affiliated tertiary care hospital in Korea. To determine the percentage of genome-driven targeted therapy applied subsequent to ctDNA test result, we employed previously reported FDA-approved companion diagnostic biomarkers and their corresponding drug lists. Cases in which FDA-approved targeted therapy was prescribed or cases in which drugs were changed due to drug resistance after ctDNA testing were assessed.

Results

Out of 102 cases evaluated, 81 cases (79.4%) displayed ctDNA sequencing results featuring actionable variants classified as Tier 1 or Tier II. Among the 73 FDA-approved drugs, 12 were administered at our hospital between January 1, 2023, and July 31, 2023. According to ctDNA results, 21 individuals (20.6% of the total cases) were either prescribed FDA-approved drugs or underwent drug changes. Among them, 15 patients (14.7%) were prescribed FDA-approved drugs, while 6 patients (5.9%) experienced alterations in their medication regimens. Of the 21 patients undergoing targeted therapy based on ctDNA test results, colorectal cancer (12/21, 57.1%) was the most prevalent, followed by NSCLC (4/21, 19.0%). Consistent with these cancer types, the most frequently administered drugs were pembrolizumab (8/21, 38.1%) and cetuximab (6/21, 28.6%).

Conclusions

While this study presents findings from an investigation at a tertiary-hospital in Korea, it underscores the significant prevalence of genome-targeted therapy adoption following ctDNA testing for solid tumors. A larger-scale study should be pursued to further validate these observations.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.