Dr. Rogers on the Potential for ctDNA to Aid Second-line Treatment Decisions in mCRC

Sherise Rogers, MD, MPH, an assistant professor of Hematology/Oncology at University of Florida Health (UFH), Division of Hematology and Oncology, Department of Medicine in the College of Medicine, discusses the potential of utilizing circulating tumor DNA (ctDNA) to help guide second-line treatment decisions in patients with metastatic colorectal cancer (mCRC).

According to information presented at the 2023 Gastrointestinal Cancers Symposium, the phase 2 RAPID 1 trial (NCT04786600) is evaluating the use of the Signatera ctDNA assay as an assessment tool for response to therapy compared with the standard approach with a CT scan.

The trial in enrolling patients with mCRC who had progression on or intolerance to first-line chemotherapy. Patients who have measurable ctDNA at baseline will be randomly assigned to ctDNA-guided intervention or the scan-guided control group. The study will compare overall survival, progression-free survival, and best overall response.

The current standard of care is to use a CT scan every 3 months to evaluate the efficacy of second-line treatments in patients with mCRC. Investigators are aiming to understand if ctDNA can be used as a rapid assessment tool, Rogers explains. When patients need to wait every 3 months for assessment by CT scan, that represents to that a patient may be on a treatment without knowing if the treatment is actually working, Rogers says.

Additionally, during the 3-month intervals between CT scans, a patient can also experience significant adverse effects (AEs) that can worsen a patient’s morbidity and their quality of life, Rogers continues. Overall, all clinicians want to ensure that they are limiting significant AEs and optimizing treatments for patients in the second-line setting.

ctDNA has the potential to give a faster indication of whether a patient is receiving a benefit from a.second-line treatment, which would allow clinicians to switch to another therapy that could improve outcomes, Rogers concludes.