Pashtoon M. Kasi, MD, MBBS, MS
Liquid biopsies may not be ready for prime time use in colorectal cancer (CRC), but they stand to show the importance of identifying clinically relevant mutations that can direct future treatment decisions, said Pashtoon M. Kasi, MD, MBBS, MS.
, Kasi, an assistant professor of oncology and senior associate consultant in the Division of Hematology/Oncology at Mayo Clinic, provided an overview of the potential for liquid biopsies in CRC and advances being made in the treatment landscape.
OncLive: Where do liquid biopsies stand in CRC?
: Liquid biopsies are done through circulating tumor DNA testing; it’s something that has rapidly made its way into research and is now making its way into practice. The most recent guidelines that came from the 2018 ASCO [Board of Directors] meeting in March 2018 are showing promise; however, they’re not ready for prime time. The only FDA-approved indication for liquid biopsies is in the sphere of lung cancer.
fusion–positive patients, which constitute about 1% to 2% of CRCs as well.
Could you elaborate on ongoing research efforts in this area?
One of the most exciting things, in terms of the use of this approach in the metastatic setting, is in a clinical trial setting. One of the clinical trials that is being developed as we speak is going to be a master protocol, where each treatment arm may be determined by the patient’s liquid biopsy results. The study is being led by many academic institutions.
As of right now, different arms are being developed based on the aberration found in each patient. We already have the HER2
arm open, in which there will be matched therapy based on circulating tumor DNA testing. Ongoing research is testing its use earlier on to determine which patients will benefit from chemotherapy and who may not need it.
Could you discuss the BEACON trial?
The BEACON trial is one of the most exciting trials that we had updates for at the 2019 ASCO Gastrointestinal Cancers Symposium. The trial is focused on patients with BRAF
V600E-mutated CRC led by Scott Kopetz, MD, PhD, FACP, of The University of Texas MD Anderson Cancer Center, and Axel Grothey, MD, of West Cancer Center. These patients comprise an unmet need; their survival in the second-line setting is about 4 to 6 months; [outcomes in these patients are] up to 3 times worse than those of patients who don’t have the BRAF
V600E mutation. These patients really don't have too many options. Historically, BRAF inhibitors didn't work. The combination of BRAF inhibitors with MEK inhibitors did not show much promise.
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