After establishing itself as a key tool for tumor profiling and patient stratification, circulating tumor DNA is now beginning to make the move into monitoring response to therapy, where it promises an early read of efficacy that could cut clinical timelines and costs.
Getting from here to there will require generation of prospective validation data across several cancer types and therapies, plus standardization of assays to measure ctDNA. Several companies have started gathering the data and forming the collaborations needed to make this happen.
ctDNA assays stand to read out drug response within weeks, instead of the months patients normally wait to get an image-based readout. These tests detect cell-free DNA that has been shed from tumors into blood and constitute one form of liquid biopsy.
Adoption of ctDNA assays would not only speed up clinical trials, it could spare patients months of exposure to a drug that isn’t working and give them a chance to move on to a different treatment sooner.
The method’s speed would be a boon for adaptive clinical trials, where one of the major aims is quick reassignment of non-responsive patients to another study arm.
Companies large and small are already using ctDNA to profile tumors and stratify patients for trials. One assay has been approved by FDA, the Cobas EGFR Mutation Test v2 from Roche and AstraZeneca plc, which detects