ASCO 2019: Predicting Treatment Outcomes in Melanoma With Circulating Tumor DNA Kinetics
Posted: Friday, June 28, 2019
Survival was not associated with baseline circulating tumor DNA (ctDNA) in patients with unresectable or metastatic melanoma treated with dabrafenib or dabrafenib plus trametinib, according to a study conducted by David Polsky, MD, PhD, of the NYU Langone Medical Center, New York, and international colleagues. Undetectable ctDNA at week 4 did seem to be linked to prolonged survival outcomes. These results were presented at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago (Abstract 9510).
“Particularly in patients with high lactate dehydrogenase, on-treatment ctDNA monitoring may be helpful for early identification of patients likely to benefit from dabrafenib or dabrafenib plus trametinib,” the authors concluded.
The investigators examined 345 patients with unresectable or metastatic melanoma treated with dabrafenib or dabrafenib plus trametinib in the phase III COMBI-d trial (ClinicalTrials.gov identifier NCT01584648). They measured BRAF V600E/K ctDNA in plasma samples at baseline and at week 4 and used mutation-specific droplet digital polymerase chain reaction assays.
Baseline ctDNA was detectable in 320 patients, or 97%, and was not found to be associated with survival. After 4 weeks of therapy, a majority of patients had a significant decrease in ctDNA. A group of 201 patients had paired samples and at baseline had identified ctDNA. Progression-free and overall survival were improved in 80 of those 201 patients, whose ctDNA changed from positive at baseline to negative at week 4. However, in 121 of the 201 patients, ctDNA remained positive.
Disclosure: The study authors’ disclosure information may be found at coi.asco.org.