Data highlights limitations of ctDNA assay used to predict outcomes in participants with renal cell carcinoma treated with adjuvant pembrolizumab in the KEYNOTE-564 trial. Dana-Farber Cancer Institute's Dr. Toni Choueiri explains that ctDNA+ was associated with worse disease-free outcomes, but sensitivity was low.
Hello everyone, I'm Doctor Tony Schwery from the Dana-Harvard Cancer Institute. It was really our pleasure on behalf of all the co-authors to analyze the CT DNA in all the participants with renal cell cancer treated with adjuvant pembrolizumab. In the keynote 564 trial. Keynote 564 trial is the trial that led to the approval of pembrolizumab as the first immunotherapy to decrease the risk of recurrence and prolong survival in renal cell cancer. This was approved several years ago. But here, one of the endpoint, one of the exploratory endpoint was the association of baseline CTDNA metric, And the dynamic of CT DNA from cycle 5, from cycle 1 to cycle 5 with the primary outcome which is disease-free survival. Most important thing here, uh, first of all, the majority of patients had, uh, CT DNA, um, uh, test that was done. However, what we found, using the 16 plaques or the 64 plaques test post surgery, That the rate of CTDNA positivity was very low, less than 10%. Actually it was around 5% in the 16 plaques, obviously higher in the high risk and M1NED and even lower, 4% for example, in the intermediate high risk group. We also found that Disease-free survival by baseline CTDNA suggests that a positivity for a CTDNA is associated with worse disease-free survival, and the clearance at cycle 5 day 1 compared to baseline was higher, and this is no surprise in the active arm of pembrolizumab. So overall, uh, the fact that we find, uh, less than 10% of patients, even using the 64 plex, uh, finding positive CTA DNA post surgery. Uh, do not really, in my opinion, support the routine use of the CTDNA, the current technology to select patient for increased risk of recurrence, um, uh, post nephrectomy for adjuvant, uh, you know, pembrolizumab. Uh, as, as a reminder, also, we used, um, Nate's 64 and 16 plaques, uh, tissue. It's a, it's a bespoke assay that is uh tissue exome based.
