The University of Southern California expert discusses next steps for the trial and how the recent results could impact the future of care for patients with prostate cancer.
Men with metastatic castrate resistant prostate cancer (mCRPC) with undetectable circulating tumor counts (CTCs) were 6.1-fold more likely to have complete response to hormonal therapy, according to findings presented at the 2020 ASCO Virtual Scientific Program.
Results from SWOG S1216, a phase III randomized trial, demonstrated that CTC count at treatment initiation was highly prognostic of 7-month prostate specific antigen (PSA) response.
In an interview with CancerNetwork, lead study author Amir Goldkorn, MD of the University of Southern California Keck School of Medicine discussed the next steps for the trial., and what the results could mean moving forward.
So, what I view as next steps are a couple of things that will hopefully happen in the near future and then some subsequent to that, in the near future in the coming year. We hope to get the final results from the entire clinical trial. So, the final overall survival data are still blinded and are expected to become unblinded in about the next year. And as soon as that happens, we could look at all the patients with all the CTC counts and actually compare those counts to their final overall survival, not just response to therapy or how long before they progressed, but to their overall survival, which is a much stronger level of evidence that everyone would like to see. It will also allow us to look at CTC counts not only as a prognostic factor, whether [patients] will do well or not, but as a predictive factor, meaning that it helps us know whether patients did better on one treatment arm versus the other. Right now, all the analysis is pooled across arms but as soon as we unblind all the overall survival data, we'll actually see, do CTCs predict better whether you'll do better on androgen deprivation with bicalutamide versus should you be put on androgen deprivation in the 617 inhibitor So, where all this will lead is, obviously our colleagues in the community would have to assess these data and decide how convinced we are based on this. And it may be adopted as a prognostic factor just to tell us, you know, how well patients are likely to do to guide therapy as I described earlier. And perhaps it would be adopted as a basis for additional studies going forward where we say, All right, let's check ctcs at baseline and let's see if the CTC numbers at baseline can tell us whether this patient will do better on an androgen deprivation with by collude amide arm or an engine deprivation. Usually that's not the standard of care anymore but Andrew and deprivation and operatic owner engine approbation with chemotherapy are entered in deprivation with a second line of androgen, like absolute, absolute amide. So we could use CTC counts, not only as a prognostic factors tell us how someone will do overall but as a predictive factor to actually help us choose between These different FDA approved therapies that are all available now, where we really need some of these biomarkers to help make a clear cut decision which way to go. So hopefully that's the direction that this will build in the coming year or two years.