Christos Kyriakopoulos, MD, on Prostate Cancer: CHAARTED2 Trial Results on Cabazitaxel and Abiraterone

Charter two was found positive for the primary outcome. At the time of the report of the results, there was a statistically significant difference of five months in terms of progression-free survival in favor of the patients who received cabazitaxel plus abirateron. For patients who received cabazitaxel and abirateron, the median progression-free survival was 14.9 months versus 9.9 months for the patients who received abirateron alone. So technically, the addition of cabazitaxel prolonged the progression-free survival by a little bit more than 50%. Even though charter two was found positive for the primary outcome, it is not a practice changing study. The main reason is because the landscape, the treatment landscape for metastatic castration-sensitive disease has changed, and there are not that many patients who are currently getting docetaxel plus androgen deprivation in the castration-sensitive setting. Nowadays, most patients receive either a double treatment, which includes treatment with abirateron or enzalutamide or any of the other second generation androgen receptor inhibitors. In cases that the patients receive treatment with docetaxel, that is usually in the context of a triplet therapy, which means that in addition to the docetaxel, they also receive treatment with abirateron or darolutamide or enzalutamide. That is the main reason that by the time these patients develop castration-resistant disease, they have already been exposed to a second generation androgen receptor inhibitor, which of course is like abirateron. As part of charter two, we did include two correlative studies that are in progress. The first one is the analysis of circulating tumor cells for splice variant seven, and the second one that we included in charter two was disease assessment using sodium fluoride PET imaging. This is ongoing work and hopefully we will be able to present those results in the future meeting. Also, as part of the study, we did collect plasma for patients who enrolled in the study, and we hope that we will be able to secure funding for some additional studies with those samples.