BERKELEY, CA (UroToday.com) - In this study we assessed the efficacy and safety of cabazitaxel administered to 49 patients in a clinical setting in the Netherlands. Efficacy data were collected retrospectively, safety data were collected as they occurred.
Recently, multiple systemic therapies for patients with metastatic castrate-resistant prostate cancer (mCRPC) have been introduced into the clinic: cabazitaxel, abiraterone acetate, sipuleucel-T, enzalutamide and radium-223 chloride. Others, such as cabozantinib, tasquinimod and ipilimumab, may be used in regular clinical practice in the near future too. With all these new therapies, there is a major need to better understand which therapy should be given to which patient. Therefore, we think it is of importance to report the use of these new therapies in clinic, to improve our understanding of them.
Our study has two major novel findings. The first one is that patients reported fewer adverse events than patients in the TROPIC registration trial. One possible explanation for this difference is that the TROPIC study assessed adverse events weekly, while in our study they were assessed once every 3 weeks. One could question the clinical relevance of adverse events that disappear within 3 weeks and have no clinical consequences. One such adverse event seems to be diarrhea: our results suggest that most diarrhea reported in the TROPIC study is clinically irrelevant, as it disappears spontaneously within 3 weeks, or with the addition of medication once diarrhea occurs. This finding underscores that diarrhea prophylaxis is currently not needed. However, randomized studies, such as CABARESC, will give a definitive answer regarding the use of diarrhea prophylaxis. On the other hand, with neutropenia remaining a significant adverse event in patients in our study, our study underlines the importance of the PROSPECTA study, which assesses the use of neutropenia prophylaxis. Furthermore, the PROSELICA study will assess whether administration of 20 mg/m2 cabazitaxel will result in fewer adverse events and similar efficacy than the 25 mg/m2 used in most patients of the Dutch compassionate use program.
Secondly, our study suggests that patients who respond well to docetaxel may also respond well to cabazitaxel. Until better markers to predict therapy response have been identified, docetaxel response may be a factor for physicians in their decision to start treatment with cabazitaxel or other therapies.
While our study was conducted retrospectively and in a relatively small number of patients, we think that the findings summarized above are of importance for physicians treating mCRPC patients, to improve our understanding of the use of cabazitaxel for these patients.
Michel D. Wissing, et al. as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.