Prostate Cancer: Summary from ASCO 2015

Castration-resistant prostate cancer: current status of therapy with Radium-223 associated with anti-androgens (enzalutamide and abiraterone) - a systematic literature review

“…Among the 696 patients evaluated, 120 used abiraterone before treatment with Ra-223 and 25 used simultaneously, in addition, 59 patients used enzalutamide before therapy with Ra-223 and 15 concomitantly. The safety profiles in relation to therapy with Ra-223 were similar regardless of prior exposure or not to enzalutamide or abiraterone, similarly to the toxicity study included in this review 19 . Patients that had prior use of abiraterone or enzalutamide had also a higher rate of previous treatment with docetaxel and higher serum levels of alkaline phosphatase and PSA (theoretically they had a higher burden of disease and had been through more lines of treatment), but no significant variation in Ra-223 toxicity.…”

“…Patients that had prior use of abiraterone or enzalutamide had also a higher rate of previous treatment with docetaxel and higher serum levels of alkaline phosphatase and PSA (theoretically they had a higher burden of disease and had been through more lines of treatment), but no significant variation in Ra-223 toxicity. Patients that used anti-androgens concomitant with Ra-223 were similar to those who did not use such drugs, except that PSA level and previous use of docetaxel were higher in the group with concomitant use of enzalutamide as compared to abiraterone or neither of the two drugs 19,20 . Contrarily to the study included in the review, in this prospective study patients that had used enzalutamide and Ra-223 were more advanced in the disease and did not show improvement in overall survival 10,19,20 .…”

“…Patients that used anti-androgens concomitant with Ra-223 were similar to those who did not use such drugs, except that PSA level and previous use of docetaxel were higher in the group with concomitant use of enzalutamide as compared to abiraterone or neither of the two drugs 19,20 . Contrarily to the study included in the review, in this prospective study patients that had used enzalutamide and Ra-223 were more advanced in the disease and did not show improvement in overall survival 10,19,20 . Another fact to be noted is that among the patients who used abiraterone and Ra-223.32% had received prior enzalutamide.…”

“…However, with the benefits seen in the COU-AA-301 and AFFIRM trials and their better tolerability, it's rational to consider abiraterone acetate or enzalutamide before chemotherapy in patients with contraindications to docetaxel or with poor general performance. Cross-resistance between abiraterone and enzalutamide, possibly related to the similarity in the mechanism of action, has been showed and there are also small, retrospective studies that, although with a potential bias due to the more advanced and aggressive disease, raise the possibility of decreased activity with docetaxel after either agent 18,19 .…”

“…An ongoing study presented as a congress poster deserves mention, since it brings new data about this question 19 . The study is a phase IIIb trial, multicenter, prospective study that is checking the OS and the treatment safety of patients who have been treated with Ra-223.…”