We know that men with metastatic castration-resistant prostate cancer (mCRPC) and visceral metastases have a worse prognosis than those with non-visceral metastases. The important question we need to understand is what, of our currently available treatments, might be effective for this more aggressive and deadly type of prostate cancer?

Results of the phase 3 AFFIRM clinical trial have demonstrated that treatment with the androgen receptor inhibitor enzalutamide (Xtandi) resulted in significant improvements in outcomes for men with mCRPC. This blog post discusses the efficacy of enzalutamide among men from the AFFIRM trial who had visceral disease.

Men who were in the AFFIRM trial who had liver and/or lung metastases at baseline were evaluated for overall survival (OS), prostate-specific antigen (PSA) response and the time to PSA and radiographic progression (rPFS).

In the analysis the men who had liver metastases (n=92), enzalutamide was associated with a lower risk of radiographic progression, improved 12-month OS and radiographic progression-free survival rates, and higher PSA response compared with men who had placebo. The men who were Enzalutamide treated who had lung metastases (n=104) had improved median OS, a substantially reduced risk of radiographic progression, improved 12-month OS and rPFS rates, increased time to PSA progression and a better PSA response rate (52.1% vs 4.9%) compared with those who received placebo.

No increase in treatment-related adverse events was observed for the visceral metastases cohort compared with the non-visceral metastases cohort. the analysis concluded that across multiple endpoints, men who have visceral metastases have better outcomes with enzalutamide than with placebo.

Of course we need a similar analysis of abiriterone (Zytiga) and the best would be a head to head look at Xtandi against Zytiga for men with visceral metastatic castration resistant prostate cancer.

Cancer. 2016 Sep 20 [Epub ahead of print] Yohann Loriot, Karim Fizazi, Johann S de Bono, David Forer, Mohammad Hirmand, Howard I Scher