Pembrolizumab is Effective in Some Men with Untreatable Advanced Prostate Cancer

In a recent study of 258 men with otherwise untreatable castrate resistant prostate cancer the immunotherapy drug Pembrolizumab showed that it was able to control the disease having a positive response lasting six months or more in 11 percent of men, with two men showing a complete response.

The trial evaluated 258 men with castrate resistant prostate cancer who had failed chemotherapy treatment. They received pembrolizumab every three weeks for 35 weeks or until their cancer progressed or they experienced intolerable toxicity.

The trial showed that 11% of the men experienced disease control for at least six months while two of the men had a complete response to the drug. Confounding the results was the finding that unlike other tumor types treated with pembrolizumab, the man’s PD-L1 status did not predict their response to the drug.

Future studies will need to look at how to identify which men will respond to pembrolizumab.  Until such time that we know who will be responsive, if you have failed all other available treatments, you should engage in a conversation with your doctor about trying pembrolizumab.  

The findings of this study were presented at the ASCO Annual Meeting in June of 2018.  The study PI, Johann de Bono from the Institute of Cancer Research, London, said: “Our study has found that immunotherapy can benefit a subset of men with advanced, otherwise untreatable prostate cancer, and these are most likely to include patients who have specific DNA repair mutations within their tumors.”

De Bono J, Goh J, Ojamaa K et al. KEYNOTE-199: Pembrolizumab (pembro) for docetaxel-refractory metastatic castration-resistant prostate cancer (mCRPC). Presented at 2018 ASCO Annual Meeting; 1–5 June 2018; Chicago, Illinois. J Clin Oncol 36, 2018 (suppl; abstr 5007). Abstract available here:

 Joel T. Nowak, MA, MSW wrote this Post.  Joel is the CEO/Executive Director of Cancer ABCs.  He is a Cancer Thriver diagnosed with five primary cancers - Thyroid, Metastatic Prostate, Renal, Melanoma, and the rare cancer Appendiceal cancer.