Men with metastatic castrate resistant prostate cancer (mCRPC) have become fortunate over the last few years as there we now have a number of new drugs available which can extend our life and can also have some palliative effects. However, as we have more treatments being approved, we find that we are faced with a significant issue, how to sequence these drugs.

The major problem causing this sequencing crisis is cross-resistance. The use of each of any of these drugs limits the use of the another drug in men who have failed the original prior therapy. This problem, cross-resistance, is not limited to any one class of these new agents but, rather involves all the approved therapies for mCRPC.

In a retrospective study of 310 men with mCRPC Cheng et al.