Prostate cancers initially need the male hormone testosterone for growth. Hormone therapies that lower the level of testosterone are among the most effective treatments for prostate cancers that have spread to other organs (metastasized). The benefits of hormone treatments do not last, however. Over time, many prostate cancers continue to grow despite hormonal therapies; these are called “castration-resistant prostate cancers.”
The purpose of this study is to assess the safety and effectiveness of an investigational drug called MLN0128 (formerly known as INK128) in men with castration-resistant prostate cancer that has continued to grow despite chemotherapy. MLN0128 works by blocking a molecular signaling pathway called mTOR that is overactive in some cancers. It is a capsule that is taken orally (by mouth).