Yesterday the U.S. Food and Drug Administration (FDA) approved the use of enzalutamide (Xtandi) for the treatment of metastatic, hormone-sensitive prostate cancer (mHSPC) — also known as metastatic, castration-rsensitive prostate cancer or mCSPC.
For the full media release announcing this approval (from Pfizer and Astellas, the manufacturers and marketers), please click here. The approval is based on data from the ARCHES trial that were initially announced at the Genitourinary Cancers Symposium in San Francisco, last February, and published by Armstrong et al. in the Journal of Clinical Oncology in July.
Note in particular that this approval of enzalutamide for the treatment of mHSPC is only when used in combination with as standard LHRH agonist such as leuprolide acetate. Enzalutamide has not been approved for the treatment of any form of advanced prostate cancer when used on its own.
Filed under: Drugs in development, Management, Treatment | Tagged: enzalutamide, hormone-sensitive, HSPC, metastatic, Xtandi |
THE "NEW" PROSTATE CANCER INFOLINK 
What is interesting is that the FDA accepted radiographic progression-free survival as a surrogate endpoint for mHSPC. The other approved medicines (Zytiga, Erleada and Taxotere) were required to prove increases in overall survival. Nubiqa, Erleada and Xtandi were approved for non-metastatic CRPC based on delay of the appearance of the first metastasis.
Allen:
The different types of approval by the FDA reflect when the approvals were granted. Radiographic progression-free and metastasis-free survival were shown to correlate accurately with overall survival shortly before the initiation of the trials of Nubiqa, Erleada and Xtandi in nmHSPC, mHSPC, and nmCRPC, thus making the use of these endpoints possible in these earlier stages of disease. When Taxotere, Zytiga, and Xtandi were initially approved, the approvals were for all for treatment of mCRPC, and overall survival was the only clearly estabished survival endpoint.
So another head to head challenge is introduced. Exciting times in clinical trial land.