Apalutamide - An Oral Androgen Receptor Inhibitor for Non-Metastatic CRPC

Janssen Biotech, Inc. (Johnson & Johnson) has submitted a New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) for their investigational treatment apalutamide.  Apalutamide is a next generation oral androgen receptor (AR) inhibitor for men with non-metastatic castration resistant prostate cancer (CRPC).

Janssen’s submission to the FDA is based on phase 3 data from their ARN-509-003 (SPARTAN) clinical trial, which assessed the safety and efficacy of apalutamide versus placebo, in men with non-metastatic CRPC who have a rapidly rising Prostate Specific Antigen (PSA) despite receiving continuous first-line androgen deprivation therapy (ADT).

The primary endpoint of this study was not overall survival but was instead metastasis-free survival (MFS) in men with non-metastatic (rising PSA but negative scans) castrate resistant prostate cancer (CRPC).

Men who are castrate resistant are at a higher risk of developing metastatic disease.   Delaying the development of metastatic disease does not necessarily mean that actual survival might also be extended, but it does translate into preserving the quality of their life.   Additional, future research, might prove that it also can provide some additional survival advantage. 


About Apalutamide (ARN-509)

Apalutamide is an investigational, next-generation oral androgen receptor inhibitor that inhibits the action of testosterone in prostate cancer cells by preventing the testosterone from binding to the androgen receptor.

ARN-509’s mode of action, blocking the ability of the cancer cell to utilize available testosterone is similar to the first line ADT treatment Casodex (bicalutamide) and the second line hormone treatment Xtandi (enzalutamide).  Neither of these drugs are currently approved for castrate resistant prostate cancer (CRPC) which is non-metastatic. 


The Competition- Xtandi

Nipping at the heels of ARN-509 is the other second line anti-androgen drug, Xtandi (enzalutamide).  Xtandi is already approved for metastatic castrate resistant prostate cancer, but the PROSPER trial, which could yield results by the mid-year 2018, is evaluating Xtandi for the earlier stage, non-metastatic prostate cancer.  

Like the SPARTAN trial, PROSPER is not evaluating survival, it is looking at disease progression.


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 Appendiceal Cancer a rare cancer.