Janssen-Biotech has submitted a new drug application to the Food and Drug Administration (FDA) for apalutamide (ARN-509) to treat non-metastatic hormone-resistant prostate cancer. Apalutamide is an oral androgen receptor inhibitor that blocks the action of testosterone in prostate cancer cells. (Whether ARN-509 differs in its mechanism of action from enzalutamide [Xtandi] is not known to this website at this point.) The drug had been tested in the Phase 3 SPARTAN clinical trial in men with non-metastatic hormone-resistant cancer who have a rapidly rising prostate specific antigen (PSA), despite receiving continuous androgen deprivation (hormone) therapy (ADT). The primary objective of the trial was to assess metastasis-free survival, or the time from randomization to first evidence of confirmed metastasis (the spread of cancer cells to another part of the body). Janssen revealed that patients receiving ADT plus apalutamide lived significantly longer without metastasis, compared to those receiving ADT plus a placebo. But the company did not disclose any further details. The hope is to treat men with prostate cancer earlier in the disease course before the cancer has metastasized.
Studies have estimated that between 10 and 20 percent of patients diagnosed with prostate cancer might develop the hormone-resistant form within about five years. Moreover, metastatic hormone-resistant prostate cancer is associated with deterioration in quality of life and few therapeutic options. For details about the FDA approval process, see the following link.