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Arbiraterone Acetate (Zytiga®)

ZYTIGA® is an FDA-approved, once-daily oral prescription medicine that is used along with prednisone to treat men with metastatic castrate-resistant prostate cancer who previously had docetaxel chemotherapy. Metastatic castration-resistant prostate cancer is cancer that is resistant to medical or surgical treatments that lower testosterone and has spread to other parts of the body.

This medication works by blocking other steps in the testosterone pathway, decreasing the production of a hormone called cytochrome P450 17A1 that stimulates cancer cells to continue to grow.

ZYTIGA, in combination with prednisone, provides physicians with an important tool for treating men with metastatic castration-resistant prostate cancer earlier in the course of their disease, before chemotherapy.

Benefits of Zytiga

According to a study of men with metastatic castration-resistant prostate cancer who had not received chemotherapy:

  • In the majority of patients in the clinical trial (Phase III testing), ZYTIGA caused the vast majority of patients to have significant reductions in their PSA levels.
  • Most patients who use ZYTIGA also have significant shrinkage of tumors, and for those with bone pain due to metastases, many also have improvement in pain level.*
  • Certain men treated with ZYTIGA plus prednisone lived longer than men treated with placebo plus prednisone (median overall survival was 35.3 months for men treated with ZYTIGA plus prednisone compared with 30.1 months for men treated with placebo [sugar pill] plus prednisone). However, the difference was not statistically significant.
  • ZYTIGA plus prednisone increased the length of time certain men lived with the disease but did not get worse as measured by imaging studies1 (i.e., bone scans). One hundred fifty of 546 men (28%) treated with ZYTIGA plus prednisone and 251 of 542 men (46%) treated with placebo (sugar pills) plus prednisone had disease progression.
  • ZYTIGA plus prednisone significantly delayed the median time to starting chemotherapy (25.2 months for patients receiving ZYTIGA plus prednisone and 16.8 months for patients receiving placebo [sugar pill] plus prednisone).

*Jacek L. Mostwin, M.D., D. Phil. (Oxon), Prostate Disorders, Summer 2012, The Johns
Hopkins bulletins

For more information and to find out if this treatment is right for you, ask your urologist. Important information about ZYTIGA, including drug interactions and side effects, can be found here.