ZYTIGA received approval from the U.S. Food and Drug Administration (FDA) for a label update on March 30, 2015. The approval was based on the results of a Phase 3 clinical study showing the drug could prolong median overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC).
ZYTIGA was approved in the U.S. in 2011, and since then more than 150,000 prostate cancer patients worldwide have been prescribed the therapy. The new results suggest that patients with mCRPC should be prescribed ZYTIGA in combination with prednisone for the treatment of their prostate tumor.
Prostate tumor cells develop adaptive mechanisms such as the capacity to produce androgen, which promotes their proliferation. Lowering androgens such as testosterone (androgen-deprivation therapy) is a treatment option to control prostate cancer growth. However, many patients develop metastasis and become resistant to this type of therapy, therefore requiring additional treatments to control cancer cell growth.
The clinical trial, sponsored by Janssen, included 1,088 men and found that ZYTIGA combined with prednisone significantly prolonged OS (34.7 months) in comparison to placebo plus prednisone treated patients (30.3 months) in men who had not previously undergone chemotherapy (chemotherapy-naïve).
“The statistically significant improvement in overall survival demonstrated in the final analysis and resulting label update help affirm the established efficacy, safety and tolerability that physicians treating men with metastatic castration-resistant prostate cancer have seen with ZYTIGA,” said Charles Ryan, Professor of Clinical Medicine, Urology at the University of California, San Francisco, and lead investigator of the study in a press release. “Representing a median follow-up of four years, this analysis adds to the robust body of clinical data supporting ZYTIGA® as an important treatment option for men with metastatic castration-resistant prostate cancer,” he added.
During the trial (49 months) there were no notable side effects, though ZYTIGA is not recommended for patients with severe hepatic impairment. Furthermore, the compound should also be used with caution in patients with a history of cardiovascular disease or with propensity to increases in blood pressure.
“This label update marks an exciting milestone for ZYTIGA and Janssen as we continue to focus on our commitment to patient care in the prostate cancer treatment space,” concluded Cynthia Guzzo, Vice President, Medical Affairs, Janssen Scientific Affairs, LLC.