Zytiga Approved by Health Canada

ZYTIGA™* (abiraterone acetate) receives Health Canada approval for treatment for metastatic prostate cancer

First Oral Treatment for Metastatic Prostate Cancer That Inhibits Androgen Production at All Three Sources

Janssen Inc. announced that after a priority review, Health Canada has approved ZYTIGA™ (abiraterone acetate), an oral medication for the treatment of men with metastatic prostate cancer. ZYTIGA™ is indicated with prednisone for the treatment of men with metastatic prostate cancer (castration-resistant prostate cancer) who have received prior chemotherapy containing docetaxel.

“This approval is an important advancement in the treatment of metastatic prostate cancer,” said Dr. Scott North, Medical Oncologist, Cross Cancer Institute, University of Alberta. “For these patients, the efficacy and safety of ZYTIGA™ will fill an important unmet medical need for additional treatment options. Most importantly, clinical trial results demonstrate extended overall survival and improved pain relief. I believe these benefits provide improved quality of life for many patients.”

ZYTIGA™: Unique Mechanism of Action

Androgens are hormones that promote the development and maintenance of male sex characteristics; however, in prostate cancer, androgens can help fuel tumour growth. Androgen production primarily occurs in the testes and adrenal glands; in men with prostate cancer, the tumour itself is an additional source of androgen. ZYTIGA™ is an androgen biosynthesis inhibitor that inhibits the CYP17 enzyme complex, which is required for the production of androgens. It is the first oral treatment for metastatic prostate cancer that inhibits androgen production at all three sources.

Results of the pivotal Phase 3 study (N=1,195) showed that at the pre-specified interim analysis, treatment with ZYTIGA™ plus prednisone resulted in a 35 per cent reduction in the risk of death (14.8 months vs. 10.9 months) and a 3.9 month difference in median survival compared to placebo plus prednisone. In an updated analysis, results were consistent with those from the interim analysis with a 4.6 month difference between the two arms in median survival (15.8 months vs. 11.2 months). The study was conducted in 147 centres in 13 countries, including 12 centres in Canada; 154 Canadian men participated in the study, which represents approximately 13 per cent of the study population.

“This new treatment is important to me because the oral dosage is very manageable and convenient and I spend less time in treatment,” said Richard Pokorny, who has been living with prostate cancer for 11 years. “I also feel stronger and have more energy, allowing me to do day-to-day tasks and enjoy quality time with my loved ones as we face this disease together.”

About Metastatic Prostate Cancer

Metastatic prostate cancer occurs when cancer has spread beyond the prostate and disease progresses despite serum testosterone below castrate levels.

Prostate cancer is the most common cancer to afflict men in Canada, excluding non-melanoma skin cancer.3 Approximately 25,500 men are expected to be diagnosed with prostate cancer in Canada in 2011, and one in seven Canadian men will develop prostate cancer during his lifetime.3 The incidence rate of prostate cancer has been increasing since 1980, likely due to an increased rate of early detection and the aging population since the chances of developing prostate cancer increases with age.3 However, according to Prostate Cancer Canada, prostate cancer is turning up in men in their 40s.4

Pivotal Study

ZYTIGA™ with prednisone was evaluated in a Phase 3, randomized, placebo-controlled, multi-centre clinical study in patients who had received prior chemotherapy containing docetaxel (N = 1,195). Patients were randomized 2:1 to receive ZYTIGA™ 1 gram daily plus prednisone 10 milligrams (mg) daily or placebo in combination with prednisone 10 mg daily (control arm).

The most common adverse reactions observed with ZYTIGA™ were myopathy, joint pain or discomfort, peripheral edema, hot flush, diarrhea, hypokalemia (low serum potassium), urinary tract infection and cough. Serious adverse reactions with ZYTIGA™ included urinary tract infections, bone fracture and hypokalemia.