ON FEBRUARY 7, 2018, the U.S. Food and Drug Administration (FDA) approved abiraterone acetate (Zytiga) tablets in combination with prednisone for metastatic high-risk castration-sensitive prostate cancer.
The FDA initially approved abiraterone acetate with prednisone in 2011 for patients with metastatic castration-resistant prostate cancer who had received prior chemotherapy. The indication was expanded in 2012 to include patients with metastatic castration-resistant prostate cancer who have not yet had chemotherapy.
THE CURRENT APPROVAL was based on LATITUDE, a placebo-controlled international clinical trial that randomized 1,199 patients with metastatic high-risk castration-sensitive prostate cancer. Patients received either abiraterone acetate at 1,000 mg orally once daily with prednisone at 5 mg once daily (n = 597), or matching placebos orally once daily (n = 602). Patients in both arms received a gonadotropin-releasing hormone or had a bilateral orchiectomy.
The major efficacy endpoint was overall survival. Median overall survival was not estimable in the abiraterone acetate arm and 34.7 months in the placebo arm (hazard ratio [HR] = 0.621, 95% confidence interval [CI] = 0.509–0.756; P < .0001).
The median time to initiation of chemotherapy was not reached for patients on abiraterone acetate with prednisone and 38.9 months for those receiving placebos (HR = 0.44, 95% CI = 0.35–0.56; P < .0001).
The most common adverse reactions in at least 5% of patients receiving abiraterone acetate on LATITUDE were hypertension, hot flush, hypokalemia, increased alanine aminotransferase or aspartate aminotransferase, headache, urinary tract infection, upper respiratory tract infection, and cough.
The recommended dose for abiraterone acetate for metastatic castration-sensitive prostate cancer is 1,000 mg orally once daily with prednisone at 5 mg orally once daily. Patients receiving abiraterone acetate should also receive a gonadotropin-releasing hormone analog concurrently or should have had bilateral orchiectomy.
Full prescribing information is available at www.accessdata. fda.gov/drugsatfda_docs/label/2018/202379s024lbl.pdf. ■