Some mornings we just wake up to great news and today is one of those mornings. The Food and Drug Administration (FDA) has just announced that they have approved Zytiga (abiraterone acetate) for use prior to chemotherapy.
This FDA announcement is an expansion of their prior approved (April 2011) for the use of Zytiga to treat men with late-stage (metastatic) castration-resistant advanced prostate cancer after treatment with chemotherapy (docetaxel).
Zytiga is taken in as a pill. It works by dramatically decreasing the production of male sex hormone testosterone, even after the more traditional forms of hormone therapy no longer are effective.
“Today’s approval demonstrates the benefit of further evaluating a drug in an earlier disease setting and provides patients and health care providers the option of using Zytiga earlier in the course of treatment,” said Richard Pazdur, M.D., director of the Office of Oncology Drug Products in the FDA’s Center for Drug Evaluation and Research.
Zytiga’s safety and effectiveness for its expanded use were established in a clinical study of 1,088 men with late-stage, castration-resistant prostate cancer who had not previously received chemotherapy. In this study participants received either Zytiga or a placebo (sugar pill) in combination with prednisone. The results between these two groups were then compared by measuring the length of time a patient lived before death (overall survival) and the length of time a patient lived without further tumor growth as assessed by imaging studies (radiographic progression-free survival, or rPFS).
Men who received Zytiga had a median overall survival of 35.3 months compared with 30.1 months for those receiving the placebo. Study results also showed Zytiga improved rPFS. The median rPFS was 8.3 months in the placebo group and had not yet been reached for patients treated with Zytiga at the time of analysis.
The study reported that the most common side effects reported in those receiving Zytiga include fatigue, joint swelling or discomfort, swelling caused by fluid retention, hot flush, diarrhea, vomiting, cough, high blood pressure, shortness of breath, urinary tract infection, and bruising.
The most common laboratory abnormalities included low red blood cell count; high levels of the enzyme alkaline phosphatase, which can be a sign of other serious medical problems; high levels of fatty acids, sugar, and liver enzymes in the blood; and low levels of lymphocytes, phosphorous and potassium in the blood.
Zytiga now offers another FDA approved option for men with advanced prostate cancer before they move on to chemotherapy (using docetaxel). Many oncologists have already been using Zytiga prior to chemotherapy, but some insurance companies have refused to pay for it prior to chemotherapy failure. This new approval should eliminate this issue as soon as these insurance companies adjust their records.
Joel T Nowak, M.A., M.S.W.