FDA Approves Zytiga Pre Chemotherapy

The FDA have approved Zytiga for use before chemotherapy it was announced today. This is tremendous news and puts Zytiga in its rightful place as a treatment option once conventional androgen deprivation therapy (ADT) has failed but before chemotherapy is needed. Zytiga is the actually the ultimate form of ADT since it induces total androgen blockade by inhibiting the biosynthesis of all androgens, so it makes sense to use Zytiga when less effective forms of ADT such as LHRH agonists have failed. Zytiga was designed as a safer option than chemotherapy so it is appropriate that Zytiga is now approved before the use of chemotherapy.

The FDA approval was based on the results from the COU-302 phase 3 clinical trials conducted on patients who had not received chemotherapy. The announcement from The FDA is as follows.

FDA expands Zytiga’s use for late-stage prostate cancer
Drug can now be used before treatment with chemotherapy
The U.S. Food and Drug Administration today expanded the approved use of Zytiga (abiraterone acetate) to treat men with late-stage (metastatic) castration-resistant prostate cancer prior to receiving chemotherapy.
The FDA initially approved Zytiga in April 2011 for use in patients whose prostate cancer progressed after treatment with docetaxel, a chemotherapy drug. Zytiga is a pill that decreases the production of male sex hormone testosterone.
In prostate cancer, testosterone stimulates prostate tumors to grow. Drugs or surgery are used to reduce testosterone production or to block testosterone’s effects. Some men have castration-resistant prostate cancer, meaning the prostate cancer cells continue to grow even with low levels of testosterone.
“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.
The FDA reviewed Zytiga’s application for this new indication under the agency’s priority review program. The program provides for an expedited six-month review for drugs that may offer major advances in treatment or provide a treatment when no adequate therapy exists.
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. Participants received either Zytiga or a placebo in combination with prednisone.
The study was designed to measure 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).
Patients 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 been reached for patients treated with Zytiga.