Today the U.S. Food and Drug Administration (FDA) lengthened the approved use of Zytiga (abiraterone acetate) as treatment for men with late-stage, castration-resistant prostate cancer (metastatic) before undergoing chemotherapy.

First approved in 2011, Zytiga is used in patients whose prostate cancer developed further after treatment with docetaxel, a chemotherapy drug. Zytiga is a pill that reduces the production of testosterone, the male sex hormone.

This drug is known to preserve quality of life, reduce the spread of cancer, as well as slow the development of pain and the decline of an individual’s overall health, according to a study released earlier this year.

A separate study also recommended Zytiga in combination with prednisone for late-stage, castration-resistant prostate cancer, and showed that Zytiga is being used successfully in over 40 different countries.

Tumor growth during prostate cancer is triggered by testosterone. Surgery or drugs are used to decrease the effects or block creation of testosterone.

Castration-resistant prostate cancer is when the prostate cancer cells keep growing even without large amounts of testosterone.

Richard Pazdur, M.D., director of the Office of Oncology Drug Products in the FDA’s Center for Drug Evaluation and Research, says,

“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.”

The FDA examined the application for this altered use of Zytiga under the agency’s priority review program. This specific program gives an accelerated six-month examination for drugs that may give major benefits in treatment or offer a treatment when no current therapy exists.

A clinical study was conducted using 1,088 men with late-stage, castration-resistant prostate cancer who had not yet undergone chemotherapy which established the successfulness and safety of Zytiga.

The study was developed to calculate the length of time a patient existed before death as well as the amount of time a patient lived without further tumor development. These two time periods were measured by imaging known as radiographic progression-free survival, or rPFS.

Patients who took Zytiga had a medical survival rate of 35.3 months, while those taking a placebo had a 30.1 month survival rate. Results showed that Zytiga enhanced rPFS. The median rPFS was 8.3 months in the placebo group, while in the other group had not been achieved yet at the time of calculation.

Side effects that were seen included:

The most frequently documented laboratory abnormalities were:

  • high levels of the enzyme alkaline phosphatase
    -this could be a sign of other medical problems
  • low levels of potassium, lymphocytes, and phosphorous in the blood
  • high levels of fatty acids, liver enzymes, and sugar in the blood

Written by Kelly Fitzgerald