Experimental drug shows promise against prostate cancer

An experimental drug called abiraterone appears to halt the production of male hormones anywhere in the body, making it a promising treatment for prostate cancer patients whose tumors have continued to grow despite hormone therapy or surgical removal of the testicles.

In a phase I clinical trial in England, 21 men with prostate cancer that was resistant to multiple hormone therapies took abiraterone once a day. Over all, 14 of the men saw their PSA, a marker of prostate cancer activity, drop by 30%, a decline that lasted for more than three months; six men experienced a drop in PSA of 90% or more.

In addition to changes in PSA, CT and bone scans showed that metastases in lymph nodes, lungs, and bone were shrinking in some patients. And eight of 11 patients who required medication for pain before the start of the study either reduced the dose or stopped the medication completely while on abiraterone.

Based on the results of this study, researchers have launched phase II trials in a larger number of patients, some of whom have cancer that is also resistant to the chemotherapy drug docetaxel (Taxotere). To learn more about these trials, log on to www.clinicaltrials.gov and search for “abiraterone” and “prostate cancer.”

SOURCE: Attard G, Reid AH, Yap TA, et al. Phase I Clinical Trial of a Selective Inhibitor of CYP17, Abiraterone Acetate, Confirms That Castration-Resistant Prostate Cancer Commonly Remains Hormone Driven. Journal of Clinical Oncology 2008; E-publication, July 21, 2008. PMID: 18645193.

[Editor’s note: Based on results of a phase III clinical trial showing that patients who took abiraterone lived about four months longer than those who didn’t, the FDA approved abiraterone (Zytiga) on April 28, 2011.]

Originally published April 2009; last reviewed May 2, 2011.