Prostate Cancer Drug Too Good To Test

Zytiga trial stopped due to impressive results

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Having a clinical trial canceled is a nightmare for researchers.  If the trial stops, researchers want it to be like this.

A study showed that adding abiraterone (Zytiga) to the treatment of advanced prostate cancer slowed the cancer progression, extended survival time, and resulted in patients having longer periods without any symptoms.

The results from the trial were so good, in fact, researchers switched the placebo group over to Zytiga halfway through the trial.

"Ask your oncologist about new treatments."

Study author Charles J. Ryan, MD, of the University of California, San Francisco gave the presentation at the American Society for Clinical Oncology's annual meeting detailing preliminary findings from the clinical trial, explaining that the placebo group was switched over to Zytiga because it would be unethical to deny patients in the trial access to the cancer drug.

"These results are the culmination of years of research, and will truly transform the way we take care of patients with advanced prostate cancer,'' said Eric J. Small, MD, a UCSF professor who worked with Dr. Ryan on Zytiga for the past nine years.

"This drug extended lives and gave patients more time when they weren't experiencing significant pain from the disease,'' concluded Dr. Ryan.

Final analysis from the trial including all study data and conclusions will be published sometime in 2014.

According to researchers, Zytiga blocks the production of hormones associated with prostate cancer growth, which slows down the cancer considerably.

The study followed 1,088 men at 151 cancer facilities throughout the world, with an average diagnosis of prostate cancer five years prior. Patients were randomly assigned to predisone plus Zytiga or prednisone with placebo.

All patients in the trial were switched to Zytiga from placebo in March after researchers concluded there was clear evidence the drug extended survival, slowed cancer progression, lowered pain medication needs, and improved general quality of life.

The time before further progression of the cancer was eight months in the placebo group and fifteen months in the Zytiga group.

Susan Halabi, PhD, of Duke University Medical Center, agreed that the potential for Zytiga was great, but since the trial was the first extensive testing of Zytiga, researchers should have continued as planned.

“The decision to stop a trial early is complex, requiring a combination of both statistical and clinical judgment,” Halabi stated. “Stopping a trial too early may fail to persuade others to change medical practice.”

Findings from research presented at conferences should be considered preliminary until published in a peer-reviewed journal.

Researchers involved in the study disclosed ties to Cougar Biotechnology, Johnson&Johnson, The Institute of Cancer Research, Janssen Research and Development, Amgen, Astellas Pharma, AstraZeneca, Bayer, GlaxoSmithKline, Novartis, Pfizer, Aragon Pharmaceuticals, Bristol-Myers Squibb, Dendreon, Exelixis, Medivation, Millennium, Ortho Biotech, Sanofi, Senior Scientific LLC, and Veridex.

Reviewed by: 
Review Date: 
June 8, 2012
Last Updated:
September 13, 2012