ASCO 2017: LATITUDE Trial: Addition of Abiraterone to Standard Hormonal Therapy Improves Outcomes in Newly Diagnosed Metastatic Prostate Cancer

Key Points

  • At a median follow-up of 30.4 months, men who received abiraterone had a 38% lower risk of death than those who received placebo.
  • The median overall survival had not yet been reached in the abiraterone group and was 34.7 months in the placebo group.
  • Abiraterone was also associated with a 53% lower risk of the cancer worsening and resulted in cancer growth being delayed by a median of 18.2 months. 

Adding abiraterone acetate (Zytiga) plus prednisone to standard hormonal therapy for men newly diagnosed with high-risk, metastatic prostate cancer lowers the chance of death by 38%. In a phase III clinical trial of 1,200 men, abiraterone also more than doubled the median time until the cancer worsened, from 14.8 months to 33 months. These data were presented today by Fizazi et al at the 2017 ASCO Annual Meeting (Abstract LBA3).

“There is a large unmet need to improve treatment for men with newly diagnosed metastatic cancer, who die of the disease within less than 5 years on average,” said lead study author Karim Fizazi MD, PhD, Head of the Department of Cancer Medicine at Gustave Roussy, University Paris-Sud in Villejuif, France. “The benefit from early use of abiraterone we saw in this study is at least comparable to the benefit from docetaxel chemotherapy, which was observed in prior clinical trials, but abiraterone is much easier to tolerate, with many patients reporting no side effects at all.”

Prostate cancer growth is fueled by testosterone. Androgen-deprivation therapy is active against prostate cancer by preventing the testicles from making testosterone. Despite androgen-deprivation therapy, the adrenal glands and prostate cancer cells continue making small amounts of androgens. Abiraterone stops the production of testosterone throughout the body by blocking an enzyme that converts other hormones to testosterone. The U.S. Food and Drug Administration previously approved abiraterone for patients with metastatic prostate cancer that worsened despite androgen-deprivation therapy.

About the LATITUDE Trial

LATITUDE is a multinational, randomized placebo-controlled phase III clinical trial of men with newly diagnosed, high-risk metastatic prostate cancer who had not previously received androgen-deprivation therapy. All patients had at least two of three risk factors: Gleason score of 8 or more, 3 or more bone metastases, or 3 or more visceral metastases.

The patients were randomly assigned to receive androgen-deprivation therapy plus abiraterone and prednisone or androgen-deprivation therapy plus placebo. Corticosteroid prednisone is routinely given with abiraterone to manage certain side effects of abiraterone, such as low potassium or high blood pressure.

Key Findings

At a median follow-up of 30.4 months, men who received abiraterone had a 38% lower risk of death than those who received placebo. The median overall survival had not yet been reached in the abiraterone group and was 34.7 months in the placebo group. Abiraterone was also associated with a 53% lower risk of the cancer worsening and resulted in cancer growth being delayed by a median of 18.2 months.

Several severe side effects were more common with abiraterone acetate and prednisone than placebo: high blood pressure (in 20% vs 10% of men), low potassium level (10.4% vs 1.3%), and liver enzyme abnormalities (5.5% vs 1.3%).

“We need to be cautious when using abiraterone in men who have an increased risk for heart problems, such as those with diabetes,” said Dr. Fizazi.

Commentary

“For men who are diagnosed with advanced prostate cancer, treatment has evolved into more effective approaches, first with chemotherapy and now with abiraterone. This is good news because using abiraterone could help many people live longer, with fairly few additional side effects,” said Sumanta Kumar Pal, MD, an ASCO expert.

This study was funded by Janssen Research and Development.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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