Real-World PSA Response Data Similar to Clinical Trials in Prostate Cancer

Stephen J. Freedland, MD, Warschaw Robertson Law Families Chair in Prostate Cancer, director, Center for Integrated Research in Cancer and Lifestyle, co-director, Cancer Genetics and Prevention Program, associate director, Faculty Development Samuel Oschin Comprehensive Cancer Institute, and professor of surgery, Cedars-Sinai Medical Center, discusses real-world data for enzalutamide (Xtandi) as treatment of patients with metastatic castration-resistant prostate cancer compared with data from the phase III PREVAIL study.

Relatively similar results were observed in the real-world data versus the PREVAIL study, which evaluated chemotherapy-naive patients who received enzalutamide. Freedland says the median prostate-specific antigen (PSA) decline was about 58%, and about 14% of patients had undetectable PSA levels.

A subset of patients did not respond to the treatment at all, and their PSA kept increasing, Freedland says. However, we know there can be inherent resistance to hormonal therapy. The median time to progression in this subset of patients was 18.5 months, Freedland also notes the reduction in PSA levels were a little lower perhaps because of drug compliance issues or investigators did not check PSA levels frequently enough to detect the best PSA decline. Time to PSA rise was a little longer, Freedland concludes.

Overall, these data are relatively similar to what has been observed in other trials. This gives researchers hope that patients can receive these drugs and experience similar benefits to what has been seen in clinical trials.

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