Oliver Sartor, MD
The median overall survival (OS) for African-American patients who received sipuleucel-T (Provenge) as a treatment for metastatic castrate-resistant prostate cancer (CRPC) increased by nearly a year when compared with Caucasian patients, based on preliminary data from the PROCEED registry presented at the 2017 American Urological Association.
, Sartor, a medical oncologist at the Tulane University School of Medicine, discussed the analysis of African-American men receiving sipuleucel-T for CRPC compared with Caucasians, and the implications of this research.
OncLive: Can you give an overview of this study?
I think most individuals are familiar with sipuleucel-T as it's been FDA approved since 2010. As part of that initial approval, the FDA requested more analyses. The response was to put together a registry called PROCEED. There are more than 1900 patients in the registry and this was a real-world experience where individuals who are receiving sipuleucel-T commercially have their various demographics and basic biochemical levels put into a database. They are followed for survival along with additional therapies. It's a simple concept of people treated with sipuleucel-T.
What were the most significant findings?
The analysis was focused on African-Americans as compared to Caucasians. Unlike many studies in the past, there was a very positive effect for African-American patients. In fact, it was surprisingly large. The basic punchline for this study is: African-Americans see more of a benefit with sipuleucel-T based on the PROCEED registry report.
The way we did the analysis was relatively convincing. We know PSA is important when it comes to predicting sipuleucel-T responsiveness and survival. We matched 420 Caucasians with 210 African-Americans looking at all their PSA scores. We then looked at a multivariate analysis to make sure that African-Americans would continue to have the effect when other factors, such as hemoglobin and alkaline phosphate were taken into account. The bottom line is we had a multivariate analysis, which in my opinion is quite convincing.
Can you explain the science behind these results?
There are 2 basic theses that you could propose. The first is that the immune system is reacting more appropriately in African-Americans—meaning the immune system in African-Americans is more effective at slowing cancer growth.
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