SUO 2018: Qualitative and Quantitative Evidence of Sipuleucel-T Induced PAP and PA2024 Specific CD8+ Cytolytic Response and its Association with Overall Survival

Phoenix, Arizona ( In this oral abstract presentation, Dr. Kibel presented a multi-institutional analysis assessing sipuleucel-T induced peripheral cellular and humoral immune response to prostatic acid phosphatase and/or PA2024. Previous studies have demonstrated that CD4 and CD8 T cells at the prostate tumor rim after neoadjuvant sipuleucel-T leads to an immune response that may mediate clinical survival benefits. To evaluate this, Kibel’s group evaluated T cell-induced cytolysis and assessed the relationship of PAP and PA2024 specific cytolytic response with survival. Flow cytometry was utilized to assess cytolytic activity with CD8 positive cells measured at baseline, 6 weeks, and 26 weeks. Real time imaging of cytolytic activity was also performed.

Dr. Kibel summarized his groups findings that cytolytic activity showed statistically significant increases at weeks 6 and 26, with the degree of cytolytic activity correlated with overall survival rates. Video evidence was provided at these time points where CD8+ T cells migrated toward PAP target cells, resulting in cell death. Additionally, cell destruction was not observed in cells which did not express PAP.

This study is thought-provoking as it provides evidence and the potential mechanism of action of sipuleucel-T induced PAP specific CT8 T cell mediated responses. Moreover, the degree of OS and magnitude of cytolytic activity has been correlated.

Presented By: Adam S. Kibel, MD

Written by: David B. Cahn, DO, MBS, Fox Chase Cancer Center, Philadelphia, PA, @dbcahn, at the 19th Annual Meeting of the Society of Urologic Oncology (SUO), November
28-30, 2018 – Phoenix, Arizona

Newsletter subscription

Free Daily and Weekly newsletters offered by content of interest

The fields of GU Oncology and Urology are rapidly advancing. Sign up today for articles, videos, conference highlights and abstracts from peer-review publications by disease and condition delivered to your inbox and read on the go.