Sipuleucel-T product characterization across different disease states of prostate cancer.

42 Background: Sipuleucel-T is an autologous cellular immunotherapy approved for the treatment of asymptomatic or minimally symptomatic metastatic castrate resistant prostate cancer (mCRPC). In the Phase 3 mCRPC trials, antigen presenting cell (APC) activation in sipuleucel-T correlated with overall survival. Here product characteristics of sipuleucel-T were compared in patients (pts) from trials in the neoadjuvant (n=42), asymptomatic or minimally symptomatic mCRPC (n=341), and mCRPC (n=104) disease states. Methods: Sipuleucel-T comprises 3 treatments approximately 2 wks apart. Cellular composition and APC activation (CD54 upregulation) were evaluated in all courses of sipuleucel-T, and cumulative CD54 upregulation was calculated for each patient. In some studies, cytokines were assayed from culture supernatants and T cell and B cell activation markers were assessed by flow cytometry during manufacture. Results: Baseline demographics were generally representative of each disease state; neoadjuvant pts we...