Effect of prior abiraterone (ABI) or enzalutamide (ENZ) on sipuleucel-T (sip-T) manufacture in PROCEED patients (pts).

185 Background: Sip-T is an autologous cellular immunotherapy indicated for asymptomatic or minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC). PROCEED is an ongoing phase 4 registry, enrolling pts receiving commercial sip-T. There are no exclusions based on prior prostate cancer treatments, so sip-T product parameters can be evaluated in pts receiving prior hormonal agents such as ABI or ENZ. Methods: Pts treated with sip-T within ≤6 mo were eligible to provide informed consent. Prior anticancer interventions were recorded at baseline. Sip-T product parameters were assessed. Results: Of 1,376 pts (as of May 2013), 108 (7.8%) received prior ABI and 58 (4.2%) received ENZ. Patients with ABI or ENZ generally had more advanced disease vs. pts without prior ABI or ENZ (WPT) and a greater proportion of the ABI and ENZ pts received prior docetaxel. There were slight differences in some sip-T product parameters in the ABI and ENZ groups, but neither manufacture nor receipt of sip-T wer...