Neoadjuvant Enoblituzumab (MGA271) in Men With Localized Intermediate and High-Risk Prostate Cancer

This is a single-center, single arm, open-label phase II study evaluating the safety, anti-tumor effect, and immunogenicity of neoadjuvant MGA271 given prior to radical prostatectomy in men with intermediate and high-risk localized prostate cancer. Eligible patients will receive MGA271 at a dose of 15mg/kg IV given weekly for 6 doses beginning 50 days prior to radical prostatectomy. 14 days after the last dose of MGA271, prostate glands will be harvested at the time of radical prostatectomy, and prostate tissue will be examined for the secondary endpoints. Follow-up evaluation for adverse events will occur 30 days and 90 days after surgery. Patients will then be followed by their urologists according to standard institutional practices, but will require PSA evaluations every 3 (±1) months during year 1 and every 6 (±2) months during years 2-3. In Amendment 1, the study was expanded to enroll an additional 16 patients for a total of 32 patients to continue evaluating safety and better estimate the clinical benefit of Enoblituzumab in terms of undetectable PSA level (\<0.1 ng/mL) at 12 months following radical prostatectomy.