Background: Managing patients ≥ 80 years old (yo) with mCRPC is challenging, given the high prevalence of comorbidities, polypharmacy, organ dysfunction, and reduced performance status (PS). Balancing treatment benefit with safety and quality of life is particularly germane for this group. Sipuleucel-T, an autologous cellular immunotherapy for mCRPC, is generally well-tolerated. Prior analyses from PROCEED, a large registry for sipuleucel-T in men with mCRPC, demonstrated that upregulation of immune cells in these elderly patients is similar to that of younger men. Here, we report on this clinical experience. Methods: PROCEED enrolled men with mCRPC treated with sipuleucel-T given every 2 weeks x 3, with no dose adjustment for organ dysfunction or drug interactions. The elderly cohort included those ≥ 80 yo. Men were followed until death, study withdrawal, or a minimum of 3 years. Results: Of 1902 patients who received ≥1 sipuleucel-T infusion, 374 (19.7%) were ≥ 80 yo. Compared to men < 80 yo (Table), this cohort was 14 years older, had worse Eastern Cooperative Oncology Group (ECOG) PS and higher prostate-specific antigen (PSA) at baseline. All grade (16.3% elderly v. 13.7% younger) and grade 3-5 (10.7% elderly v. 9.9% younger) serious adverse events were comparable between groups. However, the median overall survival (OS) of elderly men was 10.7 mo shorter than that of younger men (< 80 yo). Conclusions: Sipuleucel-T was generally well-tolerated in those ≥ 80 yo in a real-world setting and may be considered a first-line option for the elderly with asymptomatic or minimally symptomatic mCRPC. As expected, OS was shorter than in younger patients. Clinical trial information: NCT01306890

CI = confidence interval ^aKaplan-Meier