Bossi, Alberto

TPS5093 Background: Globally, docetaxel remains the standard of care for metastatic CRPC; however, its use may be delayed until pts develop symptoms. The presence of infiltrating leukocytes in CRPC tumors suggests a natural antitumor immune response is occurring. This is supported by an overall survival (OS) benefit reported in men with asymptomatic or minimally symptomatic metastatic CRPC who received sipuleucel-T. Ipi, a monoclonal antibody that binds CTLA-4, augments antitumoral activity of cytotoxic immune cells. Ipi demonstrated OS benefit in two phase III trials for advanced melanoma, with side effects that were managed using product-specific treatment guidelines. In phase I/II trials in metastatic CRPC, Ipi has shown clinical activity (as measured by prostate-specific antigen [PSA] declines and RECIST response) with a similar toxicity profile to that observed in melanoma. This global (149 sites in 24 countries) phase III study (ClinicalTrials.gov identifier: NCT01057810) evaluates Ipi vs placebo in chemotherapy-naïve pts with asymptomatic or minimally symptomatic CRPC without visceral metastases. Methods: The primary endpoint is OS; secondary endpoints include progression-free survival, time to pain progression, time to non-hormonal systemic therapy and safety characterization. The study is designed to detect a 9.3-month median difference (HR=0.7) in OS with 90% power and 0.05 two-sided significance. Pts are randomized at a 2:1 ratio to receive Ipi 10 mg/kg every 3 weeks for up to 4 doses or placebo as induction therapy. Eligible pts will receive maintenance therapy of blinded study drug every 12 weeks. The accrual goal is 600 pts randomized. Clinical trial information: NCT01057810. [Table: see text] [Table: see text]

IntroductionAdult prostatic sarcoma (PS) is a rare disease. While surgery is considered the standard approach, the role of other therapies is not completely established. We report results of the largest multicentric contemporary cohort of PS patients.Materials and MethodsThis study included 61 adult PS patients treated in 16 American and European Institutions. Median age was 64.4 years (range: 22‐87). Curative surgery was delivered in 48 patients (prostatectomy = 26, cystoprostatectomy = 22), usually with lymphadenectomy (n = 40). Curative radiotherapy (RT) was delivered in 32 patients, as radical (n = 5), neoadjuvant (n = 10), or postoperative treatment (n = 17). Eighteen patients received chemotherapy. None of the patients received hormonal therapy.ResultsMedian follow‐up was 72 months (95%CI: 55‐not reached). Five‐year local control (LC), overall survival (OS), cancer‐specific survival, disease‐free survival, and metastases‐free rates were 47%, 53%, 56%, 35%, and 35%, respectively. Notably, curative RT (neoadjuvant, adjuvant, or definitive) was associated with improved 5‐year LC (55% vs. 31%, P = 0.02) and OS (59% vs. 46%, P = 0.1). Surgically treated patients presenting with a cT3‐4 tumor (n = 31), who received RT (n = 24), had a significantly improved 5‐year LC (68% vs, 33%, P = 0.004) and OS (65% vs. 21%, P < 0.001) rates compared to patients not receiving RT. cT4 patients demonstrated a significantly lower 5‐year OS (43% vs. 61%, P = 0.006) and LC (29% vs. 69%, P < 0.001) rates. Histologic subtype was not associated with LC and OS, but patients with prostatic stromal sarcoma, rhabdomyosarcoma, or sarcomatoid carcinoma had worse 5‐year LC compared to other types (47% vs. 55%) and OS (49% vs. 58%).ConclusionAdult PS has a poor prognosis. Locally advanced tumors have poor LC and OS rates. Curative RT should be considered part of the multidisciplinary approach to PS.

2 Background: The CA184-043 phase 3 study did not reach statistical significance for its primary endpoint of OS (HR=0.85, p=0.053). However, antitumor activity was observed in other efficacy endpoints, including progression-free survival. Prespecified subset analyses were performed to understand if any prognostic features may identify mCRPC patients (pts) more likely to benefit from Ipi treatment. Methods: 799 pts were randomized to receive a single dose of radiotherapy (RT) followed by either Ipi (N=399) or Pbo (N=400). Prespecified subset analyses based on Kaplan-Meier/Cox methodology were performed using known prognostic factors for OS in mCRPC. Results: Prespecified subset analyses suggested that Ipi may be more active in pts with favorable prognostic factors, including no visceral disease, alkaline phosphatase <1.5 ULN, and hemoglobin ≥11 g/dL (Table). The safety profile in this study was consistent with previous reports of Ipi. Conclusions: Based on these subset analyses, Ipi added to RT appears to have greater activity than RT alone in pts with a favorable prognostic profile. These results support continued investigation of Ipi in the ongoing CA184-095 study in chemotherapy-naive mCRPC pts. Clinical trial information: NCT00861614. [Table: see text]