Mehmet Asim Bilen1, Kenneth R Hess2, Sumit K Subudhi3, Ana Aparicio3, Jeri Kim3, Amado J Zurita-Saavedra3, John C Araujo3, Paul G Corn3, Jessica Stover3, Sue-Hwa Lin4, Christopher J Logothetis3, Shi-Ming Tu5. 1. Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, 1365 Clifton Road NE, B4301, Atlanta, GA, 30322, USA. mbilen@emory.edu. 2. Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA. 3. Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA. 4. Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA. 5. Department of Genitourinary Medical Oncology, Unit 1374, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX, 77030-3721, USA. stu@mdanderson.org.
Abstract
BACKGROUND: We evaluated the patterns of progression and determined clinical predictors of survival in patients with castration-resistant prostate cancer (CRPCa) who received sipuleucel-T. METHODS: We retrospectively analyzed 56 consecutive patients with asymptomatic or minimally symptomatic CRPCa treated with sipuleucel-T. Age, number of bone metastases, history of prior systemic treatment, and alkaline phosphatase level (ALP) were tested as predictors of survival in a multivariate Cox proportional hazards regression model. The Kaplan-Meier method was used to estimate event-free probabilities. RESULTS: The 56 patients were a median age of 67 years (range 51-84 years). After sipuleucel-T treatment, 25 patients developed bone progression after a median of 22 months of follow-up (54% of patients were event free at 2 years) and 10% (6/56 patients) developed rapid progression. Eleven deaths were observed after a median of 28 months of follow-up. Forty-eight patients were included in the multivariate analysis for overall survival. The analysis showed that age >70 years (p = 0.012), number of bone metastases >20 (p = 0.018), prior systemic treatment (p = 0.018), and ALP level >90 IU/L (p = 0.010) significantly predicted worse overall survival. Two-year overall survival was 36% among the 16 patients with two or more of these factors and was 93% among the 32 patients with one or none of these factors (p = 0.0004). CONCLUSIONS: CRPCa patients with age (>70 years), increased tumor burden in bone (>20 metastases and/or elevated ALP level), and/or prior systemic treatment are more likely to experience rapid deterioration after sipuleucel-T. These results need to be prospectively validated.
BACKGROUND: We evaluated the patterns of progression and determined clinical predictors of survival in patients with castration-resistant prostate cancer (CRPCa) who received sipuleucel-T. METHODS: We retrospectively analyzed 56 consecutive patients with asymptomatic or minimally symptomatic CRPCa treated with sipuleucel-T. Age, number of bone metastases, history of prior systemic treatment, and alkaline phosphatase level (ALP) were tested as predictors of survival in a multivariate Cox proportional hazards regression model. The Kaplan-Meier method was used to estimate event-free probabilities. RESULTS: The 56 patients were a median age of 67 years (range 51-84 years). After sipuleucel-T treatment, 25 patients developed bone progression after a median of 22 months of follow-up (54% of patients were event free at 2 years) and 10% (6/56 patients) developed rapid progression. Eleven deaths were observed after a median of 28 months of follow-up. Forty-eight patients were included in the multivariate analysis for overall survival. The analysis showed that age >70 years (p = 0.012), number of bone metastases >20 (p = 0.018), prior systemic treatment (p = 0.018), and ALP level >90 IU/L (p = 0.010) significantly predicted worse overall survival. Two-year overall survival was 36% among the 16 patients with two or more of these factors and was 93% among the 32 patients with one or none of these factors (p = 0.0004). CONCLUSIONS: CRPCa patients with age (>70 years), increased tumor burden in bone (>20 metastases and/or elevated ALP level), and/or prior systemic treatment are more likely to experience rapid deterioration after sipuleucel-T. These results need to be prospectively validated.