Background: Phase III trials evaluating enzalutamide or abiraterone in MP-CRPC prior to docetaxel report a median survival of 35 months. SIP-T functions by stimulating cancer-specific dendritic cells and prolongs survival. IPI showed a borderline survival advantage in a large randomized trial. Thus, there may be potential synergy with SIP-T and IPI (SIPIPI) in combination. Methods: Between April 2013 and April 2014, 9 docetaxel-naive men with MP-CRPC were treated prospectively with SIP-T followed immediately by low-dose IPI 1 mg/kg given for a total of 1 to 3 doses every three weeks. As has been previously published (Immuno Targets and Therapy, March 2017), cancer-specific immunoglobulins (IGS) directed at PA2024 and PAP showed a statistically-significant increase after SIP-T and a further statistically-significant increase, above the level achieved with SIP-T, after IPI. Three patients died from progressive disease after 9, 18, and 20 months. This abstract updates the outcome and survival of the remaining 6 patients. Results: Adverse events from SIPIPI were negligible. For the 9 men, the median age, Gleason score, and number of previous hormonal interventions were 77 years, 8, and 3, respectively. Median baseline PSA and Gleason score were 1.7 and 8, respectively. Eight men had bone metastases and 1 had lymph node metastasis. For the 6 surviving men, median follow-up since SIPIPI is 50.5 months (40-53). Their median PSA as of September 2017 is 5.5 (range: 0.27–18.10). Further treatment since SIPIPI includes abiraterone (4) enzalutamide (5) radium-223 (3) docetaxel (2) cabazitaxel (1) carboplatin (1) pembrolizumab (2) and Olaparib (1). One patient continues with a stable PSA of 0.27 without any further treatment post SIPIPI except SBRT. Conclusions: In this small trial of SIPIPI performed in men with docetaxel-naive MP-CRPC, median survival has now surpassed 4 years and the 6 surviving men still maintain a relatively low median PSA of 5.5. One man continues in durable remission without any further therapy except SBRT administered immediately post IPI.