A phase II study combining ipilimumab and degarelix with or without radical prostatectomy (RP) in men with newly diagnosed metastatic noncastration prostate cancer (mNCPC) or biochemically recurrent (BR) NCPC.

Abstract

203 Background: Androgen deprivation therapy (ADT) does not completely eliminate disease in mNCPC or BRPC. We explored a multimodality treatment (tx) approach combining ADT with ipilimumab (ipi) with the aim of achieving no evidence of disease or complete elimination of disease, given the potential for cure seen with immunotherapy. Methods: Cohort A (Coh A) enrolled men with ≤ 10 bone metastases treated with induction of degarelix (deg) and ipi prior to RP and subsequent ipi q3 weeks x 3 and 8 months (mos) total of deg. Cohort B (Coh B) opened later and enrolled men with BRNCPC after RP with a doubling time ≤ 12 mos, and received ipi q3 weeks x 4 and 8 mos of deg. The primary endpoint was an undetectable PSA (<0.05) at 12 and 20 mos with non-castrate testosterone. Results: 16 pts (7 Coh A; 9 Coh B) were treated. No Coh A pts experienced immune related toxicities (irAE) that delayed surgery. 4/7 (57%) Coh A pts came off study for irAE, 1 (14%) for insurance reasons, and 2 (29%) completed all protocol requirements. In Coh B 6/9 (67%) pts have completed tx and entered follow-up. Conclusions: A combined modality approach with ipi 10mg/kg, ADT, and RP in mNCPC was associated with limiting toxicities, however 3mg/kg was better tolerated and more feasible in a BRNCPC cohort. One pt in Coh A (14%) had an undetectable PSA with testosterone recovery while evaluation of efficacy for Coh B is ongoing. The role for RP and other immunotherapeutic approaches in NCPC remain viable interests to the field. Clinical trial information: NCT02020070. [Table: see text]