Phase 2, randomized, 3-arm study of abiraterone acetate and prednisone (AAP), AAP plus degarelix (AAP+D), and degarelix (D) alone for patients (pts) with biochemically-recurrent prostate cancer (PC) following radical prostatectomy (RP).

5016Background: Androgen deprivation therapy (ADT) with GnRH analogs does not entirely suppress androgen signaling. AAP + ADT decreases blood and intratumoral testosterone (T) levels by ≥1 log, and in pre-RP trials resulted in greater pathologic responses relative to ADT alone. Trial designs that can rapidly assess therapies (txs) are critical given the long natural history of PC and resources required for phase 3 trials. Using a novel endpoint (endpt) (undetectable PSA [PSA0] with T recovery [rec]), we hypothesized that AAP+D given in the rising PSA state post-RP, a low volume but potentially lethal setting, could eliminate all disease, a prerequisite to cure. Methods: Post RP ± salvage radiotherapy pts with a rising PSA ≥1.0 ng/ml, doubling time ≤9 months (mo), no metastases (met) on CT/bone scan, and T ≥150 ng/dl were eligible [NCT01751451]. Prior ADT ≤8 mo was allowed. Pts were randomized (1:1:1) to AA 1000 mg + P 5 mg QD (Grp 1), AAP + monthly D (Grp 2), or monthly D (Grp 3) for 8 mo, followed by ces...