LBA63 - PRESTO: A phase III, open-label study of androgen annihilation in patients (pts) with high-risk biochemically relapsed prostate cancer (AFT-19)

Background

Pts with biochemically relapsed prostate cancer (BRPC) following radical prostatectomy (RP) and a short PSA doubling time (PSADT) are at risk for distant metastases. Apalutamide (APA), an androgen receptor (AR) antagonist, and abiraterone acetate plus prednisone (AAP), prolong survival in the metastatic setting. We evaluated if intensification of androgen deprivation therapy (ADT) prolongs biochemical progression-free survival (bPFS) in BRPC.

Methods

PRESTO is a randomized phase III, open-label trial in pts with BRPC and PSADT ≤ 9 months (mo), without distant metastases on conventional imaging (NCT03009981). Pts were randomized 1:1:1 to receive a finite 52-week treatment course with ADT, ADT + APA, or ADT + APA + AAP, stratified by PSADT (< 3 vs 3–9 mo), with post-treatment follow-up. The primary endpoint of bPFS (serum PSA > 0.2 ng/mL following treatment) was compared for each experimental arm vs. control. Secondary endpoints included safety, patient-reported quality of life (QOL), time to testosterone (T) recovery (> 50 ng/dL) (TTTR), metastasis-free survival (MFS) and time to castration resistance (TTCR).

Results

504 pts were randomized to ADT alone (N = 167), ADT + APA (N = 168) or ADT + APA + AAP (N = 169). At first planned interim analysis, both experimental arms significantly prolonged bPFS compared to the control arm (median 24.9 mo for ADT + APA vs 20.3 mo for ADT, HR = 0.52 (95% CI: 0.35–0.77); median 26.0 mo for ADT + APA + AAP vs 20.0 mo for ADT, HR = 0.48 (95% CI: 0.32–0.71)). Median TTTR was 3.9, 3.8 and 4.7 mo in ADT, ADT + APA, and ADT + APA + AAP arms, respectively. The most common grade ≥ 2 adverse event (AE) was hypertension (19.4%, 23.4%, 30.4% in ADT, ADT + APA and ADT + APA + AAP arms, respectively). Eight pts (1.8%) across all treatment arms stopped treatment for AEs. Follow-up for analysis of QOL, MFS and TTCR is ongoing.

Conclusions

More complete AR blockade with APA in addition to ADT prolongs bPFS with a manageable safety profile, without impacting TTTR following a finite duration of treatment. More hypertension was seen in the AAP-containing treatment arm. Intensification of ADT should be considered in high-risk BRPC. Support: AFT, Janssen; https://acknowledgments.alliancefound.org.

Clinical trial identification

NCT03009981.

Editorial acknowledgement

Legal entity responsible for the study

Alliance Foundation Trials, LLC.

Funding

Janssen.

Disclosure

R. Aggarwal: Financial Interests, Personal, Advisory Board: AstraZeneca, Merck, Novartis, Dendreon, Bayer, Modra, Exelixis, Jubilant Therapeutics, Pfizer; Financial Interests, Institutional, Research Grant: Janssen, Zenith Epigenetics, Amgen. S.T. Tagawa: Financial Interests, Personal, Advisory Board: Convergent Therapeutics, AIkido Pharma; Financial Interests, Personal, Other, Consultant: EMD Serono, Telix Pharma, Blue Earth Diagnostics, POINT Biopharma, Myovant, Bayer, 4D Pharma, Gilead, Pfizer, Janssen, Astellas, AbbVie, Novartis, Seagen, Clarity; Financial Interests, Personal, Stocks/Shares: AIkido Pharma; Financial Interests, Personal, Other, Patent co-inventor: Gilead; Financial Interests, Institutional, Invited Speaker: Medivation, Astellas, Janssen, Amgen, BMS, AstraZeneca, Bayer, Merck, Clovis, Seagen, Gilead, Novartis, POINT Biopharma, Clarity, Ambrx, Phosplatin. M.J. Morris: Financial Interests, Personal, Advisory Board: Oric, Pfizer, Exelixis, Lantheus, AstraZeneca, Amgen, Daiichi, Convergent; Financial Interests, Personal, Stocks/Shares: Doximity; Financial Interests, Institutional, Invited Speaker: Novartis, Corcept, Celgen, Janssen. All other authors have declared no conflicts of interest.