Suttmann H.1, Mulders P.F.A.2, Molina A.3, Goodman, Jr. O.B.4, Flaig T.W.5, Li J.6, Kheoh T.3, De Bono J.S.7, Scher

H.I.8

1Urologikum Hamburg, Dept. of Urology, Hamburg, Germany, 2Radboud University Nijmegen Medical Centre, Dept. of

Urology, Nijmegen, The Netherlands, 3Janssen Research & Development, Dept. of Clinical Research & Development,

Los Angeles, United States of America, 4Comprehensive Cancer Centers of Nevada, Dept. of U Oncology, Las Vegas,

United States of America, 5University of Colorado Cancer Center, Dept. of Therapeutic Oncology, Aurora, United

States of America, 6Janssen Research & Development, Dept. of Clinical Research & Development, Raritan, United

States of America, 7Institute of Cancer Research and The Royal Marsden Hospital, Dept. of Cancer Therapeutics,

Sutton, United Kingdom, 8Memorial Sloan-Kettering Cancer Center, Dept. of Genitourinary Oncology, New York, United States of America

INTRODUCTION & OBJECTIVES: Visceral disease is a negative prognostic factor in mCRPC patients and may be

less responsive to hormonal therapy. AA, a selective androgen biosynthesis inhibitor, inhibits androgen synthesis from

adrenal and intratumoral sources. Improved overall survival (OS) with AA vs prednisone (P) was demonstrated in a

randomized trial of patients with mCRPC post-docetaxel. Here we further assess the effect of AA on OS and other

clinical outcomes in post-docetaxel mCRPC patients with visceral disease (liver or lung, but not nodal-only

metastases).

MATERIAL & METHODS: In COU-AA-301, patients with mCRPC previously treated with docetaxel were randomized

2:1 to AA (1000 mg) + P (5 mg BID) (n=797) or placebo + P (n=398). The primary end point was OS. Data shown

herein represent the updated analysis (775 events) of patients with (n=352) or without (n=843) visceral disease.

RESULTS: The OS benefit of AA was similarly improved in patients with visceral disease (4.6 mos) and without

visceral disease (4.8 mos) (Table). Treatment with AA led to significant reductions in the risk of radiographic

progression or death in patients with visceral disease (40%) or without visceral disease (32%). Soft-tissue objective

response rates were superior with AA in both groups. PSA response rates (50% reduction) were significantly improved

by AA in both groups. Grade 3/4 adverse events (AEs) were similar in both groups. Hypertension, hypokalemia, and

LFT abnormalities were observed with AA in patients with and without visceral disease.

105 Exploratory analysis of the visceral disease patient subset in COU-AA-301, a phase III study of abiraterone acetate (AA) in metastatic castration-resistant prostate cancer (mCRPC)

Eur Urol Suppl 2013;12;e105

rPFS = radiographic progression-free survival

CONCLUSIONS: AA has substantial anti-tumor activity and provides clinical benefit, including improvements in OS

and rPFS in post-docetaxel mCRPC patients with visceral disease, indicating it is a therapeutically active treatment

option for CRPC patients. Safety/tolerability of AA in patients with visceral disease was similar to that reported

previously in mCRPC.

Patients with Visceral Disease Patients without Visceral Disease

AA (N=253) P (N=99) p values AA (N=544) P(N=299) p values

OS, median (mos) HR (95% CI) 12.9 8.3 p=0.1022

0.79 (0.60, 1.05) 17.1 12.3 p<0.00010.69 (0.58, 0.83)

rPFS, median (mos) HR (95% CI) 5.6 2.8 p=0.0002

0.60 (0.46, 0.78) 5.9 5.1 p<0.00010.68 (0.58, 0.80)

PSA response rate 28% 7% p<0.0001 30% 5% p<0.0001

Objective response rate Relative risk (95% CI) 11% 0% NE 19% 5% 3.51 (1.53, 8.04)

Grade 3/4 AEs 62% 65% 60% 60%