MP67-12: Anti-Androgens and Cabazitaxel in Defining Complete Response in Prostatectomy (ACDC Trial) (ACDC-RP)

Jaime Herrera-Caceres, Anthony Joshua, Joan Sweet, Joseph Chin, Aaron Hansen, Robert Hamilton, Srikala Sridhar, Antonio Finelli, Alexandre Zlotta, Neil Fleshner, Eric Winquist

Introduction: High-risk prostate cancer (PC) has a significant risk of recurrence when treated with unimodal therapy. The utility of neoadjuvant therapy, prior to RP has yet to be defined. The Princess Margaret Cancer Centres’ ACDC study investigates the application of agents used for castration resistant PC in the neoadjuvant setting by comparing the use of abiraterone(AA)+prednisone(P)+leuprolide(LHRH) with or without cabazitaxel prior to RP in 76 high-risk patients. Herein, we report early results and protocol modifications.

Methods: This phase II trial will randomize patients to two treatment arms: Arm A (AA/P + LHRH + cabazitaxel 25 mg/m2 with peg-filgrastim 6 cycles) or Arm B (AA/P + LHRH) for 6 months prior to RP. The primary objective is to compare the pathological complete response (CR) between the treatment arms. We present the RP outcomes and safety data for the first 40 participants.

Results: Out of 40 randomized participants, 33 completed study procedures and underwent RP. One participant (Arm B) completed study drug treatment, but opted for radiation therapy, while 2 participants (both in Arm B) were discontinued due to hepatoxicity.  At RP, 4 participants exhibited CR (2 from each arm) and an additional 11 patients exhibited near CR (less than 5% tumor volume, 8 in Arm A). Table 1 demonstrates patient characteristics, pathologic results and Grade 3 adverse events rates. Of note, 2 patients (both in cabazitaxel arm) developed post-operative thrombo-embolic events post RP and two experienced febrile neutropenia.

Conclusions: Early findings indicate significant tumor response with 45% of patients exhibiting CR or near CR. Reduction in dosage of Cabazitaxel to 20 mg/m2 as well as need for extended post-operative thromboembolic prophylaxis have been implemented. Source of

Funding: Ontario Institute of Cancer Research

Sanofi

Janssen Inc.

AMGEN