ASCO GU 2022: Bone Mineral Density in Men With De Novo Metastatic Castration-Sensitive Prostate Cancer Treated With or Without Abiraterone Plus Prednisone in the PEACE-1 Phase 3 Trial

(UroToday.com) In the Rapid Abstract Session on the first day of the American Society for Clinical Oncology (ASCO) Genitourinary Cancer Symposium 2022, Dr. Roubaud presented an analysis of bone mineral density in men treated on the PEACE-1 trial. As presented at ASCO 2021 and ESMO 2021, the initial results of the PEACE-1 trial demonstrated the addition of abiraterone plus prednisone to androgen deprivation therapy (ADT) with or without docetaxel improved overall survival in men with de novo metastatic castration sensitive prostate cancer (mCSPC). In terms of assessing the toxicity of abiraterone acetate and prednisone, a planned study amendment sought to analyze whether the addition of abiraterone acetate and prednisone was associated with increased bone loss. It is well known that ADT is associated with bone loss and fracture. However, the involvement of next-generation hormone therapies in this process is somewhat less clear.

As previously reported, the PEACE-1 trial (NCT01957436) randomized patients to receive either docetaxel and ADT or abiraterone, prednisone, docetaxel, and ADT (in addition to a 2x2 factorial randomization to local prostate radiotherapy).

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Dual x-ray absorptiometry (DEXA) was used to assess the bone mineral density (g/cm2) of the lumbar spine (L), femoral neck (F) and total hip (H) at baseline, month 6, month 12, and month 24. The authors assessed the mean percentage change in BMD values between baseline and each time point, as well as T-scores.

Among the entire PEACE-1 cohort, 210 patients had available BMD data, of whom 182 (87%) had available data at baseline, 109 (52%) had data at month 6, 94 (45%) had data at month 12, and 109 (52%) had data at month 24. Among the 195 patients examined, 97 were treated with abiraterone acetate and prednisone and 98 without.

In terms of baseline characteristics, in both arms, the median age was 65 years and 69 patients (71%) were ECOG PS 0. The median body mass index (BMI) was 25.6 among those treated with abiraterone acetate and prednisone and 26.5 kg/m2 in those treated without abiraterone acetate and prednisone.

As shown in the figure below, the mean T score changes in the first 24 months of therapy were essentially superimposable between the two treatment groups.

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When examining the change in bone mineral density, there appeared to be a non-significant, early increase in BMD among those patients who receive abiraterone. However, by 24 months, the results were nearly interchangeable.

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In conclusion, Dr. Roubaud emphasized that this is the first prospective assessment of BMD in a randomized trial of patients treated with abiraterone acetate and prednisone. While there was evidence of a bone loss increase in both arms over time, there was minimal difference in bone loss between patients who received abiraterone acetate and prednisone in addition to docetaxel and ADT during the first two years of therapy.

Presented by: Guilhem Roubaud, MD, Institut Bergonié


Written By: Christopher J.D. Wallis, MD, Ph.D., Assistant Professor in the Division of Urology at the University of Toronto, @WallisCJD on Twitter during the 2022 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, Thursday Feb 17 – Saturday Feb 19, 2022

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