Bone-protecting agents (BPAs) reduced the risk of bone fractures in patients with metastatic castration-resistant prostate cancer (mCRPC) who received enzalutamide, with or without radium-223 (Ra223), according to results from a phase 3 trial.
These results were presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting by Silke Gillessen, MD, of the Oncology Institute of Southern Switzerland in Bellinzona.
The phase 3 PEACE III trial (ClinicalTrials.gov Identifier: NCT02194842) included 267 patients with asymptomatic or mildly symptomatic mCRPC. They were randomly assigned to enzalutamide alone (n = 133) or enzalutamide with Ra223 (n = 134).
In all, there were 136 patients enrolled after the use of a BPA became mandatory. BPA use became mandatory after the premature unblinding of another trial, ERA223 (ClinicalTrials.gov Identifier: NCT02043678), demonstrated an increased risk of bone fractures with abiraterone plus Ra223.
In the PEACE III trial, the risk of fractures was found to be lower in patients who received BPAs, which included bisphosphonates and denosumab.
At 12 months, the cumulative incidence of bone fractures in the enzalutamide-Ra223 arm was 37.1% without a BPA and 2.7% with a BPA.
At 12 months in the enzalutamide-alone arm, the cumulative incidence of bone fractures was 15.6% without a BPA and 2.6% with a BPA.
At 21 months, the cumulative incidence of bone fractures in the enzalutamide-Ra223 arm was 52.0% without a BPA and 4.3% with a BPA.
At 21 months in the enzalutamide-alone arm, the cumulative incidence of bone fractures was 21.9% without a BPA and 2.6% with a BPA.
“Our updated safety analysis confirms that the risk of fractures is well controlled in both arms when patients receive a bone-protecting agent,” Dr Gillessen concluded.
Disclosures: This research was supported by Bayer-Astellas. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Gillessen S, Choudhury A, Rodriguez-Vida A, et al. Decreased fracture rate by mandating bone protecting agents in the EORTC 1333/PEACEIII trial combining Ra223 with enzalutamide versus enzalutamide alone: an updated safety analysis. J Clin Oncol. 2021;39:(suppl 15; abstr 5002). doi:10.1200/JCO.2021.39.15_suppl.5002
This article originally appeared on Cancer Therapy Advisor