Decrease in Fracture Rate with Mandatory Bone-protecting Agents in the EORTC 1333/PEACE-3 Trial Comparing Radium-223...

Area of Science:

• Oncology
• Radiopharmaceuticals
• Clinical Trials

Background:

• Bone health is critical for managing metastatic castration-resistant prostate cancer (mCRPC).
• International guidelines recommend bone-protecting agents (BPAs) for mCRPC patients with bone metastases.
• Previous data predates the availability of androgen receptor pathway inhibitors (ARPIs).

Purpose of the Study:

• To report fracture rates from an interim safety analysis of the PEACE-3 trial.
• To compare radium-223 (223Ra) plus enzalutamide versus enzalutamide alone in first-line mCRPC.
• To assess the impact of mandated BPA use during the trial.

Main Methods:

• International prospective phase 3 PEACE-3 trial.
• Interim safety analysis comparing radium-223 (223Ra) plus enzalutamide vs. enzalutamide monotherapy.
• Mandatory BPA use implemented based on interim findings from the ERA-223 trial.

Main Results:

• BPA use increased from 46.1% to 97% after mandate.
• Fracture rates significantly decreased in both arms with BPA therapy.
• In enzalutamide monotherapy arm, fractures decreased from 15.6% to 2.6% at 1 year with BPA.

Conclusions:

• The PEACE-3 interim analysis highlights the high fracture risk in mCRPC patients.
• Compliance with BPA administration guidelines is essential in the ARPI era.
• BPAs are critical for mitigating fractures in mCRPC patients receiving ARPIs.