ASCO 2021: Bone-Protecting Agents With Enzalutamide Treatment for Metastatic Prostate Cancer
Posted: Monday, June 28, 2021
Adding radium-223 to enzalutamide treatment appears to increase the risk of bone fractures for patients with asymptomatic or mildly symptomatic metastatic castration-resistant prostate cancer, but continuous treatment with bone-protecting agents seems to “abolish” this increased risk, according to updated safety results from a phase III trial. Bertrand F. Tombal, MD, PhD, of the Université catholique de Louvain in Brussels, and colleagues presented these findings during the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 5002). These findings confirm the results of an earlier analysis presented in 2019.
“Skeletal fractures, pathological or not, are a frequent and underestimated adverse event of systemic treatment of advanced prostate cancer,” the authors wrote.
The EORTC 1333/PEACE III trial included 253 patients, 134 of them after the use of bone-protecting agents became mandatory in 2017. The safety population included 237 patients, 122 of them after bone-protecting agents became mandatory. All patients had asymptomatic or mildly symptomatic metastatic castration-resistant prostate cancer. The researchers randomly assigned patients to treatment with enzalutamide plus radium-223 or enzalutamide alone.
After 1.5 years of follow-up, among patients who received bone-protecting agents, 3% of those receiving enzalutamide plus radium-223 had a bone fracture, compared with 4% of patients receiving enzalutamide alone. Far more patients who did not receive bone-protecting agents had bone fractures: 46% of patients receiving enzalutamide plus radium-223, compared with 22% of patients receiving enzalutamide alone.
The study authors concluded that their findings stress “the importance of complying to international recommendations in terms of giving bone-protecting agents to metastatic castration-resistant prostate cancer patients.”
Disclosure: The study authors’ disclosures may be found at coi.asco.org.