Combination Therapy with Enzalutamide Yields 31 Percent Improvement in Radiological Progression-Free Survival for mCRPC
For patients with metastatic castration-resistant prostate cancer (mCRPC) and bone metastasis, the combination of enzalutamide and Ra223 led to a median overall survival rate of 42.3 months in contrast to 35 months for enzalutamide alone, according to research presented at the 2024 European Society for Medical Oncology Congress (ESMO) in Spain.
Combining enzalutamide with radium-223 may provide significant improvements in radiological progression-free survival (PFS) and overall survival (OS) rates for patients with metastatic castration-resistant prostate cancer (mCRPC) and bone metastasis.
In a study recently presented at the 2024 European Society for Medical Oncology Congress (ESMO) in Barcelona, Spain, researchers compared the combination of enzalutamide (Xtandi, Astellas Pharma/Pfizer) and Radium 223 (Ra223, Xofigo, Bayer) to the use of enzalutamide alone in 446 patients with mCRPC and bone metastasis.
(Editor’s note: This article has been adapted with permission from its original publication on our sister site Urology Times.)
The researchers noted a 31 percent reduction in radiological progression with the combination treatment in comparison to enzalutamide alone. At two years, 45 percent of those receiving combination therapy had no radiological progression (in contrast to 36 percent for enzalutamide alone), according to the study authors. The study findings also revealed that combination therapy led to a 42.3-month median overall survival (OS) in comparison to 35 months for enzalutamide alone.
In a new study presented at the 2024 European Society for Medical Oncology Congress (ESMO), researchers found that the combination of enzalutamide and Radium 223 led to 31 percent reduction in radiological progression in comparison to enzalutamide alone for patients with mCRPC and bone metastasis. (Image courtesy of Adobe Stock.)
“These results support the combination of enzalutamide plus radium-223 plus a bone-protecting agent as a potential new first-line mCRPC treatment option for patients with prostate cancer and bone metastases who have not received a prior androgen receptor pathway inhibitor,” noted lead study author Silke Gillessen, M.D., a medical oncologist at the Oncology Institute of Southern Switzerland in Bellinzona, Switzerland.
Patients were eligible for inclusion in PEACE-3 if they had mCRPC and bone metastases, were asymptomatic or mildly symptomatic, had a WHO performance status of 0 or 1, had not received prior treatment with enzalutamide, Ra223, apalutamide (Erleada), or darolutamide (Nubeqa), no known visceral metastases, and were receiving ongoing ADT. Patients were randomly assigned 1:1 to standard-of-care enzalutamide, 160 mg once daily or enzalutamide, 160 mg once daily plus Ra223 every 4 weeks for 6 cycles.
The primary end point was investigator-assessed rPFS. Key secondary end points included safety, OS, time to next systemic treatment progression, and time to first symptomatic skeletal event.
Regarding time to next systemic treatment, 51 percent of patients in the enzalutamide-alone arm started a new systemic treatment at two years vs 31 percent of patients in the combination group. There was no difference in time to pain progression or time to symptomatic skeletal event.
In terms of adverse events (AEs), “In general, the combination was very well tolerated. Only a few patients had to stop treatment due to toxicity,” noted Dr. Gillessen. The investigators reported no drug-related deaths. The most common grade 3-5 treatment-emergent adverse events included hypertension, fatigue, fracture, anemia, and neutropenia.
Reference
1. Gillessen S, Choudhury A, Saad F, et al. A randomized multicenter open label phase III trial comparing enzalutamide vs a combination of radium-223 (Ra223) and enzalutamide in asymptomatic or mildly symptomatic patients with bone metastatic castration-resistant prostate cancer (mCRPC): First results of EORTC-GUCG 1333/PEACE-3. Presented at: 2024 European Society for Medical Oncology Annual Congress. September 13-17, 2024. Barcelona, Spain. Abstract LBA1. Available at: https://cslide.ctimeetingtech.com/esmo2024/attendee/confcal/session/calendar?q=LBA1 . Accessed September 14, 2024.
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