RALU Study: Impact of Sequencing Radionuclide Therapies on Outcomes in Prostate Cancer

By: Victoria Kuhr, BA
Posted: Friday, March 24, 2023

Kambiz Rahbar, MD, of University Hospital Münster, Germany, and colleagues reported that sequencing treatment with the radionuclide lutetium Lu-177–prostate-specific membrane antigen (PSMA)-617 (Lu-177–PSMA-617) after radium-223 was clinically possible and well tolerated by patients with metastatic castration-resistant prostate cancer. Additionally, similar rates of overall survival were observed in patients regardless of whether they received Lu-177–PSMA-617 within 6 months or after 6 months of completing radium-223. These findings were presented at the 2023 American Society of Clinical Oncology (ASCO) Genitourinary (GU) Cancers Symposium (Abstract 73).

“The question RALU set out to ask is whether it is safe to sequence two radionuclide therapies, an alpha and a beta emitter, in patients with metastatic castration-resistant prostate cancer,” said Dr. Rahbar at the meeting.

The study analyzed patients with metastatic castration-resistant prostate cancer. Group 1 had patients treated with Lu-177–PSMA-617 within 6 months of radium-223 treatment. Group 2 had patients treated with this therapy 6 months or more after radium-223 treatment.

A total of 132 patients were included in the study, with 42 in group 1 and 90 in group 2. The median patient age was 72 and 74 in groups 1 and 2, respectively. The median prostate-specific antigen values were 366 ng/mL and 268 ng/mL, respectively. The median alkaline phosphatase values were 133 U/L and 149 U/L, respectively. Additionally, 40% and 64% of patients in groups 1 and 2, respectively, had four or more prior therapies. As for median overall survival from the start of Lu-117–PSMA-617, it was 12 months in group 1 and 13.2 months in group 2.

Overall, 71% and 82% of patients in groups 1 and 2, respectively, experienced any-grade treatment-related adverse events. Treatment-related deaths occurred in 2% of patients in group 1 and 4% of patients in group 2.

Disclosure: For full disclosures of the study authors, visit coi.asco.org.

2023 ASCO GU Cancers Symposium