Study: 177Lutetium-PSMA-617 After 223Radium for mCRPC Safe, Effective

For patients who received 223Ra as part of routine disease management, “subsequent 177Lu-PSMA therapy was clinically feasible and well tolerated, with acceptable myelosuppression rates,” according to investigators. Source: Getty Images

Treatment with ¹⁷⁷lutetium-PSMA-617 (¹⁷⁷Lu-PSMA) is safe and effective in patients with metastatic castration-resistant prostate cancer (mCRPC) who have previously received ²²³radium (²²³Ra), according to study findings presented at the European Society for Medical Oncology’s 2022 Congress (ESMO 2022) in Paris, France.

In a study of 133 patients who participated in the RALU trial, Kambiz Rahbar, MD, of the University of Münster Medical Center in Münster, Germany, and colleagues found that the median overall survival from the start of ¹⁷⁷Lu-PSMA was 13.2 months overall, 12.0 months for patients who received ²²³Ra followed by chemotherapy and then ¹⁷⁷Lu-PSMA, and 14.0 months for those who received chemotherapy followed by ²²³Ra and then ¹⁷⁷Lu-PSMA, respectively.

During treatment with ¹⁷⁷Lu-PSMA, investigators observed a 50% or greater decline in PSA in 42% of patients overall, 46% of those who received ²²³Ra followed by chemotherapy and then ¹⁷⁷Lu-PSMA, and 36% of those who received chemotherapy followed by ²²³Ra and then ¹⁷⁷Lu-PSMA.

“In patients for whom ²²³Ra had been used as part of routine disease management, subsequent ¹⁷⁷Lu-PSMA therapy was clinically feasible and well tolerated, with acceptable myelosuppression rates,” Dr Rahbar’s team concluded in a poster presentation.

The effectiveness of ¹⁷⁷Lu-PSMA in patients previously treated with ²²³Ra was similar to other findings with ¹⁷⁷Lu-PSMA, indicating no cross-resistance, according to Dr Rahbar and colleagues.

The study population had a median age of 73 years, and 56% had received 4 or more life-prolonging therapies, including abiraterone, enzalutamide, docetaxel, and cabazitaxel. All patients had bone metastases, and 27% had visceral metastases.

The latest findings echo those of a recently published real-world study led by Oliver Sartor, MD, of Tulane University School of Medicine in New Orleans, Louisiana. He and his collaborators examined the use of ¹⁷⁷Lu-PSMA following ²²³Ra for bone-metastatic CRPC. The median time between the treatments was 8 months. The median overall survival was 28 months from the start of ²²³Ra and 13.2 months from the start of ¹⁷⁷Lu-PSMA, the investigators reported in the Journal of Nuclear Medicine. The authors acknowledged that their small sample size precludes definitive conclusions, but noted that their data, especially related to the duration of ¹⁷⁷Lu-PSMA, suggest that the use of this medication after ²²³Ra is feasible in a real-world setting.

References

Rahbar K, Essler M, Eiber M, et al. Lutetium-177-prostate-specific membrane antigen therapy (177Lu-PSMA) in patients (Pts) with prior radium-223 (223Ra): Safety and effectiveness outcomes. Presented at: ESMO 2022, September 9-13, Paris, France. Abstract 1392P.

Sartor O, la Fourgère C, Essler M, et al. ¹⁷⁷Lu-Prostate-specific membrane antigen ligand after ²²³Ra treatment in men with bone-metastatic castration-resistant prostate cancer: Real-world clinical experience. J Nucl Med. 2022;63:410-414. doi:10.2967/jnumed.121.262240