Quantitative Analysis of 68Ga-PSMA-11 PET, Clinical Outcomes in Patients With mCRPC

¹⁷⁷Lu-PSMA-617 is a prostate-specific membrane antigen (PSMA)-targeted radioligand therapy in patients with metastatic castration-resistant prostate cancer (mCRPC). Further analysis using quantitative PSMA positron emission tomography or computed tomography may provide additional information on the potential benefits of ¹⁷⁷Lu-PSMA-617.

The VISION trial from Phillip H. Kuo, MD, and colleagues published in Radiology sought to determine the connection between quantitative baseline ⁶⁸Ga-PSMA-11 PET/CT, treatment response, and outcomes in patients with mCRPC.

In the exploratory secondary analysis, patients were randomized to receive either ¹⁷⁷Lu-PSMA-617 therapy plus standard of care (SOC) treatment or SOC therapy alone. Researchers used univariable and multivariable analysis to investigate connections between quantitative PET parameters, radiographic progression-free survival (rPFS), overall survival (OS), objective response rate, and prostate-specific antigen response.

Of the 826 participants, the median whole-body tumor SUV_mean was 7.6, including a hazard ratio (HR) range of 0.86-1.43 across all outcomes (P<.001). Dr. Kuo and colleagues noted that whole-body tumor SUV_mean was the most effective predictor of ¹⁷⁷Lu-PSMA-617 efficacy.

For risk of an rPFS event and death, a 1-unit whole-body tumor SUV_mean increase related to a 12% and 10% decrease, respectively. Researchers also reported that SOC plus ¹⁷⁷Lu-PSMA-617 led to a prolonged rPFS and OS in all SUV_mean quartiles compared with SOC only. No identifiable optimum across patients receiving ¹⁷⁷Lu-PSMA-617 was found.

“Baseline ⁶⁸Ga-PSMA-11 PET/CT whole-body tumor SUV_mean was the best predictor of ¹⁷⁷Lu-PSMA-617 efficacy in participants in the VISION trial,” the investigators wrote. “Improvements in rPFS and OS with ¹⁷⁷Lu-PSMA-617 plus SOC were greater among participants with higher whole-body tumor SUV_mean, with evidence for benefit at all SUVmean levels.”