Using baseline gallium (68Ga) gozetotide (68Ga-PSMA-11) PET/CT imaging, researchers determined that a higher SUVmean was strongly associated with improved outcomes with (177Lu) vipivotide tetraxetan (177Lu-PSMA-617) in men with prostate-specific membrane antigen (PSMA) PET-positive metastatic castration-resistant prostate cancer (mCRPC).
Phillip Kuo, MD, PhD, of University of Arizona, and colleagues presented these findings from a substudy of the VISION trial at the 2022 ASCO Annual Meeting (Abstract 5002).
In the VISION trial, patients with PSMA PET-positive mCRPC previously treated with at least one androgen receptor pathway inhibitor and one to two taxane regimens were randomly assigned to 177Lu-PSMA-617 plus standard of care or standard of care alone. 68Ga-PSMA-11) PET/CT imaging was used to determine eligibility for 177Lu-PSMA-617.
In this substudy, Kuo and colleagues studied associations between clinical outcomes and imaging data from baseline scans in 548 patients assigned to 177Lu-PSMA-617 that had images that met quality requirements.
The majority of patients (92.7%) had PSMA uptake in the bone. In both the whole-body and regional analyses, there were significant association of PSMA PET parameters to clinical outcomes.
Specifically, higher whole-body SUVmean was associated with improved radiographic progression-free survival (hazard ratio [HR]=0.86; 95% CI, 0.82-0.90; P<.001), overall survival (HR=0.88; 95% CI, 0.84-0.91; P<.001), overall response rate (odds ratio [OR]= 1.43; 95% CI, 1.24-1.65; P<.001), and prostate-specific antigen 50 response (OR=1.34; 95% CI, 1.23-1.45; P<.001).
The researchers also noted that absence of PSMA-positive lesions in the bone, liver, and lymph node, and lower PSMA-positive tumor loads were all indicators of good prognosis.
These findings “support use of 68Ga-PSMA-11 PET/CT scan to identify patients who will benefit from PSMA-targeted radioligand therapy,” the researchers concluded.