The clinical efficacy of targeted radioligand therapy with (177Lu) vipivotide tetraxetan (177Lu-PSMA-617) was seen in patients with advanced prostate-specific membrane antigen (PSMA) PET-positive metastatic castration-resistant prostate cancer (mCRPC) regardless of prior treatment or standard of care chosen, according to a post-hoc analysis of data from the VISION trial (Abstract 5001).
According to Nitin Vaishampayan, MD, of Wayne State University School of Medicine and colleagues, who will present the analysis at the 2022 ASCO Annual Meeting, these findings suggest that “disease biology rather than prior and concomitant treatment context drives outcomes.”
In the VISION trial, patients with disease previously treated with at least one androgen receptor pathway inhibitor (ARPI) and one to two taxane regimens were randomly assigned to 177Lu-PSMA-617 plus standard of care or standard of care alone. 177Lu-PSMA-617 significantly prolonged radiographic progression-free survival and overall survival compared with standard of care in patients with advanced PSMA PET-positive mCRPC. The therapy was granted Food and Drug Administration approval based on these results.
This post-hoc analysis was done to examine radiographic progression-free survival and overall survival in the context of prior and concomitant cancer-directed treatments, which the researchers said were generally well balanced between study groups.
The subgroup analyses were done by number of prior ARPIs, taxane regimens, non-taxane regimens and immunotherapies, prior treatment with bone-sparing agents, 223Ra and PARP inhibitors, and for concomitant treatment with ARPIs, radiation therapy, and bone-sparing agents.
Radiographic progression-free survival and overall survival benefits with 177Lu-PSMA-617 were consistent across all prior treatment subgroups and regardless of concomitant systemic and radiation therapy.
The researchers noted benefits in patients who had not received a second prior taxane. Radiographic progression-free survival rate was 58.2% in patients with one prior taxane compared with 34.8% in those with two or more. Overall survival rate was 62.1% for those with one prior taxane compared with 30.9% in those with two or more.
In their conclusion, the researchers wrote that some of the small differences seen in subgroup outcomes may warrant further study, “to better understand the predictors of improved clinical benefit.”