6-mo Triple AR Blockade + Metastasis-Directed RT Yields 83% Deep PSA Response in Synchronous PSMA-PET Oligometastatic Prostate Cancer

In a pooled post-hoc look at the Phase 2 SOLAR (NCT03298087) and SATURN (NCT03902951) trials, 50 PSMA-PET-defined castrate-sensitive oligometastatic patients (≤5 lesions) received 6 months of leuprolide, abiraterone + prednisone, and apalutamide plus stereotactic body RT to all mets; synchronous cases (treatment-naïve) also had prostate surgery or definitive RT. Synchronous disease showed 83% “deep” PSA response (<0.05 ng/ml or <2 ng/ml post-RT) versus 50% in metachronous recurrences (p = 0.018) and enjoyed significantly longer progression-free and eugonadal PFS (p < 0.05), while prior ADT predicted resistance. For perspective, standard AAP + ADT in high-risk metastatic CSPC drives PSA ≤ 0.1 ng/ml at 6 months in ~40% of men, and the ARASENS triplet (darolutamide + ADT + docetaxel) reaches ~67% undetectable PSA, positioning this finite multimodal regimen at the top of the response curve with only half a year of systemic therapy.