mCRPC patients (pts) with high PSMA expression without discordant FDG avid disease on paired PSMA and FDG PET/CT scans received up to 6 cycles of Lu-PSMA-617 (6-8 GBq) every 6 weeks in conjunction with 200mg of pembrolizumab every 3 weeks for up to 2 years....PSA50-RR was 73% (27/37 [95% CI: 56-86]) and 7/9 (78%) pts with RECIST measurable disease had a partial response....The combination of Lu-PSMA-617 and pembrolizumab had promising activity.