NEPC Study: An Exploratory Safety and Efficacy Study With PSMA, SSTR2 and GRPR Targeted Radioligand Therapy in Metastatic Neuroendocrine Prostate Cancer.

The screening period for each participant includes imaging with 3 radioligand imaging (RLI) compounds to assess expression level of PSMA, SSTR2 and GRPR. Participants will be assigned to the radioligand treatment (RLT) corresponding to their predominantly expressed target based on blinded independent central review (BICR). During the treatment period, participants will receive up to 6 cycles of the assigned RLT, corresponding to a total dose of 44.4 GBq (+/-10%) for \[177Lu\]Lu-PSMA-617 or \[177Lu\]Lu-DOTA-TATE , and 55.5 GBq (+/-10%) for \[177Lu\]Lu-NeoB. No crossover to a different type of RLT is allowed. At least six weeks after receiving the first cycle of RLT, participants must be scanned again with up to 3 RLIs but must be scanned, with at least with one RLI corresponding to the received RLT, which is recommended to be performed first. All post-baseline PET/CT scans should be performed using the same PET/CT imaging agent and same PET/CT camera, acquisition and reconstruction protocols as used for screening PET/CT for the participant. The post-treatment follow-up period consists of a 42-days Safety follow-up visit. The planned duration of treatment is up to 36 weeks for all treatment arms in this study, with treatment given every 6 weeks ±7 days. Participants may be discontinued from treatment earlier due to unacceptable toxicity or disease progression, and/or at the discretion of the Investigator or the participant. Protocol Amendment 7 follows the Sponsor's business decision to halt enrollment on 05-Jan-2026. The premature closure of the trial was not driven by any safety concerns identified in the study to date.