LuX: Xaluritamig in Participants With Metastatic Castrate Resistant Prostate Cancer and Suboptimal Response to Lutetium 177 Vipivotide Tetraxetan

This is a phase 2a, open label, single arm, multi-site study of xaluritamig in mCRPC patients following treatment with ≥1 ARPI, taxane chemotherapy (if eligible) and stable or partial PSA response following 2 cycles of lutetium 177 vipivotide tetraxetan. Participants will continue treatment until clinical or radiographic progression of disease, withdrawal, or toxicity requiring discontinuation of therapy. All participants will be evaluated for overall response per RECIST v1.1,8 radiographic progression free survival (rPFS) by Prostate Cancer Working Group 3 (PCWG3) criteria, and PSA response. Approximately 30 participants will be enrolled. There is no data on response with alternative treatments following lutetium 177 vipivotide tetraxetan against which to benchmark the response rate. This phase 2a study will serve as an exploratory pilot to determine if a larger phase 2b study is warranted in this setting.

Inclusion Criteria: To be included in this study, participants should complete all screening procedures and meet all of the following criteria (i.e., evaluations performed as part of routine care prior to informed consent can be used for screening and eligibility confirmation): • Willing and able to provide, or have a legally authorized representative provide, written informed consent and privacy authorization for the release of personal health information. A signed informed consent must be obtained before screening procedures are performed. NOTE: Privacy authorization may be either included in the informed consent or obtained separately. * 18 years of age and above * Histological, pathological, and/or cytological confirmation of adenocarcinoma of the prostate. * Prior orchiectomy and/or ongoing androgen-deprivation therapy and a castrate level of serum testosterone (\