RecruitingPhase 2Drug trialPacritinib in Participants With Metastatic Castrate-Resistant Prostate Cancer That Progressed on or After Prior Treatment With Androgen Receptor Signaling InhibitorsThis is a single-arm, open-label phase 2 study to evaluate the role of pacritinib for patients with metastatic castrate-resistant prostate cancer that have progressed on ARSI. Patients will receive pacritinib 200 mg twice daily. To be eligible, patients must have a biopsy of a metastatic site within 30 days of treatment that demonstrates positive STAT5 activation status