AlphaBreak (FPI-2265) & AcTION (225Ac-PSMA-617)

AlphaBreak and AcTION, led by trial NCT06402331, are the trials that will help decide whether alpha-emitting PSMA drugs become the next step after Pluvicto in PSMA-positive metastatic castration-resistant prostate cancer. AlphaBreak tests FPI-2265, an actinium-225 PSMA-I&T agent from AstraZeneca and Fusion, after lutetium PSMA therapy, while Novartis' AcTION programme tests actinium-225 PSMA-617 in post-lutetium and lutetium-naive settings, and Bayer's PAnTHA phase 1 of 225Ac-PSMA-Trillium reported at ASCO GU 2026. ClinicalTrials.gov lists AlphaBreak (NCT06402331) as phase 2, active and no longer recruiting, with an actual enrolment of 110 (registry record last updated 8 April 2026). Nuclide links them to targeted alpha therapy, the actinium-225 PSMA agents record, and to Fusion, AstraZeneca, Novartis and Bayer. AlphaBreak has stopped recruiting and has posted no results; dry mouth and actinium-225 supply are the constraints, and whether alpha emitters help after lutetium is the question they exist to answer.