{"entity":{"id":"alphabreak","kind":"trial","name":"AlphaBreak (FPI-2265) & AcTION (225Ac-PSMA-617)","aka":[],"tldr":"The actinium-225 PSMA trials that will help decide whether alpha-emitting PSMA drugs become the next step after Pluvicto.","summary":"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.","status":"active","asOf":"2026-09-27","links":[{"label":"ClinicalTrials.gov NCT06402331","url":"https://clinicaltrials.gov/study/NCT06402331"}],"tags":[],"related":["ac-225"],"indications":["prostate","prostate-mcrpc"],"sections":[],"technologies":["targeted-alpha-therapy"],"targets":[],"drugs":["ac225-psma"],"companies":["fusion-pharma","astrazeneca","novartis","bayer"],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"nct":"NCT06402331","phase":"2","setting":"PSMA-positive mCRPC: actinium-225 PSMA radioligands vs standard of care, including after 177Lu-PSMA","sponsor":"AstraZeneca (Fusion); Novartis","enrolled":110,"enrolledBasis":"registry","outcomes":[],"replication":"Ongoing phase 2 of 225Ac-PSMA-I&T after 177Lu-PSMA (ClinicalTrials.gov: active, not recruiting, 110 enrolled); no results."},"route":"/trials/alphabreak/","neighbours":{"isotope":[{"id":"ac-225","kind":"isotope","name":"Actinium-225","route":"/isotopes/ac-225/"}],"indication":[{"id":"prostate-mcrpc","kind":"indication","name":"Metastatic castration-resistant prostate cancer","route":"/indications/prostate-mcrpc/"},{"id":"prostate","kind":"indication","name":"Prostate cancer","route":"/indications/prostate/"}],"technology":[{"id":"targeted-alpha-therapy","kind":"technology","name":"Targeted alpha therapy","route":"/technologies/targeted-alpha-therapy/"}],"drug":[{"id":"ac225-psma","kind":"drug","name":"Actinium-225 PSMA agents","route":"/drugs/ac225-psma/"}],"company":[{"id":"astrazeneca","kind":"company","name":"AstraZeneca","route":"/companies/astrazeneca/"},{"id":"bayer","kind":"company","name":"Bayer","route":"/companies/bayer/"},{"id":"fusion-pharma","kind":"company","name":"Fusion Pharmaceuticals (AstraZeneca)","route":"/companies/fusion-pharma/"},{"id":"novartis","kind":"company","name":"Novartis","route":"/companies/novartis/"}],"section":[{"id":"f-alpha-therapy","kind":"section","name":"Targeted alpha therapy","route":"/fronts/f-alpha-therapy/"}],"roadmap":[{"id":"alpha-therapy-roadmap","kind":"roadmap","name":"Alpha-emitter roadmap: radium-223 → 225Ac-PSMA-617 → a phase 3 pipeline","route":"/roadmaps/alpha-therapy-roadmap/"},{"id":"psma-theranostics-roadmap","kind":"roadmap","name":"PSMA theranostics roadmap: antigen discovery → PSMA PET → 177Lu-PSMA-617 → earlier lines and alpha","route":"/roadmaps/psma-theranostics-roadmap/"}]}}