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

Source: https://nuclide.cc/trials/alphabreak/  
Nuclide record `alphabreak` (Trial). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

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.

## Fields

- Kind: Trial
- Status: active
- Last checked: 2026-09-27
- Registry id: 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
- Replication: Ongoing phase 2 of 225Ac-PSMA-I&T after 177Lu-PSMA (ClinicalTrials.gov: active, not recruiting, 110 enrolled); no results.

## Sources

- ClinicalTrials.gov NCT06402331: https://clinicaltrials.gov/study/NCT06402331

## Connected records

- isotopes: [Actinium-225](https://nuclide.cc/isotopes/ac-225/)
- indications: [Metastatic castration-resistant prostate cancer](https://nuclide.cc/indications/prostate-mcrpc/), [Prostate cancer](https://nuclide.cc/indications/prostate/)
- technologies: [Targeted alpha therapy](https://nuclide.cc/technologies/targeted-alpha-therapy/)
- drugs: [Actinium-225 PSMA agents](https://nuclide.cc/drugs/ac225-psma/)
- companies: [AstraZeneca](https://nuclide.cc/companies/astrazeneca/), [Bayer](https://nuclide.cc/companies/bayer/), [Fusion Pharmaceuticals (AstraZeneca)](https://nuclide.cc/companies/fusion-pharma/), [Novartis](https://nuclide.cc/companies/novartis/)
- fronts: [Targeted alpha therapy](https://nuclide.cc/fronts/f-alpha-therapy/)
- roadmaps: [Alpha-emitter roadmap: radium-223 → 225Ac-PSMA-617 → a phase 3 pipeline](https://nuclide.cc/roadmaps/alpha-therapy-roadmap/), [PSMA theranostics roadmap: antigen discovery → PSMA PET → 177Lu-PSMA-617 → earlier lines and alpha](https://nuclide.cc/roadmaps/psma-theranostics-roadmap/)

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JSON: https://nuclide.cc/api/v1/entities/alphabreak.json