# Actinium-225 PSMA agents

Source: https://onco.cc/drugs/ac225-psma/  
OnCo record `ac225-psma` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Alpha-emitting PSMA drugs that produce responses even after Pluvicto fails, held back mainly by isotope supply.

## Summary

Novartis (225Ac-PSMA-617, phase 3 AcTION), Bayer (225Ac-PSMA-Trillium with albumin binder, PAnTHA phase 1 at ASCO GU 2026), Fusion/AstraZeneca (FPI-2265, 225Ac-PSMA-I&T, phase 3 AlphaBreak), and academic 225Ac-PSMA data from South Africa and Germany. Xerostomia from salivary uptake is dose-limiting.

## Fields

- Kind: Treatment
- Status: phase-3
- Last checked: 2026-09-04
- Code: 225Ac-PSMA-617, 225Ac-PSMA-I&T, BAY 3563254 (Trillium)
- Modality: Targeted alpha therapy
- Mechanism: PSMA ligand with 225Ac; four alpha emissions per decay chain.
- Dosing: IV infusion; Trial regimens ~100 kBq/kg every 6-8 weeks

## Sources

- ClinicalTrials.gov: trials of Actinium-225 PSMA agents: https://clinicaltrials.gov/search?intr=225Ac-PSMA-617

## Connected records

- cancers: [Metastatic castration-resistant prostate cancer](https://onco.cc/cancers/prostate-mcrpc/), [Prostate cancer](https://onco.cc/cancers/prostate/)
- technologies: [Actinium-225 supply: thorium stocks, accelerators and radium targets](https://onco.cc/technologies/actinium-225-supply/), [Targeted alpha therapy](https://onco.cc/technologies/targeted-alpha-therapy/)
- targets: [PSMA](https://onco.cc/targets/psma/)
- companies: [AstraZeneca](https://onco.cc/companies/astrazeneca/), [Bayer](https://onco.cc/companies/bayer/), [Fusion Pharmaceuticals (AstraZeneca)](https://onco.cc/companies/fusion-pharma/), [Novartis](https://onco.cc/companies/novartis/)
- trials: [AlphaBreak (FPI-2265) & AcTION (225Ac-PSMA-617)](https://onco.cc/trials/alphabreak/), [Phase Ib/II Platform Study of Multiple Anti-Cancer Agents in Participants With Metastatic Prostate Cancer](https://onco.cc/trials/nct07590934/)
- ideas: [Alpha-emitting PSMA therapy at first metastatic diagnosis](https://onco.cc/ideas/idea-alpha-first-mhspc/), [Recover legacy radium-226 sources worldwide as the feedstock for actinium-225](https://onco.cc/ideas/idea-reg-legacy-radium-recovery-ac225/)
- pairings: [Beta radioligand → alpha radioligand](https://onco.cc/pairings/beta-then-alpha/)
- roadmaps: [Radiopharmaceutical roadmap: iodine → lutetium → actinium](https://onco.cc/roadmaps/radiopharma-roadmap/)
- people: [Clemens Kratochwil](https://onco.cc/people/clemens-kratochwil/)
- bottlenecks: [Manufacturing cost and time for living and radioactive medicines](https://onco.cc/bottlenecks/b-manufacturing-cell-therapy/)
- biomarkers: [PSMA expression by PET (PSMA-positive)](https://onco.cc/biomarkers/psma-pet-expression/)

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JSON: https://onco.cc/api/v1/entities/ac225-psma.json