{"entity":{"id":"idea-alpha-first-mhspc","kind":"idea","name":"Alpha-emitting PSMA therapy at first metastatic diagnosis","aka":[],"tldr":"If Pluvicto helps at first diagnosis, an alpha version might do more against microscopic disease, when tumour burden is smallest.","summary":"This speculative idea would give alpha-emitting PSMA therapy with actinium-225 at the first metastatic diagnosis of hormone-sensitive prostate cancer, alongside hormone therapy. Short-range alpha emission suits small-volume disease and is oxygen-independent, and early treatment avoids the PSMA heterogeneity of castration resistance; PSMAddition established beta-emitter therapy here. The hypothesis is deeper PSA nadirs and longer radiographic progression-free survival than lutetium-177 PSMA-617 at equal or lower salivary dose; salivary toxicity and actinium-225 supply are limiting. The test is a randomised phase 2 with PSMA PET-based dosimetry, salivary gland protection and the undetectable-PSA rate at one year as primary endpoint.","asOf":"2026-09-06","links":[{"label":"ClinicalTrials.gov NCT04720157: PSMAddition","url":"https://clinicaltrials.gov/study/NCT04720157"}],"tags":[],"related":["lu-177","ac-225"],"indications":["prostate"],"sections":[],"technologies":["targeted-alpha-therapy","radioligand-therapy"],"targets":[],"drugs":["ac225-psma","pluvicto"],"companies":[],"institutions":[],"pathways":[],"terms":["alpha-vs-beta","dosimetry"],"trials":["psmaddition"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"hypothesis":"225Ac-PSMA added to ADT + ARPI in high-volume de novo mHSPC produces deeper PSA nadirs and longer rPFS than 177Lu-PSMA-617 at equal or lower cumulative salivary dose.","rationale":"Short-range alpha emission suits small-volume disease; early treatment avoids PSMA heterogeneity that develops under castration resistance.","test":"Phase 2 randomised 225Ac-PSMA vs 177Lu-PSMA-617 in mHSPC with PSMA PET-based dosimetry, salivary gland protection, and undetectable-PSA rate at 12 months as primary.","maturity":"speculative"},"route":"/ideas/idea-alpha-first-mhspc/","neighbours":{"isotope":[{"id":"ac-225","kind":"isotope","name":"Actinium-225","route":"/isotopes/ac-225/"},{"id":"lu-177","kind":"isotope","name":"Lutetium-177","route":"/isotopes/lu-177/"}],"indication":[{"id":"prostate","kind":"indication","name":"Prostate cancer","route":"/indications/prostate/"}],"technology":[{"id":"radioligand-therapy","kind":"technology","name":"Radioligand therapy (beta emitters)","route":"/technologies/radioligand-therapy/"},{"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/"},{"id":"pluvicto","kind":"drug","name":"Lutetium-177 vipivotide tetraxetan","route":"/drugs/pluvicto/"}],"term":[{"id":"alpha-vs-beta","kind":"term","name":"Alpha vs beta emitters","route":"/terms/alpha-vs-beta/"},{"id":"dosimetry","kind":"term","name":"Dosimetry","route":"/terms/dosimetry/"}],"trial":[{"id":"psmaddition","kind":"trial","name":"PSMAddition","route":"/trials/psmaddition/"}],"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/"}]}}