Phase 1 data presented at ESMO
Full-Life Technologies has reported preliminary results from an ongoing Phase 1 dose-escalation study of [225Ac]Ac-FL-020, an investigational PSMA-targeted alpha radiopharmaceutical, in patients with metastatic castration-resistant prostate cancer. The data were shown as an E-Poster at the ESMO Congress 2026 in Madrid, which runs from October 23 to 27, the company said.
As of an October 9, 2026 data cut-off, 18 patients had received the drug at 6, 7 and 8 MBq, and 17 were evaluable for prostate-specific antigen response, according to the release. The U.S. Food and Drug Administration has granted [225Ac]Ac-FL-020 Fast Track Designation for the treatment of mCRPC.
Response rates by prior treatment
Across all 17 evaluable patients, 88.2% (15 of 17) recorded a PSA decline of at least 50% from baseline, 76.5% (13 of 17) of at least 80%, and 47.1% (8 of 17) of at least 90%. Among the nine patients with no prior lutetium-177 therapy, the rates were 100%, 88.9% and 66.7%. Among the eight patients previously exposed to lutetium-177, they were 75%, 62.5% and 25%.
The release also reported one complete response on PSMA-PET imaging after two cycles at 7 MBq, in a patient whose best response to earlier lutetium-177 therapy had been progressive disease.
Safety and planned Phase 2
The safety population covered 39 patients. No dose-limiting toxicities and no deaths considered related to the study drug were observed. Three treatment-related serious adverse events were reported — anemia, nausea and thrombocytopenia — and no serious treatment-related renal or hepatobiliary adverse events were reported. Xerostomia was predominantly Grade 1, with no Grade 3 cases.
Safety findings to date have supported dose escalation through 10 MBq, and a Phase 2 dose-optimization study is planned in which patients would be randomized to two dosing regimens, consistent with recent FDA draft guidance on dose optimization for radiopharmaceuticals. The release describes the findings as preliminary and subject to change with further follow-up, and states that [225Ac]Ac-FL-020 is investigational and has not been approved by any regulatory authority.
