AAA817

P1, N=60, Recruiting, Endocyte | Trial completion date: Mar 2026 --> Jan 2027 | Trial primary completion date: Mar 2026 --> Jan 2027

P1, N=60, Recruiting, Endocyte | Trial completion date: Oct 2025 --> Jan 2026 | Trial primary completion date: Oct 2025 --> Jan 2026

We reported 2 cases with recurrent hemangiopericytoma grade III with high expression of 68Ga-PSMA-11 in PET/CT. Based on the performed examination, one of them received targeted α-therapy with the IV injection of 225Ac-PSMA-617.

Targeted α-therapy is one of the most promising fields in novel targeted cancer therapy, with several early- and late-stage clinical trials for neuroendocrine tumors and metastatic prostate cancer already in progress, along with significant interest and investment in additional early-phase studies. Together, these studies will help us understand the short- and long-term toxicity of targeted α-therapy and potentially identify suitable therapeutic combination partners.

The most common side-effect was transient fatigue (50%) followed by grade I/II xerostomia (29%). Ac-PSMA-617 TAT showed promising disease control rate, even when all other therapeutic options were exhausted, with low treatment-related toxicities.

Treatment with 225Ac-PSMA617 (vs. 177Lu-PSMA617) improved RLT outcomes and tended to enhance the differences in therapeutic efficacy between experimental groups. Systematic assessment of intra- and inter-lesion PSMA heterogeneity is currently not feasible clinically; however, this issue might be addressed by individual patient dosimetry to optimize safely delivered maximal tumor doses. Clinical studies designed to determine intra- and inter-lesion PSMA heterogeneity and to optimize PSMA-RLT for each patient are highly warranted.