Case Report: [225Ac]Ac-PSMA-617 therapy in a patient with metastatic castration-resistant prostate cancer (mCRPC) and intracranial meningioma

Background Prostate cancer is the most commonly diagnosed oncological disease among men not only in Russia but also worldwide, while meningioma is the one of the most commonly diagnosed primary central nervous system (CNS) intracranial tumor. However, their combination occurs quite rarely. Prostate-specific membrane antigen radioligand therapy (PSMA RLT) might be an extremely perspective treatment option for these patients as both neoplasms are characterized by PSMA expression. Methods After PET/CT demonstrated a high [ 68 Ga] 68 Ga-PSMA-11 uptake level in metastatic castration-resistant prostate cancer (mCRPC) and intracranial meningioma in a 77-year old patient, we performed four administrations of [ 225 Ac]Ac-PSMA-617. evaluating the prostate-specific antigen (PSA) dynamics and the structural response by brain MRI and PET/CT with [ 68 Ga]Ga-PSMA-11. In addition, we evaluated the patient’s complaints and his hematological indications. Results After treatment, the patient revealed a remarkable decrease in the [ 68 Ga]Ga-PSMA-11 uptake level based on the PET/CT data, a decrease in the PSA level by 99.8%, and a decrease in the meningioma size by 90.6%. Among the unfavorable symptoms, high-grade xerostomia (CTCAE v5.0) was revealed. The hematological parameters remained stable for the whole period of observation. Conclusions The presented clinical case report describes a unique positive experience on the use of [ 225 Ac]Ac-PSMA-617 therapy in mCRPC and brain meningioma, thus allowing us to expand our understanding of PSMA RLT as a method for the treatment of not only prostatic tumors but also tumors of non-prostatic locations.