3322 - Analysis of Theranostic ¹⁷⁷Lu-PSMA-617 Therapy Efficacy and Toxicity in Patients with Advanced Prostate Cancer

A. Y. Zhang¹, H. F. Bertsch², A. A. Chaudhary³, and A. L. Salner²; ¹UCONN School of Medicine, Farmington, CT, ²Hartford HealthCare Cancer Institute, Hartford, CT, ³Hartford HealthCare Cancer Institue, Hartford, CT

Purpose/Objective(s): Theranostics has emerged as a potential diagnostic and treatment approach for patients with metastatic castration-resistant prostate cancer (mCRPC), offering targeted therapy for tumors with high likelihood of progression. High PSMA uptake on PET imaging has been found to be a prognostic factor for decreased overall survival of mCRPC patients. PSMA is targeted via radioligand ¹⁷⁷Lu-PSMA-617 to deliver beta-particle radiation to the PSMA-positive tumor cells. Studies have demonstrated the efficacy of this agent and resulted in its FDA approval. This retrospective study of 45 mCRPC patients treated with ¹⁷⁷Lu-PSMA-617 at the Hartford HealthCare Cancer Institute from September 2022 till September 2023, our first year in treating this patient population. Materials/

Methods: : Efficacy of the therapy was evaluated via PSA response to treatment, qualitative measures following each treatment, and imaging for those patients whose tumors are non-PSA expressing. Toxicity of therapy categorized into patient reported and provider reported adverse events was graded by CTCAE guidelines.
Results: Mean age was 72.8 (49 – 85). ¹⁷⁷Lu-PSMA-617 efficacy was demonstrated with 69% of patients with quantitative response to therapy and 62% of patients having positive response through treatment end. 42% of patients had PSA response of 50% or greater, and 4% had complete PSA response (undetectable marker). The most prevalent adverse events included fatigue in 50% of patients and transient increase in pain due to flare reaction in 25% of patients.
Conclusion: 177Lu-PSMA-617 treatment in mCRPC patients resulted in excellent positive response, comparable to previous studies, while maintaining high treatment compliance and minimal adverse events. Utilization of this agent in real-world treatment of prostate cancer patients may help prolong overall survival with low toxicity profile.