Therapeutic Efficiency and Response to 2.0 GBq (55mCi) 177Lu-EB-PSMA in Patients With mCRPC

Prostate cancer is one of the most common cancers and the second most frequent cause of cancer deaths for adult men. With the advances in the diagnosis and treatment of prostate cancer, some patients with localized prostate cancer can achieve good curative results, but there are still 10%～20% of patients progress to metastatic castration-resistant prostate cancer (mCRPC) every year, only one third of patients with mCRPC survive more than five years. Radioligand therapy targeting prostate specific membrane antigen (PSMA), which is overexpressed in most prostate cancer and even further increased in metastatic and castration-resistant carcinomas, has been demonstrated as an effective and safe therapy in men with mCRPC. 177Lu-PSMA-617 has also shown desired effect. However, 177Lu-PSMA-617, as a small molecule imaging agent, is cleared very quickly from the circulation. Therefore, radiotherapy that is based on small molecules requires high doses and frequent administrations, leading to systemic toxicity. To increase tumor accumulation and retention for radioligand therapy, and reduce dosage of 177Lu, the investigators conjugated a truncated Evans blue (EB) molecule and DOTA chelator onto PSMA-617 (EB-PSMA) and labeled it with 177Lu. The investigators have published some articles demonstrated 177Lu-EB-PSMA had much higher accumulation in prostate cancer lesions than 177Lu-PSMA-617 and also showed an ideal effect. This study is designed to assess the efficiency and response to 177Lu-EB-PSMA (55 mCi) in patients with mCRPC.