Therapeutic response and side effects of repeated radioligand therapy with 177Lu-PSMA-DKFZ-617 of castrate-resistant metastatic prostate cancer

// Hojjat Ahmadzadehfar 1 , Elisabeth Eppard 1 , Stefan Kürpig 1 , Rolf Fimmers 2 , Anna Yordanova 1 , Carl Diedrich Schlenkhoff 1 , Florian Gärtner 1 , Sebastian Rogenhofer 3 , Markus Essler 1 1 Department of Nuclear Medicine, University Hospital Bonn, Bonn, Germany 2 Institute for Medical Biometry, Informatics and Epidemiology, University of Bonn, Bonn, Germany 3 Department of Urology, University Hospital Bonn, Bonn, Germany Correspondence to: Hojjat Ahmadzadehfar, e-mail: Hojjat.ahmadzadehfar@ukb.uni-bonn.de , nuclearmedicine@gmail.com Keywords: PSMA, 177 Lu, prostate cancer, radioligand therapy, PSA Received: October 26, 2015     Accepted: January 27, 2016     Published: February 08, 2016 ABSTRACT Prostate-specific membrane antigen (PSMA) is highly expressed on prostate epithelial cells and strongly up-regulated in prostate cancer (PC), making it an optimal target for the treatment of metastasized PC. Radioligand therapy (RLT) with 177 Lu-PSMA-DKFZ-617 (Lu-PSMA) is a targeted therapy for metastatic PC. In this study, we retrospectively analyzed the side effects and the response rate of 24 hormone and/or chemorefractory PC patients with a mean age of 75.2 years (range: 64–82) with distant metastases and progressive disease according to the PSA level, who were treated with Lu-PSMA. Median PSA was 522 ng/ml (range: 17–2360). Forty-six cycles of Lu-PSMA were performed. Of the 24 patients, 22 received two cycles. Eight weeks after the first cycle of Lu-PSMA therapy 79.1% experienced a decline in PSA level. Eight weeks after the second cycle of Lu-PSMA therapy 68.2% experienced a decline in PSA relative to the baseline value. Apart from two cases of grade 3 anemia, there was no relevant hemato- or nephrotoxicity (grade 3 or 4). These results confirmed that Lu-PSMA is a safe treatment option for metastatic PC patients and has a low toxicity profile. A positive response to therapy in terms of decline in PSA occurs in about 70% of patients.