TY - JOUR T1 - Predictors of Response to Radioligand Therapy of Metastatic Castrate-Resistant Prostate Cancer with <sup>177</sup>Lu-PSMA-617 JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 312 LP - 319 DO - 10.2967/jnumed.116.178228 VL - 58 IS - 2 AU - Justin Ferdinandus AU - Elisabeth Eppard AU - Florian C. Gaertner AU - Stefan Kürpig AU - Rolf Fimmers AU - Anna Yordanova AU - Stefan Hauser AU - Georg Feldmann AU - Markus Essler AU - Hojjat Ahmadzadehfar Y1 - 2017/02/01 UR - http://jnm.snmjournals.org/content/58/2/312.abstract N2 - Radioligand therapy (RLT) with 177Lu-PSMA-617 (PSMA is prostate-specific membrane antigen) is a novel targeted therapy for metastatic prostate cancer. In this study, we evaluated the effect of different pretherapeutic parameters on the therapeutic response measured by prostate-specific antigen (PSA) 2 mo after RLT. Methods: RLT was performed in 40 hormone-refractory patients with distant metastases and progressive disease (mean age, 71.4 y). 68Ga-PSMA-11 PET/CT was performed in all patients 1–2 wk before RLT. All patients were treated with a mean of 6 GBq. The SUVmax of tumor lesions was determined using region-of-interest analysis. Complete blood counts, renal and liver function assessments, previous therapies, pain medication, and SUVs were included in the analysis. PSA was assessed 2 mo after RLT. Results: In the univariate analysis, younger age, higher levels of γ-glutamyl transferase, lower pretherapeutic hemoglobin, a higher Gleason score, a higher number of platelets, higher C-reactive protein, regular need for pain medication, and higher lactate dehydrogenase had a negative impact on the therapeutic response; however, the multivariate analysis revealed that the most significant independent factors were the number of platelets and regular need for pain medication. The response was independent of the amount of PSMA uptake as well as previous therapies and other measured factors. Conclusion: A PSA decline of more than 50% was observed significantly more in patients without a regular need for analgesics. ER -