title: Early side effects and first results of radioligand therapy with (177)Lu-DKFZ-617 PSMA of castrate-resistant metastatic prostate cancer: a two-centre study.
abstract: BACKGROUND
  Radioligand therapy (RLT) with (177)Lu-DKFZ-617 PSMA (Lu-PSMA) (prostate-specific membrane antigen) is a novel targeted therapy of metastatic prostate cancer. We analysed retrospectively the early side effects and the response rate in the first patients, who received a therapy with Lu-PSMA in our departments.
  
  
  METHODS
  RLT was performed in ten hormone- and/or chemo-refractory patients with distant metastases and progressive disease (mean age 73.5 years). (68)Ga-PSMA HBED-CC PET/CT was performed in all patients prior to RLT. The median PSA level prior to the therapy was 298.5 ng/ml (range 5-853 ng/ml). All patients received CBC, renal and liver function tests the day before and 2 days after application (mean administered activity 5.6 GBq, range 4.1-6.1 GBq), followed by further tests every 2 weeks. All patients were contacted by telephone every week regarding side effects or any positive and negative changes.
  
  
  RESULTS
  Eight weeks after the therapy, seven patients (70 %) experienced a PSA decline, of whom six experienced more than 30 % and five more than 50 %. Three patients showed a progressive disease according to the PSA increase. No patient experienced any side effects immediately after injection of Lu-PSMA. Relevant hematotoxicity (grade 3 or 4) occurred 7 weeks after the administration in just one patient. The same patient showed a leucopenia grade 2. Two patients showed a disturbance of only 1 hematologic cell line, whereas one patient showed a reduction of grades 1 and 2 in leucocytes and thrombocytes, respectively. Six patients did not show any hematotoxicity during the 8 weeks after therapy. There was no relevant nephrotoxicity (grade 3 or 4).
  
  
  CONCLUSIONS
  Our initial results indicate that RLT with Lu-PSMA is safe and seems to have low early side-effect profile. A relevant PSA decline was detected in 70 % of patients.
authors.affiliation: Department of Nuclear Medicine, University Hospital Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany, Hojjat.ahmadzadehfar@ukb.uni-bonn.de.
authors.forename: Hojjat
authors.initials: H
authors.lastname: Ahmadzadehfar
authors.forename: Kambiz
authors.initials: K
authors.lastname: Rahbar
authors.forename: Stefan
authors.initials: S
authors.lastname: Kürpig
authors.forename: Martin
authors.initials: M
authors.lastname: Bögemann
authors.forename: Michael
authors.initials: M
authors.lastname: Claesener
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Eppard
authors.forename: Florian
authors.initials: F
authors.lastname: Gärtner
authors.forename: Sebastian
authors.initials: S
authors.lastname: Rogenhofer
authors.forename: Michael
authors.initials: M
authors.lastname: Schäfers
authors.forename: Markus
authors.initials: M
authors.lastname: Essler