Early side effects of radio ligand therapy with 177-Lutetium-PSMA of metastatic castrate-resistant prostate cancer

Objectives Peptide radionuclide ligand therapy (PRLT) with 177Lu-PSMA-DKFZ 617 (LU-PSMA) (prostate-specific membrane antigen)is a novel targeted therapy of metastatic prostate cancer.We present the first clinical experiences assessing early possible side effects of this therapy.

Methods PRLT was performed in nine hormone and/or chemo refractory patients with distant metastases and progressive disease (mean age: 72 y/o).68Ga-PSMA PET/CT was performed in all patients 1-2 weeks prior to PRLT. Median PSA was 334 ng/ml (range: 65-853). Salivary glands were protected with ice packs during therapy. All patients received CBC,renal and liver function tests on the day before and two days after application(median administered activity 5.9 GBq, range 4.1 - 6.3 GBq),followed by further tests every two weeks.All patients were contacted by telephone every week regarding side effects or any positive and negative changes.

Results 7 patients showed in Ga-PSMA-PET bone and lymph node metastases,of whom four patients also had residual/locally recurrent tumor. Only Two patients had only massive lymph node metastases. All lesions detected by PET/CT exhibited high Lu-PSMA uptake on post-therapy planar and SPECT/CT scan performed two days after application.Although the treatment was well tolerated by all patients without any significant adverse effects, one patient complained one day after the application of mild nausea and one patient with known history of nausea and vomiting vomited two times on the second day.Two patients mentioned a mild dry mouth at discharge, which was better two weeks later. No hematological toxicity more than grade 1 was observed in the first four weeks. No significant renal and hepatic function changes occurred.

Conclusions Our initial results indicate that PRLT with Lu-PSMA is safe and seems to have low early side effects profile.