Purpose: [177Lu]Lu-PSMA-617 radioligand therapy (177Lu-PSMA) is a novel treatment for metastatic castration-resistant prostate cancer (mCRPC), which could also be applied to patients with metastatic hormone-sensitive prostate cancer (mHSPC) with PSMA expression. In this prospective study (NCT03828838), we analyzed toxicity, radiation doses, and treatment effect of 177Lu-PSMA in pateints with low-volume mHSPC. Patients and Methods: Ten progressive patients with mHSPC following local treatment, with a maximum of ten metastatic lesions on [68Ga]Ga-PSMA-11 PET/diagnostic-CT imaging (PSMA-PET) and serum PSA doubling time <6 months received two cycles of 177Lu-PSMA. Whole-body single-photon emission CT/CT (SPECT/CT) and blood dosimetry was performed to calculate doses to the tumors and organs at risk (OAR). Adverse events (AE), laboratory values (monitoring response and toxicity), and quality of life were monitored until week 24 after cycle 2, the end of study (EOS). All patients underwent PSMA-PET at screening, 8 weeks after cycle 1, 12 weeks after cycle 2, and at EOS. Results: All patients received two cycles of 177Lu-PSMA without complications. No treatment-related grade III–IV adverse events were observed. According to dosimetry, none of the OAR reached threshold doses for radiation-related toxicity. Moreover, all target lesions received a higher radiation dose than the OAR. All 10 patients showed altered PSA kinetics, postponed androgen deprivation therapy, and maintained good quality of life. Half of the patients showed a PSA response of more than 50%. One patient had a complete response on PSMA-PET imaging until EOS and two others had only minimal residual disease. Conclusions: 177Lu-PSMA appeared to be a feasible and safe treatment modality in patients with low-volume mHSPC.
Bibliographical noteFunding Information:
B.M. Privéreports grants from Dutch Prostate Cancer Foundation and grants from Radboud Oncology Foundation during the conduct of the study. S.M.B. Peters reports grants from Radboud Oncologie Fonds and grants from Prostaatkanker-stichting during the conduct of the study. I.M. van Oort reports grants from Radboud Oncologie Fonds and grants from Prostaatkankerstichting during the conduct of the study; I.M. van Oort also reports grants from Astellas, Janssen, Bayer, and MSD/AstraZeneca outside the submitted work. P. Zámecnik reports grants from Radboud Oncologie Fonds and grants from Prostaatkankerstichting during the conduct of the study; P. Zámecnik is a scientific advisor to Saving Patients’ Lives Medical (SPL Medical) B.V., the Netherlands. M.J.M. Uijen reports grants from Radboud Oncologie Fonds and grants from Prostaatkankerstichting during the conduct of the study. A. Eek reports personal fees from Radboud Oncology Fund and personal fees from Dutch Prostate Cancer Foundation during the conduct of the
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