| E.1 Medical condition or disease under investigation | 
| E.1.1 | Medical condition(s) being investigated | 
| Oligo-metastatic adenocarcinoma of the prostate. |  | 
| E.1.1.1 | Medical condition in easily understood language |  | 
| E.1.1.2 | Therapeutic area | Diseases [C] - Cancer [C04] | 
| MedDRA Classification | 
| E.1.3 | Condition being studied is a rare disease | No | 
| E.2 Objective of the trial | 
| E.2.1 | Main objective of the trial | 
| The main objective of this study is to assess the difference in the fraction of patients with low volume, hormone sensitive metastatic PCa that
 meet EOT 1 criteria after 177Lu-PSMA RLT compared to those that have
 a deferred androgen deprivation treatment schedule.
 EOT 1 is defined by:
 - Clinical progression determined by the treating physician (e.g.
 increasing pain from metastases)
 - A 100% increase in PSA after cycle one blood draw (BASELINE) during
 study. Exception: PSA increase in the first 12 weeks after the first
 treatment injection as was defined by the PCWG3 criteria.
 |  | 
| E.2.2 | Secondary objectives of the trial | 
| - To assess ADT free survival in patients receiving 177Lu-PSMA RLT. ADT free survival is defined by the date ADT is started or death related to
 PCa.
 - To evaluate the clinical efficacy of multiple doses 177Lu-PSMA
 radioligand therapy in patients with low volume, hormone sensitive
 metastatic PCa.
 - To assess progression free survival, defined as from the time frominclusion to date of evidence of: clinical progression, death from any
 cause, PSA progression, or radiographic progression, whichever occurs
 first.
 - To evaluate the tolerability and toxicity of 177Lu-PSMA RLT defined by
 NCI Common Terminology Criteria for Adverse Events v5.0.
 - To evaluate the quality of life before and up to 6 months after 177Lu-
 PSMA RLT using the following questionnaires: EORTC QLQ-C30, QLQPR25
 & xerostomia inventory.
 |  | 
| E.2.3 | Trial contains a sub-study | No | 
| E.3 | Principal inclusion criteria | 
| - Histological proven adenocarcinoma of the prostate with archived tumor material.
 - Biochemical recurrence or clinical progression (PSA > 1.0 μg/l).
 - ECOG 0-1.
 - PSA-doubling time < 6 months.
 - 18F-PSMA-PET-CT positive metastases in bones and/or lymph nodes
 (N1/M1ab): ≥1, maximally 5 metastases .
 - Local treatment for oligometastases with radiotherapy or surgery
 appears to be no option anymore (due to prior treatment or the location
 of the metastatic lesions).
 - No prior hormonal therapy (including any androgen directed treatment
 such as Bicalutamide, Apalutamide, Abiraterone or Enzalutamide) or
 taxane based chemotherapy (docetaxel or cabazitaxel); testosterone >
 1.7 nmol/l.
 Exception: local prostate cancer treated with local radiotherapy plus
 adjuvant ADT; these patients need to be stopped with ADT at least 6
 months.
 - No visceral metastases.
 - Laboratory values:
 • White blood cells > 3.0 x 109/l
 • Platelet count > 75 x 109/l
 • Hemoglobin > 6.2 mmol/l
 • ASAT, ALAT < 3 x ULN
 • MDRD-GFR ≥ 50 ml/min
 - Signed informed consent.
 |  | 
| E.4 | Principal exclusion criteria | 
| - A detectable lesion on the 18F-PSMA PET/CT with significant PSMA avidity, defined by a SUVmax > 10 (partial volume corrected).
 - A known subtype other than prostate adenocarcinoma.
 - Previous PSMA based radioligand treatment.
 - Visceral or brain metastases.
 - Any medical condition present that in the opinion of the investigator
 will affect patients' clinical status when participating in this trial.
 - Prior hip replacement surgery potentially influencing performance of
 PSMA PET/CT.
 - Sjogren's syndrome.
 - A second active malignancy other than prostate cancer.
 - Patients who are sexually active and not willing/able to use medically
 acceptable forms of barrier contraception.
 |  | 
| E.5 End points | 
| E.5.1 | Primary end point(s) | 
| To assess the difference in the fraction of patients that have disease progression during the 6 month follow up of this study after 177Lu-PSMA
 RLT or a deferred androgen deprivation treatment schedule.
 |  | 
| E.5.1.1 | Timepoint(s) of evaluation of this end point |  | 
| E.5.2 | Secondary end point(s) | 
| - ADT-free survival. - PSA response.
 - Toxicity based on NCI CTCAE v5.0 criteria.
 - Radiological state of the disease, expressed in the difference in amount
 and size of suspicious nodes on 18F-PSMA PET/CT and (whole body) MRI
 between pre- and post-therapy.
 - Quality of Life assessments.
 |  | 
| E.5.2.1 | Timepoint(s) of evaluation of this end point | 
| During study and up to End-of-Study (Week 24). |  | 
| E.6 and E.7 Scope of the trial | 
| E.6 | Scope of the trial | 
| E.6.1 | Diagnosis | No | 
| E.6.2 | Prophylaxis | No | 
| E.6.3 | Therapy | Yes | 
| E.6.4 | Safety | Yes | 
| E.6.5 | Efficacy | Yes | 
| E.6.6 | Pharmacokinetic | No | 
| E.6.7 | Pharmacodynamic | No | 
| E.6.8 | Bioequivalence | No | 
| E.6.9 | Dose response | No | 
| E.6.10 | Pharmacogenetic | No | 
| E.6.11 | Pharmacogenomic | No | 
| E.6.12 | Pharmacoeconomic | No | 
| E.6.13 | Others | No | 
| E.7 | Trial type and phase | 
| E.7.1 | Human pharmacology (Phase I) | No | 
| E.7.1.1 | First administration to humans | No | 
| E.7.1.2 | Bioequivalence study | No | 
| E.7.1.3 | Other | No | 
| E.7.1.3.1 | Other trial type description |  | 
| E.7.2 | Therapeutic exploratory (Phase II) | Yes | 
| E.7.3 | Therapeutic confirmatory (Phase III) | No | 
| E.7.4 | Therapeutic use (Phase IV) | No | 
| E.8 Design of the trial | 
| E.8.1 | Controlled | Yes | 
| E.8.1.1 | Randomised | Yes | 
| E.8.1.2 | Open | Yes | 
| E.8.1.3 | Single blind | No | 
| E.8.1.4 | Double blind | No | 
| E.8.1.5 | Parallel group | No | 
| E.8.1.6 | Cross over | No | 
| E.8.1.7 | Other | No | 
| E.8.2 | Comparator of controlled trial | 
| E.8.2.1 | Other medicinal product(s) | No | 
| E.8.2.2 | Placebo | No | 
| E.8.2.3 | Other | Yes | 
| E.8.2.3.1 | Comparator description |  | 
| E.8.2.4 | Number of treatment arms in the trial | 2 | 
| E.8.3 | The trial involves single site in the Member State concerned | Yes | 
| E.8.4 | The trial involves multiple sites in the Member State concerned | No | 
| E.8.5 | The trial involves multiple Member States | Yes | 
| E.8.5.1 | Number of sites anticipated in the EEA | 4 | 
| E.8.6 Trial involving sites outside the EEA | 
| E.8.6.1 | Trial being conducted both within and outside the EEA | No | 
| E.8.6.2 | Trial being conducted completely outside of the EEA | No | 
| E.8.7 | Trial has a data monitoring committee | No | 
| E.8.8 | Definition of the end of the trial and justification where it is not the last
                        visit of the last subject undergoing the trial |  | 
| E.8.9 Initial estimate of the duration of the trial | 
| E.8.9.1 | In the Member State concerned years | 2 | 
| E.8.9.1 | In the Member State concerned months | 6 | 
| E.8.9.1 | In the Member State concerned days |  |