First-in-human Diagnostic Imaging Profile of the Theranostic Pair [68Ga]Ga-DOTA-STR-17126 and Low Dose [177Lu] Lu-DOTA-STR-17126 in Patients With Advanced or Metastatic Cancer

NCT07608848 | Recruiting Early Phase 1 DMC

• 2 other identifiers: 2025-11-1840ACTRN12626000679381
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

This is an open-label, first-in-human, exploratory Phase 0 study evaluating the safety and diagnostic imaging performance of the DOTA-STR-17126 theranostic pair in patients with advanced or metastatic breast or prostate cancer. The study investigates \[68Ga\]Ga-DOTA-STR-17126 for PET imaging and, in patients with positive GRPR uptake, a low dose of \[177Lu\]Lu-DOTA-STR-17126 for SPECT imaging and dosimetry. The primary objective is to assess safety and tolerability. Secondary objectives include evaluation of imaging quality, biodistribution, pharmacokinetics, and radiation dosimetry. Exploratory objectives assess correlations between GRPR expression in tumour tissue and imaging uptake. The study is conducted at a single centre in Australia, with 12 evaluable participants (up to 20 enrolled), and supports the development of a GRPR-targeted theranostic approach for personalised cancer management.

Conditions

Metastatic Breast Cancer; Metastatic Prostate Cancer; GRPR-Targeted Molecular Imaging; Theranostic Radiopharmaceuticals; Cancer; Active Cancer; Theranostic; Radiopharmaceutical

Outcome Measures

Primary Outcomes (1)

• Number of participants with adverse events (AEs), serious adverse events (SAEs), with abnormal laboratory parameters (hematology, blood chemistry, and urinalysis), abnormal Physical examinations findings

  1\. To evaluate adverse events (AEs) and serious adverse events (SAEs) by means of Common Toxicity Criteria Adverse Events (CTCAE version 5.0 Nov 2017); Assess occurrence and severity of AEs and SAEs; Monitor safety laboratory parameters (haematology, blood chemistry, and urinalysis) before, during and after IMP injections. The Common Terminology Criteria for Adverse Events (CTCAE) is a standardized, 1-5 severity grading system for classifying cancer treatment side effects (adverse events). Grades range from mild (1) to death (5). It is widely used in oncology to determine treatment safety, drug dosage modifications, and to document clinical trial toxicity

  Day 43

Secondary Outcomes (6)

• Standardized Uptake Value (SUV) of [⁶⁸Ga]Ga-DOTA-STR-17126

  Day 2 post-dose

• PET/CT image quality of [⁶⁸Ga]Ga-DOTA-STR-17126

  Day 2 post-dose

• Tumour to Background Ratio (TBR) of [⁶⁸Ga]Ga-DOTA-STR-17126

  Day 2 post-dose

• Concentration of [68Ga]Ga-DOTA-STR-17126 and [177Lu]Lu-DOTA-STR-17126

  Day 1 post-dose, Day 2, Day 4, Day 8

• Percentage of injected activity (%IA) in tumour and non-tumour organs

  Day 1 post-dose, Day 2, Day 4, Day 8

Other Outcomes (2)

• Number of tumour lesions within tumour tissue sample that are positive for GRPR expression based on immunohistochemistry (IHC)

  Pre-dose

• Staining intensity (% of positive cells and intensity) in tumour tissue

  Pre-dose

Study Arms (1)

[68Ga]Ga-DOTA-STR-17126 and Low Dose [177Lu]Lu-DOTA-STR-17126

EXPERIMENTAL

The intervention involves administration of two radiopharmaceuticals under investigation: Part 1: \[68Ga\] Ga-DOTA-STR-17126 is used as a PET imaging tracer to identify tumour lesions with high expression of GRPR. Participants will receive a single intravenous bolus dose of 150+/-50MBq (50 micrograms) of DOTA-STR-17126 precursor. Part 2: Participants who have GRPR positive lesions identified by \[68Ga\] Ga-DOTA-STR-17126 PET imaging will receive a low Dose \[177Lu\] Lu-DOTA-STR-17126. Eligible participant(s) will receive 1.0+/-0.5GBq (50 microgram peptide) dose of \[177Lu\] Lu-DOTA-STR-17126, administered as a slow intravenous infusion. SPECT/CT scans will be performed to assess the biodistribution, dosimetry, and extrapolation of potential therapeutic dose potential of the radiopharmaceutical.

Drug: [177Lu]Lu-DOTA-STR-17126; Drug: [68Ga]Ga-DOTA-STR-17126

Interventions

[177Lu]Lu-DOTA-STR-17126 DRUG

Participants will receive a low dose of \[177Lu\]Lu-DOTA-STR-17126, dose activity: 1.0+/-0.5 GBq (50 micrograms peptide) of \[177Lu\]Lu-DOTA-STR-17126 precursor will be administered as a slow infusion.

[68Ga]Ga-DOTA-STR-17126 and Low Dose [177Lu]Lu-DOTA-STR-17126

[68Ga]Ga-DOTA-STR-17126 DRUG

Participants will receive a single intravenous bolus dose of 150+/-50MBq (25 - 50 micrograms) of \[68Ga\]Ga-DOTA-STR-17126 precursor.

[68Ga]Ga-DOTA-STR-17126 and Low Dose [177Lu]Lu-DOTA-STR-17126

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Ability to understand and willingness to provide informed consent
• Adults ≥ 18 years of age
• Must have the following histologically or cytologically confirmed diagnosis of advanced or metastatic i. breast cancer ii. prostate cancer
• Eastern Cooperative Oncology Group (ECOG) Performance Status 0-1
• Participant must have clinical or radiological documented tumour progression as established by the Investigator within 30 days of signing consent for the study
• Participants who have exhausted standard-of-care systemic therapies in their metastatic setting. At least one detectable by conventional imaging tumour lesion with any diameter of ≥ 1 cm in size
• Participants must have adequate organ and bone marrow function, defined as follows:
• i. Absolute neutrophil count (ANC) ≥ 1000 cells/mm3 ii. Platelet count ≥ 100,000/mm3 iii. Haemoglobin ≥ 9.0 g/dL iv. AST, ALT, alkaline phosphatase ≤ 3 times upper limit of normal (ULN) if there is no evidence of liver metastases or ≤5 ULN in the presence of liver metastases v. Total bilirubin ≤ 2 times upper limit of normal (ULN) vi. Creatinine ≤ 2 times ULN and creatinine clearance (CrCL) ≥ 60mL/min using the Cockcroft Gault equation (Appendix 2)
• Able to remain still for up to 60 minutes per scan
• Any other condition which, in the opinion of the Investigator, would preclude participation in this study Optional: Participants that have available archival tissue (at least 15 consecutive, unstained, formalin-fixed, paraffin embedded (FFPE) slides or 1 FFPE block), or a fresh tumour biopsy sample that opt to provide samples will be used for GRPR analysis (histology staining or RNA measurements). Participants without any archival tissue or fresh biopsy sample, or who refuse to provide archival tissue are still eligible for the study.

You may not qualify if:

• Known hypersensitivity to the investigational medicinal products (DOTA-STR-17126) or any of the excipients.
• Participants with Class 3 or 4 New York Heart Association (NYHA) Congestive Heart Failure.
• Average QTc (using the Fridericia correction calculation) \> 470 msec for females and QTcF \>450 msec for males on screening ECG or history of congenital long QT syndrome.
• Clinically significant bleeding within two weeks prior to trial entry (i.e., gastrointestinal bleeding, intracranial bleeding).
• Pregnant or lactating women. i. For female participants of childbearing potential or male participants with female partner of childbearing potential, who are not willing to practice highly effective contraception during the trial and for at least 6 months after \[177Lu\] Lu-DOTA-STR-17126 administration ii. Sexually active males must use a condom during intercourse while taking the drug and for 4 months after stopping treatment and should not father a child in this period. A condom is required to be used also by vasectomized men in order to prevent delivery of the drug via seminal fluid. Female partners of childbearing potential should use highly effective contraceptive methods during and up to 6 months after stopping treatment.
• Have any medical condition that impairs complete bladder emptying. Participants with permanent urinary indwelling catheter (IDC) or nephrostomy may be allowed to enrol on a case-by-case basis in discussion with Principal Investigator, if it is determined not to put the patient at an increased risk of adverse drug effects and/or interfere with the integrity of study outcome.
• Major surgery, defined as any surgical procedure that involves general anaesthesia and a significant incision (i.e., larger than what is required for placement of a central venous access, percutaneous feeding tube, or biopsy) within 30 days before study day 1 or anticipated surgery within the subsequent 43 days (6 weeks).
• Has an additional active malignancy requiring therapy within the past 2 years.
• History of another malignancy within 3 years before study enrolment. A subject with the following malignancies is allowed if considered cured or unlikely to recur within 3 years:
• i. Carcinoma of the skin without melanomatous features ii. Curatively treated cervical carcinoma in situ iii. Bladder tumours considered superficial such as non-invasive (T1a) and carcinoma in situ (T1s), thyroid papillary cancer with prior treatment
• Active, uncontrolled bacterial, viral, or fungal infection(s) requiring systemic therapy within 30 days prior to trial enrolment.
• Psychiatric illness/social situations that would interfere with compliance with study requirements.
• Cannot undergo PET/CT scanning because of weight limits (350 lbs or 160 kg).
• Prior exposure to any other GRPR-targeting therapeutic agents.
• Prior treatment with any systemic anti-cancer therapy including chemotherapy, immunotherapy, biological therapy, radiation therapy, biologic, hormonal or herbal therapy, or any investigational therapy or investigational device, unless:

Sponsors & Collaborators

• Integrated Haematology and Oncology Network: lead

Study Sites (1)

Icon Cancer Centre Hollywood

Perth, Western Australia, 6009, Australia

RECRUITING

MeSH Terms

Conditions

Breast Neoplasms; Prostatic Neoplasms; Neoplasms

Condition Hierarchy (Ancestors)

Neoplasms by Site; Breast Diseases; Skin Diseases; Skin and Connective Tissue Diseases; Genital Neoplasms, Male; Urogenital Neoplasms; Genital Diseases, Male; Genital Diseases; Urogenital Diseases; Prostatic Diseases; Male Urogenital Diseases

Study Officials

• Nat Lenzo, MD

  Integrated Hematology Oncology Network (Icon Group)

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Amma P Owusu, RN BSc MN

CONTACT

+61498120411; research.iit@icon.team

Duncan Colyer, RN BN PGDip

CONTACT

research.iit@icon.team

Study Design

• Study Type: interventional
• Phase: early phase 1
• Allocation: NA
• Masking: NONE
• Purpose: DIAGNOSTIC
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: All participants are enrolled into one treatment/imaging group, with no control or comparison arm. Every participant follows the same study pathway (initial PET imaging with \[68Ga\]Ga-DOTA-STR-17126, with optional progression to low-dose \[177Lu\]Lu-DOTA-STR-17126 based on imaging findings), consistent with an open-label, non-randomised, single-arm, exploratory Phase 0 design.

Study Record Dates

• First Submitted: April 21, 2026
• First Posted: May 27, 2026
• Study Start: May 28, 2026
• Primary Completion (Estimated): May 30, 2028
• Study Completion (Estimated): May 31, 2029
• Last Updated: June 10, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR, ANALYTIC CODE
• Time Frame: 2029 for 12 months
• Access Criteria: Email the study's central contact, provide a reason for your request, subject to review by the PI and Sponsor Oversight committee. You may be required to enter into a data sharing agreement.

Locations

AU (1)