Recruiting
Early Phase 1

GzmB-Targeted Cu-64

Sponsor:

Ratio Therapeutics, Inc.

Code:

NCT07774650

Conditions

Healthy Volunteer

Eligibility Criteria

Sex: All

Age: 18 - 60

Healthy Volunteers: Accepted

Interventions

Granzyme-B targeted [64Cu]-labeled PET radiotracer

Study Details

Brief summary:

This is an exploratory clinical study of copper-64 \[Cu-64\]-labeled granzyme B (GzmB)-targeted compounds for PET/CT imaging. The goal is to determine how GzmB-Targeted \[Cu-64\]-labeled compounds are distributed in the body by assessing PET/CT images and blood samples, and to assess the safety profile after a single intravenous dose.

Up to 6 healthy volunteers (3 female, 3 male) will receive one injection of a GzmB-targeted \[Cu-64\]-labeled compound, then undergo multiple whole-body PET/CT scans, blood and urine tests over about 24 hours, and a follow-up phone call around Day 7. Up to 2 GzmB-Targeted \[Cu-64\]-labeled compounds may be assessed (i.e. maximum of 12 healthy volunteers in total in the study).

Researchers will look at the blood activity of GzmB-Targeted \[Cu-64\]-labeled compound and the organ distribution and movement of the product in the body. They will also evaluate any changes in physical examination assessments, vital signs, ECG, and clinical laboratory measurements from pre-administration to post-administration.

Conditions

Healthy Volunteer

Study ID

NCT07774650

Start date

Jul 8, 2026

Status verified date

Aug, 2026

Completion date

Dec, 2026

Anticipated

Primary completion date

Dec, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 60

Healthy Volunteers: Accepted

Inclusion Criteria:

1. Adult male or female participants 18-60 years of age judged to be in good health by the Investigator
2. No clinically significant laboratory abnormalities; all tests of liver and kidney function within normal limits
3. Capable of giving signed informed consent, which includes compliance with requirements and restrictions listed in the ICF and this protocol
4. Female participants of childbearing potential and male participants who are fertile and have female partners of childbearing potential must agree to use adequate birth control throughout the study to the conclusion of follow-up.

Exclusion Criteria:

1. Pregnant or breast-feeding female participants (female participants of childbearing potential must have negative pregnancy tests at Screening and pre-dose Day 0)
2. Inadequate venous access (at least two distinct access sites allowing for separate test agent administration and PK blood sampling are required)
3. Inability or unwillingness to undergo serial PET/CT imaging
4. Active infection or malignancy
5. Known or suspected inflammatory, autoimmune or fibrotic disease
6. Major surgery or other intensive medical treatment in the 3 months prior to planned study injection, as assessed by the investigator
7. Received a radioisotope within 7 physical half-lives of that radioisotope prior to planned study injection
8. Known allergy/hypersensitivity to PET/CT tracers or compounds similar to GzmB-Targeted Compounds
9. Concurrent participation in a clinical trial of investigational product(s)
10. Participation in other research protocols or clinical care where there was radiation exposure such that the exposure from the last year, in addition to the radiation exposure expected from participation in this clinical study, exceeds the effective dose of 50 mSv, which would be above the acceptable annual limit established by US federal guidelines
11. Significant intercurrent illness or psychiatric illness/social situation that could place the participant at undue risk during study participation, significantly alter study outcomes, or affect participant compliance with study requirements for dosing and evaluation, as determined by the investigator

Study Design

Enrollment

12 participants

Anticipated

Allocation

Non randomized

Intervention Model

Sequential

Primary purpose

Diagnostic

Interventions and Outcome Measures

Arms

experimental: [Cu-64]RTX-4001

Arm Description: Single IV administration of \[Cu-64\]RTX-4001, a Granzyme-B-targeted PET radiotracer, in healthy adult volunteers.

experimental: [Cu-64]RTX-4002

Arm Description: Single IV administration of \[Cu-64\]RTX-4002, a Granzyme-B-targeted PET radiotracer, in healthy adult volunteers.

Interventions

Granzyme-B targeted [64Cu]-labeled PET radiotracer

Single intravenous administration of a Granzyme-B targeted \[64Cu\]-labeled positron emission tomography (PET) radiotracer to assess pharmacokinetics, biodistribution, and radiation dosimetry in adult healthy volunteers.

Primary outcome measure

  • Determine the maximum concentration (Cmax) of radiation (Pharmacokinetics) in the blood after a single dose of the GzmB-Targeted [Cu-64]-labeled compound [ Time Frame: 24 hour period post injection. ]
  • Determine the time to maximum concentration (Tmax) in the blood after a single dose of the GzmB-Targeted [Cu-64]-labeled compound [ Time Frame: 24 hour period post injection ]
  • Determine the area under the curve (AUC) in blood after a single injection of the GzmB-Targeted [Cu-64]-labeled compound [ Time Frame: 24 hour period post injection. ]
  • Determine the elimination half-life in the blood post a single injection of the GzmB-Targeted [Cu-64]-labeled compound [ Time Frame: 24 hour period post injection ]
  • Determine the clearance in the blood after single injection of the GzmB-Targeted [Cu-64]-labeled compound [ Time Frame: 24 hour period post injection ]
  • Determine the volume of distribution in the blood after a single injection of the GzmB-Targeted [Cu-64]-labeled compound [ Time Frame: 24 hour period post injection ]
  • Evaluate the organ distribution of radioactivity for a single dose of GzmB-targeted [Cu64]-labeled compound [ Time Frame: 24 hour period post injection ]
  • Evaluate the safety profile for a single dose of the GzmB-Targeted [Cu-64]-labeled compound in adult healthy volunteers [ Time Frame: From injection to 8 days post injection ]

Central Contacts and Locations

Central contacts

Anna Carberry

203-444-6025clinicrecruitment@indd.org

Locations

Xing Imaging

Recruiting

New Haven, Connecticut, United States, 06510

More Information

Sponsor

Ratio Therapeutics, Inc.

Last update posted

Sep 1, 2026

Last verified

Aug, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Ratio Therapeutics, Inc. on 2026-09-01.