Phase 1/2a Study to Evaluate the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics and Effect on Body Weight of RN3161 as Monotherapy and in Combination With Tirzepatide in Adults With Overweight and Obesity

NCT07245771 | Recruiting Phase 1 DMC

• 1 other identifier: RN3161-101
• Study Type: interventional
• Target: 104
• Locations: 1 country
• Sites: 1

Brief Summary

Study to assess the safety, pharmacokinetics (the amount of study drug or any of its breakdown products in your body) and pharmacodynamics (how the study drug affects your body) of RN3161 alone (healthy volunteers) and RN3161 with tirzepatide (overweight and obese subjects)

Conditions

Obesity &Amp; Overweight

Keywords

obesity; overweight; healthy volunteers

Outcome Measures

Primary Outcomes (10)

• Blood Pressure

  Number of participants with blood pressure changes measured in mmHg

  180 Days

• ECG PR interval

  Number of participants with change in PR interval measured as milliseconds

  180 days

• Physical Examination

  Number of participants with changes seen by physical examination of skin, lymph nodes, eyes, ears, throat, chest, abdomen, musculoskeletal system and nervous system

  180 days

• Blood Chemistry Laboratory

  Number of participants with changes in blood levels of sodium, potassium, chloride, calcium magnesium, creatinine, bilirubin, phosphate, AST, ALT, alkaline phosphatase, glucose, albumin, urea in standard units

  180 days

• Adverse Events

  Incidence of adverse events reported

  180 days

• Heart Rate

  Number of participants with change in heart rate measured in beats per minute

  180 days

• ECG QRS Complex

  Number of participants with changes in QRS complex measured in milliseconds

  180 days

• ECG QT interval

  Number of participants with change in QT interval measured by Frederica method in milliseconds

  180 days

• Blood Hematology Laboratory

  Number of participants with changes in blood hemoglobin, hematocrit, platelets, neutrophils and leukocytes measured in standard units

  180 days

• Blood Coagulation Laboratory

  Number of participants with changes in plasma prothrombin time, activated partial thromboplastin time, and international normalized ratio measured in standard units

  180 days

Secondary Outcomes (2)

• Plasma and Urine Pharmacokinetics

  180 Days

• Presence of ADA

  180 days

Other Outcomes (5)

• Effect of RN3161 on plasma insulin

  180 days

• Assess RN3161 effect on plasma LDL

  180 days

• Effect of RN3161 on plasma HDL

  180 days

Study Arms (4)

RN3161

EXPERIMENTAL

Investigational Product

Drug: RN3161

Placebo Control

PLACEBO COMPARATOR

placebo control

Drug: Placebo Control

RN3161 and tirzepatide

EXPERIMENTAL

In Part 3, RN3161 co-administered with tirezepatide

Drug: RN3161; Drug: Tirzepatide

Placebo and tirzepatide

ACTIVE COMPARATOR

In Part 3; Placebo co-administered with tirzepatide

Drug: Placebo Control; Drug: Tirzepatide

Interventions

RN3161 DRUG

Investigational Product

RN3161; RN3161 and tirzepatide

Placebo Control DRUG

0.9% normal saline SC injection

Placebo Control; Placebo and tirzepatide

Tirzepatide DRUG

In Part 3; randomized to either RN3161 + tirzepatide or placebo + tirzepatide

Placebo and tirzepatide; RN3161 and tirzepatide

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• BMI:
• Obesity: BMI ≥ 30 kg/m² for participants with no Asian ancestry and ≥ 27.5 kg/m² for participants with Asian ancestry that has been stable (± 5%) for the previous 3 months (based on participant self-report or available medical records), with or without a weight-related comorbidity (excluding diabetes)
• Overweight: BMI 27 to \<30 kg/m² for participants with no Asian ancestry and 23.0 to \<27.5 kg/m² for participants with Asian ancestry that has been stable (± 5%) for the previous 3 months (based on participant self-report or available medical records), with at least 1 weight-related comorbidity (excluding diabetes)
• Weight-related comorbidities include a diagnosis of the following:
• Hypertension: seated BP ≤ 140/90 mm Hg; receiving ≤ 2 stable (≥ 4 weeks) agents limited to ACE inhibitors, angiotensin receptor blockers, calcium channel blockers, or thiazide ≤ 25 mg, or untreated
• Dyslipidemia: stable use of lipid-lowering agents for dyslipidemia (LDL-C \< 150 mg/dL, triglycerides \< 300 mg/dL)
• Osteoarthritis

You may not qualify if:

• self-reported or documented weight gain or loss \>5% within 3 months prior to screening
• use of GLP1R agonists within 6 months of screening
• intolerance to GLP-1 medications in the past
• use of non-GLP1R medications for weight loss within 3 months of screening
• HbA1c \>6.5%
• diagnosis of significant liver disease
• history of malignancy or anaphylaxis
• use of any siRNA agent in the prior 12 months

Sponsors & Collaborators

• Ikaria Bioscience Pty Ltd: lead
• Shanghai Rona Therapeutics Co., Ltd.: collaborator

Study Sites (1)

Nucleus Network Pty Ltd

Melbourne, Victoria, 3004, Australia

RECRUITING

MeSH Terms

Conditions

Obesity; Overweight

Interventions

Tirzepatide

Condition Hierarchy (Ancestors)

Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Glucagon-Like Peptide-1 Receptor; Glucagon-Like Peptide Receptors; Receptors, G-Protein-Coupled; Receptors, Cell Surface; Membrane Proteins; Proteins; Amino Acids, Peptides, and Proteins; Receptors, Gastrointestinal Hormone; Receptors, Peptide

Study Officials

• Philip Ryan, MD

  Nucleus Network Pty Ltd.

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: randomized to study drug or placebo

Study Record Dates

• First Submitted: September 20, 2025
• First Posted: November 24, 2025
• Study Start: November 4, 2025
• Primary Completion (Estimated): February 15, 2027
• Study Completion (Estimated): August 15, 2027
• Last Updated: November 24, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will share

Locations

AU (1)