Phase 1/2a: RN3161 alone and with tirzepatide for safety, how the drug works in the body, and effects on weight in adults with overweight or obesity

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This phase 1/2a trial tests RN3161 as a single agent and in combination with tirzepatide to characterize safety, tolerability, pharmacokinetics, pharmacodynamics, and effects on body weight. RN3161 will be given alone to healthy volunteers and given with tirzepatide to adults meeting prespecified BMI ranges (with Asian ancestry thresholds applied where specified), and placebo control arms are included. Participants will undergo clinical monitoring and serial blood sampling to measure drug levels, biological activity, adverse events, and changes in body weight over the dosing period. Early phase portions emphasize safety and PK/PD, while the phase 2a portion looks for preliminary signals of weight change and combination tolerability.

Why it matters

Who can join: the full rules

Inclusion Criteria:

* 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

Exclusion Criteria:

* 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

Where it's running

• Nucleus Network Pty Ltd
  Melbourne, Victoria, Australia Recruiting

Study contacts

• Principal investigator: Philip Ryan, MD — Nucleus Network Pty Ltd.

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.