Can a new injection tame the toxic ammonia of urea cycle disorders?
NCT ID NCT07773246
First seen Aug 19, 2026 · Last updated Aug 21, 2026 · Updated 2 times
Summary
This early-stage trial is evaluating an experimental drug called KRRO-121, given as a shot under the skin, to see if it is safe and tolerable. The study first tests KRRO-121 in healthy adults, then in people with urea cycle disorders—a group of inherited conditions that impair the body's ability to remove ammonia, a toxic byproduct of protein breakdown. The goal is to understand how the drug behaves in the body and whether it might help manage these disorders.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- KRRO-121, an experimental drug given as a subcutaneous injection
- What this could lead to
- If successful, KRRO-121 could offer a new treatment option to help manage urea cycle disorders, potentially reducing the risk of dangerous ammonia buildup.
- What could go wrong
- This is an early-phase trial focused on safety, so it's unknown if KRRO-121 will be effective. Possible side effects and the need for long-term treatment are key uncertainties.
Why investors are watching
Korro Bio is testing KRRO-121, a drug for urea cycle disorders, in a small phase 1/2 trial with 30 participants. The study checks safety first, then how the drug works in patients. For a small company, this readout is a key test of whether its main pipeline candidate is viable.
If it works: If the trial shows KRRO-121 is safe and shows signs of working, Korro Bio could advance the drug to later-stage studies. That result would validate the company's core research program.
If it fails: The trial could fail to show safety or effectiveness, or the company could face delays. Trials often fail, and for a small company with few other assets, a negative result would be a serious setback.
AI-written from the trial record. Speculative, and not investment advice.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 1/2
Runs two stages together: safety and dose first, then whether the treatment works.
- Participants
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About 30 people
The number the study aims to enrol. It can still change while the study runs.
- Expected to start
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Sep 2026
An estimate. Start dates often move.
- Expected to finish
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Sep 2027
An estimate. End dates often move.
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 65 years
- Sex
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Anyone
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * Adult male or female participants, 18 to 65 years of age * Healthy as determined by medical history, physical examination, vital signs, 12-lead electrocardiogram (ECG), and screening laboratory assessments, in the opinion of the Investigator. * Female participant of childbearing potential or male participant that is willing to use an approved, reliable means of contraception * Willing and able to provide signed written informed consent and to comply with all study requirements Exclusion Criteria: * Any medical history that is clinically significant in the opinion of the Principal Investigator and Sponsor Medical Monitor * Any laboratory value at screening or predose on Day -1 outside the local laboratory reference range that is clinically significant in the opinion of the Principal Investigator and Sponsor Medical Monitor * Evidence of active systemic infection at Screening or Day 1 requiring antimicrobial, antiviral, or antifungal therapy * Use of any investigational drug or device within 3 months or 5 half-lives (whichever is longer) prior to Day 1 * Concurrent participation in any other interventional clinical study
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The places running it
1 site. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Locations
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Nucleus Network Pty Ltd
Melbourne, Victoria, 3004, Australia
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