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A study to evaluate the effectiveness of R2R01 in preventing acute kidney injury in patients at high risk following heart surgery.

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study focuses on preventing Acute Kidney Injury, which is a sudden episode of kidney failure or damage that happens or develops within a short period of time. The research is specifically looking at patients at high risk for this condition following Cardiac Surgery, such as procedures involving the heart valves, the aorta, or a Coronary Artery Bypass Graft. These surgeries often require the use of a Cardiopulmonary Bypass machine, which is a device that temporarily takes over the function of the heart and lungs during the operation.

The purpose of the study is to evaluate the safety and effectiveness of a drug called R2R01. This medication is a Relaxin Agonist, which is a type of substance designed to activate specific proteins in the body to achieve a therapeutic effect. During the study, participants will receive either R2R01 or a placebo containing Sodium Chloride via a subcutaneous injection, which is an injection given into the fatty tissue just under the skin.

Participants will be assigned to different groups to receive different doses of the medication or the placebo. The study is double-blind, meaning that neither the participants nor the medical staff know which substance is being administered. The course of the study involves monitoring the participants after their surgery to observe how their kidneys function and to track any side effects that may occur.

The research process

The trial runs in 3 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Administration of study medication

    After joining the study, a subcutaneous injection, which is an injection administered just under the skin, is provided.

    One of two substances is administered: either the test medication named r2r01 at a dose of 5 mg, or a placebo consisting of sodium chloride (a salt solution) at a dose of 0.75 ml.

    The assignment of the test medication or the placebo is determined by a double-blind process, meaning neither the patient nor the medical staff knows which substance is being given.

  2. Step 2

    Postoperative monitoring

    Following cardiac surgery, there is monitoring of kidney function to check for acute kidney injury, which is a sudden episode of kidney failure or damage.

    Kidney health is assessed through blood tests measuring serum creatinine (a waste product used to check kidney function) and cystatin c (another protein used to evaluate kidney filtration) at specific intervals: 12, 24, 48, and 72 hours after surgery, and then at 7 days and 30 days after surgery.

  3. Step 3

    Evaluation of recovery and health outcomes

    The length of stay in the intensive care unit (icu) and the hospital is recorded.

    The occurrence of any adverse events, which are any unexpected medical problems or side effects, is tracked.

    The status of kidney function and any need for renal replacement therapy (treatments like dialysis that perform the functions of the kidneys) is monitored through day 30 after surgery.

Who can join the trial?

18 criteria

  • You must be at least 18 years old.
  • You must be able to communicate clearly with the study doctor, understand the study requirements, and sign a written informed consent form, which is a document where you agree to participate after being told all the details.
  • You must be scheduled for a planned (not emergency) heart surgery, such as coronary artery bypass graft (surgery to improve blood flow to the heart), valve surgery (surgery on the heart valves), or aorta surgery (surgery on the main artery that carries blood from the heart).
  • The surgery must involve cardiopulmonary bypass, which is a machine that takes over the function of the heart and lungs during surgery.
  • You must have certain risk factors for developing acute kidney injury, which is a sudden episode of kidney damage or failure.
  • If you are having only one type of surgery, you must have at least two risk factors; if you are having a combination of surgeries, you must have at least one risk factor.
  • Risk factors include having diabetes mellitus (a condition affecting blood sugar) that requires medicine.
  • Risk factors include having hypertension, which is high blood pressure.
  • Risk factors include a history of chronic heart failure, a condition where the heart cannot pump blood as well as it should, specifically classified as NYHA class III or higher (a way of measuring how much heart failure limits your daily activity).
  • Risk factors include having a left ventricular ejection fraction (LVEF) of 40% or less, which is a measurement of how much blood the main pumping chamber of your heart pushes out with each beat.
  • Risk factors include peripheral vascular disease, which is a disease where blood vessels in the arms or legs are narrowed or blocked.
  • Risk factors include having had a stroke or a transient ischemic attack (TIA), which are sudden issues with blood flow to the brain that cause nervous system symptoms.
  • Risk factors include atrial fibrillation, which is an irregular and often rapid heart rhythm, confirmed by an ECG (a test that records the electrical activity of your heart).
  • Risk factors include anemia, which means you have a low red blood cell count or low hemoglobin (the protein in red blood cells that carries oxygen), measured at 11 g/dL or less.
  • Risk factors include a Body Mass Index (BMI) of 30 or higher, which is a measure of body fat based on your height and weight.
  • Risk factors include being 70 years of age or older at the time of the screening.
  • You must have stable renal function, meaning your kidney health and how well they work is steady and not changing unexpectedly, as judged by the doctor.
  • You must agree not to participate in any other medical research studies from the time you sign the consent form until you finish the study.

Who cannot join the trial?

23 criteria

  • You are currently participating in another medical study that tests a new treatment.
  • You have had a kidney transplant, which is a surgery where a healthy kidney from a donor is placed into your body.
  • You have glomerulonephritis, which is an inflammation or swelling of the tiny filters in your kidneys.
  • You have experienced cardiogenic shock (a condition where the heart suddenly cannot pump enough blood), hemodynamic instability (unstable blood pressure), or required mechanical ventilation (the use of a machine to help you breathe) within 7 days before your surgery.
  • You have used a mechanical circulatory support device, such as an intra-aortic balloon pump (IABP) or a left ventricular assist device (LVAD), which are machines used to help the heart pump blood, within 7 days before your surgery.
  • You received inotropes or vasopressors, which are medications used to strengthen heart contractions or increase blood pressure, within 48 hours before your surgery.
  • You have sepsis, which is a serious and life-threatening reaction to an infection throughout the body.
  • You have endocarditis, which is an infection of the inner lining of your heart chambers or valves.
  • You have any other active infection that requires you to take antibiotics.
  • You have severe liver disease, measured by a specific scoring system called the Child-Pugh score.
  • You have received or will receive chemotherapy (cancer treatment) within the last 4 weeks or during the study that might affect how your kidneys work, such as platinum agents.
  • You have already been enrolled and assigned to this specific study before.
  • Your surgery is scheduled as an emergent surgery, which means it is an unplanned, urgent procedure needed immediately.
  • You are pregnant or nursing (breastfeeding).
  • You have a known hypersensitivity, or an allergic reaction, to the study medication or any of its ingredients.
  • You have any medical or social situation that makes it difficult for you to give informed consent (agreeing to the study after understanding all the details), cooperate, or participate.
  • Your planned heart surgery is "off-pump," meaning it will be done without using a cardiopulmonary bypass (CPB) machine (a machine that takes over the function of the heart and lungs during surgery).
  • The expected time using the cardiopulmonary bypass (CPB) machine is less than 60 minutes.
  • Your body weight is less than 50 kg or more than 120 kg.
  • You have acute kidney injury (AKI), which is a sudden episode of kidney failure or damage, at the time you join the study.
  • You are currently undergoing, or have recently undergone (within 4 weeks), or are scheduled for renal replacement therapy, such as dialysis, to do the work of your kidneys.
  • You have had a nephrectomy, which is the surgical removal of a kidney.
  • You have chronic kidney disease (CKD) at stage 4 or higher, which means your kidneys have a significantly reduced ability to filter waste from your blood, measured by a Glomerular Filtration Rate (GFR) of 30 or less.
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Investigated drugs

R2R01 is an experimental medication being tested to see if it can help prevent acute kidney injury in patients who are at high risk after undergoing heart surgery.

What is already known about the treatment

  • R2R01

    This experimental drug is administered as a liquid through a small injection under the skin. Currently being studied in clinical trials, it is being tested to see if it can help prevent kidney damage in patients undergoing major heart surgeries. It belongs to a class of drugs called relaxin agonists, which work by mimicking a natural hormone to help protect organs and improve blood flow at a cellular level.

  • Sodium chloride

    This substance is provided as a liquid solution for injection under the skin and serves as a placebo in this study. It is a common salt solution used in medicine to maintain the body's fluid and electrolyte balance. In this trial, it is used as a neutral comparison to help researchers determine if the experimental drug is truly effective.

Investigated diseases

Cardiac Surgery Associated Acute Kidney Injury - This condition involves a sudden decrease in kidney function that occurs following heart operations. It often develops after procedures such as bypass surgery, valve repair, or aortic surgery, especially when a heart-lung machine is used. The injury happens when the kidneys are unable to properly filter waste from the blood. It can progress from mild changes in kidney performance to more significant impairment. The severity of the condition is typically measured by changes in specific blood markers.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2025-523037-25-00Protocol codeR2R01-CSA-AKI-201Estimated enrolment440 patientsSponsorRiver 2 Renal Corp.

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