Inclusion Criteria:

• Male or female subjects ≥ 18 years of age at Screening.
• Able and willing to comply with all study procedures.
• Stable kidney function per Investigator assessment and no known episodes of AKI during the preceding 4 weeks.
• Scheduled to undergo non-emergent coronary and/or valve surgery(ies) requiring cardiopulmonary bypass, including:
  • CABG alone;
  • Combined CABG surgery/repair of 1 or more cardiac valves;
  • Cardiac valve(s) replacement or repair alone.
• Female and male subjects of childbearing potential must agree to use 2 forms of contraception, with at least 1 being a barrier method, or abstain from sexual activity for 30 days following study drug administration.
• Male subjects must agree not to donate or sell sperm for 30 days following study drug administration.

Exclusion Criteria:

• Presence of AKI (KDIGO criteria) at the time of Screening.
• Surgery to be performed without cardiopulmonary bypass.
• Surgery to be performed under conditions of circulatory arrest or hypothermia with rectal temperature <28°C (82.4°F).
• eGFR ≤20 mL/min/1.73m2 or need for dialysis.
• Surgery for aortic dissection or to correct a major congenital heart defect.
• Administration of iodinated contrast media within 24 hours prior to cardiac surgery or evidence of contrast-induced nephropathy prior to cardiac surgery.
• Cardiogenic shock or hemodynamic instability within the 24 hours prior to surgery and requirement for inotropes or vasopressors or other mechanical devices, such as intra-aortic balloon counter-pulsation.
• Requirement for any of the following within 7 days prior to cardiac surgery:
  • Defibrillator or permanent pacemaker;
  • Mechanical ventilation;
  • Intra-aortic balloon counter-pulsation;
  • Left ventricular assist device;
  • Other forms of mechanical circulatory support.
• Known history of cancer within the past 2 years, except for carcinoma in situ of the cervix or adequately treated basal cell carcinoma of the skin.
• Known or suspected sepsis at time of Screening or confirmed or treated endocarditis within 30 days prior to cardiac surgery.
• Other current active infection requiring systemic antibiotic treatment.
• Inadequate hepatic function, defined as total bilirubin or alanine aminotransferase or aspartate aminotransferase > 2 X the upper limit of normal at time of Screening or Child Pugh Class C liver disease or higher.
• Any congenital coagulation disorder.
• Asplenia (anatomic or functional).
• History of photosensitivity or active skin disease that, in the opinion of the Investigator, could be worsened by RBT-1.
• Known hypersensitivity or previous anaphylaxis to SnPP or any tin-based product.
• Serum ferritin > 500 ng/mL or those who have received IV iron within 28 days of Screening.
• Pregnancy or lactation.
• Treatment with an investigational drug or participation in an interventional study within 30 days prior to administration of study drug.
• In the opinion of the Investigator, any disease processes or confounding variables that would inappropriately alter the outcome of the study.
• Inability to comply with the requirements of the study protocol.

Eligibility last updated 9/27/21. Questions regarding updates should be directed to the study team contact.