Renibus Therapeutics Announces Oral Presentation on Phase 3 PROTECT Trial Data for RBT-1 at the American Association for Thoracic Surgery (AATS) Annual Meeting
Clinical study in cardiac surgery patients demonstrates favorable safety profile; exploratory analyses suggest potential benefit in higher-risk populations
SOUTHLAKE, Texas, April 30, 2026 /PRNewswire/ -- Renibus Therapeutics® ("Renibus"), a clinical-stage biopharmaceutical company focusing on the prevention and treatment of cardio, renal and metabolic diseases, today announced the oral presentation of data from the Phase 3 PROTECT trial evaluating RBT-1 at the 106th American Association for Thoracic Surgery (AATS) Annual Meeting, taking place May 2-5, 2026 in Chicago, IL.
RBT-1 is a novel pharmacologic preconditioning agent with antioxidant and anti-inflammatory properties. The PROTECT Phase 3 study evaluated whether a single preoperative infusion of RBT-1 could reduce postoperative complications in patients undergoing cardiac surgery requiring cardiopulmonary bypass. The randomized, double-blind, placebo-controlled, trial randomized 433 patients across 34 sites in the United States and Canada. Patients undergoing non-emergent coronary artery bypass grafting (CABG), and/or valve surgery, were randomized 1:1 to receive RBT-1 or placebo 24 to 48 hours prior to surgery. Patients were followed for outcomes through postoperative day 60.
The PROTECT study did not meet its primary endpoint, a hierarchical composite (win ratio) of death, dialysis-requiring AKI, 30-day cardiopulmonary readmission, and ICU days (WR 0.87 [0.66, 1.15], p=0.33), and key secondary endpoints were also not statistically significant. The study population was predominantly low-risk, with approximately 70% of patients having a predicted operative mortality risk of <2% using the Society of Thoracic Surgeons' (STS) risk calculator, which limited the ability to detect a treatment effect in the overall cohort. Post-hoc analyses suggest that RBT-1 may improve clinical outcomes in higher-risk patients, including those with chronic kidney disease and higher STS operative risk scores. "While the study did not meet its primary endpoint in the overall population, we observed treatment effect trends in higher-risk patient populations that may inform a more targeted development strategy," said Dr. Jeffrey Keyser, Chief Executive Officer of Renibus Therapeutics. "These findings support the underlying biology of RBT-1 and provide important direction for future development."
RBT-1 was generally safe and well-tolerated. The most common treatment-related adverse events were photosensitivity and transient infusion-related reactions. Importantly, no treatment-related adverse events resulted in delayed or cancelled surgeries.
"Post-operative complications remain a significant unmet need in higher-risk cardiac surgery patients," said Michael E. Jessen, MD, Chair of the Department of Cardiovascular & Thoracic Surgery, University of Texas Southwestern Medical Center. "The observed trends in higher-risk patients are clinically relevant and support continued investigation of RBT-1 in more targeted populations to better understand its potential role in reducing postoperative complications."
Renibus plans to further evaluate the data to inform next steps in the development of RBT-1, with a focus on patient populations most likely to benefit. The AATS presentation can be found on the Company's website at www.Renibus.com.
Oral Presentation Details:
Title: "A Phase 3 Randomized, Double-Blind, Multi-Center, Placebo-Controlled Study Evaluating the Efficacy of RBT-1 in Reducing Postoperative Complications in Patients Undergoing Non-Emergency Cardiac Surgery"
Abstract Presenter: Michael Jessen, University of Texas Southwestern Medical Center
Session: Perioperative Care Rapid Fire Orals
Date/Time: Monday, May 4, 2026, 7:30am-9:00am CDT
More information on AATS can be found at the meeting website.
About Renibus Therapeutics
Renibus Therapeutics® is a clinical late-stage biopharmaceutical company focused on the prevention and treatment of cardiac, renal, and metabolic diseases. Renibus' lead program, veverimer, is currently in Phase 3 development for the treatment of metabolic acidosis in adults with chronic kidney disease. The Company's second late-stage program, RBT-1, recently completed the PROTECT Phase 3 trial evaluating RBT-1 in patients undergoing cardiac surgery. Results from this trial suggest that further development in risk-enriched patients may be warranted and is currently under evaluation. RBT-1 has received Breakthrough and Fast Track designations from the FDA.
For more information, please visit the Company's website at www.Renibus.com and engage with us on LinkedIn.
Investor and Media Contact:
Amy Conrad
Juniper Point
[email protected]
858-914-1962
Business Development Contact
Jamie Donadio
CFO, Renibus
[email protected]
SOURCE Renibus Therapeutics
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