SOUTHLAKE, TEXAS, April 30, 2026
Renibus Therapeutics has announced the oral presentation of Phase 3 PROTECT trial data for its investigational therapy RBT-1 at the prestigious American Association for Thoracic Surgery (AATS) Annual Meeting 2026, highlighting key findings in patients undergoing cardiac surgery with cardiopulmonary bypass. The study evaluated the potential of RBT-1, a novel pharmacologic preconditioning agent with antioxidant and anti-inflammatory properties, to reduce postoperative complications, a major clinical challenge in cardiac surgery. While the trial did not meet its primary endpoint, the results revealed clinically meaningful trends in higher-risk patient populations, offering new insights for targeted therapeutic development and future clinical strategies.
Phase 3 PROTECT Trial Evaluates Cardiac Surgery Outcomes
The PROTECT Phase 3 clinical trial was a randomized, double-blind, placebo-controlled, multicenter study involving 433 patients across 34 sites in the United States and Canada, designed to assess whether a single preoperative infusion of RBT-1 could improve postoperative outcomes. Patients undergoing coronary artery bypass grafting (CABG) and/or valve surgery were randomized to receive either RBT-1 or placebo 24 to 48 hours prior to surgery, with outcomes monitored through postoperative day 60.
The study’s primary endpoint—a composite measure including mortality, dialysis-requiring acute kidney injury (AKI), readmission rates, and ICU duration—was not statistically met. However, the trial provided valuable clinical insights, particularly regarding patient stratification and risk-based treatment response, which are increasingly important in modern clinical trial design.
Subgroup Analysis Highlights Benefit in High-Risk Patients
Advertisement
Despite the overall study outcome, post-hoc analyses identified promising trends in higher-risk patient populations, including those with chronic kidney disease and elevated surgical risk scores. Approximately 70% of enrolled patients were classified as low-risk, which may have limited the ability to detect a statistically significant treatment effect across the entire cohort. In contrast, patients with higher baseline risk demonstrated improved clinical outcomes, suggesting that RBT-1’s mechanism of action may be particularly beneficial in more vulnerable populations.
These findings support a refined development strategy focused on targeted patient groups, aligning with the broader industry trend toward precision medicine and risk-adapted clinical trials. Additionally, RBT-1 demonstrated a favorable safety profile, with no treatment-related adverse events leading to surgical delays or cancellations, reinforcing its potential as a safe adjunct therapy in perioperative care.
Advancing Clinical Development and Regulatory Strategy
The presentation of Phase 3 data at AATS underscores Renibus’ commitment to advancing innovative therapies for cardio-renal diseases, an area with significant unmet medical need.
From a GxP perspective, the PROTECT trial adhered to Good Clinical Practice (GCP) standards, ensuring robust data integrity, patient safety, and regulatory compliance. The insights gained from this study are expected to guide future clinical trial design, focusing on risk-enriched populations where therapeutic benefit may be maximized. RBT-1 has already received Breakthrough Therapy and Fast Track designations from the FDA, highlighting its potential to address critical gaps in perioperative care. Moving forward, Renibus plans to further analyze the data to determine next-stage development pathways, including potential additional trials and regulatory engagement. As healthcare systems increasingly prioritize precision-based treatment approaches, the development of RBT-1 represents a promising step toward reducing postoperative complications and improving patient outcomes in cardiac surgery, reinforcing the company’s role in driving innovation in biopharmaceutical research and clinical development.
Source: Renibus Therapeutics press release
