Renibus Presents Phase 2 Results on RBT-1, a First-in-Class Preconditioning Agent, at the American Society for Enhanced Recovery and Perioperative Medicine (ASER PM) 2023 Meeting

-Results demonstrate that treatment with RBT-1 prior to cardiac surgery may reduce the risk of  post-operative anemia and need for blood transfusion and iron supplementation-  

 -Pivotal Phase 3 study of RBT-1 to be initiated in Q4 2023-

SOUTHLAKE, Texas, September 11, 2023 – Renibus Therapeutics® (“Renibus”), a clinical-stage biopharmaceutical company focusing on the prevention and treatment of cardio-renal and metabolic diseases, today presented Phase 2 results on RBT-1 (stannic protoporfin/iron sucrose) during a poster session at 2023 American Society for Enhanced Recovery and Perioperative Medicine (ASER PM 2023), taking place in Nashville, TN at Vanderbilt University, Sept. 11-13, 2023.   Renibus is advancing RBT-1 toward Phase 3 development for its lead indication to reduce post-operative complications following cardiothoracic surgery.

Patients who undergo cardiac surgery are at risk of anemia from blood loss, inflammation, and red blood cell lysis, which leads to the use of blood products and increases the risk of post-operative complications in the hospital setting.  RBT-1 is a potent inducer of anti-inflammatory, antioxidant and iron-scavenging pathways – activation of these pathways, along with the iron content of RBT-1, may improve iron levels, iron utilization, and reduce resistance to the erythropoietin protein.  The data presented at ASER PM 2023 demonstrated that RBT-1 increased cytoprotective protein levels and improved clinical outcomes in a recently completed Phase 2 study.

“As an Intensivist, practicing in a post-cardiac surgery ICU, I am focused on improving patient safety and enhancing the quality of care, all while utilizing the most advanced interventions to reduce any complications following cardiac surgery,” said Ashish K. Khanna, M.D., M.S., FCCP, FCCM, Associate Professor and Vice-Chair for Research, Director Perioperative Outcomes and Informatics Collaborative, at Wake Forest University School of Medicine.  “I believe that therapeutic agents that modulate inflammatory pathways during the operative period in cardiac surgery have tremendous potential as  preconditioning agents to reduce the risk of post-operative complications, including anemia and the need for blood transfusions or iron supplements.  I look forward to RBT-1 advancing toward Phase 3 and closer to patients who can benefit greatly from its use.”

Summary of Phase 2 RBT-1 Results Presented at ASER PM 2023:

RBT-1 was studied in a multicenter, double-blind, placebo controlled, Phase 2 clinical trial in patients undergoing coronary artery bypass graft (CABG) and/or cardiac valve surgery on cardiopulmonary bypass (CPB). The trial enrolled 152 patients from cardiac surgery centers in the US, Canada and Australia, 132 patients were evaluable for the primary endpoint (ITT population) and 121 were evaluable for clinical outcomes (mITT population), as pre-specified in the statistical analysis plan.

121 patients who were scheduled to undergo CABG and/or valve surgery on CPB received one intravenous dose of RBT-1 or placebo between 24 to 48 hours before surgery. Incidence of post-operative anemia, need for blood transfusion, and iron supplementation were recorded.  Hemoglobin levels were followed through hospital discharge after surgery.  Several clinically meaningful improvements were observed. These results are summarized below:

  • A significant reduction of 49% in the incidence of post-operative anemia, as reported by the investigators, was observed in response to RBT-1 compared with placebo (p=0.0447).
  • A 33% reduction in the need for blood transfusion was observed in the RBT-1 group compared with placebo.
  • Similarly, a 42% reduction in the need for iron supplementation was observed in the RBT-1 group compared with placebo.
  • When comparing all patients who required both blood transfusion and iron, a statistically significant reduction was observed in the RBT-1 group compared with placebo (RBT-1: 0.0% vs Placebo: 12.2%; p=0.0046).
  • Importantly, hemoglobin levels at discharge in patients who received RBT-1 were comparable to those who received placebo despite lesser rates of blood transfusion and iron supplementation (RBT-1: 9.8 g/dL vs Placebo: 9.8 g/dL).

Poster Presentation Details at ASER PM 2023:

Title: RBT-1, a Pharmacologic Preconditioning Agent, Reduces the Incidence of Anemia, Blood Transfusion, and Use of Supplemental Iron in Patients Undergoing Cardiac Surgery

Session: Poster Session, Parthenon Foyer

Date and Time: September 11, 2023, 4:00 PM-5:00 PM

Following conclusion of AESR PM 2023, the poster will be available on the publications page of the Renibus website at  More information on the ASER PM meeting can be found here: ASER 2023 – Nashville, TN (

About RBT-1

RBT-1 (stannic protoporfin/iron sucrose) is a potent inducer of anti-inflammatory, antioxidant and iron-scavenging pathways that is advancing toward Phase 3 development for its lead indication to reduce post-operative complications following cardiothoracic surgery.

The Phase 2 study of RBT-1 (NCT04564833), which was completed in February 2023, was a randomized, double-blind, multi-center, placebo-controlled trial evaluating the effect of RBT-1 in patients undergoing elective coronary artery bypass graft (CABG) and/or cardiac valve surgery. Renibus announced positive final results from this study in May 2023, which supports the advancement of RBT-1 into a pivotal Phase 3 study.

In June 2023, RBT-1 was granted Breakthrough Therapy designation status from the U.S. FDA to reduce the risk of complications in patients undergoing cardiothoracic surgery.

In July 2023, Renibus reached agreement with the FDA on the Phase 3 program for RBT-1.

About Renibus

Renibus is a clinical stage biopharmaceutical company dedicated to treating, improving and extending patients’ lives by developing products to prevent disease progression, improve outcomes and protect against organ damage associated with cardiorenal and metabolic diseases.  Renibus’ first-in-class lead program is RBT-1, a drug that will enter a Phase 3 pivotal trial in cardiothoracic surgery in Q4 2023. RBT-3 is a novel, low molecular weight iron nanoparticle that has the potential to rapidly resolve iron deficiency and may reduce the risk of cisplatin-induced nephrotoxicity. RBT-9 (stannic protoporfin) is a potent anti-inflammatory and antioxidant drug with broad spectrum anti-viral properties. It has been investigated in a 42-patient Phase 2, randomized, placebo-controlled trial in high-risk patients with COVID-19. The data from this trial indicated the RBT-9 has the potential to significantly improve clinical outcomes in life threatening viral infections. Additional pre-clinical work is underway to help inform the clinical development strategy.

For more information, please visit the Company’s website at and engage with us on LinkedIn.

Investor and Media Contact:

Amy Conrad
Juniper Point

Business Development Contact
Frank Stonebanks
Co-CEO, Renibus