Transplant Therapeutics Consortium Receives FDA Notice of Reviewability for the iBox Scoring System Full Qualification Package

The iBox Scoring System is a novel composite biomarker endpoint predictive of long-term graft survival after kidney transplantation

On track to be the first qualified reasonably likely surrogate endpoint in transplant for use in the FDA accelerated approval pathway

FDA aims for a 10 month review of the Full Qualification Package

MOUNT LAUREL, N.J., July 30, 2025 /PRNewswire/ -- The American Society of Transplant Surgeons (ASTS) and American Society of Transplantation (AST) announced today that the Transplant Therapeutics Consortium (TTC) received notification from FDA of the Reviewability of the Full Qualification Package (FQP) for the iBox Scoring System, a novel reasonably likely surrogate efficacy endpoint for kidney transplant clinical trials. The FDA Drug Development Tool qualification program aims to communicate the final decision within 10 months targeting April 2026. The Full Qualification Package is the final step in the FDA qualification process and iBox scoring system is the first transplant endpoint to reach this stage of qualification.

Improving the long-term survival of transplanted kidneys is an important area of unmet need for transplantation recipients. The current efficacy failure endpoint has typically shown non-inferiority of immunosuppressive regimens but the iBox Scoring System is proposed to be used to demonstrate the superiority of a new agents compared to the standard of care as a co-primary endpoint in pivotal drug therapeutic studies. As a reasonably likely surrogate endpoint, the iBox scoring system would be used in the Accelerated Approval Pathway at the FDA designed to allow for earlier approval of drugs that treat serious conditions and fill an unmet medical need.     

"It's not surprising that using a clinical trials endpoint that is nearly four decades old has been a significant impediment to the development of new therapeutics for maintenance immunosuppression and has contributed to the relatively stagnate long-term outcomes of kidney transplants. I applaud the FDA for working with the TTC to develop the iBox as a coprimary endpoint for clinical trials in kidney transplantation. We have recognized the strong push from the patient community for new agents that promote both longer survival of transplanted organs and improved safety and tolerability. I hope that this is the first of many collaborative efforts to validate and implement new drug development tools to achieve that end," said Kenneth Newell, MD, PhD, Professor of Surgery, Emory University and Executive Committee Member of the TTC.

Paul T. Conway, Vice President and Chair of Policy and Global Affairs, American Association of Kidney Patients (AAKP) and a 28-year kidney transplant recipient stated, "For decades, bipartisan national policy priorities, across multiple presidential administrations and Congresses, have included transplantation and sustainable long-term transplant outcomes as a means for saving more lives, protecting livelihoods, and reducing patient and taxpayer burdens. Yet, due to policy barriers, the transplant drugs patients currently depend upon to avoid organ rejection and a return to the transplant waiting list have failed to evolve and pose serious risks to both organ recipients and grafts. AAKP is optimistic that recent FDA action on the iBox is a signal the agency is putting transplant patients first, accelerating transplant drug development and re-aligning internal FDA decision-making to better advance long-standing American policy priorities." Conway previously served as the inaugural Chair of the FDA's Patient Engagement Advisory Committee for medical devices.

"We celebrate this step toward a regulatory process that will allow for many more drugs to enter into the transplant drug development path. The patient community has been starved of new approaches to keep their precious grafts alive and thriving for a longer time, with fewer side effects and complications. As a person living with transplants derived from selfless individuals, I can speak for the transplant patient community in applauding this progress toward our goal of leveraging modern day science to achieve one transplant for life," said Dr. Karin Hehenberger, President Lyfebulb, and a kidney and pancreas transplant recipient.

About iBox

The iBox scoring system is a composite endpoint that utilizes multiple clinically relevant features (estimated glomerular filtration rate (eGFR), proteinuria, anti-human leukocyte antigen donor-specific antibody, and kidney graft biopsy histopathology) at one-year post-transplant to predict 5-year graft survival. The iBox scoring system (NCT03474003), has been developed and validated in a landmark publication released in the BMJ by a team of researchers led by Professor Alexandre Loupy in Paris French NIH (Inserm), APHP and Université Paris Cité, comprising 7557 patients from 10 academic centers from Europe and the US and 3 Randomized controlled trials.

About FDA Accelerated Approval

The FDA Accelerated Approval Program is designed to facilitate and expedite development of drugs that treat serious conditions, and fill an unmet medical need based on a reasonable likely surrogate endpoint (RLSE) that is supported by strong mechanistic and/or epidemiologic rationale. The Qualification of the iBox would allow it to be used as a RLSE for accelerated approval of novel new immunosuppressants for kidney transplantation. The Accelerated Approval program has historically been successful advancing new innovative therapies for HIV and cancer and most recently promoted the introduction of 4 new drugs for IgA nephropathy, a chronic kidney disease with no approved therapies 5 years ago before the use of proteinuria as a surrogate endpoint. 

About TTC

The Transplant Therapeutics Consortium (TTC) is a public-private partnership with the FDA founded in 2017 by the American Society of Transplantation (AST) and the American Society of Transplant Surgeons (ASTS). This collaboration unites the transplant community, industry leaders, and regulatory agencies dedicated to the development of innovative tools, methods and processes for facilitating advancement of new innovative therapies to improve the lives of solid organ transplant recipients.

This submission of the FQP was accomplished by employing the resources of the TTC members and engaging with FDA throughout the biomarker qualification process. TTC is supported through funding and input from the AST*, ASTS*, argenx*, Arkana Laboratories*, Bristol Myers Squibb*, CareDx*, Critical Path Institute, CSL, CTI Clinical Trial Services, Inc.*, Eledon*, European Society of Organ Transplantation, the U.S. Food and Drug Administration (FDA), Hansa Biopharma*, HUS Helsinki University Hospital, Immucor, KU Leunven, Memo Therapeutics AG*, Natera, National Institutes of Health, Novartis, Paris Transplant Group, Pirche, Sanofi*, Takeda*, Talaris Therapeutics, Thermo Fisher Scientific, The Transplantation Society, Transplant Genomics*, University of Manitoba, and Veloxis Pharmaceuticals*. Any groups that would like to join in this effort or have information or data that may contribute to further advances, can contact JoAnn Gwynn at jgwynn@myast.org.

*Denotes Current TTC Members

The Transplant Therapeutics Consortium (TTC) was launched in April 2017 and co-founded by the American Society of Transplantation (AST) and the American Society of Transplant Surgeons (ASTS). TTC brings together pharmaceutical companies, diagnostic companies, academic and nonprofit partners working toward a common goal of moving the field forward toward drug development solutions in transplantation.

American Society of Transplantation 

Founded in 1982, the American Society of Transplantation (AST) is a non-profit, 501(c)3 organization dedicated to advancing the field of transplantation and improving patient care by promoting research, education, advocacy, organ donation, and service to the community through a lens of equity and inclusion. The society is the largest transplant organization in North America (consisting of nearly 5,000 professional members), representing a majority of the nation's medical professionals engaged in the field of transplantation.

Learn more at myAST.org.

American Society of Transplant Surgeons  

The American Society of Transplant Surgeons (ASTS) was founded in 1974 by 127 surgeons to unite the professionals who were advancing the fledgling field of organ transplantation. 

From this small group of dedicated individuals, we have grown to represent over 2,000 transplant professionals who are dedicated to saving and improving lives through the transformative power of organ donation and transplant surgery. Learn more about ASTS by visiting our website at ASTS.org.

MEDIA CONTACTS:

Shauna O'Brien – AST: sobrien@myAST.org

Anna Shults – ASTS: anna.shults@asts.org

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SOURCE American Society of Transplantation