NCT05917522

Assessment of Biomarker-Guided CNI Substitution In Kidney Transplantation

Assessment of Biomarker-Guided Calcineurin Inhibitor (CNI) Substitution In Kidney Transplantation (RTB-015)

• Status: Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 800 (estimated)
• Sponsor: National Institute of Allergy and Infectious Diseases (NIAID) · NIH
• Sex: All
• Age: 18 Years – 70 Years
• Healthy volunteers: Not accepted

Summary

800 adult first time kidney transplant recipients will be enrolled in the Observational Study and followed to evaluate their Human Leukocyte Antigen (HLA)-DR/DQ molecular mismatch (mMM) score as a risk-stratifying prognostic biomarker. Six months after transplant the study will identify those who meet the eligibility criteria for the Nested Randomized Control Trial (RCT). 300 eligible subjects will be randomized 2:1 to abatacept or Standard of care (SOC) in the randomization and followed for 18 months monitoring for safety and improvement in renal function, neurocognitive function, and a life participation patient reported outcome measure (PROM). The primary objective of the Observational Study is to test the validity of the HLA-DR/DQ mMM score as a prognostic biomarker for stratification of post-transplant alloimmune risk. Whereas the objective of the Nested RCT is to test whether a superior outcome in kidney function (primary endpoint), as well as secondary endpoints (neurocognitive function, and life participation PROM), will be achieved in patients who are transitioned from Tacrolimus (TAC) to abatacept, while maintaining efficacy (freedom from biopsy proven acute rejection).

Detailed description

Observational Study: Enrolling 800 adult first time kidney transplant recipients. Consent and enrollment will be targeted to occur pre- or post-kidney transplant during the initial hospitalization. All subjects enrolled in the study will be followed observationally to evaluate HLA-DR/DQ molecular mismatched (mMM) as a risk-stratifying prognostic biomarker. This prospective, multi-center, observational study of 800 kidney transplant recipients at clinically low risk for alloimmune memory (DSA negative pre-kidney transplant) who are initiated on standard of care (SOC) therapy will be used to satisfy the FDA requirement to prospectively evaluate the HLA mMM score as a prognostic biomarker for post-kidney transplant outcomes in a real-world cohort. Donor-recipient HLA-DR/DQ mMM score will be determined at enrollment and recipients will be followed over 24 months post- kidney transplant for primary alloimmune events (i.e., T cell Mediated Rejection (TCMR), DSA, and Antibody Mediated Rejection (ABMR) ). Nested RCT (SOC versus conversion to abatacept): We will follow subjects in the Observational Study for the initial 6 months to identify those who meet the stringent "immune-quiescent" randomization criteria: absence of biopsy proven acute rejection (BPAR) on a for-cause or 6-month surveillance biopsy; and absence of DSA. In addition, these subjects must have absence of infection (e.g., BKV/CMV), and be on at least MMF ≥500 mg p.o. bid at the time of randomization. From this "immune-quiescent" group those individuals with a low or intermediate HLA-DR/DQ mMM score will be eligible for the Nested RCT. 300 eligible subjects will be randomized 2:1 to abatacept or SOC in the randomization phase (Abatacept arm: 200 vs. SOC arm: 100) to have adequate power for detecting differences between the treatment groups. Subjects enrolled into the trial's screening phase (0-6 months post-transplant) of the Observational Study will identify at least 360 kidney transplant recipients who exhibit immune quiescence and who meet the 6-months post-kidney transplant eligibility criteria for the Nested RCT. These individuals will be re-consented prior to randomization at 6-months post-kidney transplant.

Conditions

• Kidney Transplant

Interventions

Type	Name	Description
BIOLOGICAL	Abatacept	Injection: 125 mg/mL of a clear to slightly opalescent, colorless to pale-yellow solution in a single-dose prefilled ClickJect autoinjector
PROCEDURE	Standard of Care at US Transplant Centers	Control group, remaining on SOC (Tacrolimus/ Mycophenolic Acid (MPA)/ Prednisone (Pred))

Timeline

• Start date: 2023-12-07
• Primary completion: 2027-07-01
• Completion: 2029-07-01
• First posted: 2023-06-26
• Last updated: 2026-03-23

Locations

15 sites across 1 country: United States

Regulatory

• FDA-regulated drug study