Kidney Week

Abstract: FR-PO1026

Comparison of Immediate- and Extended-Release Tacrolimus Formulations in Living-Donor Kidney Transplantation (LDKT)

Session Information

• Transplantation: Clinical - Pharmacology and Nonkidney Solid Organ Transplants
  November 07, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

• 2102 Transplantation: Clinical

Authors

• Azhar, Muhammad, The University of Arizona College of Medicine Tucson, Tucson, Arizona, United States

Muhammad Azhar, MD

• Koksal, Ali Riza, The University of Arizona College of Medicine Tucson, Tucson, Arizona, United States

Ali Riza Koksal, MD

• Yilmaz, Bulent, The University of Arizona College of Medicine Tucson, Tucson, Arizona, United States

Bulent Yilmaz, MD

• Ariyamuthu, Venkatesh Kumar, The University of Arizona College of Medicine Tucson, Tucson, Arizona, United States

Venkatesh Kumar Ariyamuthu, MD, MBA, FASN

• Qannus, Abd Assalam, The University of Arizona College of Medicine Tucson, Tucson, Arizona, United States

Abd Assalam Qannus, MD

• Tanriover, Bekir, The University of Arizona College of Medicine Tucson, Tucson, Arizona, United States

Bekir Tanriover, MD, MBA, MPH

Background

Standard maintenance immunosuppression in LDKT typically includes tacrolimus, mycophenolate mofetil (MMF), and ±steroids. Tacrolimus is available in three formulations: immediate-release tacrolimus (IR-Tac), including brand-name Prograf and generic tacrolimus, and extended-release tacrolimus (Envarsus XR). Envarsus XR has gained increasing use (20% of LDKT recipients at any given time) due to its lower peak levels and potentially reduced side effect profile and making it a preferred option for fast metabolizers. However, comparative analyses of these formulations on LDKT outcomes remain limited.

Methods

We analyzed national UNOS data for adult LDKT recipients in the U.S. from 2018–2023, excluding recipients of multi-organ transplants, pediatric patients, and those who received multiple induction agents during the index hospitalization. We included patients who remained on the same tacrolimus and MMF formulation at both discharge and conditionally at 1-year follow-up (N: Prograf=5,050; Generic Tacrolimus=10,981; Envarsus XR=2,458). Primary outcomes included unadjusted rates of acute rejection (AR) at 1-year and all-cause (ACGF) and death censored graft failures (DCGF) at last follow-up. Cox proportional hazards models were used to evaluate ACGF and DCGF, adjusted using inverse probability weighting (IPW) to account for differences in donor, recipient, and transplant characteristics. Covariate balance was assessed using standardized mean differences (SMD), with SMD<0.1 indicating good balance.

Results

Unadjusted 1-year AR rates were 4.9% (Prograf), 5.1% (Generic Tacrolimus), and 3.8% (Envarsus XR) (p=0.03). Graft failure rates during median 2.8–3.8 years of follow-up were 6.7%, 6.1%, and 4.1% (p<0.001) for ACGF and 2.4%, 2%, 1.5% for DCGF, respectively (p=0.02). In IPW-adjusted Cox models, compared to the Prograf reference group, there were no statistically significant differences in ACGF risk (Generic Tacrolimus: HR=1.13, 95% CI: 0.97–1.33, p=0.12; Envarsus XR: HR=0.98, 95% CI: 0.73–1.30, p =0.88) or in DCGF risk (Generic Tacrolimus: HR=1.09, 95% CI: 0.84–1.42, p = 0.51; Envarsus XR: HR=0.85, 95% CI: 0.55–1.33, p =0.48).

Conclusion

Envarsus XR demonstrates non-inferiority to IR-Tac formulations with respect to acute rejection and graft failure outcomes in LDKT.

Funding

• Commercial Support – Veloxis Pharmaceutical, Inc

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.20258etj8gdc