Evaluation of Immunosuppressive Therapy Individualization Using Biomarkers in Living Donor Kidney Transplant Recipients: A Multicenter Randomized Study

The primary objective of this multicenter, randomized study is to determine the effect of individualizing **immunosuppressive therapy** based on baseline immunologic risk stratification using two biomarkers: ELISPOT IFN-γ d-sp and HLA-enhanced mismatch. The study aims to assess the impact on a composite endpoint, which includes loss of renal function, incidence of biopsy-confirmed clinical acute rejection (BPAR), and development of donor-specific antibodies (dnDSA) at two years of follow-up in patients receiving kidney transplants from living donors. This is compared with patients managed under a standard, non-individualized immunosuppressive regimen. The clinical relevance of this objective lies in potentially improving transplant outcomes and reducing complications associated with kidney transplants.

Secondary objectives include evaluating whether individualized stratification of immunological risk and therapeutic optimization can reduce patient mortality, renal graft loss, and the development of subclinical and chronic rejection as advised on protocol biopsies at 3 and 24 months. Additionally, the study will assess the incidence of opportunistic infections, treatment-derived metabolic disorders such as diabetes mellitus, dyslipidemia, and hypertension, as well as malignancies, both cutaneous and non-cutaneous, over a two-year follow-up period. The study will also evaluate the economic cost savings associated with these interventions. Furthermore, changes in the allogeneic d-sp response over the two years of follow-up, including dnDSA, ELISPOT IFN-γ d-sp, and cytokines CXCL9/CXCL10 in urine, will be assessed. The transcriptional profile of rejection risk according to the kidney solid-organ rejection test (kSORT) and the cellular antiviral response against CMV, EBV, and VBK viruses will also be evaluated.

The clinical trial involves **adult men and women** aged 18 years and older, who are recipients of a first **kidney transplant** from a living donor. The study population includes both male and female participants, with no vulnerable populations selected. Participants are required to have an AB0 compatible transplant and must be HLA-incompatible with at least one HLA mismatch at any antigen level. The trial does not specify the total number of participants, as this information was not provided by the sponsor. Participants must have a calculated PRA of 75% or less by solid phase technique and should not have current or historical class I and class II donor-specific anti-HLA antibodies. Lifestyle considerations include the requirement for females of childbearing potential to use highly reliable contraception methods throughout the study and for a specified period after treatment. Similarly, sexually active men must use barrier methods of contraception during and after treatment with Mycophenolate Mofetil (MMF). Participants must also agree not to donate blood or sperm during and after the treatment period. The trial population was selected based on these criteria to ensure the safety and efficacy of the individualized immunosuppressive therapy being studied.

The clinical trial is designed as a **randomized**, double-blind, controlled study to evaluate the efficacy of individualizing immunosuppressive therapy based on baseline immunologic risk stratification in patients undergoing kidney transplant from living donors. The trial aims to assess the impact of this approach on a composite endpoint, including loss of renal function, incidence of biopsy-confirmed clinical acute rejection, and development of donor-specific antibodies over a follow-up period of two years. The study will involve adult participants who are recipients of a first kidney transplant from a living donor with at least one HLA mismatch. The trial will span approximately ten years, with an estimated end date in March 2027.

Participants will undergo a series of study visits, beginning with an inclusion visit to screen for eligibility based on specific criteria, such as age, transplant compatibility, and absence of certain antibodies. Following the inclusion visit, participants will be randomized into either the individualized treatment group or the standard treatment group. Regular follow-up visits will be scheduled to monitor the participants' health status, adherence to the treatment protocol, and any adverse events. These visits will also include protocol biopsies at three and 24 months to assess for subclinical and chronic rejection. The end-of-study visit will occur at the conclusion of the two-year follow-up period, where the primary and secondary endpoints will be evaluated.

The expected length of participant involvement is two years, with conditions for early termination including significant adverse reactions, non-compliance with the study protocol, or withdrawal of consent. The trial will utilize a range of immunosuppressive agents, including **prednisone**, **basiliximab**, **tacrolimus monohydrate**, **mycophenolate mofetil**, **methylprednisolone**, and **rabbit anti-human thymocyte immunoglobulin**, administered either orally or intravenously, depending on the specific medication. The study is classified as a low-intervention clinical trial, as the medications are used according to their technical data sheets or routine clinical practice, minimizing additional risk to participants.

The clinical trial involves the administration of several **experimental medications**. The first medication is **Prednisone**, marketed as Prednisona Pensa 5 mg comprimidos EFG. This medication is provided in tablet form and is administered orally. The maximum daily dose is 20 mg, with a total dose not exceeding 20 mg per day. The treatment period can extend up to 1000 days. Prednisone is a chemical substance classified under the ATC code H02AB, which corresponds to glucocorticoids.

Another medication used in the trial is **Basiliximab**, available as Simulect 20 mg powder for solution for injection or infusion. This medication is administered intravenously. The maximum daily dose is 20 mg, with a total dose not exceeding 80 mg. The treatment period is limited to 1 day. Basiliximab is a protein-based substance, specifically a monoclonal antibody, and is categorized under the ATC code L04AC02.

**Tacrolimus Monohydrate** is also included in the trial, marketed as tacrolimus cinfa 1 mg cápsulas duras EFG. This medication is provided in hard capsule form and is administered orally. The maximum daily dose is 15 mg, with a total dose not exceeding 15 mg per day. The treatment period can extend up to 1000 days. Tacrolimus Monohydrate is a chemical substance classified under the ATC code L04AD02.

**Mycophenolate Mofetil** is administered as Micofenolato Mofetile Accord 250 mg capsule rigide. This medication is provided in hard capsule form and is administered orally. The maximum daily dose is 1000 mg, with a total dose not exceeding 1000 mg per day. The treatment period can extend up to 1000 days. Mycophenolate Mofetil is a chemical substance classified under the ATC code L04AA06, which corresponds to mycophenolic acid.

**Methylprednisolone** is used in the trial as Metilprednisolona NORMON 40 mg polvo y disolvente para solución inyectable EFG. This medication is provided as a solution for injection and is administered intravenously. The maximum daily dose is 500 mg, with a total dose not exceeding 1000 mg. The treatment period is limited to 1 day. Methylprednisolone is a chemical substance classified under the ATC code H02AB04.

Lastly, **Rabbit Anti-Human Thymocyte Immunoglobulin** is administered as TIMOGLOBULINA 5 mg/ml, polvo para solución para perfusión. This medication is provided as a solution for infusion and is administered intravenously. The maximum daily dose is 200 mg, with a total dose not exceeding 750 mg. The treatment period is limited to 1 day. This substance is structurally diverse and blood-derived, classified under the ATC code L04AA04.

Throughout the trial, participant compliance with the dosing schedules is monitored to ensure adherence to the prescribed treatment regimens. No non-experimental treatments, such as standard-of-care therapy, placebo, or comparator treatments, are specified in the trial documentation.

The efficacy of the clinical trial will be assessed through a composite primary endpoint evaluated at 2 years of follow-up. This endpoint includes the proportion of patients experiencing any of the following: loss of renal function, incidence of biopsy-confirmed clinical acute rejection (BPAR), and development of donor-specific anti-HLA antibodies (dnDSA). Secondary endpoints will be measured at 24 months and include mortality from any cause, kidney graft loss, incidence and severity of subclinical and chronic rejection, incidence of opportunistic infections, treatment-related metabolic disorders, cardiovascular events, malignancy, and the proportion of patients maintaining treatment according to protocol. Additionally, changes in immune response will be evaluated using biomarkers such as dn-DSA, ELISPOT IFN-γ d-sp, Memory B cell Elispot, urine cytokines CXCL9 and CXCL10, and transcriptional profile in blood of rejection risk according to the kSORT test. The antiviral cellular response against CMV, EBV, and VBK viruses will also be assessed. Economic cost and adherence to treatment will be studied using a mobile health application, and serious adverse reactions related to immunosuppressive treatment will be documented.