A Study Comparing Siplizumab With Rabbit Anti-Thymocyte Globulin to Help the Body Accept a Kidney Transplant

NCT07508787 | Not Yet Recruiting Phase 2 DMC FDA Drug

• 1 other identifier: TCD601B205
• Study Type: interventional
• Target: 120
• Locations: 0 countries
• Sites: N/A

Brief Summary

The goal of this clinical trial is to learn if siplizumab can prevent rejection of a kidney transplant in adult participants with end stage kidney disease. The main questions it aims to answer are: How many adverse events do participants receiving two different doses of siplizumab have compared to rabbit anti-thymocyte globulin (rATG)? How many participants successfully keep their kidney transplant after receiving siplizumab or rATG? This will be calculated as those participants that did not: die; have their kidney fail to work properly (graft loss); their body rejects their transplant (tissue sample (biopsy)-proven acute rejection: BPAR); or who were lost to follow-up. How does the body respond to siplizumab after dosing at each of the 2 dose levels? How does siplizumab work in the body compared to rATG? Selected participants will be divided into 3 groups. In 2 of the groups, participants will be given siplizumab at one of the two study medicine doses. Participants in the third group will be given rATG. All participants will take the usual anti-rejection medicines given before, during, and after a kidney transplant. All participants will also be given medicines before the study drug to lower the risk of reactions, and medicines used to prevent or treat infections after the transplant. Participants will be asked to provide their medical history at the first visit at the study site where you will have your kidney transplant. At the first visit and other visits participants will be asked to provide their medication history, have a physical exam, check vital signs, have blood drawn for tests, and have non-invasive tests that record the electrical activity of your heart (ECG) and blood draws. Participants will be monitored for 12 months after transplant surgery.

Conditions

Renal Transplant Failure and Rejection

Outcome Measures

Primary Outcomes (1)

• Assessment of the safety of 2 dose levels of siplizumab versus rATG.

  Number and percentage of participants at 12 months post-transplant experiencing adverse events (AEs), serious adverse events (SAEs), and adverse events of special interest (AESIs).

  12 months

Secondary Outcomes (9)

• Assessment of the incidence of composite efficacy failure (defined as death, graft loss, biopsy-proven acute rejection [BPAR], or loss-to-follow-up) and their individual components.

  12 months

• Assessment of the incidence of composite efficacy failure (defined as death, graft loss, biopsy-proven acute rejection [BPAR], or loss-to-follow-up) and their individual components.

  12 months

• Assessment of the incidence of composite efficacy failure (defined as death, graft loss, biopsy-proven acute rejection [BPAR], or loss-to-follow-up) and their individual components.

  12 months

• Assessment of the incidence of composite efficacy failure (defined as death, graft loss, biopsy-proven acute rejection [BPAR], or loss-to-follow-up) and their individual components.

  12 months

• Assessment of the incidence of composite efficacy failure (defined as death, graft loss, biopsy-proven acute rejection [BPAR], or loss-to-follow-up) and their individual components.

  12 months

Study Arms (3)

Low dose siplizumab

EXPERIMENTAL

Drug: Siplizumab

High dose siplizumab

EXPERIMENTAL

Drug: Siplizumab

Rabbit anti-thymocyte globulin

ACTIVE COMPARATOR

Drug: Rabbit anti-thymocyte globulin

Interventions

Siplizumab DRUG

A non-agonistic, humanized, anti-CD2 monoclonal antibody of the IgG1κ class

Also known as: TCD601

High dose siplizumab; Low dose siplizumab

Rabbit anti-thymocyte globulin DRUG

An anti-human thymocyte immunoglobulin preparation made of purified polyclonal antibodies derived from rabbits

Also known as: Thymoglobulin

Rabbit anti-thymocyte globulin

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Recipients of a renal allograft from a non-HLA identical living or deceased donor.
• Recipients of a kidney with a cold ischemia time \< 30 hours; hypothermic machine perfusion within the same timeframe is acceptable.
• Women of childbearing potential, defined as all women physiologically capable of becoming pregnant, must agree to use highly effective methods of contraception.

You may not qualify if:

• Transplant recipients seronegative for EBV.
• Transplant recipients receiving a kidney from a non-heart beating donor (ie, DCD) whose organ is retrieved from an uncontrolled DCD or whose donor age \> 55 years of age.
• Multi-organ transplant recipients (eg, kidney-pancreas, organ other than kidney), dual-kidney transplant recipients, recipients with more than one prior kidney transplant, or hematopoietic stem cell transplantation recipients.
• Presence of current or historical DSA via single-antigen bead assay or local SoC. The MFI cut-off value used to determine the presence of DSA will be defined as per the institutional SoC. Results within 3 months prior to transplant are acceptable.
• ABO-incompatible recipient.
• Administration of complement inhibitor therapy within 6 months prior to the transplant, or likely to require treatment with complement inhibitor therapy during the study.
• Participants receiving immunosuppressive therapies prior to transplant for pre-existing conditions must be candidates for the protocol-defined regimen.
• History of malignancy of any organ system, except for localized excised non-melanomatous skin lesions or carcinoma in situ of the cervix.
• Seropositive for human immunodeficiency virus or hepatitis B surface antigen. Participants who are seropositive for hepatitis C virus (HCV) are excluded without proof of sustained viral response after anti-HCV treatment.
• Recipient of a kidney from a donor who tests positive for human immunodeficiency virus or hepatitis B surface antigen/hepatitis B core protein.
• History of hypersensitivity to any of the study drugs or to drugs of similar chemical classes (eg, siplizumab, rATG, TAC, MPA derivatives, CS).
• Evidence of active tuberculosis (TB) infection (participants with a history of latent TB may become eligible after treatment with anti-TB therapy according to national guidelines).
• Participants with severe systemic infection(s), at the time of screening or within 2 weeks prior to randomization

Sponsors & Collaborators

• Nefro Avillion Clinical Development, LLC: lead

MeSH Terms

Conditions

Rejection, Psychology

Interventions

siplizumab; Antilymphocyte Serum; thymoglobulin

Condition Hierarchy (Ancestors)

Social Behavior; Behavior

Intervention Hierarchy (Ancestors)

Immune Sera; Antibodies; Immunoglobulins; Immunoproteins; Blood Proteins; Proteins; Amino Acids, Peptides, and Proteins; Serum Globulins; Globulins; Biological Products; Complex Mixtures

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Pharmacy will prepare infusion based on randomization code prior to administration by study investigator. To maintain the blind, matching infusions of normal saline will be administered (IV) as placebo for different dosing regimens.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: Participants will be randomized in a 1:1:1 ratio to a low dose of siplizumab, a high dose of siplizumab and rATG.

Study Record Dates

• First Submitted: March 11, 2026
• First Posted: April 2, 2026
• Study Start: April 29, 2026
• Primary Completion (Estimated): March 28, 2028
• Study Completion (Estimated): March 28, 2028
• Last Updated: April 2, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share