Kidney Week

Abstract: FR-PO1211

B-Cell Maturation Antigen-Targeted T-Cell Engager Therapy with Cizutamig for HLA Desensitization in Highly Sensitized Kidney Transplant Candidates

Session Information

• Transplantation: Clinical - Rejection, Biomarkers, and Pharmacology
  October 23, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

• 2002 Transplantation: Clinical

Authors

• La Manna, Gaetano, Universita degli Studi di Bologna, Bologna, Emilia-Romagna, Italy

Gaetano La Manna, MD, PhD

• Gessaroli, Elisa, Universita degli Studi di Bologna, Bologna, Emilia-Romagna, Italy

Elisa Gessaroli, MD

• Kervella, Delphine, Hospital Universitari Vall d'Hebron, Barcelona, CT, Spain

Delphine Kervella, MD, PhD

• Corradetti, Valeria, IRCCS Azienda Ospedaliero-Universitaria di Bologna Policlinico di Sant'Orsola, Bologna, Emilia-Romagna, Italy

Valeria Corradetti, MD, PhD

• Martínez Lacalle, Anna, Hospital Universitari Vall d'Hebron, Barcelona, CT, Spain

Anna Martínez Lacalle

• Moreso, Francesc J., Hospital Universitari Vall d'Hebron, Barcelona, CT, Spain

Francesc J. Moreso, MD, PhD

• Giuliodori, Silvia, Universita degli Studi di Parma, Parma, Emilia-Romagna, Italy

Silvia Giuliodori, PhD, ScD

• Haddon, David, Candid Therapeutics Inc, San Diego, California, United States

David Haddon, PhD

• Wung, Peter, Candid Therapeutics Inc, San Diego, California, United States

Peter Wung, MD

• Lu, Tim, Candid Therapeutics Inc, San Diego, California, United States

Tim Lu, MD, PhD

• Comai, Giorgia, Universita degli Studi di Bologna, Bologna, Emilia-Romagna, Italy

Giorgia Comai, MD

• Bestard, Oriol, Hospital Universitari Vall d'Hebron, Barcelona, CT, Spain

Oriol Bestard, MD, PhD

Introduction

Highly sensitized kidney transplant (KT) candidates face prolonged transplant inaccessibility due to broad anti-HLA humoral sensitization. B-cell maturation antigen (BCMA)/CD3 bispecific T-cell engager therapy with cizutamig may provide a unique biological breadth spanning both memory B-cell and plasma cell compartments to reduce serological memory and facilitate access to KT.

Case Description

Two highly sensitized KT candidates from two European centers received compassionate-use cizutamig for HLA desensitization. Patient (P)1 was a 55-year-old man with Alport syndrome, one prior graft loss and cPRA 96.99%, with >13 years on waitlist without transplant offers. P2 was a 43-year-old man with IgAN, three prior graft losses, cPRA 100% and >4 years listed without offers. They both received weekly IV cizutamig dosing regimens with step-up dosing. Treatments were well tolerated in both patients, without major adverse events. By week 4, peripheral CD19+ B cells were completely depleted. By week 10, IgA and IgM were undetectable and IgG reached 500 mg/dL requiring IVIg replacement. Notably, a bone marrow aspirate at week 10 after last full dose in P2 revealed no B or plasma cells. In both patients, cPRA values started to decrease after week 2. Between week 2 and 8, cPRA (>2000MFI) decreased slowly but progressively, especially for class I anti-HLA Ab. A decrease in cPRA was observed during follow-up for both class I and II, including those against previously recognized HLA antigens. P1 was transplanted with a negative FCXM at week 13; he did not experience DSA rebound or rejection and achieved a cPRA of 76.77% at last follow-up. P2 was reactivated on the waitlist with a current cPRA of 87.29% (week 28).

Discussion

Cizutamig induced sustained B-cell/plasma-cell depletion and reduced alloantibody burden in two highly sensitized KT candidates, enabling access to compatible KT after therapy. Longer follow-up is needed to define effect durability, safety, as well as patient and transplant outcomes.