Daratumumab for Late Antibody-Mediated Rejection

The DARTABMR study is a comprehensive case-control research project designed to evaluate the efficacy of daratumumab in treating late antibody-mediated rejection (ABMR) in kidney transplant recipients with de novo donor-specific antibodies (DSA). The primary objective is to determine whether daratumumab offers superior outcomes compared to standard therapies like intravenous immunoglobulin (IVIG), plasmapheresis, and rituximab.

Study Design and Population:

This is a retrospective and prospective case-control study involving kidney transplant recipients diagnosed with late ABMR, defined as occurring more than 12 months post-transplant. Patients are divided into two groups: the case group receiving daratumumab (1800 mg subcutaneously, weekly for four doses, then monthly for six doses) and a control group previously treated with standard therapies. Inclusion criteria encompass first or subsequent kidney transplants with biopsy-proven ABMR and presence of de novo DSA. Exclusion criteria include active infections, significant comorbidities, prior daratumumab treatment, contraindications, and non-adherence to immunosuppression protocols. Patients are matched based on ABMR diagnosis timing, baseline kidney function, DSA characteristics, number of transplants, age, and ethnicity to minimize confounding.

Intervention and Data Collection:

All participants, both cases and controls, are maintained on a standardized immunosuppressive regimen consisting of tacrolimus, mycophenolate mofetil (MMF), and steroids, with specified targets and documentation of any deviations. Data collected encompass demographic information, clinical history, immunosuppressive details, kidney function tests (creatinine, eGFR), DSA levels (via Luminex), and biopsy findings using Banff scoring and molecular analyses. For the daratumumab group, assessments occur at baseline, during treatment, and after the last dose, including monitoring for infections, adverse events, and immune profiles via flow cytometry and cell-free DNA (cfDNA). For controls, retrospective data on treatment regimens, kidney function, DSA levels, biopsy results, infections, and safety are gathered.

Outcome Measures and Analysis:

The primary endpoint is treatment success, defined by improvement or stabilization of kidney function, significant reduction in DSA levels (e.g., ≥50% MFI decrease), and favorable biopsy changes. Graft survival during follow-up is also considered. Secondary analyses compare changes in kidney function, DSA levels, biopsy scores, and incidence of adverse events between groups. Statistical methods include chi-square or Fisher's exact tests for success rates, t-tests or ANOVA for continuous variables, and regression analyses to control for residual confounders.

Summary:

Overall, the DARTABMR aims to provide evidence on whether daratumumab can improve outcomes in late ABMR cases with de novo DSA, potentially influencing future treatment protocols for this challenging clinical scenario.