This prospective trial will assess the safety, tolerability, pharmacokinetics, immunogenicity, pharmacodynamics and efficacy of the fully human CD38 monoclonal antibody felzartamab in kidney transplant recipients with late active or chronic-active ABMR. The study is designed as a randomized, controlled, double-blind pilot phase 2 trial. Participants will be randomized to receive either felzartamab or placebo for a period of six months, and then followed for another six months. After six and twelve months, study participants will be subjected to follow-up allograft biopsies.
This prospective bi-center study (University of Vienna, Charité Universitätsmedizin Berlin; Sponsor: Medical University of Vienna, Vienna, Austria; Funder: MorphoSys AG, Planegg, Germany) is an investigator-driven pilot trial designed to assess the safety\&tolerability (primary endpoint), pharmacokinetics, immunogenicity, pharmacodynamics and efficacy (preliminary assessment) of the fully human CD38 monoclonal antibody felzartamab in kidney transplant recipients diagnosed with late active or chronic-active antibody-mediated rejection (ABMR) after kidney transplantation. Adult renal allograft recipients with anti-HLA donor-specific antibodies (DSA) and biopsy-proven ABMR (Banff 2019 classification) ≥180 days post-transplantation will be identified and recruited at the kidney transplantation outpatient services of the two center sites. The primary endpoint will be safety and tolerability. Participants will be randomized to receive either felzartamab (intravenous administration) or placebo (1:1 randomization stratified by study site and according to ABMR categories) for a period of 6 months (administration of felzartamab/placebo at day 0, 7, 14, 21, and thereafter in 4-weekly intervals. After six (week 24) and twelve months (week 52), study participants will be subjected to follow-up allograft biopsies. Primary goals of the trial are to assess the safety, pharmacokinetics and pharmacodynamics (peripheral blood plasma cell and natural killer cell depletion) of a 6-month course of treatment over a period of 12 months. The trial will in addition provide first data on efficacy (progression/activity of rejection, blood biomarkers) and potential associations of treatment with parameters reflecting clinical progression of allograft dysfunction, including the course of estimated glomerular filtration rate.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
22
Intravenous infusion in regular intervals over 6 months
Intravenous infusion in regular intervals over 6 months
Medical University of Vienna
Vienna, Austria
Charité University
Berlin, Germany
Incidence of treatment-emergent adverse events
(Serious) adverse events will be classified using the Medical Dictionary for Regulatory Activities (MedDRA). Documentation of an AE will include the assessment of its relationship with the study drug (unrelated, related) and the severity of AE will be graded on a three-point scale (mild, moderate, severe).
Time frame: 12 months
Felzartamab serum concentration
Total felzartamab serum concentration (ELISA, ng/mL)
Time frame: At day 0, week 1, 2, 3, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 44, 48 and 52
Anti-Felzartamab antibodies
Concentration of anti-felzartamab antibodies in serum (ELISA, ng/mL)
Time frame: At day 0, week 1, 2, 3, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 44, 48 and 52
Morphologic ABMR categories
Phenotyping of renal transplant biopsies: active ABMR vs. chronic active ABMR vs. chronic inactive ABMR
Time frame: At week 24 and at week 52
Serum donor-specific antibody (DSA) levels
Mean fluorescence intensity (MFI) of the immunodominant DSA (Luminex)
Time frame: Week 0, 12, 24, and 52
Serum immunoglobulin levels
Ig (sub)classes (ELISA, Nephelometry, mg/dL)
Time frame: Week 0, 12, 24, and 52
Leukocyte subsets in peripheral blood
Counts of circulating plasma cells, natural killer cells, T and B cell subpopulations (flow cytometry, cell counts)
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Time frame: Week 0, 1, 4, 8, 12, 24, and 52
Immunologic biomarkers
CXCL9 and CXCL10 levels in blood and urine, BAFF levels in blood (ELISA, Luminex)
Time frame: Week 0, 12, 24, and 52
Torque Teno virus
Torque Teno virus (TTV) levels in plasma (quantitative PCR)
Time frame: Week 0, 12, 24, and 52
eGFR
Estimated GFR (CKD-EPI, mL/min/1.73m2)
Time frame: At day 0, week 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 44, 48 and 52
Proteinuria
Urinary protein excretion in spot urine (protein/creatinine ratio in mg/g)
Time frame: At day 0, week 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 44, 48 and 52
Graft loss
Graft failure: time (months) to event (Kaplan Meier)
Time frame: 12 months
Death
Patient death: time (months) to event (Kaplan Meier)
Time frame: 12 months
Glomerulitis plus peritubular capillaritis sum score
Grading of renal transplant biopsies using a semiquantitative score (g+ptc 0-6); higher = worse prognosis
Time frame: At week 24 and at week 52
Transplant glomerulopathy score
Grading of renal transplant biopsies using a semiquantitative score (cg 0-3); higher = worse prognosis
Time frame: At week 24 and at week 52
C4d score
Grading of renal transplant biopsies using a semiquantitative score (c4d 0-3); higher = worse prognosis
Time frame: At week 24 and at week 52
Molecular ABMR score
ABMR score (0.0-1.0, dimensionless number) assessed via the Molecular Microscope Diagnostic Platform (MMDx); higher = worse prognosis
Time frame: At week 24 and at week 52
Molecular ABMR categories
Molecular archetype analysis of rejection phenotypes using the Molecular Microscope Diagnostic Platform (MMDx). Phenotypes: early-stage ABMR; fully developed ABMR; late-stage ABMR
Time frame: At week 24 and at week 52