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Felzartamab infusions for adults with kidney transplants and late isolated microvascular inflammation

A Double-Blind, Placebo-Controlled, Multicenter, Randomized Phase 2 Trial Evaluating the Efficacy and Safety of Felzartamab in Recipients of Kidney Transplants With Late Isolated Microvascular Inflammation (MVI)

Phase 2 Interventional Biogen · NCT07219043

This study will try felzartamab infusions in adults with kidney transplants who developed late isolated microvascular inflammation to see if the inflammation goes away after 24 weeks.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment81 (estimated)
Ages18 Years to 74 Years
SexAll
SponsorBiogen Industry-sponsored
Drugs / interventionseculizumab, tocilizumab, rituximab, felzartamab
Locations23 sites (Los Angeles, California and 22 other locations)
Trial IDNCT07219043 on ClinicalTrials.gov

What this trial studies

This is a Phase 2, randomized, placebo-controlled study (Part A) comparing felzartamab to placebo in kidney transplant recipients with biopsy-confirmed late isolated microvascular inflammation (MVI ≥2) who are donor-specific antibody (DSA) negative. Eligible participants must have an adequate recent biopsy (preferably within 1 month, no more than 3 months) and be at least 6 months post-transplant; Cohort 1 is evaluated at Week 24 with follow-up through Week 52 across Cohorts 1 and 2. Primary outcome is the proportion of participants without signs of active inflammation in the transplanted kidney at 24 weeks; secondary outcomes include kidney function, immune activity, safety, pharmacokinetics, and immunogenicity. The trial is sponsored by Biogen and is being run at three clinical sites in California.

Who should consider this trial

Good fit: Adults at least 6 months after kidney transplant with biopsy-confirmed isolated MVI (MVI ≥2), DSA-negative and without T cell–mediated rejection, with an adequate biopsy performed within the protocol time window are ideal candidates.

Not a fit: Patients with DSA-positive antibody-mediated rejection, concurrent T cell–mediated rejection, inadequate or old biopsies, or those less than 6 months post-transplant are unlikely to match this study or to benefit from its specific aims.

Why it matters

Potential benefit: If successful, felzartamab could reduce microvascular inflammation and help preserve kidney function in transplant recipients with isolated MVI.

How similar studies have performed: Therapies targeting B cells or plasma cells have shown promise in some antibody-mediated rejection settings, but using felzartamab specifically for isolated MVI is a relatively novel approach and not yet established.

Eligibility criteria

Show full inclusion / exclusion criteria 
Key Inclusion Criteria:

* MVI (MVI ≥2), donor specific antibody (DSA)-negative that is either complement activation (C4d) negative or C4d positive (biopsy-confirmed) without T cell-mediated rejection (TCMR) per central reading, as defined by the Banff 2022 criteria.
* Biopsy must be within 3 months (preferably within 1 month) prior to randomization and meet adequate criteria (option a preferred over option b):

  1. Adequate: 10 or more non-sclerotic/evaluable glomeruli and two muscular arteries
  2. Minimally Adequate: at least 7 non-sclerotic/evaluable glomeruli and one muscular artery
* For participants who received any prior treatment for antibody-mediated rejection (AMR), MVI, or TCMR as outlined in Exclusion Criterion 5, the biopsy must be performed at least 6 weeks after completing (or stopping) prior treatment.
* Kidney transplant at least 6 months prior to Screening visit (recipients of either living or deceased donors).
* DSA: Human leukocyte antigen (HLA) Class I and II antigen-specific DSA-negative (preformed and de novo DSA) as determined by the local laboratory's definition of positivity using single-antigen bead-based assays within 3 months prior to randomization.

Key Exclusion Criteria:

* Transplant: Blood type (ABO)-incompatible transplant.
* History of multiple organ transplants including en bloc and dual kidney transplants.
* Presence of HLA donor-specific antibodies.
* Acute, rapid decline in renal function, defined as a participant likely to require renal replacement therapy within the next 30 days as determined by the Investigator.
* Prior AMR or TCMR treatment (with the exception of corticosteroids) within 3 months prior to randomization is excluded as listed below. Participants who received any of these treatments between 3 and 6 months prior to randomization must have both a renal biopsy (IC3) and DSA testing at least 6 weeks after completing (or stopping) treatment in order to confirm continuing MVI≥2 and DSA negative status and to determine eligibility:

  1. Intravenous or subcutaneous immunoglobulin (IVIg or subcutaneous immunoglobulin \[SCIg\]) or plasma exchange (PLEX).
  2. Complement system inhibitors (e.g., eculizumab).
  3. Proteasome inhibitors (e.g., bortezomib).
  4. The anti-interleukin-6 receptor (anti-IL-6R) tocilizumab.
  5. Any B cell-depleting therapy (including anti-CD20 agents \[e.g., rituximab\]) within 3 months prior to randomization.
  6. Any other investigational agent within 3 months or 5 half-lives (whichever is longer) of randomization.

Note: Other protocol-defined Inclusion/Exclusion criteria may apply.

Where this trial is running

Los Angeles, California and 22 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Microvascular InflammationKidney TransplantKidney Transplant Rejection
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.