Obinutuzumab to reduce PLA2R antibodies in primary membranous nephropathy

Obinutuzumab Induced Decreases of PLA2Rab in MN: a Pilot Study

We will try obinutuzumab to see if it quickly lowers anti‑PLA2R antibody levels in adults with high‑risk primary membranous nephropathy who still have heavy proteinuria despite ACEi/ARB treatment.

Quick facts

• Phase: Phase2; Phase3
• Study type: Interventional
• Enrollment: 20 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Radboud University Medical Center (Academic / other)
• Drugs / interventions: obinutuzumab, cyclophosphamide, rituximab
• Locations: 1 site (Nijmegen)
• Trial ID: NCT07163611 on ClinicalTrials.gov

What this trial studies

This open‑label, single‑center pilot interventional study at Radboud University Medical Center enrolls 20 adults with high‑risk primary membranous nephropathy and positive anti‑PLA2R antibodies. Participants receive obinutuzumab 1000 mg on days 1 and 15, with two additional infusions after six months if antibodies remain positive and proteinuria exceeds 2 g/24 h. The protocol measures the disappearance rate (half‑life) of anti‑PLA2R antibodies and tracks immunological and clinical remission, adverse events, and quality of life over 52 weeks with scheduled visits through week 52. The design focuses on early antibody kinetics to identify rapid responders versus non‑responders and to link antibody changes to proteinuria and clinical outcomes.

Who should consider this trial

Good fit: Adults (≥18 years) with primary membranous nephropathy who are PLA2R‑antibody positive (≥80 RU/ml) with proteinuria ≥3.5 g/24 h despite at least six months of optimized ACE‑inhibitor or ARB therapy, serum albumin <30 g/L, and eGFR ≥30 ml/min/1.73 m2.

Not a fit: Patients with secondary membranous nephropathy, recent rituximab or other recent immunosuppression, very low PLA2R titers, eGFR <30 ml/min/1.73 m2, or life‑threatening nephrotic complications are unlikely to benefit from this protocol.

Why it matters

Potential benefit: If successful, this approach could produce faster antibody clearance and earlier remission of proteinuria, potentially reducing nephrotic complications and the duration of immunosuppression.

How similar studies have performed: Retrospective series and case reports suggest obinutuzumab can work in rituximab‑refractory membranous nephropathy and it has shown efficacy in other autoimmune nephritides, but prospective randomized data in PMN remain limited.

Eligibility criteria

Inclusion Criteria:

* Age ≥ 18 years.
* Diagnosis of PMN, confirmed by:

  1. Kidney biopsy or
  2. Positive serum PLA2Rab test either by IFT and/or ELISA)
* Serum PLA2Rab titer \> 80 RU/ml
* Proteinuria ≥ 3.5 g/24h despite supportive treatment for at least 6 months with a maximally tolerated and stable dose of ACE-i or ARB.
* Serum albumin \< 30 g/l measured by BCP assay.
* eGFR ≥ 30 ml/min/1.73m2.
* Treatment with immunosuppression is warranted, as determined by the treating physician.

Exclusion Criteria:

* Secondary MN (e.g., hepatitis B or C infection, human immunodeficiency virus infection, active infection, systemic lupus erythematosus, sarcoidosis, IgG4-related, drug-induced, malignancy).
* RTX within 12 months prior to inclusion.
* CNI within 2 months prior to inclusion.
* Treatment with other immunosuppressive drugs within 6 months prior to inclusion.
* Proteinuria must not have decreased by \> 50% over 6 months whilst taking ACEi/ARB.
* Life-threatening nephrotic syndrome resistant to treatment.
* \> 20% increase in serum creatinine not otherwise explained during antiproteinuric supportive treatment.
* Pregnancy or breastfeeding. Women of childbearing age and male patients with female partners of childbearing potential not willing to use contraception throughout the study and for at least 6 months after the last dose of obinutuzumab.
* Suspected or known hypersensitivity, allergy, and/or immunogenic reaction history to monoclonal antibodies, corticosteroid, cyclophosphamide, any of their ingredients, and any other drugs from these same pharmacotherapeutic groups.
* Known active infection of any kind or recent major episode of infection.
* Any disorder or condition which might pose an unacceptable risk to patient's safety and well-being that might interfere with completion of the study.
* Inability to understand or comply with the requirements of the study.
* Incapable of recognizing the nature, significance, and scope of the clinical trial or giving consent even with a legal representative.
* Use of an investigational agent.

Where this trial is running

Nijmegen

• Department of Nephrology, Radboud University Medical Center — Nijmegen, Netherlands (Recruiting)

Study contacts

• Principal investigator: Anne-Els Van de Logt, M.D., PhD — Radboud University Medical Center
• Study coordinator: Ruben Visch, M.D.

Conditions Membranous Nephropathy - PLA2R Induced; PLA2R antibody kinetics; membranous nephropathy; obinutuzumab