Oblenio Bio has announced the first-in-human dosing of LBL-051, an off-the-shelf tri-specific T cell engager engineered to deplete both B cells and long-lived plasma cells simultaneously. 

Oblenio Bio has dosed the first set of patients in a Phase Ia trial of LBL-051, an experimental tri-specific T cell engager designed to completely eliminate both B cells and plasma cells. If successful, the approach could help in efforts to achieve long-lasting drug-free remission for autoimmune diseases.

The first-in-human study is evaluating LBL-051, which simultaneously targets BCMA, CD19 and CD3. Unlike therapies that focus solely on B cells, the investigational treatment is designed to deplete both B cells and antibody-producing plasma cells before allowing the immune system to rebuild.

Researchers hope this ’immune reset’ approach could provide more durable disease control for patients whose autoimmune conditions no longer respond to existing medicines.

The open-label, multicentre Phase Ia trial is recruiting patients with refractory autoimmune diseases across multiple indications. Participants will receive subcutaneous doses while investigators assess safety, tolerability, biological activity and the therapy’s ability to deplete immune cells in blood and tissue.

What is an immune reset?

Many autoimmune medicines suppress the immune system continuously to reduce inflammation. Immune-reset therapies aim to temporarily eliminate the immune cells driving disease before allowing the immune system to regenerate. The goal is to achieve prolonged remission without ongoing treatment, although researchers are still determining which patients are most likely to benefit and how durable those responses can be.

Why this matters

The autoimmune treatment landscape has developed quickly in recent years, with growing interest in therapies capable of resetting the immune system rather than suppressing it indefinitely.

While B-cell depleting drugs such as anti-CD20 antibodies have improved care for several autoimmune diseases, they do not eliminate long-lived plasma cells, which continue producing the antibodies that drive disease. Researchers increasingly believe removing both cell populations may lead to deeper and more durable remissions.

LBL-051 has been designed with this challenge in mind by targeting CD19 and BCMA simultaneously while recruiting T cells through CD3 to eliminate both immune cell types.

If the strategy proves successful in humans, it could broaden the role of T cell engagers beyond oncology and establish a new therapeutic approach for autoimmune disease.

Building on encouraging preclinical data

Oblenio recently presented preclinical findings at the European Alliance of Associations for Rheumatology (EULAR) 2026 Congress, reporting complete depletion of B cells and plasma cells with minimal cytokine release.

“LBL-051 preclinical data have shown complete depletion of both B and plasma cells through dual targeting of CD19 and BCMA, with minimal cytokine release,” said Dr Ricardo Grieshaber-Bouyer, Professor of Clinical Systems Immunology and Head of the Clinical Trial Unit at FAU Erlangen-Nürnberg and Principal Investigator of the study. ”These data support LBL-051’s potential to achieve full B lineage immune reset consistently, which may outperform the results from approaches using a single B cell target.”

The study’s adaptive dose-escalation design is intended to generate early proof-of-concept data while maintaining close safety monitoring.

What it means for researchers

Interest in immune-reset therapies has accelerated following encouraging results from CAR-T cell therapies in severe autoimmune diseases. However, CAR-T treatments remain personalised, expensive and difficult to manufacture.

By contrast, LBL-051 is being developed as an off-the-shelf biologic that could offer similar biological effects without the logistical challenges associated with cell therapy.

“Our Phase Ia trial design marks a significant step forward in the clinical development of T cell engagers for autoimmunity. This differentiated strategy will rapidly generate proof-of-concept data in high unmet need populations,” said Chief Medical Officer Tapan Maniar. “We look forward to demonstrating LBL-051’s potential to achieve a broad and durable immune reset and advancing CD19 and BCMA dual-targeting.”

For drug developers, the study will be important to find out whether tri-specific T cell engagers can safely modulate the immune system outside cancer.

Key takeaways

  • First patients have received LBL-051 in a Phase Ia first-in-human trial.
  • The therapy targets CD19, BCMA and CD3 to eliminate both B cells and plasma cells.
  • Researchers hope complete immune-cell depletion will produce a more durable immune reset than existing B-cell therapies.
  • The study will generate the first clinical evidence on the safety and biological activity of this tri-specific T cell engager in autoimmune disease.
  • Positive early data could strengthen growing interest in off-the-shelf immune-reset therapies as an alternative to complex cell therapies.

What happens next?

The immediate focus will be on early safety data from the dose-escalation study, together with evidence that LBL-051 can successfully deplete both B cells and plasma cells in patients.

Researchers will also be watching closely for signs that the treatment produces the sustained immune reset seen in preclinical studies without triggering excessive cytokine release or other immune-related toxicities. Those findings will help determine whether tri-specific T cell engagers can emerge as a practical new platform for treating autoimmune disease.

 

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