Neihulizumab

Drug Overview

Neihulizumab (also known as AbGn-168H) is an investigational, humanized monoclonal antibody designed to target and bind to the CD162 protein, also known as P-selectin Glycoprotein Ligand-1 (PSGL-1). This protein is primarily expressed on the surface of activated T-cells and other inflammatory leukocytes. By binding to CD162, neihulizumab aims to selectively induce the programmed cell death (apoptosis) of these activated, “pathogenic” T-cells while sparing resting or memory T-cells that are essential for normal immune defense.

In the clinical landscape of March 2026, neihulizumab is recognized as a potential “immune-resetting” therapy. It is being developed for a range of T-cell-mediated inflammatory and autoimmune diseases, as well as certain hematologic conditions where T-cell activity is maladaptive. Unlike traditional immunosuppressants that broadly “turn off” the immune system, neihulizumab is designed to be a more surgical tool—identifying and eliminating the specific T-cells that are actively driving inflammation without leaving the patient’s entire immune system vulnerable to infection.

• Generic Name: Neihulizumab.
• Code Name: AbGn-168H.
• Drug Class: Monoclonal Antibody; Immune Modulator; Apoptosis Inducer.
• Mechanism: Targeting CD162 (PSGL-1) to induce apoptosis of activated T-cells.
• Route of Administration: Intravenous (IV) infusion or Subcutaneous (SC) injection.
• FDA Approval Status: Investigational. As of March 2026, neihulizumab is not FDA-approved. It has been evaluated in several Phase 1 and Phase 2 trials for conditions including psoriasis, psoriatic arthritis, and steroid-refractory graft-versus-host disease (GVHD).

What Is It and How Does It Work? (Mechanism of Action)

Neihulizumab works by exploiting a specific “vulnerability” that T-cells develop only when they are in an activated, aggressive state.

1. Targeting CD162 (PSGL-1)

CD162 is a protein that helps T-cells “roll” along the walls of blood vessels so they can exit the bloodstream and enter tissues to cause inflammation.

• Specific Binding: Neihulizumab binds to a specific part of the CD162 molecule that is highly accessible on activated T-cells.
• Resting Cell Sparing: Because resting (inactive) T-cells do not utilize CD162 in the same way, the antibody does not trigger their destruction, which is a major safety advantage over broad immunosuppressants.

2. Induction of Apoptosis

Once neihulizumab binds to CD162, it sends a powerful “death signal” into the activated T-cell.

• Caspase Activation: The binding triggers a cascade of enzymes called caspases, which are the executioners of the cell’s internal suicide program.
• Cell Clearance: The activated T-cell then undergoes apoptosis (programmed cell death) and is naturally cleared by the body’s scavenger cells (macrophages).

FDA-Approved Clinical Indications

There are currently no FDA-approved indications for neihulizumab.

Clinical research through 2026 has primarily focused on:

• Plaque Psoriasis: Investigated for its ability to clear skin lesions by eliminating the T-cells that attack skin tissue.
• Psoriatic Arthritis (PsA): Evaluated for reducing joint pain and inflammation in patients who have not responded to standard TNF inhibitors.
• Steroid-Refractory Acute Graft-versus-Host Disease (aGVHD): Studied as a “rescue therapy” for patients whose T-cells are attacking their own bodies after a bone marrow transplant.
• Type 1 Diabetes (T1D): Early-phase trials have explored whether neihulizumab can protect remaining insulin-producing cells by eliminating the T-cells that target the pancreas.

Dosage and Administration Protocols

As an investigational drug, neihulizumab dosing is strictly managed within clinical trials (such as the AbGn-168H-03 or AbGn-168H-04 trials).

Clinical Efficacy and Research Results

As of early 2026, results from Phase 2 trials have provided significant insights into the drug’s “durable” clinical effect:

• Psoriasis Clearance: In Phase 2 trials for plaque psoriasis, neihulizumab showed that it could achieve significant skin clearance (PASI-75) that persisted for several months even after treatment was stopped. This supports the “immune-reset” theory.
• GVHD Survival: In studies of acute GVHD, the drug has shown promise in reducing the severity of the attack on the liver, gut, and skin, which are the primary targets of the donor’s T-cells.
• Biomarker Evidence: Clinical data has confirmed a rapid and specific reduction in the number of CD162-high activated T-cells in the blood of treated patients, proving that the drug is hitting its intended biological target.

Safety Profile and Side Effects

Neihulizumab is generally considered to have a favorable safety profile compared to traditional systemic immunosuppressants.

Common Side Effects (>15%):

• Infusion-Related Reactions: Mild fever, chills, or rash occurring during or shortly after the IV administration.
• Upper Respiratory Infections: Common to most immune-modulating drugs.
• Headache and Fatigue: Reported by some patients during the first few weeks of treatment.

Serious Risks:

• Cytopenia: A temporary drop in certain white blood cell counts, though this typically recovers quickly.
• Infection Risk: While more selective than other drugs, there is still a potential risk of increased vulnerability to certain infections during the active treatment window.
• Immunogenicity: The potential for the body to develop “anti-drug antibodies,” which could make the drug less effective over time or cause allergic reactions.

Research Areas

In the fields of Stem Cell and Regenerative Medicine, neihulizumab is being used to study “Immune Tolerance.” Researchers are investigating whether neihulizumab can be used alongside stem cell transplants to “pre-clear” the patient’s reactive T-cells, potentially reducing the need for long-term anti-rejection drugs. In 2026, there is also intense focus on “Neuro-inflammation.” Scientists are exploring if neihulizumab can cross the blood-brain barrier to eliminate activated T-cells involved in diseases like Multiple Sclerosis (MS). Furthermore, studies are exploring if the drug can help “re-balance” the immune system in patients with chronic fatigue syndrome associated with persistent T-cell activation.

Patient Management and Practical Recommendations

Pre-treatment Requirements:

• Tuberculosis (TB) Screening: Standard requirement for all immune-modulating biological therapies.
• Baseline Immune Panel: Comprehensive blood work to establish the starting state of the patient’s T-cell populations.

“Do’s and Don’ts” List:

• DO report any signs of a new infection, such as a fever or persistent cough, immediately to your oncology or rheumatology team.
• DO complete the entire prescribed course of treatment even if your symptoms improve early; the goal is a complete “reset” of the pathogenic cells.
• DON’T receive any live-virus vaccines (like the MMR or shingles vaccine) while on neihulizumab without consulting your doctor.
• DON’T ignore persistent skin rashes or joint pain, as these may indicate that your underlying condition is not yet fully controlled.

Legal Disclaimer

The information provided is for educational and informational purposes only and does not constitute medical advice. Neihulizumab (AbGn-168H) is an investigational agent and is not approved by the U.S. FDA for any indication. Access is limited exclusively to registered clinical trials. Always consult with a qualified specialist regarding your specific diagnosis and eligibility for research participation.