FDA Approves Kresladi: A Historic First Gene Therapy for Severe LAD-I

In a landmark decision for rare disease treatment, the FDA approved Kresladi (marnetegragene autotemcel) on March 27, 2026. This marks the first-ever gene therapy specifically designed for pediatric patients suffering from severe Leukocyte Adhesion Deficiency Type I (LAD-I).

This approval is a lifeline for children with biallelic variants in the ITGB2 gene who do not have a matched sibling donor for a traditional bone marrow transplant.

Understanding the Breakthrough

Severe LAD-I is a devastating immune deficiency that prevents white blood cells (neutrophils) from leaving the bloodstream to reach the site of an infection. Without this “exit ramp,” the body cannot fight off bacteria or fungi, often leading to fatal complications in early childhood.

How Kresladi Works:

Personalized Therapy: The treatment uses the patient’s own blood stem cells.
Genetic Repair: These cells are genetically modified to carry functional copies of the ITGB2 gene.
Restoration: Once infused back into the patient, these modified cells begin producing neutrophils that express CD18 and CD11a—the essential proteins needed for white blood cells to function and fight infection.

Clinical Evidence and Safety

The FDA utilized the Accelerated Approval pathway, recognizing the urgent need for this treatment.

Aspect	Findings from Clinical Study
Primary Metric	Significant increase in CD18 and CD11a expression on neutrophils.
Durability	Effects were observed at 12 months and remained sustained through 24 months.
Common Side Effects	Anemia, low platelet counts, mouth sores, and respiratory infections.
Regulatory Path	Granted Fast Track, Orphan Drug, and Rare Pediatric Disease designations.

A New Standard of Care

For many families, the only previous option was a high-risk allogeneic hematopoietic stem cell transplant. Kresladi offers a “potentially transformative” alternative that targets the root cause of the disease using the patient’s own cells, reducing the risks associated with donor rejection.

Rocket Pharmaceuticals, the manufacturer, will continue to conduct post-approval studies to verify the long-term clinical benefits as part of the FDA’s requirements.