FDA Grants Rocket Priority Review for Gene Therapy to Treat Rare Immune Disorder

Rare Daily Staff

The U.S. Food and Drug Administration granted Rocket Pharmaceuticals Priority Review for its experimental gene therapy RP-L201 for severe leukocyte adhesion deficiency-I, a rare genetic immune disorder.a

The agency is expected to act on the application by March 31, 2024.

Severe Leukocyte Adhesion Deficiency-I (LAD-I) is a rare, autosomal recessive pediatric disease caused by mutations in the ITGB2 gene encoding for the beta-2 integrin component CD18. CD18 is a key protein that facilitates leukocyte adhesion and extravasation from blood vessels to combat infections. As a result, children with severe LAD-I are often affected immediately after birth. During infancy, they suffer from recurrent life-threatening bacterial and fungal infections that respond poorly to antibiotics and require frequent hospitalizations. Children who survive infancy experience recurrent severe infections including pneumonia, gingival ulcers, necrotic skin ulcers, and septicemia. Without a successful bone marrow transplant, survival beyond childhood is rare. Currently the only potential curative treatment is an allogeneic hematopoietic stem cell transplant, which may not be available in time for these children and itself has substantial morbidity and mortality.

RP-L201 is an experimental gene therapy that contains patient-derived hematopoietic stem cells that have been genetically modified with a lentiviral vector to deliver a functional copy of the ITGB2 gene, which encodes for the beta-2 integrin component CD18, a key protein that facilitates leukocyte adhesion and enables their extravasation from blood vessels to fight infection.

Rocket holds FDA Regenerative Medicine Advanced Therapy, Rare Pediatric Disease, and Fast Track designations in the United States, PRIME and Advanced Therapy Medicinal Product designations in the European Union, and Orphan Drug designation in both regions for the program.

Positive top-line data from the global phase 1/2 study of RP-L201 demonstrated 100 percent overall survival at 12 months post-infusion, and for the entire duration of follow-up, for all nine LAD-I patients with 12 to 24 months of available follow-up. Data also showed large decreases compared with pre-treatment history in the incidences of significant infections, combined with evidence of resolution of LAD-I-related skin lesions and restoration of wound repair capabilities. All primary and secondary endpoints were met, and RP-L201 was very well tolerated in all patients with no treatment related serious adverse events.

“Today’s acceptance of the BLA by the FDA marks a significant milestone for Rocket towards our goal of delivering a one-time gene therapy to patients facing the devastating effects of severe LAD-I,” said Kinnari Patel, president and chief operating officer of Rocket Pharma. “For these patients, survival beyond childhood is uncommon. Bone marrow transplant is currently the only treatment option, has substantial morbidity and mortality, and may not be available in time for these children.”

Photo: Kinnari Patel, president and chief operating officer of Rocket Pharma