FDA Grants Fast Track Designation to Rocket Pharmaceuticals’ Gene Therapy for IMO

Rare Daily Staff

The U.S. Food and Drug Administration granted Fast Track designation to Rocket Pharmaceuticals’ RP-L401, a lentiviral gene therapy for the treatment of Infantile Malignant Osteopetrosis.

Infantile Malignant Osteopetrosis (IMO) is a rare, severe autosomal recessive disorder caused by mutations in the TCIRG1 gene, which is critical for the process of bone resorption. Mutations in TCIRG1 interfere with the function of osteoclasts, cells that are essential for normal bone remodeling and growth, leading to skeletal malformations, including fractures and cranial deformities which cause neurologic abnormalities including vision and hearing loss. Patients often have endocrine abnormalities and progressive, frequently fatal bone marrow failure. As a result, death is common within the first decade of life. IMO has an estimated incidence of 1 in 200,000.

Although an allogenic bone marrow transplant for IMO can allow for the restoration of bone resorption by donor-derived osteoclasts that originate from hematopoietic cells, long-term survival rates are low and severe transplant-related complications are frequent.

RP-L401 was licensed from Lund University and Medizinische Hochschule Hannover.

Rocket’s non-randomized, open-label phase 1 clinical trial of RP-L401 for the treatment of IMO will enroll two pediatric patients, one month of age or older. The trial is designed to assess safety and tolerability of RP-L401, as well as preliminary efficacy, including potential improvements in bone abnormalities/density, hematologic status and endocrine abnormalities.

“Advancing five programs into the clinic in five years is a testament that we are on our way towards achieving that mission,” said Kinnari Patel, chief operating officer and executive vice president of development at Rocket. “IMO is one of the most devastating pediatric disorders, and we are grateful to our team and our collaborators for all of the work that they’ve done in moving this program forward for children and their families.”

The FDA’s Fast Track program facilitates the development of products intended to treat serious conditions that have the potential to address unmet medical needs. The designation enables greater access to the FDA for the purpose of expediting the product’s development, review, and potential approval. In addition, the Fast Track program allows for eligibility for Accelerated Approval and Priority Review, if relevant criteria are met, and Rolling Review, which means a company can submit completed sections of its Biologic License Application for review by FDA, rather than waiting until every section is completed before the entire application can be reviewed.

Photo: Kinnari Patel, chief operating officer and executive vice president of development at Rocket