Rocket Pharmaceuticals, a clinical-stage company advancing an integrated and sustainable pipeline of genetic therapies for rare childhood disorders, announces that the U.S. Food and Drug Administration (FDA) has granted Fast Track designation to RP-L401, the Company’s lentiviral vector (LVV)-based gene therapy for the treatment of Infantile Malignant Osteopetrosis (IMO), a rare, severe monogenic bone resorption disorder characterized by skeletal deformities, neurologic abnormalities and bone marrow failure.

Rocket Pharmaceuticals, a clinical-stage company advancing an integrated and sustainable pipeline of genetic therapies for rare childhood disorders, today announces that the U.S. Food and Drug Administration (FDA) has granted Fast Track designation to RP-L401, the Company’s lentiviral vector (LVV)-based gene therapy for the treatment of Infantile Malignant Osteopetrosis (IMO), a rare, severe monogenic bone resorption disorder characterized by skeletal deformities, neurologic abnormalities and bone marrow failure.

“We are proud to announce Rocket’s fifth Fast Track designation, an accomplishment that truly embodies our mission and vision of bringing curative gene therapies to children suffering from rare disorders,” said Kinnari Patel, Pharm. D., MBA, Chief Operating Officer and Executive Vice President, Development at Rocket. “Advancing five programs into the clinic in five years is a testament that we are on our way towards achieving that mission. 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 (BLA) for review by FDA, rather than waiting until every section is completed before the entire application can be reviewed.

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. University of California, Los Angeles will serve as the lead trial site under principal investigator Donald B. Kohn, M.D., Professor of Microbiology, Immunology and Molecular Genetics, Pediatrics (Hematology/Oncology), Molecular and Medical Pharmacology, and member of the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at the University of California, Los Angeles.

RP-L401 was in-licensed from Lund University, under the research leadership of Dr. Johan Richter, M.D., Ph.D. and Dr. Ilana Moscatelli, Ph.D. The vector was in-licensed through a collaboration with Dr. Axel Schambach, M.D., Ph.D. of the Medizinische Hochschule Hannover.

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 which 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. The only treatment option currently available for IMO is an allogenic bone marrow transplant (HSCT), which allows for the restoration of bone resorption by donor-derived osteoclasts which originate from hematopoietic cells. Long-term survival rates are lower in IMO than those associated with HSCT for many other non-malignant hematologic disorders; severe HSCT-related complications are frequent. There is an urgent need for additional treatment options.

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