–Rocket’s Largest Lentiviral Pipeline Opportunity with an Estimated Prevalence of 3,000 to 8,000 Patients in the U.S. and EU–

–Precedent-Setting Global Phase 1 Study with Commercial Manufacturer is Now Enrolling–

NEW YORK, NY, USA I October 22, 2019 I Rocket Pharmaceuticals, Inc. (NASDAQ: RCKT) (“Rocket”), a leading U.S.-based multi-platform clinical-stage gene therapy company, today announces the clearance of the Company’s Investigational New Drug (IND) application by the U.S. Food and Drug Administration (FDA) for RP-L301. RP-L301 is the Company’s lentiviral vector (LVV)-based gene therapy for the treatment of Pyruvate Kinase Deficiency (PKD) that was in-licensed from the Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) and Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IIS-FJD). The IND acceptance follows the recent clearance of the Investigational Medicinal Product Dossier (IMPD) for RP-L301 by the Spanish Agency for Medicines and Health Products (AEMPS) in September. The trial will be led by principal investigator Sandeep Soni, M.D., Clinical Associate Professor of Stem Cell Transplantation and Regenerative Medicine at the Stanford University School of Medicine.

“RP-L301 represents the first gene therapy candidate in development for PKD, a hematologic disorder in which the current treatment options, chronic blood transfusions and splenectomy, are associated with burdensome side effects and end-organ damage,” said Gaurav Shah, M.D., Chief Executive Officer and President of Rocket. “Promising preclinical RP-L301 data suggest correction of multiple key disease elements, including hemoglobin increases, reticulocyte reduction, and correction of splenomegaly. We look forward to advancing this potentially curative gene therapy into the clinic in the fourth quarter on behalf of the pediatric and adult PKD patients and families in need.”

“In less than 12-months, four Rocket-sponsored INDs received clearance from the FDA. The RP-L301 IND marks an important milestone as it is the first global Phase 1 study for Rocket in the U.S. and EU. This achievement would not have been possible without the team’s dedication and commitment to bringing first and best in class curative gene therapies to patients as quickly as possible,” said Kinnari Patel, Pharm.D., MBA, Chief Operating Officer and Head of Development of Rocket.

The global Phase 1 open-label, single-arm, clinical trial will enroll six adult and pediatric transfusion-dependent PKD patients in the U.S. and Europe. The trial will be comprised of three cohorts to assess RP-L301 in young pediatric, older pediatric and adult populations. Rocket intends to complete the adult cohort before moving into pediatric patients. The trial is designed to assess the safety, tolerability and preliminary efficacy of RP-L301. Lucile Packard Children’s Hospital Stanford will serve as the lead site in the U.S. for adult and pediatric patients. Hospital Infantil Universitario Niño Jesús will serve as the lead site in Europe for pediatrics and Hospital Universitario Fundación Jiménez Díaz will serve as the lead site in Europe for adult patients.

About Pyruvate Kinase Deficiency
Pyruvate Kinase Deficiency (PKD) is a rare, monogenic red blood cell disorder resulting from a mutation in the PKLR gene encoding for the pyruvate kinase enzyme, a key component of the red blood cell glycolytic pathway. Mutations in the PKLR gene result in increased red cell destruction and the disorder ranges from mild to life-threatening anemia. PKD has an estimated prevalence of 3,000 to 8,000 patients in the United States and the European Union. Children are the most commonly and severely affected subgroup of patients. Currently available treatments include splenectomy and red blood cell transfusions, which are associated with immune defects and chronic iron overload.

About Rocket Pharmaceuticals, Inc.
Rocket Pharmaceuticals, Inc. (NASDAQ: RCKT) (“Rocket”) is an emerging, clinical-stage biotechnology company focused on developing first-in-class gene therapy treatment options for rare, devastating diseases. Rocket’s multi-platform development approach applies the well-established lentiviral vector (LVV) and adeno-associated viral vector (AAV) gene therapy platforms. Rocket’s clinical programs using LVV-based gene therapy are for the treatment of Fanconi Anemia (FA), a difficult to treat genetic disease that leads to bone marrow failure and potentially cancer, Leukocyte Adhesion Deficiency-I (LAD-I), a severe pediatric genetic disorder that causes recurrent and life-threatening infections which are frequently fatal, and Pyruvate Kinase Deficiency (PKD) a rare, monogenic red blood cell disorder resulting in increased red cell destruction and mild to life-threatening anemia. Rocket’s first clinical program using AAV-based gene therapy is for Danon disease, a devastating, pediatric heart failure condition. Rocket’s pre-clinical pipeline program is for Infantile Malignant Osteopetrosis (IMO), a bone marrow-derived disorder. For more information about Rocket, please visit www.rocketpharma.com.

SOURCE: Rocket Pharmaceuticals