Rocket Pharmaceuticals Presents First Evidence of Long-Term Improvement and Stabilization in Blood Counts and Durable Mosaicism in RP-L102 “Process A” for Fanconi Anemia

Rocket Pharmaceuticals, Inc. (NASDAQ: RCKT) (“Rocket”), a leading U.S.-based multi-platform clinical-stage gene therapy company, today presents updated long-term follow-up from the Phase 1/2 clinical trial of RP-L102 at the European Society of Cell and Gene Therapy (ESGCT) 27^th Annual Congress in Barcelona, Spain. RP-L102 is the Company’s lentiviral vector (LVV)-based gene therapy for the treatment of Fanconi Anemia (FA). The data are included in an oral presentation by Dr. Juan Bueren, Scientific Director of the FA gene therapy program and Head of the Hematopoietic Innovative Therapies Division at CIEMAT in Spain / CIBERER / IIS-FJD, entitled, “Gene Therapy for Patients with Fanconi Anaemia.”

“Two critical validations for an FA gene therapy product are: 1) stem cell engraftment in the absence of cytotoxic conditioning and 2) evidence of sustained clinical improvement. We are proud to report that the maturing long-term data from the patients treated with RP-L102 meet both of these requirements,” said Gaurav Shah, M.D., Chief Executive Officer and President of Rocket. “In all four patients, bone marrow MMC-resistance, a key measure of phenotypic reversal and engraftment, meets or exceeds the 10% threshold agreed to by the FDA and EMA for the upcoming registration-enabling Phase 2 trial, and all four patients now resemble FA mosaic patients as evaluated by peripheral T-cell chromosomal fragility assay. Remarkably, patients 02002 and 02006, who received what we consider adequate drug product similar to the upcoming Phase 2 trial, now demonstrate durable robust bone marrow MMC-resistance levels of approximately 60% and 32%, respectively, confirming phenotypic correction in long-term bone marrow stem and progenitor cells. Of note, each of the four initial patients continue to show evidence of a proliferative advantage, with ongoing increases in peripheral mononuclear cell VCNs. In addition, improvement or stabilization of peripheral blood counts, which had declined substantially prior to gene therapy, suggests a halt in bone marrow failure progression. In patient 02002, hemoglobin levels are now similar to those in the first year after birth, and all lineages in patients 02002 and 02006 are now stable or improving.”