Rocket Pharmaceuticals Presents Preclinical Data of RP-A501 for Danon Disease at the American Society of Gene and Cell Therapy 2019 Annual Meeting

– Biodistribution of RP-A501 Demonstrates High Concentration in
Heart, the End-Organ Target in Danon Disease –

– Phase 1 Clinical Trial to Begin in Second Quarter of 2019 –

NEW YORK–(BUSINESS WIRE)–Rocket
Pharmaceuticals, Inc. (NASDAQ: RCKT) (“Rocket”), a leading
U.S.-based multi-platform clinical-stage gene therapy company, today
presents preclinical data of RP-A501 at the American Society of Gene and
Cell Therapy 2019 Annual Meeting in Washington, D.C. RP-A501 is the
Company’s adeno-associated viral vector (AAV)-based gene therapy for the
treatment of Danon disease. The data is included in an oral presentation
by Annahita Keravala, Ph.D., Associate Vice President, AAV Platform,
entitled, “Systemic Delivery of AAV9.LAMP2B for the Treatment of Danon
Disease: Toxicology Studies in Mice and Cynomolgus Monkeys.”

“Additional preclinical RP-A501 data continue to augment the evidence
regarding this vector’s potential to prevent, reduce, or reverse cardiac
dysfunction. RP-A501 conferred high vector copy number (VCN) and LAMP2
protein expression in all four heart chambers, suggesting optimal
tropism and uptake of the gene therapy. Specifically, VCNs in the ~10
range were about ten-fold higher in heart chambers versus skeletal
muscle and most central nervous system tissues. Importantly, protein
expression in all four heart chambers was higher in treated non-human
primates versus wild type; this differential was most pronounced in
cardiac muscle. Transduction and expression in the heart is critically
important for Danon disease patients because heart failure is the
overwhelming cause of mortality,” said Jonathan Schwartz, M.D., Chief
Medical Officer and Senior Vice President, Clinical Development of
Rocket.

Investigational New Drug application (IND)-enabling toxicology studies
were conducted in wild-type mice and non-human primates. Three dose
levels were tested in mice, including 3×10¹³ vg/kg, 1×10¹⁴
vg/kg, and 3×10¹⁴ vg/kg. The highest dose level from the
murine study, 3×10¹⁴ vg/kg, was tested in non-human primates.
No dose-related adverse events were observed at all tested doses in both
mice and non-human primates. Vector genomes, mRNA and protein expression
were widely distributed across key tissues with high levels of
transduction, transcription and translation detected in the heart,
skeletal muscle, diaphragm and liver.

The ASGCT presentation also highlights previously reported preclinical
efficacy data of RP-A501 in LAMP-2 knockout (KO) mice which showed
dose-dependent improvements and restoration of cardiac function, with
responses observed in both older and younger KO mice.

Full results from the ASGCT presentation will be available online at the
conclusion of the oral presentation: https://www.rocketpharma.com/asgct-presentations/

About Danon Disease

Danon disease is caused by mutations in the gene encoding
lysosome-associated membrane protein 2 (LAMP-2), an important mediator
of autophagy. It is estimated to have a prevalence of 15,000 to 30,000
patients in the U.S. and the European Union. The disease is often fatal
in male patients in the second or third decade of life due to rapidly
progressive heart failure. Available therapies for Danon disease include
cardiac transplantation, which is associated with substantial
complications and is not considered curative. There are no specific
therapies available for the treatment of Danon disease.

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 lead clinical program is a
LVV-based gene therapy for the treatment of Fanconi Anemia (FA), a
difficult to treat genetic disease that leads to bone marrow failure and
potentially cancer. Rocket’s additional pipeline programs for bone
marrow-derived disorders are for Pyruvate Kinase Deficiency (PKD),
Leukocyte Adhesion Deficiency-I (LAD-I) and Infantile Malignant
Osteopetrosis (IMO). Rocket is also developing an AAV-based gene therapy
program for a devastating, pediatric heart failure indication, Danon
disease. For more information about Rocket, please visit www.rocketpharma.com.

Rocket Cautionary Statement Regarding Forward-Looking Statements

Various statements in this release concerning Rocket’s future
expectations, plans and prospects, including without limitation,
Rocket’s expectations regarding the safety, effectiveness and timing of
product candidates that Rocket may develop, including in collaboration
with academic partners, to treat Fanconi Anemia (FA), Leukocyte Adhesion
Deficiency-I (LAD-I), Pyruvate Kinase Deficiency (PKD), Infantile
Malignant Osteopetrosis (IMO) and Danon disease and the safety,
effectiveness and timing of related pre-clinical studies and clinical
trials, may constitute forward-looking statements for the purposes of
the safe harbor provisions under the Private Securities Litigation
Reform Act of 1995 and other federal securities laws and are subject to
substantial risks, uncertainties and assumptions. You should not place
reliance on these forward-looking statements, which often include words
such as “believe”, “expect”, “anticipate”, “intend”, “plan”, “will
give”, “estimate”, “seek”, “will”, “may”, “suggest” or similar terms,
variations of such terms or the negative of those terms. Although Rocket
believes that the expectations reflected in the forward-looking
statements are reasonable, Rocket cannot guarantee such outcomes. Actual
results may differ materially from those indicated by these
forward-looking statements as a result of various important factors,
including, without limitation, Rocket’s ability to successfully
demonstrate the efficacy and safety of such products and pre-clinical
studies and clinical trials, its gene therapy programs, the preclinical
and clinical results for its product candidates, which may not support
further development and marketing approval, Rocket’s ability to commence
a registrational study in FA within the projected time periods, the
potential advantages of Rocket’s product candidates, actions of
regulatory agencies, which may affect the initiation, timing and
progress of pre-clinical studies and clinical trials of its product
candidates, Rocket’s and its licensors ability to obtain, maintain and
protect its and their respective intellectual property, the timing, cost
or other aspects of a potential commercial launch of Rocket’s product
candidates, Rocket’s ability to manage operating expenses, Rocket’s
ability to obtain additional funding to support its business activities
and establish and maintain strategic business alliances and new business
initiatives, Rocket’s dependence on third parties for development,
manufacture, marketing, sales and distribution of product candidates,
the outcome of litigation, and unexpected expenditures, as well as those
risks more fully discussed in the section entitled “Risk Factors” in
Rocket’s Annual Report on Form 10-K for the year ended December 31,
2018. Accordingly, you should not place undue reliance on these
forward-looking statements. All such statements speak only as of the
date made, and Rocket undertakes no obligation to update or revise
publicly any forward-looking statements, whether as a result of new
information, future events or otherwise.

Contacts

Claudine Prowse, Ph.D.
SVP, Strategy, Corporate Development and IRO
Rocket
Pharma, Inc.
The Empire State Building, Suite 7530
New York,
NY 10118
www.rocketpharma.com
[email protected]