Rocket Pharmaceuticals Announces Patient Dosing Has Commenced in Phase 1 Clinical Trial of RP-A501, the First Gene Therapy to Treat a Monogenic Heart Failure Syndrome

NEW YORK–(BUSINESS WIRE)–Rocket
Pharmaceuticals, Inc.
(NASDAQ: RCKT) (“Rocket”), a leading
U.S.-based multi-platform clinical-stage gene therapy company, today
announces that patient dosing has commenced in the open-label, Phase 1
clinical trial of RP-A501, the Company’s adeno-associated viral vector
(AAV)-based gene therapy for the treatment of Danon disease. University
of California San Diego (UCSD) Health is the initial and lead center for
the Phase 1 clinical trial under the leadership of Eric Adler, M.D.,
Director of Cardiac Transplant and Mechanical Circulatory Support at UC
San Diego Health and Professor of Medicine at University of California,
San Diego School of Medicine and Barry Greenberg, M.D. Dr. Greenberg is
the Director of the Advanced Heart Failure Treatment Program at UC San
Diego Health and Professor of Medicine at UC San Diego School of
Medicine, and is principal investigator of the trial.

“The initiation of patient dosing in our Phase 1 trial is a significant
milestone for our RP-A501 program, the first investigational gene
therapy for a monogenic heart failure syndrome,” said Gaurav Shah, M.D.,
Chief Executive Officer and President of Rocket. “Danon disease is a
rapidly progressive cardiomyopathy where we believe gene therapy can
make a meaningful difference in patient outcomes. Current standards of
care for Danon disease, including heart transplant, are not curative and
are associated with considerable morbidity and mortality. As a result,
median survival for male Danon disease patients has been reported at age
19, caused by progressive heart failure. This underscores the urgent
need for new treatment options like RP-A501 gene therapy for the
patients and families contending with this debilitating, fatal disease.”

“The advancement of RP-A501 into the clinic is a monumental step forward
for the treatment of this devastating disease and, more broadly, the
treatment of rare cardiac disorders,” said Dr. Adler. “The team at UC
San Diego Health is pleased to be the initial and lead center for the
Phase 1 clinical trial of RP-A501 and we look forward to rapidly
advancing it through the clinic on behalf of patients and families in
need.”

The non-randomized, open-label Phase 1 trial is expected to enroll 12-24
pediatric and young adult male patients. Two dose levels will be
investigated in four patient cohorts separated by pediatric and adult
age groups. The first cohort will receive a low dose level of 6.7×1013
genome copies/kg. Upon completion of patient dosing at the low
dose, the Company plans to move to a higher dose. The study is designed
to assess the safety and tolerability of a single infusion of RP-A501.
Additional outcome measures include cardiomyocyte and skeletal muscle
transduction by gene expression, histologic correction via
endomyocardial biopsy, and clinical stabilization via cardiopulmonary
testing. Further information about the clinical program is available here.

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 first two clinical
programs are 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, and an AAV-based gene therapy for
Danon disease, a devastating, pediatric heart failure condition.
Rocket’s pre-clinical pipeline programs for bone marrow-derived
disorders are for Pyruvate Kinase Deficiency (PKD), Leukocyte Adhesion
Deficiency-I (LAD-I) and Infantile Malignant Osteopetrosis (IMO). 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, 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 pre-clinical and clinical results for its product
candidates, which may not support further development and marketing
approval, 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
Rocket
Pharma, Inc.
The Empire State Building, Suite 7530
New York,
NY 10118
www.rocketpharma.com
investors@rocketpharma.com