Rocket Pharmaceuticals Reports Second Quarter 2021 Financial Results and Highlights Recent Progress - Working with FDA on Changes to Clinical Trial Protocol in Danon Disease Trial; Rocket Anticipates Trial Will Resume in

Rocket Pharmaceuticals Reports Second Quarter 2021 Financial Results and Highlights Recent Progress

- Working with FDA on Changes to Clinical Trial Protocol in Danon Disease Trial; Rocket Anticipates Trial Will Resume in 3Q-

Durable Benefit Observed in Low Dose Cohort (6.7e13 dose) in Danon Disease; Removing Higher Dose Cohort (1.1e14 dose) From Future Dosing Plans; Full Clinical Update Expected in 4Q -

Results from FA, LAD-I, PKD Trials Presented at 24th ASGCT Annual Meeting Show Preliminary Evidence of Activity and Favorable Tolerability -

Updates in FA, LAD-I, PKD and IMO Also Expected in 4Q -

Sheet with $426.8 Million in Cash; Cash Runway Expected into 2H'23 -

to Be Held at 4:30 p.m. ET Today-

CRANBURY, NJ - Aug. 9, 2021 - Rocket Pharmaceuticals, Inc. (NASDAQ: RCKT), a clinical-stage company advancing an integrated and sustainable pipeline of genetic therapies for rare

childhood disorders, today reports financial results for the quarter ending June 30, 2021 and updates on the Company's key pipeline developments, business operations, and upcoming milestones.

"We are grateful to the FDA for its support and for working with us on our Danon program toward resuming our trial, which we believe will

occur in the third quarter," said Gaurav Shah, M.D., chief executive officer of Rocket Pharma. "Further, we have observed durable clinical benefit in the low dose adult cohort, which we believe is supportive of its potential as a viable Phase 2 dose.

As of July 2021, we see improvement in two of three low dose patients in NYHA class. In these two patients, we also observed substantial improvement of a key marker of heart failure, BNP, which decreased from a pretreatment baseline by 75 percent in

one patient and 79 percent in the other as well as improvement in cardiac output by 35 percent in one patient and 62 percent in the other as measured by invasive hemodynamics. The third patient has demonstrated stabilization of NYHA class and BNP.

Given the positive benefit/risk profile in the low dose, and additionally to mitigate safety concerns observed at the higher dose, in agreement with FDA we will no longer treat Danon patients with the higher dose (1.1e14). With our full focus on the

low dose, we look forward to progressing our trial on behalf of Danon patients devastated by this disease."

Dr. Shah continued, "We also presented positive data across three of our lentiviral-based gene therapy programs at ASGCT in May, which we

believe support the growing potential of these programs to treat Fanconi Anemia (FA), LAD-1 and PKD patients. Based on these results, we continue our momentum toward advancing these programs. In the case of our FA program, two recent publications

reinforce the natural history, clinical design and methods being utilized in our Phase 1/2 FA trial of RP-L102. We look forward to providing updates on all five of our programs in the fourth quarter of 2021."

Dr. Shah added, "Finally, and importantly, we are deeply saddened that the first patient dosed in our Phase 1 IMO trial, has passed way from

pulmonary hemorrhage related to thrombocytopenia following conditioning therapy and also related to underlying osteopetrosis. This event was considered likely not related to RP-L401 gene therapy. Consistent with the trial protocol, enrollment has

been temporarily paused pending a comprehensive evaluation in collaboration with the Independent Data Monitoring Committee, which will include a review of the conditioning regimen and other potential safety measures to mitigate the impact of

underlying disease on treatment. This outcome underscores the need to find cures for this devastating disease and has furthered our commitment and dedication to patients and our mission to develop curative gene therapies for rare disease."

Key Pipeline and Operational Updates

Fanconi Anemia (FA):

Infantile Malignant Osteopetrosis (IMO):

The first patient in the Phase 1 study, a six-year-old child with severe IMO-related anemia and bone abnormalities, was infused with

RP-L401 without immediate complications. During the initial weeks after therapy, the patient died of pulmonary complications, most likely pulmonary hemorrhage related to thrombocytopenia following conditioning therapy and also related to underlying

osteopetrosis. Pulmonary hemorrhage is a rare but documented complication of HSCT, and pulmonary complications, including life-threatening and fatal

complications, have been observed to occur with high frequency in osteopetrosis patients undergoing allogeneic HSCT procedures.

The patient death is not considered to be RP-L401-related by study investigators and as corroborated by autopsy findings. In accordance

with the trial protocol, enrollment has been temporarily paused pending a comprehensive evaluation in collaboration with the Independent Data Monitoring Committee.

Leukocyte Adhesion Deficiency-I (LAD-I):

Pyruvate Kinase Deficiency (PKD):

Anticipated Milestones

Upcoming Investor Conference

Second Quarter Financial Results

Conference Call Details

Rocket management will host a conference call today at 4:30 p.m. ET. To access the call and webcast, please visit the events section of the website. The webcast replay will be available on the Rocket website following the completion of the call.

Investors may access the conference call by dialing (866) 939-3921 from locations in the United States or +1 (678) 302-3550 from outside the United States.

Please refer to conference ID number 50210581.

About Rocket Pharmaceuticals, Inc.

Rocket Pharmaceuticals, Inc. (NASDAQ: RCKT) ("Rocket") is advancing an integrated and sustainable pipeline of genetic therapies that correct the root cause of

complex and rare childhood disorders. The company's platform-agnostic approach enables it to design the best therapy for each indication, creating potentially transformative options for patients afflicted with rare genetic diseases. Rocket's clinical

programs using lentiviral vector (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, Pyruvate Kinase Deficiency (PKD) a rare, monogenic red blood cell disorder resulting in increased red cell destruction and mild to

life-threatening anemia and Infantile Malignant Osteopetrosis (IMO), a bone marrow-derived disorder. Rocket's first clinical program using adeno-associated virus (AAV)-based gene therapy is for Danon disease, a devastating, pediatric heart failure

condition. 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

its guidance for 2021 in light of COVID-19, the safety, effectiveness and timing of product candidates that Rocket is developing to treat Fanconi Anemia (FA), Leukocyte Adhesion Deficiency-I (LAD-I), Pyruvate Kinase Deficiency (PKD), Infantile

Malignant Osteopetrosis (IMO) and Danon Disease, the actions of the FDA regarding the clinical hold on Rocket's Danon Disease program 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 monitor the impact of COVID-19 on its business operations and take steps to ensure the safety of patients, families and employees,

the interest from patients and families for participation in each of Rocket's ongoing trials, our expectations regarding the delays and impact of COVID-19 on clinical sites, patient enrollment, trial timelines and data readouts, our expectations

regarding our drug supply for our ongoing and anticipated trials, 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 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, 2020, filed March 1, 2021 with the SEC. 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.

Selected Financial Information

(amounts in thousands, except share and per share data)