Rocket Pharmaceuticals (NASDAQ: RCKT) details early RP-A501 safety in Danon trial
Rhea-AI Filing Summary
Rocket Pharmaceuticals reported a positive clinical safety update from the initial three patients treated with RP-A501 under the modified protocol in its global, pivotal Phase 2 trial for Danon disease. The patients received a recalibrated dose of 3.8 × 10¹³ GC/kg plus an immunomodulatory regimen of rituximab, sirolimus, and corticosteroids, given sequentially with at least four weeks between infusions. To date, no thrombotic microangiopathy, capillary leak syndrome, or other significant safety concerns have been observed in these patients.
The pivotal Phase 2 study is designed as a 12-patient, single-arm trial. Rocket is actively engaging with the FDA to align on the path to dosing additional patients and completing the trial and expects an update on the regulatory pathway, as well as a comprehensive Danon disease program update, in the second half of 2026. RP-A501 is a single intravenous AAV9.LAMP2B gene therapy that has demonstrated safety and efficacy in clinical studies and holds multiple U.S. and EU regulatory designations, including RMAT, Fast Track, Rare Pediatric Disease, Orphan Drug, ATMP, and PRIME.
Positive
- Initial safety at recalibrated dose de-risked: three Danon patients received RP-A501 at 3.8 × 10¹³ GC/kg with immunomodulation and showed no thrombotic microangiopathy, capillary leak syndrome, or other significant safety concerns.
Negative
- None.
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8-K Event Classification
2 items: 7.01, 9.01
2 items
Item 7.01
Regulation FD Disclosure
Disclosure
Material non-public information disclosed under Regulation Fair Disclosure, often investor presentations or guidance.
Item 9.01
Financial Statements and Exhibits
Exhibits
Financial statements, pro forma financial information, and exhibit attachments filed with this report.
Key Figures
Initial patients treated: 3 patients
Recalibrated RP-A501 dose: 3.8 × 10¹³ GC/kg
Planned trial size: 12 patients
+2 more
5 metrics
Initial patients treated
3 patients
Initial three patients treated under the modified RP-A501 Phase 2 protocol
Recalibrated RP-A501 dose
3.8 × 10¹³ GC/kg
Dose used in the modified pivotal Phase 2 trial with immunomodulatory regimen
Planned trial size
12 patients
Single-arm global pivotal Phase 2 study design for RP-A501 in Danon disease
Minimum interval between infusions
4 weeks
Treatments proceeded sequentially with at least four weeks between RP-A501 infusions
Planned update timing
second half of 2026
Expected timing for regulatory pathway and comprehensive Danon program updates
Key Terms
thrombotic microangiopathy (TMA), capillary leak syndrome, recombinant adeno-associated serotype 9 (AAV9), RMAT, +2 more
6 terms
thrombotic microangiopathy (TMA) medical
"no thrombotic microangiopathy (TMA), capillary leak syndrome, or other significant safety"
Thrombotic microangiopathy (TMA) is a medical condition where small blood vessels become blocked by clots and damaged cells, which can quickly impair organ function like the kidneys or brain. For investors, TMA matters because it is a serious safety signal in drug development and patient care—its occurrence can trigger regulatory action, costly trials or label changes, litigation risk, and sudden shifts in a company’s market value, much like a product recall affects a manufacturer.
capillary leak syndrome medical
"no thrombotic microangiopathy (TMA), capillary leak syndrome, or other significant safety"
A rare medical condition in which fluids and proteins rapidly escape from small blood vessels into surrounding tissues, causing sudden swelling, low blood pressure and reduced blood flow to organs — like a pipe developing leaks so the contents pool where they shouldn’t. Investors pay attention because it can appear as a serious side effect of drugs or treatments, affecting clinical trial outcomes, regulatory decisions, product labeling, sales prospects and legal risk.
recombinant adeno-associated serotype 9 (AAV9) medical
"consists of a recombinant adeno-associated serotype 9 (AAV9) capsid containing a functional"
RMAT regulatory
"RP-A501 holds FDA RMAT, Fast Track, Rare Pediatric Disease, and Orphan Drug"
A Regenerative Medicine Advanced Therapy (RMAT) designation is a regulatory fast-track status for cell, gene or tissue-based therapies that show promise for treating serious conditions. It acts like an express lane with extra support from regulators—potentially shortening review time and enabling earlier approval paths—which can reduce development risk and speed a therapy toward the market, making it a material value signal for investors in biotech stocks.
lysosome-associated membrane protein medical
"mutation has been identified in the gene encoding for lysosome-associated membrane protein"
autophagy medical
"LAMP2, an important mediator of autophagy and primarily expressed in heart"
Autophagy is a natural cellular process where cells break down and recycle damaged parts and unwanted material, like a house cleaning system that removes clutter to keep things running smoothly. For investors, autophagy matters because many drugs and therapies aim to boost, inhibit, or redirect this process to treat diseases; success or failure in manipulating autophagy can affect the commercial prospects and valuation of biotech companies.
AI-generated analysis. How Rhea-AI works. Not financial advice.
FAQ
What did Rocket Pharmaceuticals (RCKT) disclose about RP-A501 safety in Danon disease?
Rocket reported a positive early safety update from the first three Danon disease patients treated with RP-A501 under a modified Phase 2 protocol, with no thrombotic microangiopathy, capillary leak syndrome, or other significant safety concerns observed to date.
How many patients has Rocket Pharmaceuticals (RCKT) treated under the modified RP-A501 Phase 2 protocol?
Rocket has treated three patients so far under the modified Phase 2 protocol for RP-A501 in Danon disease. Treatment was given sequentially with at least four weeks between infusions as part of a planned 12-patient, single-arm pivotal trial.
What dose of RP-A501 is used in Rocket Pharmaceuticals’ (RCKT) modified Phase 2 Danon trial?
The recalibrated RP-A501 dose in the modified Phase 2 protocol is 3.8 × 10¹³ GC/kg. This dose is paired with rituximab, sirolimus, and corticosteroids and was selected to preserve therapeutic potential while optimizing the benefit–risk profile.
What is the design of Rocket Pharmaceuticals’ (RCKT) pivotal Phase 2 trial of RP-A501?
The pivotal RP-A501 study is a 12-patient, single-arm Phase 2 trial in Danon disease. Patients receive a single intravenous infusion of RP-A501 at the recalibrated dose plus immunomodulation, with sequential dosing and a minimum four-week interval between infusions.
When will Rocket Pharmaceuticals (RCKT) give further updates on the Danon disease program?
Rocket expects to provide both a regulatory pathway update for the RP-A501 Phase 2 trial and a comprehensive Danon disease program update in the second half of 2026, following ongoing interactions with the FDA.
What regulatory designations does RP-A501 have according to Rocket Pharmaceuticals (RCKT)?
RP-A501 holds RMAT, Fast Track, Rare Pediatric Disease, and Orphan Drug designations in the U.S., and ATMP and PRIME designations in the EU, reflecting regulatory recognition of its potential for Danon disease.
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549
FORM 8-K
CURRENT REPORT
Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934
Date of Report (Date of earliest event reported): August 3, 2026
(Exact name of registrant as specified in its charter)
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Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the
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Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
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| Item 7.01. |
Regulation FD Disclosure.
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On August 3, 2026, Rocket Pharmaceuticals, Inc. (the “Company”) issued a press release announcing a positive
clinical safety update regarding the initial three patients treated under the modified protocol for its global, pivotal Phase 2 trial of RP-A501 in Danon disease.
A copy of the press release is included as Exhibit 99.1 hereto and is incorporated herein by reference.
The information under this Item 7.01, including Exhibit 99.1, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of
1934, as amended, (the “Exchange Act”) or otherwise subject to the liabilities of that section, and shall not be deemed to be incorporated by reference into the filings of the Company under the Securities Act or the Exchange Act, except as shall be
expressly set forth by specific reference in such filing.
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Financial Statements and Exhibits.
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99.1
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Press Release of Rocket Pharmaceuticals, Inc. dated August 3, 2026.
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Cover Page Interactive Data File (embedded within the Inline XBRL document).
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SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its
behalf by the undersigned hereunto duly authorized.
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Rocket Pharmaceuticals, Inc.
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Date: August 3, 2026
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/s/ Martin Wilson
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Martin Wilson
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General Counsel and Chief Corporate Officer
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Exhibit 99.1
Rocket Pharmaceuticals Announces Positive Clinical Safety Update from Initial Three Patients
Treated with RP-A501 Under Modified Phase 2 Protocol for Danon Disease
Initial three patients were treated safely; RP-A501 was well-tolerated with no TMA or capillary leak syndrome observed
Rocket is actively engaging with the FDA to align on the path to pivotal trial completion; regulatory pathway update expected in the second half of 2026
Comprehensive Danon disease program update on track for the second half of 2026
CRANBURY, NJ – August 3, 2026 – Rocket Pharmaceuticals, Inc. (Rocket or the Company) (NASDAQ: RCKT), a fully integrated, commercial-stage biotechnology company advancing genetic medicines for rare and devastating diseases, focused on inherited
cardiovascular disorders, today announced a positive clinical safety update regarding the initial three patients treated under the modified protocol for its global, pivotal Phase 2 trial of RP-A501 in Danon disease. Early safety has been promising
with the Company now engaging with the U.S. Food and Drug Administration (FDA) to align on the pathway for treating additional patients and completing the pivotal Phase 2 trial under the modified protocol.
The patients received RP-A501 at the recalibrated dose of 3.8 × 10¹³ GC/kg together with a refined immunomodulatory regimen comprised of rituximab, sirolimus, and corticosteroids. Treatment proceeded sequentially, with a minimum of four weeks between infusions. To date, no thrombotic microangiopathy (TMA), capillary leak syndrome, or
other significant safety concerns have been observed in these patients. The pivotal Phase 2 trial was designed as a 12-patient, single-arm study. The Company is actively engaging with the FDA to align on the path to dosing additional patients and
completing the trial and expects to provide an update on the regulatory pathway in the second half of 2026.
“These encouraging early safety observations from the initial three patients treated with RP-A501 reinforce our strong confidence in the program that was built on
transformative results from the Phase 1 trial which reflect the potential of gene therapy to address genetic cardiomyopathies,” said Gaurav Shah, M.D., Chief Executive Officer of Rocket Pharmaceuticals. “We are working with the FDA to align on the
path to completing the pivotal Phase 2 trial as promptly as possible.”
"The recalibrated Phase 2 dose was selected with the expectation that it will deliver potency consistent with the dose at which RP-A501 demonstrated meaningful efficacy
in patients in Phase 1," said Syed Rizvi, M.D., Chief Medical Officer of Rocket Pharmaceuticals. "This recalibration accounts for the higher proportion of full capsids in the current drug product in the setting of Danon disease and was developed in
consultation with leading experts and the FDA. We anticipate that the dose will preserve RP-A501's therapeutic potential while optimizing its benefit-risk profile."
The Company remains on track to provide a comprehensive Danon disease program update in the second half of 2026.
About RP-A501
RP-A501 is Rocket’s investigational gene therapy for the treatment of Danon disease and the first gene therapy for a cardiovascular condition to demonstrate safety and
efficacy in clinical studies. RP-A501 has the potential to restore or stabilize cardiac function in patients with Danon disease. RP-A501 consists of a recombinant adeno-associated serotype 9 (AAV9) capsid containing a functional version of the
human LAMP2B transgene (AAV9.LAMP2B) which is administered as a single intravenous (IV) infusion. In clinical studies, RP-A501 has been shown to target
cardiac cells (cardiomyocytes) and deliver the functional LAMP2B gene to heart tissue, which led to improved cardiac structure and function in patients.
RP-A501 holds FDA RMAT, Fast Track, Rare Pediatric Disease, and Orphan Drug designations in the U.S. along with ATMP and PRIME designations in the EU.
About Danon Disease
Danon disease is a rare X-linked inherited, multi-organ lysosomal-associated disorder with a devastating clinical course. The causative mutation has been identified in
the gene encoding for lysosome-associated membrane protein, otherwise known as LAMP2, an important mediator of autophagy and primarily expressed in heart, skeletal muscle and brain tissue. This mutation results in accumulation of autophagosomes
and glycogen, particularly in cardiac muscle and other tissues, which ultimately leads to heart failure, and for male patients, frequent death during adolescence or early adulthood. The only available definitive treatment option for Danon disease
is cardiac transplantation, which is associated with substantial complications and is not considered curative, representing the high unmet medical need for patients with Danon disease.
About Rocket Pharmaceuticals, Inc.
Rocket Pharmaceuticals, Inc. (NASDAQ: RCKT) is a fully integrated, commercial-stage biotechnology
company advancing genetic medicines for rare and devastating diseases, with a strategic focus on inherited cardiovascular disorders and additional programs in hematology and immunology. Rocket's cardiovascular portfolio includes three
clinical-stage gene therapy programs targeting hypertrophic, arrhythmogenic, and dilated cardiomyopathies, together representing one of the broadest pipelines focused on inherited heart disease. The Company's integrated platform combines
proprietary AAV manufacturing capabilities, extensive clinical experience in cardiac gene therapy, and long-term safety and efficacy data supporting advancement across its cardiovascular portfolio.
For more information about Rocket, please visit www.rocketpharma.com and follow us on LinkedIn, YouTube, and X.
Rocket Cautionary Statement Regarding Forward-Looking Statements
This press release contains forward-looking statements concerning Rocket’s future expectations, plans and prospects that involve risks and uncertainties, as well as
assumptions that, if they do not materialize or prove incorrect, could cause our results to differ materially from those expressed or implied by such forward-looking statements. We make such forward-looking statements pursuant to the safe harbor
provisions of the Private Securities Litigation Reform Act of 1995 and other federal securities laws. All statements other than statements of historical facts contained in this release are forward-looking statements. 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. These forward-looking statements include, but are not limited to, statements concerning the safety and effectiveness of RP-A501 in its pivotal Phase 2 trial under the modified protocol, the Company's ability to align with the FDA on
the path to treating additional Danon disease patients, Rocket's cash runway and financial position, Rocket's expectations of our ability to obtain additional funding to conduct our planned research and development efforts, the expected timing and
data readouts of Rocket's ongoing and planned clinical trials, the expected timing and outcome of Rocket's regulatory interactions and planned submissions, Rocket's ability to develop sales and marketing capabilities or enter into agreements with
third parties to sell and market its product candidates and Rocket's ability to expand its pipeline to target additional indications that are compatible with its gene therapy technologies. 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, the results of Rocket's ongoing and planned clinical trials, Rocket's dependence on third parties for development, manufacture, marketing, sales and distribution of product candidates, the outcome of litigation, unexpected expenditures,
Rocket's competitors' activities, including decisions as to the timing of competing product launches, pricing and discounting, Rocket’s ability to develop, acquire and advance product candidates into, enroll a sufficient number of patients into,
and successfully complete, clinical studies, Rocket’s ability to acquire additional businesses, form strategic alliances or create joint ventures and its ability to realize the benefit of such acquisitions, alliances or joint ventures, our ability
to achieve the expected benefits of our portfolio prioritization and strategic restructuring, including extending our cash runway, Rocket’s ability to obtain and enforce patents to protect its product candidates, and its ability to successfully
defend against unforeseen third-party infringement claims, 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, 2025, filed February 26, 2026 with
the SEC and subsequent filings with the SEC including our Quarterly Reports on Form 10-Q. 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.
Investors & Media
Meg Dodge
mdodge@rocketpharma.com