Slides
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© 2026 Rocket Pharmaceuticals HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 RP-A501 Danon Disease Program Update Rocket Pharmaceuticals October 6, 2026
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© 2026 Rocket Pharmaceuticals 2 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 DISCLAIMER This presentation 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 actual results to differ materially from those expressed or implied by suc h f orward - looking statements. Rocket makes these statements pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995 and other federal securities l aws . Forward - looking statements often include words such as “believe,” “expect,” “anticipate,” “intend,” “plan,” “estimate,” “seek,” “will,” “may,” “suggest” or similar terms, variation s o f such terms or the negative of those terms. These forward - looking statements include, but are not limited to, statements concerning Rocket’s cash runway and financial posit ion; its ability to obtain additional funding to conduct planned research and development efforts; the potential safety and effectiveness of RP - A501, including at the recalibrated dose under the modified protocol; its ability to continue enrollment and dosing, complete the pivotal study and achieve its prespecified efficacy success criterion; the expected timin g a nd results of ongoing and planned clinical trials; the expected timing and outcome of regulatory interactions and submissions, including a potential biologics license application seeking ac cel erated approval; Danon disease prevalence and addressable patient estimates; patient identification and referral efforts; potential commercial opportunity and revenue; commercializati on plans, including the development of sales and marketing capabilities and relationships with treatment centers and other third parties; and potential development in additional patien t p opulations. Although Rocket believes that the expectations reflected in these forward - looking statements are reasonable, it cannot guarantee such outcomes. Actual results may differ materially as a result of various important factors, including, without limitation, clinical trial results and safety findings, including the ri sk of additional serious adverse events; Rocket’s ability to identify and enroll eligible patients and successfully complete clinical studies; the possibility that earlier clinical observations or no ncl inical findings may not predict subsequent clinical outcomes; changes in regulatory requirements or expectations; Rocket’s ability to obtain regulatory approval and meet applicable post - appr oval requirements; manufacturing, product - quality and supply risks; dependence on third parties for development, manufacture, marketing, sales and distribution; the availability o f s ufficient funding and unexpected expenditures; the accuracy of population estimates and assumptions underlying commercial models; pricing, reimbursement, market acceptance and competiti on; the outcome of litigation; Rocket’s ability to achieve the expected benefits of its portfolio prioritization and strategic restructuring; and its ability to obtain and enforce pate nts and defend against third - party infringement claims. Additional risks are described 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 Securities and Exchange Commission, and subsequent filings with the SEC, including its Quarterly Reports on Form 10 - Q. RP - A501 is investigational, and its safety and efficacy have not been established. Clinical observations presented here are base d on small, uncontrolled studies with varying follow - up. Preliminary findings may change as additional data become available, and results from earlier cohorts may not predict outcome s a t the recalibrated dose under the modified protocol. Meeting the pivotal study’s efficacy success criterion would not, by itself, establish that RP - A501 will receive regulatory appr oval. FDA’s assessment would consider the complete application, including safety, efficacy, manufacturing and product - quality information. Danon disease prevalence and addressable patient estimates are based on available data and assumptions and are subject to uncertainty. Estimated prevalence and identified patient records do not establish the number o f p atients eligible for treatment. Revenue illustrations are internal modeling scenarios, rather than financial guidance, and depend on clinical success, regulatory approval, the approve d p atient population, patient identification, pricing, reimbursement and treatment uptake. Opportunities in additional patient populations would require further development and app lic able regulatory approvals. 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, except as required by law.
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© 2026 Rocket Pharmaceuticals 3 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 Criteria used to select programs RP-A501 Danon Disease P rogram Update Compelling development path: $1B+ commercial opportunity Updated Phase 1 data Evidence of disease reversal or stabilization up to 7 years post RP - A501 Initial Phase 2 data Preliminary efficacy up to 36 months data from Cohorts 1 - 3 Recalibrated dose safety Positive safety observations: 3 patients treated safely at recalibrated dose + optimized immunomodulation Pivotal path FDA agreement to complete Cohort 4 supporting BLA submission for accelerated approval; PRV eligible Commercial Opportunity 10 - 11K US epidemiology ( 20K+ including EU5); 900+ Danon patients recorded in US; $1B+ global peak opportunity with initial indication
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© 2026 Rocket Pharmaceuticals 4 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 Catastrophic in males, with rapid progression and early mortality Danon Males Rapid Decline from Symptom Onset to End - Stage Heart Failure 2 - 4 Illustrative; derived from natural history registries & cohorts Age ( years ) 0 30 5 10 15 20 25 Cardiac Symptom Onset Diagnosis Loss of cardiac function Leads to end - stage HF, life threatening arr h ythmias Death, Heart transplant OPTIMAL POOR Cardiac Function Rapid disease progression Clinical Presentation Hallmark Cardiac Manifestation and Potential Multi - System Involvement 1 Neurocognitive • Learning disabilities* • Mild cognitive deficits* Visual • Retinopathy Skeletal Muscle • Proximal muscle weakness* Psychiatric • Anxiety • Mood Disorders Gastrointestinal • Hepatomegaly • Elevated Transaminases Cardiac • Left ventricular hypertrophy* • Left ventricular dilation • Conduction abnormalities *Key symptoms that contribute to the classical clinical triad • 1. Hong KN, Eshraghian EA, Arad M, et al. J Am Coll Cardiol . 2023;82(16):1628 – 1647. 2. Maron BJ, Roberts WC, Arad M, et al. JAMA. 2009;301(12):1253 – 1259. 3. Boucek D, Jirikowic J, Taylor MRG. Genet Med. 2011;13(6):563 – 568. 4. Hong KN, Eshraghian E, Khedro T, et al. J Am Heart Assoc. 2025;14(7):e038394. Danon Disease is a Highly Aggressive, Underdiagnosed, Rare Genetic Cardiomyopathy
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© 2026 Rocket Pharmaceuticals 5 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 PATIENT & FAMILY VOICE I ’d lost both my mum and brother as they waited for transplants .” I thought it would be for a couple days. But that turned into eight months.” M other of Danon patient - deterioration and mechanical support while awaiting a donor heart Transplant - Free S urvival M atters : M ore T ime Al ive with Ow n F unctioning H eart Only ~25% ultimately receive h eart t ransplant ( HTx ) • D onor scarcity & matching constraints • Diagnosis, referral & listing delays • C linical deterioration/eligibility loss HTx carries substantial lifelong medical and family burden • Lifelong immunosuppression • Rejection & s erious infection • Organ toxicity • Graft failure/ retransplantation HTx , heart transplantation; LVAD, left ventricular assist device; 1. Hong et al. JAHA. 2025;14:e038394. 2. ISHLT Fast Facts. 2024. 3. Hong et al. J Card Fail. 2022;28:664 – 669. 4. Lotan et al. Ci rc Genom Precis Med. 2020;13:e003117. 5. Velleca et al. J Heart Lung Transplant. 2023;42:e1 – e141. 6. Royal Brompton & Harefield Hospitals, “My story — Caroline Earnshaw”: https://www.rbht.nhs.uk/patients - visitors/patients/patient - support - services/patient - experience - and - involvement/patient/my - story - caroline - earnshaw . 7. Cleveland Clinic Children’s, “Heart Transplant Patient Finds New Life at Cleveland Clinic Children’s”: https://my.clevelandclinic.org/patient - stories/100 - heart - transplant - patient - finds - new - life - at - cleveland - clinic - childrens . No Approved Disease-Modifying Therapy Exists Heart transplantation is the only end - stage rescue and only for a few Danon patient and emergency HTx recipient; daughter also has Danon - 4 affected family members across 3 generations. HTx HTx is lifesaving, but carries early mortality risk 10+ yrs Median survival after HTx in general population 87.1% 5 - year graft survival in Danon HTx cohort 5 of 8 D ied within 1 year after HTx /LVAD in a Danon cohort HTx can be effective Early mortality remains
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© 2026 Rocket Pharmaceuticals 6 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 Danon Disease Biology is Exceptionally Suited to LAMP2B Gene Addition A clear molecular defect. A direct therapeutic approach. A measurable path from biology to clinical impact. DANON DISEASE: LAMP2B deficiency LAMP2 Gene Addition: Restores Cellular Recycling Diseased cardiomyocyte cellular injury, hypertrophy and adverse remodeling Lysosome (little to no LAMP2B) Impaired a utophagosome and lysosomal fusion X - linked LAMP2 mutation AAV9 with functional LAMP2B coding sequence Gene addition to cardiomyocytes Lysosome Autophagosome cellular material to be recycled LAMP2B restored on lysosome membrane Autolysosome fusion restored Hea l thier Cardiomyocyte restored cellular homeostasis & cleanup of cellular debris Schematic; not drawn to scale. Informed by published LAMP2/LAMP2B, autophagy and AAV gene - addition biology (1 - 3). 1. McNally EM, Spencer MJ. N Engl J Med. 2025;392:1028 – 1032. 2. Argiro A, et al. JACC Heart Fail. 2024;12(2):248 – 260. 3. Greenbe rg B, et al. N Engl J Med. 2025;392:972 – 983. Autophagosome cellular material to be recycled Harmful build - up accumulation of autophagic vacuoles & cellular debris D egraded materials restored cellular recycling & clearance
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© 2026 Rocket Pharmaceuticals 7 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 Phase 1 and Phase 2 Study of RP-A501 in Danon Disease Global, single - arm, Pivotal Phase 2 Trial of RP - A501 ongoing; 12 - Patients aligned with FDA IM, immunomodulatory regimen; LAMP2, lysosome - associated membrane protein 2; LTFU, Long - term follow - up ; LV, left ventricular; LVMI, left ventricular mass Index 1. Greenberg B., et al. N Engl J Med. 2025;392(10):972 - 983; 2. Gene Therapy Study of RP - A501 in Male Patients With Danon Disease . ClinicalTrials.gov identifier NCT06092034 Adult/Adolescent (n=3) 6.7 x 10 13 GC/kg RP - A501 IM regimen: Steroid (n=1); Steroid + Tacrolimus (n=2) Adult/Adolescent (n=2) 1.1 x 10 14 GC/kg RP - A501 IM regimen: Rituximab + Steroid + Tacrolimus Cohort 1 Cohort 2 Cohort 1A Adult/Adolescent (n=1) 6.7 x 10 13 GC/kg RP - A501 IM regimen: Rituximab + Steroid + Sirolimus Pediatric (n=3) + 6.7 x 10 13 GC/kg RP - A501 IM regimen: Rituximab + Steroid + Sirolimus Adult/Adolescent and Pediatric with C3 inhibitor (n=2) 6.7 x 10 13 GC/kg RP - A501 IM regimen: Rituximab + Steroid + Sirolimus + C3 inhibitor Cohort 1 Cohort 2 Cohort 3 Adult/Adolescent and Pediatric (n= 12 ) 3.8 x 10 13 GC/kg RP - A501 IM regimen: Rituximab + Steroid + Sirolimus Cohort 4 Pediatric (n=2) 6.7 x 10 13 GC/kg RP - A501 IM regimen: Rituximab + Steroid + Sirolimus Phase 1: 3 years (completed) Phase 1 LTFU: up to 10 years (ongoing) Pivotal Phase 2 (ongoing) 2 Current Status: Enrolling and treating remaining Cohort 4 patients (n=9) in Pivotal Phase 2 Study Co - Primary Endpoints (at 12 months ): • Improvements in LAMP2 protein expression ( ≥ Grade 1 from baseline) • Reductions in Left Ventricular Mass (LVMI; ≥10%) +Included initial sequential Pediatric Safety Run - in (n=2) Pivotal Phase 2 Trial Phase 1 Results in NEJM ‘24 1
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© 2026 Rocket Pharmaceuticals 8 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 Cohort Patient BL M6 M12 M18 M24 M30 M36 M60 6.7 × 10 13 GC/kg Adult/adolescent 1 0 NP NP 0 * 0 * 2 0 NP 3 0 NP NP 1.1 × 10 14 GC/kg Adult/adolescent* 4 0 NP NP 6.7 × 10 13 GC/kg Pediatric 6 0 NP NP 7 0 NP NP Myocardial LAMP2 Protein Expression † Grade 0 = no staining NP = not performed = Grade 1 ( ≤25%) = Grade 2 (26% – 50%) = Grade 3 (51% – 74%) = Grade 4 ( ≥75%) Legend: IHC Staining Grade ¶ (% Positive Cardiomyocytes) Pre - infusion Visit 0 Post - infusion Visit 1 Post - infusion Visit 2 Post - infusion Visit 3 6 7 6.7 × 10 13 GC/kg Pediatric, N=2 2 3 6.7 × 10 13 GC/kg Adult/adolescent, N=3 100 µm M12 M12 M24 M24 M36 M36 M12 M9 M24 M24 M36 M36 Representative LAMP2 IHC Images 100 µm †Reflects 9M visit biopsy as 12M biopsy not performed. *Grade 0 LAMP2 protein IHC staining at the 30 - and 36 - month assessments, however, LAMP2B vector RNA and DNA (VCN) levels have persisted through 60 months of follow - up ¶ Grading of LAMP2 protein expression by IHC was done by a board - certified pathologist in a blinded fashion. The semi - quantitative grading reflects the extent of LAMP2 protein expressing cardiomyocytes in the entirety of biopsy sample according to the scale. *Patient 5 had LV systolic dysfunction (LVEF <40%) at enrollment and had progressive heart failure requiring transplantation 5m following RP - A501 treatment and is not evaluable for efficacy. RP-A501 Phase 1 Study: Sustained Cardiomyocyte LAMP2 Expression Durable myocardial LAMP2 protein expression seen in all patients BL, baseline; IHC, Immunohistochemistry; LAMP2, lysosome - associated membrane protein 2; m, month(s); Data Extraction Date: July 31, 2026 Patient ID 1 1001 2 1002 3 1005 4 1006 6 1008 7 1009 100 µm
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© 2026 Rocket Pharmaceuticals 9 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 Improved Stabilized Worsened Cohort Patient Age at Most RV (y) Most Recent Visit (m) Δ LVMI,* BL to RV (g/m 2.7 ) Δ IVSd, BL to RV (mm) Δ LVPWd, BL to RV (mm) Δ NT - proBNP, BL to RV (ng/L) Δ cTnI, † BL to RV (ng/mL) Δ NYHA Class Δ KCCQ - 12, BL to RV 1:Low Dose Adult/ Adolescent 1 24 84 ‡ - 32%, 85.0 to 57.8 +2%, 19.8 to 20.2 - 30%, 18.8 to 13.2 - 31%, 336 to 233 - 99%, 0.60 to 0.01 II to I +56, 44 to 100 2 26 72 - 31%, 260.2 to 178.9 - 29%, 60.1 to 42.6 - 71%, 39.1 to 11.3 - 90%, 5119 to 489 - 96%, 1.46 to 0.06 II to I +24, 64 to 88 3 23 54 ‡ - 12%, 98.2 to 86.7 - 30%, 30.9 to 21.7 - 56%, 32.1 to 14.1 - 45%, 841 to 460 - 76%, 0.28 to 0.07 II to II +7, 77 to 84 2:High Dose Adult/ Adolescent 4 23 36 - 7%, 68.6 to 63.6* +5%, 18.0 to 19.0 - 27%, 24.0 to 17.4 - 65%, 720 to 249 - 39%, 0.47 to 0.29 II to I +9, 79 to 89 3:Low Dose Pediatric 6 a 15 36 - 47%, 141.5 to 74.7 - 32%, 42.4 to 29.0 - 2%, 22.8 to 22.3 - 75%, 1629 to 406‡ - 84%, 1.78 to 0.28 II to I +13, 50 to 63 7 14 36 +3%, 82.0 to 84.9* +13%, 18.5 to 20.9 +66%, 14.9 to 24.7 - 35%, 1912 to 1238 - 31%, 1.08 to 0.74 II to I +36, 52 to 88 *Centrally evaluated (blinded) MRI data were utilized for LVMI when available. All other measurements of cardiac structure an d f unction reflect centrally evaluated (blinded) echocardiogram data. † Central laboratory assessment of cTnI w as performed on cryopreserved and non - cryopreserved samples. Values for cTnI from high - sensitivity and earlier tests. High - sensitivity and earlier assay s are expressed in ng/ mL. ‡ F or Patient 1, NYHA class and KCCQ - 12 assessments occurred at Month 84, and all other assessments at Month 72. For Patient 3, NYH A class assessment occurred within the Month 84 visit window, and all other assessments at Month 54. a Patient underwent heart transplant at 4.8 years post - RP - A501 infusion; post data cut. RP-A501 Phase 1: Benefit Observed Across All Key P arameters up to 7 years Lower cardiac biomarkers accompany stable or reduced LV mass index and improved quality - of - life scores Patient ID 1 1001 2 1002 3 1005 4 1006 6 1008 7 1009 BL, Baseline; BNP, Brain Natriuretic Peptide; cTnI , cardiac troponin I; LAMP2, lysosome - associated membrane protein 2; IVSd , Int er ventricular Septum in diastole; KCCQ, Kansas City Cardiomyopathy Questionnaire; LV, Left Ventricle; LVEF, Left Ventricular Ejection Fract ion ; LVMI, Left Ventricular Mass Index, LVPWd , Left Ventricular Posterior Wall in diastole; m, month(s); MRI, magnetic resonance imaging; NT - Pro - BNP, N - terminal pro – B - type n atriuretic peptide; NYHA, New York Heart Association, RV, (Most) Recent Visit; y, year(s) Data Extraction Date: July 31, 2026
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© 2026 Rocket Pharmaceuticals 10 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 Improved or Stabilized Cardiac Biomarkers and L V mass in RP-A501 P atients Differs significantly from expanded natural history data BNP ( pg /ml) Age [years] N = 22 patients r 2 = 0.846 LV mass (g) Age [years] BNP increases by 42.17 ± 18.46 pg /mL per year in untreated Danon males* LV Mass increases by 39.86 ± 4.01 g per year in untreated Danon males* N = 20 patients r 2 = 0.246 Baseline M9 M12 M18 M24 M30 M36 M42 M48 M54 M60 0 500 1000 1500 2000 Months Post Gene Therapy BNP (ng/L) 1 2 3 4 6 7 100 6 12 18 24 30 36 42 48 54 60 0 100 200 300 400 500 600 700 800 900 1000 Months Since RP-A501 Infusion LV mass (g) 1 2 3 4 6 7 Baseline *Unpublished data from International Danon Disease Registry BNP, Brain Natriuretic Peptide; LV, Left Ventricle; Data Extraction Date: July 31, 2026 (Phase 1 RP - A501 study) 6 12 18 24 30 36 42 48 54 60 0 100 200 300 400 500 600 700 800 900 1000 Months Since RP-A501 Infusion LV mass (g) 1 2 3 4 6 7 Baseline
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© 2026 Rocket Pharmaceuticals 11 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 - 16% - 14% - 18% - 11% - 32% - 15% RP-A501 Phase 1 Summary LAMP2 expression and LVMI improvements seen as early as 6 months post RP - A501 * Where possible, cardiac MRI assessments shown (patients 1, 4, and 7); otherwise, echocardiogram data presented. † Utilized 18 m data when 12m assessment was not done. ‡ Reflects 9M visit biopsy as 12M biopsy not performed. LAMP2, lysosome - associated membrane protein 2; LVMI, left ventricular mass index; MRI, magnetic resonance imaging; m, month(s). Data Extraction Date: July 31, 2026 Summary of Phase 1 in Relation to Pivotal Co-Primary Endpoints • All patients showed ≥10% LVMI decrease and LAMP2 protein expression increase ( ≥ Grade 1) at ~12m , representing 100% response rate based on pivotal Ph 2 endpoints • All patients showed d urable myocardial LAMP2 protein expression and improved or sustained LVMI at most recent visit M12 M18 † M18 † M12 M12 M12 LVMI % Change: Baseline to 12m † Patient 1* Patient 2 Patient 3 Patient 4* Patient 6 Patient 7* Patient ID 1 1001 2 1002 3 1005 4 1006 6 1008 7 1009 ‡ ‡ Reflects 9M visit biopsy as 12M biopsy not performed. Myocardial LAMP2 Protein Expression
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© 2026 Rocket Pharmaceuticals 12 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 RP-A501 Pivotal Phase 2 T rial Design Pivotal, global, single - arm, open - label trial 1 FDA, US Food and Drug Administration; hsTnI , high - sensitivity troponin I; LAMP2, lysosome - associated membrane protein 2; LV, left ventricular; LVMI, left ventricular mass Index; IM, immunomodulatory; NYHA, New York Heart Association; 1. Gene Therapy Study of RP - A501 in Male Patients With Danon Disease . ClinicalTrials.gov identifier NCT06092034 Pediatric and Adult/Adolescent (n= 12 ) Recalibrated dose: 3.8 x 10 13 GC/kg RP - A501 Revised IM regimen: Rituximab + Steroid + Sirolimus Cohort 4 * Initial patients received RP - A501 at the recalibrated dose of 3.8 × 10¹³ GC/kg with a refined immunomodulatory regimen and enhanced safety monitoring. Dosing proceeded sequentially, with at least four weeks between infusions. The recalibrated Phase 2 dose was selected to deliver a therapeutic profile consistent with the dose at which RP - A501 demonstrated meaningful efficacy in Phase 1 patients. Key eligibility criteria M ales age ≥8 years, LAMP2 mutation, NYHA II - III, evidence of LV hypertrophy, elevated hsTnI Co - Primary Endpoint To support accelerated approval, co - primary endpoint consisting of improvements in LAMP2 protein expression ( ≥ Grade 1 from baseline) and reductions in Left Ventricular Mass (LVMI; ≥10% ↓ ) at 12 - month post - infusion Patient 9 * Patient 8 * Patient 7 * + 9 patients (total n=12) ✓ Cohort 1 - 3 completed ✓ FDA agreement obtained to support completion of pivotal study ✓ Pivotal data package: 12 patients at recalibrated dose + revised immunomodulatory regimen (Cohort 4) ✓ Clinical sites ready to enroll and dose ✓ High inbound patient interest based on favorable benefit/risk ✓ Patients identified to support completion of clinical study ✓ Clear path to BLA submission to support accelerated approval
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© 2026 Rocket Pharmaceuticals 13 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 BL, Baseline; cTnI , cardiac troponin I; LAMP2, lysosome - associated membrane protein 2; IVSd , Int er ventricular Septum in diastole; KCCQ, Kansas City Cardiomyopathy Questionnaire; LV, Left Ventricle; LVEF, Left Ventricular Ejection Fract ion ; LVMI, Left Ventricular Mass Index, LVPWd , Left Ventricular Posterior Wall in diastole; m, month(s); NT - Pro - BNP, N - terminal pro – B - type natriuretic peptide; NYHA, New Yor k Heart Association, RV, (Most) Recent Visit; y, year(s) Data Extraction Date : August 7, 2026 Improved Stabilized Worsened Cohort Patient Age at Most RV (y) Most Recent Visit (m) Δ LVMI, BL to RV (g/m 2.7 ) Δ IVSd , BL to RV (mm) Δ LVPWd, BL to RV (mm) Δ NT - proBNP, BL to RV (ng/L) Δ cTnI, BL to RV (ng/mL) Δ NYHA Class Δ KCCQ - 12 OS, BL to RV Cohort 1: Adult/ Adolescent 2 - 1 20 24 - 36%, 65.5 to 41.9 - 28%, 21.8 to 15.6 - 7%, 16.5 to 15.4 - 19%, 125 to 101 - 49%, 0.04 to 0.02 II to I 0, 100 to 100 Cohort 2: Pediatric 2 - 2 16 36 - 35%, 65.4 to 42.8 - 39%, 16.0 to 9.7 - 10%, 10.4 to 9.4 - 7%, 54 to 50 - 14%, 0.02 to 0.01 II to I +2, 98 to 100 2 - 3 15 24 +9%, 187.1 to 204.8 - 4%, 28.2 to 27.1 - 17%, 26.1 to 21.7 - 19%, 7966 to 6465 +122%, 0.33 to 0.73 III to I +16, 64 to 79 2 - 4 12 18 - 30%, 202.2 to 140.5 +17%, 39.3 to 46.0 +24%, 22.5 to 27.9 - 30%, 69855 to 49135 - 14%, 0.82 to 0.71 II to II +35, 35 to 71 Preliminary Efficacy of Phase 2 Study RP-A501: Up to 36 months Preliminary findings show stabilization or improvement in key disease measures All measurements of cardiac structure and function (LVEF, LV Mass, LVMI, IVSd and LVPWd ) utilized centrally evaluated echocardiogram data (blinded review) for all participants. In Phase 2 Cohort 3, two patients treated with immunomodulatory regimen containing a C3 - inhibitor experienced serious adverse ev ents. Cohort 3 is discontinued and data from the two subjects were not included. Patient ID 2-1 2004 2-2 2001 2-3 2002 2-4 2007 2-5 2005 2-6 2008 2-7 2017 2-8 2020 2-9 2019 Cohort 4 Updates and Rationale • Dose recalibrated to account for the higher full - to - empty capsid ratio • I mmunomodulation revised based on early Phase 2 safety findings
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© 2026 Rocket Pharmaceuticals 14 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 Modified Protocol Delivers Favorable Pivotal Cohort 4 Safety Profile a Patients 2 - 3, 2 - 4 and 2 - 6; b Patient 2 - 8. GGT, Gamma - glutamyltransferase ; IM, immunomodulatory; TEAE, Treatment Emergent Adverse Events Data Extraction Date : Aug 7 , 2026 Phase 2 Preferred Term (Grade ≥3) Cohorts 1 & 2 (n=4) Cohort 3 (n=2) Cohort 4 (n=3) Subject with at least 1 Serious TEAE ( Grade ≥3) 3 (75.0) 2 (100) 1 (33.3) Thrombotic microangiopathy a 2 (50.0) 1 (50.0) 0 Acute kidney injury 1 (25.0) 1 (50.0) 0 Renal failure 1 (25.0) 0 0 Gamma - glutamyltransferase increased b 0 0 1 (33.3) Hepatic enzyme increased 1 (25.0) 0 0 Cardiac arrest 1 (25.0) 0 0 Posterior reversible encephalopathy syndrome 1 (25.0) 0 0 Rhabdomyolysis 1 (25.0) 0 0 Aplastic anemia 0 1 (50.0) 0 Disseminated intravascular coagulation 0 1 (50.0) 0 Cytokine release syndrome 0 1 (50.0) 0 Hypertransaminasaemia 0 1 (50.0) 0 Pneumothorax 0 1 (50.0) 0 Sepsis 0 1 (50.0) 0 Shock 0 1 (50.0) 0 Retroperitoneal hemorrhage 0 1 (50.0) 0 Grade ≥3 Serious Treatment Emergent Adverse Events Related to RP - A501 Pivotal Cohort 4 (recalibrated dose with modified IM regimen) • No evidence of thrombotic microangiopathy, capillary leak or other complement - mediated events • Elevated GGT observed in 1 patient; resolved and patient discharged after 12 days. • All 3 patients discharged by 1 - 2 weeks post - infusion Number Patient ID 2-1 2004 2-2 2001 2-3 2002 2-4 2007 2-5 2005 2-6 2008 2-7 2017 2-8 2020 2-9 2019
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© 2026 Rocket Pharmaceuticals 15 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 No Evidence of TMA, CLS, or Other Severe Complement-Mediated T oxicities in Cohort 4 Platelets and Terminal Complement Complex (sC5b9) of the initial 3 patients up to 3 months post - treatment CLS, Capillary Leak Syndrome; sC5b9, soluble C5b9; TMA, Thrombotic microangiopathy Data Extraction Date: September 4, 2026 ‡ ‡ A decrease in platelet count was observed at Week 8 - 9 in the absence of symptoms or signs suggestive of platelet dysfunction or deficit. All concomitant medi c ations were reviewed to discontinue any potential contributors; it was not deemed clinically significant by the investigator and Sponsor and resolved following medication modifications. *The sC5b9 lower limit of detection per the validated assay at the clinical site is <170 ng/mL; reported value s of <170 ng/mL are shown as 170 ng/ mL. Patient 2 - 7 Patient 2 - 8 Patient 2 - 9 Normal Range Normal Range Patient ID 2-7 005 - 2017 2-8 012-2020 2-9 012-2019 Platelets Complement Marker (sC5b9)
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© 2026 Rocket Pharmaceuticals 16 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 PHASE 1 DURABILITY Up to 7 Years of clinical benefit observed Clinical benefit and improvements observed with durable biomarker in all patients at latest trial follow - up 100% overall survival; median transplant - free survival not reached at median follow - up: 5.7 years (range: 4.3 – 7.1 years) Mirrors Phase 1 Trajectory Improvement or stabilization of cardiac hypertrophy, heart failure symptoms, quality of life scores, and biomarkers of cardiac injury and stress replicate the trajectory of Phase 1 responders Generally Well - Tolerated Recent protocol optimizations suggest successful mitigation of complement - mediated toxicities* *In Phase 2 Cohort 3, two patients treated with immunomodulatory regimen containing a C3 - inhibitor experienced serious adverse e vents. The cohort is discontinued and data from the two subjects were not included. RP-A501 Demonstrated Durable Efficacy with a T olerable Safety Profile SAFETY AND TOLERABILITY PHASE 2 EARLY EFFICACY
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© 2026 Rocket Pharmaceuticals 17 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 RP-A501 Pivotal Phase 2 Milestones TODAY Enrollment and dosing 9 additional patients in Cohort 4 MID - 2027 Dosing completion Last patient dosed 12 - month follow - up MID - 2028 TOPLINE TARGET* LATE - 2028 BLA regulatory filing PRV eligible; Accelerated Approval; Priority review CO - PRIMARY EFFICACY ENDPOINTS AT 12 MONTHS ≥ Grade 1 Improvement in LAMP2 protein expression from baseline ≥10% Reduction in left ventricular mass index (LVMI) *MID - 2028 target is provisional pending alignment with dosing completion and 12 - month follow - up. Primary efficacy readout from pivotal Cohort 4
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© 2026 Rocket Pharmaceuticals 18 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 Schematic Male Disease Progression HTX Danon Patients HCM Symptomatic Danon Patients Pre - HCM Danon Patients Estimated Epidemiology of Danon Disease is 20K+ across US & EU5 5.4K Genotype-Based Analysis Pathogenic & likely Pathogenic LAMP2 Variants Based on comprehensive molecular characterization of confirmed Danon Disease + population genomic anchor Classic loss - of - function LAMP2 variants Population allele frequency of 3 variant categories 1 from g nomAD 2 Other P/LP LAMP2 variants 6 variant categories 3 identified through RW datasets 4 with confirmed DD 62% (~6.6K) 38% (~4.1K) Phenotype-Based Analysis Natural History and Real - World Modeling Based on Danon disease natural history modeling + real - world patient data Patients with HCM Phenotype 5 Age & sex - specific DD yield modeling with HCM population ~5.1K Pre - cardiomyopathy and DCM Patients~5.4K Age- and sex-specific natural history model built with 700+ patient data DCM, dilated cardiomyopathy; DD, Danon disease; EU5; Germany, France, Italy, Spain, UK; HCM, hypertrophic cardiomyopathy; HTx , heart transplantation; P/LP, pathogenic/likely pathogenic; RW, real - world; 1. Stop - gain (Nonsense), Frameshift and Canonical splice - site variant categories 2. non - UKBB g nomAD v4.11 1. non - UKBB g nomAD v4.11 Genome Aggregation Database 3. includes Start - loss, Exon/gene deletions/duplications, Missense, Synonymous and Intronic variant categories 4. variant records of confirmed DD patients from genetic testing labs Invitae , Ambry Genetics and GeneDx , real - world Natural History Cohorts, Rocket Natural History Study, Repository of published RW Danon patient cases 5. HCM & DD claims/EHR databases ( Cellworks , Forian ) covering >310M lives ESTIMATED DANON POPULATION 10 - 11K PATIENTS ~6-7K Female ~4K Male Anchor Scaling Anchor Scaling 450+ patient records 9+ variant categories Independent genotype and phenotype - based analyses converge on similar estimate of 10 - 11K US patients
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© 2026 Rocket Pharmaceuticals 19 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 Over 900 Identified US Danon Disease Patients Representing a current diagnosis rate under 10% CM, Cardiomyopathies; DD, Danon disease; HCM, hypertrophic cardiomyopathy; HTx , heart transplantation 1. Data as of July 2026; over 80% of patients reported in ICD - 10 code and genetic testing lab data have been identified in the last 5 years; ICD - 10 code for Danon available from Q4 2023. 2. Non - sponsored de - identified test data purchased through commercial genetic testing labs; 3. Does not include VUS patients; business rules for de - identification and de - duplication; 4. E stimated based on Danon true prevalence modeling and patients found; 5. Longoni M, et al Real - world utilization of guideline - directed genetic testing in inherited cardiovascular diseases; 6. Bui QM, et al. Real - world Genetic Testing Practices in Cardiomyopathy, 2026 ≥15 patients 5 - 14 patients 2 - 4 patients 1 patient Gender 45% 55% Institutional coverage (% of pts) 30% 60% 100% Top 25 Top 100 Est. DD Diagnosis Rate 4 <10% Genetic Testing Rates in Cardiomyopathies (%) 1.6 % 2.6 % 13.8 % Adult HCM 5 Adults with CM (<=40) 6 Pediatric CM 6 Sources 1 900 Claims/ EHR Genetic Test Data 2 Field Effort HCP Reported De - duplicated for unique 3 patient counts Patients cumulatively identified and include those who received HTx or subsequently experienced disease - related mortality All Institutions (n=290)
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© 2026 Rocket Pharmaceuticals 20 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 Accelerating Danon Diagnosis: Focused P ath to Launch Aspiration: every person with HCM or a Danon disease signature and every at - risk relative of a confirmed Danon patient is genetically evaluated so no Danon diagnosis is missed Illustrative Diagnoses Ramp External tailwinds HCM recognition & CMI entry into pediatrics Ecosystem momentum around cardio genomics & broader testing Genotype - driven trials in cardiomyopathies <10% At launch ( Mid - 2029) Longer term Diagnosed Share of Target Population Drive cardiologists to test young HCM & urgency with Danon signature Expand diagnostic infrastructure & access Empower patients & caregivers to seek genetic evaluation Multiply diagnoses through the family cascade HCM, hypertrophic cardiomyopathy; CMI , Cardiac myosin inhibitors
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© 2026 Rocket Pharmaceuticals 21 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 Addressable Opportunity in Danon Extends Beyond Males with HCM HCM, hypertrophic cardiomyopathy; Illustrative, non - risk - adjusted peak annual commercial opportunity based on internal assumptions regarding addressable populati ons, diagnosis, treatment eligibility, pricing, access and uptake. Potential lifecycle expansions require additional clinical evidence and regulatory alignment and approval. Actual in dications, eligible populations, timing and commercial outcomes may differ. Segment sizes are not drawn to scale. Danon F emales with earlier - onset HCM Danon Males with HCM $1B+ GLOBAL PEAK ANNUAL OPPORTUNITY UNLOCK DANON OPPORTUNITY ◷ T reat earlier Shift treatment upstream Capture fast progressors Intervene before irreversible progression ◎ Reach underdiagnosed females Treat patients historically missed Danon Males pre - HCM Danon Females with l ater - onset C ardiomyopathy $2B+ GLOBAL PEAK ANNUAL OPPORTUNITY Danon gene therapy addressable segment Expand the window, extend the impact, transform the disease
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© 2026 Rocket Pharmaceuticals 22 HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474 New Evidence and a Defined Pivotal Path Sustained Clinical Benefit RP - A501 conferred durable disease reversal/stabilization through 36 months and up to 7 years post - RP - A501 infusion Preliminary efficacy in initial 4 patients in Phase 2 further corroborates long - term benefit identified in Phase 1 and LTFU Early safety at the recalibrated dose No TMA, capillary leak, or significant complement - mediated adverse events through 3 months in the first three patients Attractive Commercial Opportunity US e pidemiology of 10 - 11K US ( 20K including Europe); over 900 D anon disease patients recorded in US alone; $ 1B global peak potential for 1 st indication Efficacy target At least 7 of 12 responders at 12 months Each responder must meet both criteria Myocardial LAMP2 expression ≥ Grade 1 from baseline LVMI reduction ≥10% from baseline Dosing completion expected mid-2027 Current cash runway now into Q3’28 RP - A501 is investigational. Initial safety follow - up is limited for Phase 2 Cohort 4. One RP - A501 - related Grade 3 increase in ga mma - glutamyltransferase (GGT) was reported and resolved. Safety data as of September 4, 2026. Approval requires FDA review of the complete application.
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HTML/HEX code: #7f2722 HTML/HEX code: #67335B HTML/HEX code: #445367 HTML/HEX code: #c03a32 HTML/HEX code: #03adb1 HTML/HEX code: #00646f HTML/HEX code: #747474