Regenxbio Inc. · NASDAQ:RGNX
Regenxbio — Q4 2025 Earnings Presentation
23 slides from Regenxbio's earnings presentation, Mar 5, 2026
Slide 1: RGX-202 Gene Therapy for Duchenne: Interim Phase I/II Clinical Data
RGX-202, An Investigational Gene Therapy for the Treatment of Duchenne Muscular Dystrophy: Interim Phase I/II Clinical Data Carolina Tesi-Rocha, MD Clinical Professor of Neuromuscular Medicine Stanford Medicine Children’s Health MDA 2026 Clinical & Scientific Conference Orlando, FL Wednesday, March
Slide 2: RGX-202: A Differentiated Therapeutic Approach
RGX-202: A Differentiated Therapeutic Approach NOVEL CONSTRUCT IMMUNE SUPPRESSION MANUFACTURING • NAV® AAV8 vector • Comprehensive, proactive • Leading purity levels • Muscle-specific promoter immune suppression (>80% full capsids) in regimen implemented Duchenne gene therapy • Only microdystrophin
Slide 3: RGX-202 Contains Key Elements of Full-Length Dystrophin
RGX-202 Contains Key Elements of Full-Length Dystrophin Only microdystrophin construct with C-terminal (CT) domain FULL LENGTH-DYSTROPHIN RGX-202 MICRODYSTROPHIN Dystrophin CT Domain Dystrophin CT Domain Associated Protein Associated Protein Complex (DAPC) Complex (DAPC) Cell membrane Cell membrane
Slide 4: Preclinical Studies Indicated the CT Domain Preserved Skeletal and Cardiac Muscle
Preclinical Studies Indicated the CT Domain in RGX-202 Microdystrophin Preserved Skeletal and Cardiac Muscle Health and Enabled Muscle Resilience ABD1 H1 R1 R2 R3 H3 R24 H4 CR CT HOW THE CT DOMAIN MAY CONTRIBUTE TO IMPROVED OUTCOMES1 Microdystrophin+CT domain better protected the muscle against cont
Slide 5: RGX-202 Immune Suppression Regimen
RGX-202 Immune Suppression Regimen Liver Injury Administration of AAV Gene Therapy Thrombocytopenia / Myositis / Myocarditis Thrombotic Microangiopathy Complement Adaptive Activation Immunity Mediated Events Mediated Events D-9 D-7 D-1 D0 D2 D4 D6 D8 D10 D12 W2 W3 W4 W5 W6 W7 M2 M4 M6 1 Yr. Eculizum
Slide 6: AFFINITY DUCHENNE Interim Phase I/II Data
AFFINITY DUCHENNE® Interim Phase I/II Data © 2026 REGENXBIO INC. • ALL RIGHTS RESERVED.
Slide 7: AFFINITY DUCHENNE Phase I/II Trial Design
AFFINITY DUCHENNE® Phase I/II Trial Design Dose escalation and expansion Key Eligibility Criteria Phase I/II Trial Endpoints • Boys aged 1 to <12yo at screening • Primary Endpoint: Safety • Genetically confirmed DMD (mutations in exons 18 and above) • Biomarker Endpoint: Microdystrophin expression •
Slide 8: Phase I/II Interim Key Baseline Demographics
Phase I/II, Interim Data Phase I/II Interim Key Baseline Demographics VARIABLE MEAN DOSE LEVEL 1 DOSE LEVEL 2 (PIVOTAL DOSE) (range) 1X1014 GC/kg 2X1014 GC/kg Age range at screening (number dosed) 4-11 (n = 3) 1-3 (n = 3) 4-11 (n = 7) 7.1 3.2 8.7 Age at Dosing (yrs) (4.4-10.5) (2.3-3.7) (5.8-12.1) 9
Slide 9: I/II Interim Safety
Phase I/II, Interim Data Phase I/II Interim Safety RGX-202 was well tolerated with no SAEs or AESIs up to 24 months RGX-202 TREATMENT DOSE LEVEL 1 D O S E L E V E L 2 (PIVOTAL DOSE) TOTAL Emergent adverse events 1X1014 GC/kg 2X1014 GC/kg N = 13 Age Range 4-11 1-3 4-11 All Age Ranges (number dosed) D
Slide 10: Pivotal Dose: Liver Safety Findings
Phase I/II, Interim Data Pivotal Dose: Liver Safety Findings Up to 24 Months Mean GGT and total bilirubin not exceeding ULN Gamma Glutamyl Transferase (U/L) Bilirubin (umol/L) 100 75 Gamma Glutamyl Transferase (U/L) 80 60 3xULN GGT Bilirubin (umol/L) 60 45 40 30 ULN GGT ULN bilirubin 20 15 0 0 Basel
Slide 11: Pivotal Dose: Reductions in CK and Other Biomarkers at 1 Year
Phase I/II, Interim Data Pivotal Dose: Reductions in CK and Other Biomarkers Observed at 1 Year MONTH 12 0 Mean % Change from Baseline ALT AST CK LDH -10 -20 -30 -40 -50 N 7 7 8 8 Data cut date: January 5, 2026 Bars represent mean +/- SEM © 2026 REGENXBIO INC. • ALL RIGHTS RESERVED. 11 ALT: Alanine
Slide 12: Biomarkers Supported Robust Expression, Transduction, and Localization
Phase I/II, Interim Data Phase I/II Biomarkers Supported Consistent Robust Expression, Transduction, and Sarcolemmal Localization of RGX-202 Microdystrophin RGX-202 Microdystrophin1 VCN Positive Fibers2 WEEK 12 BIOPSY % copies/nucleus % (Western Blot) (qPCR) (Immunofluorescence) 4-7 60.6 9.8 79.33 (
Slide 13: AFFINITY DUCHENNE External Control Methodology
AFFINITY DUCHENNE® External Control Methodology STEP 1 STEP 2 External Data Sources Filter EC Participants by Key Entry Criteria Further Balance Baseline Covariates of RGX and EC • FOR-DMD Group at Individual Patient Level • Stable dose of corticosteroid for 12 weeks SAP Primary Method: Propensity-S
Slide 14: Dose Level 1: NSAA Outcomes at 2 Years
Phase I/II, Interim Data 35 30 Dose level 1: 25 1C NSAA Outcomes 20 at 2 Years NSAA 1A NSAA performance exceeded 15 1B expected disease trajectory 10 5 0 Data cut date: January 5, 2026 Fig 1. NSAA total score trajectories for individual patients by age (in grey) and the fitted mean and 4 6 8 10 12 1
Slide 15: Pivotal Dose: NSAA Outcomes at 1 Year
Phase I/II, Interim Data 35 30 2F 2D Pivotal Dose: 25 2C NSAA Outcomes 2A 2B 2G 20 at 1 Year NSAA performance exceeded 15 2E* external controls and expected 10 disease trajectory 5 0 Data cut date: January 5, 2026 Fig derived from Muntoni et al. NSAA total score trajectories for individual patients
Slide 16: Pivotal Dose: Functional Improvements at 1 Year Compared with External Controls
Phase I/II, Interim Data Pivotal Dose: Functional Improvements at 1 Year Compared with External Controls Exceeded external controls using propensity score weighting LSMean Difference Endpoint RGX, n EC, n Favoring RGX-202 (95% CI) vTTStand 7 211 0.044 (0.023 to 0.066) vTTRW 7 229 0.316 (0.224 to 0.4
Slide 17: Pivotal Dose: Functional Improvements in Participants Aged 8+
Phase I/II, Interim Data Pivotal Dose: Functional Improvements at 1 Year Compared with External Controls in Participants Aged 8+ (n=5) Exceeded external controls using propensity score weighting LSMean Difference Endpoint RGX, n EC, n Favoring RGX-202 (95% CI) vTTStand 5 115 0.059 (0.030 to 0.089) v
Slide 18: Cardiac Data
Cardiac Data © 2026 REGENXBIO INC. • ALL RIGHTS RESERVED.
Slide 19: Cardiac MRI is the Gold Standard in DMD
Cardiac MRI is the Gold Standard in DMD Superior accuracy and reproducibility1 • Cardiac MRI (cMRI) provides accurate and reproducible measurements of ejection fraction (EF) • cMRI is not dependent on acoustic windows, which may be poor in participants with DMD • Small longitudinal changes in EF are
Slide 20: Pivotal Dose: Cardiac Function Remained Stable Through 1 Year
Phase I/II, Interim Data Pivotal Dose: Cardiac Function Remained Stable Through 1 Year BASELINE 12 MONTHS Subjects (N) 7 7 Age 8.7* 9.7 Mean (range) (5.8-12.1) (6.8-13.1) Left Ventricular Ejection Fraction 61.7 % 61.6% Mean (range) (54-72**) (57-74) Median 60% 60% Global Circumferential Strain*** -2
Slide 21: AFFINITY DUCHENNE Confirmatory Trial
AFFINITY DUCHENNE® Confirmatory Trial Currently Enrolling Key Eligibility Criteria • Boys aged 1+ years at screening • Genetically confirmed DMD: except those with deletions or point mutations in exons 8, 9, and/or 10 • No pre-existing antibodies to the gene therapy (AAV8 capsid) Aged 1 to <4yo Aged
Slide 22: Phase I/II Interim Results and Next Steps
AFFINITY DUCHENNE® Phase I/II Trial Interim Results Phase I/II Interim Data Summary RGX-202 was well-tolerated, with no SAEs or AESIs observed Robust expression, transduction and localization of RGX-202 microdystrophin • All participants demonstrated microdystrophin expression levels above 10% at We
Slide 23: Acknowledgements
Acknowledgements We Thank the Participants and their Families Phase I/II Investigators REGENXBIO Erika Bergerud Vanessa Jimenez Shravani Billa Tim Kelly Aravindhan Veerapandiyan, M.D., Arkansas Children’s Hospital Wesley Bond Ye Liu Nancy Kuntz, M.D., Anne and Robert H. Lurie Children’s Hospital Nid