Regenxbio Inc. · NASDAQ:RGNX

Regenxbio — World Muscle Society Annual Congress 2025

7 slides from Regenxbio's conference presentation, October 2025

  1. Slide 1: RGX-202, an Investigational Gene Therapy for the Treatment of Duchenne Muscular Dystrophy: Interim Clinical Data

    RGX-202, an Investigational Gene Therapy for the Treatment of Duchenne Muscular Dystrophy: Interim Clinical Data Stephen Pakola, M.D. Chief Medical Officer REGENXBIO

  2. Slide 2: Disclosure

    Disclosure • I have the following conflict/s of interest to declare: • Employee of REGENXBIO and owns stock/other equity

  3. Slide 3: AFFINITY DUCHENNE Phase I/II Trial Design

    AFFINITY DUCHENNE® Phase I/II Trial Design Dose escalation and expansion Key Eligibility Criteria 1 to <4yo ✓ Boys aged 1 to <12yo at screening • 10-meter walk without assistance ✓ Genetically confirmed DMD (mutations in exons • Stable dose on or off corticosteroids x 12 weeks 18 and above) • Weight

  4. Slide 4: Phase I/II Interim Safety

    Phase I/II Interim Safety RGX-202 Treatment-Emergent Dose Level 1 Dose Level 2 (Pivotal Dose) Total Adverse Events (1x1014 GC/kg) (2x1014 GC/kg) n = 13 4-11 1-3 4-11 Age Range Dose All Age Dose Evaluation Younger Boys (number dosed) (n = 3) (n = 3) Evaluation/Expansion Ranges (n = 7) SAE 0 0 0 0 Cen

  5. Slide 5: Biomarkers Support Consistent Robust Expression, Transduction, and Sarcolemmal Localization of RGX-202 Microdystrophin

    Phase I/II Interim Biomarkers Support Consistent Robust Expression, Transduction, and Sarcolemmal Localization of RGX-202 Microdystrophin RGX-202 Mean at 12 Weeks Dose Level 1 Dose Level 2 (Pivotal Dose) Microdystrophin (min, max) 1x1014 GC/kg 2x1014 GC/kg DL 2, 12 weeks Age range at 4-7 8-11 1-3 4-

  6. Slide 6: Pivotal Dose Participants Demonstrate Improvement in Function and Exceed External Controls at 12 Months

    Phase I/II, Interim Data Pivotal Dose Participants Demonstrate Improvement in Function and Exceed External Controls at 12 Months NSAA Timed Function Tests TTStand 10MWR TTClimb -2.0 8 ∆ -1.6 ∆ -1.1 ∆ -1.2 N=4 -1.5 6 Mean Change in Time (Seconds) N=4 N=4 -1.0 N=4 Mean Change in NSAA 4 -0.5 0.0 2 ∆*=6

  7. Slide 7: Pivotal Dose Participants Exceed Expected NSAA Trajectory Across Multiple Methods

    Phase I/II, Interim Data Pivotal Dose Participants Exceed Expected NSAA Trajectory Across Multiple Methods NSAA Performance Baseline to Month 12 35 A 30 B 25 Baseline NSAA score C D 20 RGX-202 Change from Baseline NSAA 15 cTAP Model Predicted Change Natural History External 10 5 0 4 6 8 10 12 14 16

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