Regenxbio Inc. · NASDAQ:RGNX

Regenxbio — SSIEM 2023

14 slides from Regenxbio's conference presentation, Aug 30, 2023

  1. Slide 1: RGX-111, An Investigational Gene Therapy for Severe MPS I

    RGX-111, An Investigational Gene Therapy for the Treatment of Severe Mucopolysaccharidosis Type I (MPS I) Interim Analysis of the First in Human Study and a Single IND Patient Raymond Y. Wang, MD Division of Metabolic Disorders, CHOC Children’s Hospital / Department of Pediatrics, University of Cali

  2. Slide 2: MPS I is a Systemic Disease Representing a Wide Spectrum of Severity

    MPS I is a Systemic Disease Representing a Wide Spectrum of Severity Severity of Disease Manifestations Correlates with Degree of alpha-l-iduronidase (IDUA) Deficiency Hurler (60%) Hurler-Scheie (23%) Scheie (13%) Symptom Onset 0.5 y 3.0 y 7.8 y Age of diagnosis 0.8 y 3.9 y 9.3 y 35% IQ < 85 Cogniti

  3. Slide 3: RGX-111: MPS I Phase I/II Clinical Study Summary

    RGX-111: MPS I Phase I/II Clinical Study Summary NCT03580083 on ClinicalTrials.gov Participants Cohorts (dose levels) Data Enrollment of 8 MPS I Genome copies/g brain mass participants with CNS Primary Endpoint is Safety involvement or severe MPS I RGX-111 Secondary & Exploratory (≥ 4 months of age)

  4. Slide 4: RGX-111 Phase I/II Trial and Single Patient Investigator-Initiated IND

    RGX-111 Phase I/II Trial and Single Patient Investigator-Initiated IND  As of January 17, 2023, 8 participants were dosed in the Phase I/II trial and 1 in the single patient IND protocol  Age at dosing from 4 months to 13 years in Phase I/II trial and 20 months in single patient IND  IDUA Mutatio

  5. Slide 5: RGX-111 Interim Safety Summary

    RGX-111 Interim Safety Summary Phase I/II Trial and Single Patient Investigator-Initiated IND No SAEs are considered related to RGX-111 or the administration procedure  9 serious adverse events (SAE) reported in 4 participants SAE  SAEs reported: Bronchiolitis, bronchopneumonia, sinusitis, 2 centr

  6. Slide 6: Cerebrospinal Fluid (CSF) GAGs Heparan Sulfate

    Cerebrospinal Fluid (CSF) GAGs Heparan Sulfate (HS) Individual Participants Concentration (ng/mL) Cohort 1 – Phase 1/2 Time on Study Cohort 2 – Phase 1/2 (Weeks) Single Patient IND  Decreased CSF heparan sulfate in majority of participants through last time point available  Measurable CSF IDUA enz

  7. Slide 7: Neurodevelopmental Assessments

    Neurodevelopmental Assessments Age and developmentally appropriate validated instruments for neurodevelopmental testing were used to evaluate all participants n=6* Bayley Scale of Infant and Toddler Wechsler Abbreviated Scale of Development, Third Edition (BSID-III) Intelligence (WASI-II) for chrono

  8. Slide 8: Neurodevelopmental Function

    Neurodevelopmental Function BSID-III Cohort 1 – Phase I/II Cohort 2 – Phase I/II Cognition Expressive Language Fine Motor Single Patient IND Age Equivalence (months) +/- 1S D +/- 2S D Age (months)  All participants show continued developmental skill acquisition on all subtests  At last assessment,

  9. Slide 9: Neurodevelopmental Assessments and Function

    Neurodevelopmental Assessments and Function BSID* Cognitive Subtest Age Equivalence (months) BSID cognitive function in 2 participants** demonstrates higher AEq than available natural history data Cohort 1 – Phase I/II; n = 1 Cohort 2 – Phase I/II; n = 3 Age Single Patient IND; n = 1 ** 1 participan

  10. Slide 10: Neurodevelopmental Assessments and Adaptive Function for 13 Year Old Phase I/II Participant

    Neurodevelopmental Assessments and Adaptive Function for 13 Year Old Phase I/II Participant WASI-II and VABS-III VABS-III Age Equivalent Scores (year : month) BL Week of Assessment Week 52 Week 78 WASI- II Composite Scores Age 13y 14y 2m 14y 8m 2m Week of BL Week 52 Week 78 Assessment 13y 2m 14y 2m

  11. Slide 11: Systemic Effects: Plasma I0S6

    Systemic Effects: Plasma I0S6 I0S6 is a non-reducing end (NRE) disaccharide of glycosaminoglycans shown to be elevated in plasma, urine and CSF of MPS I patients1,2,3,4,5 Plasma I0S6 concentration (ng/ml) Cohort 1 – Phase I/II Cohort 2 – Phase I/II Single Patient IND Time on Study Not on ERT / ERT n

  12. Slide 12: Systemic Effects: Urine Total GAGs

    Systemic Effects Urine Total GAGs Total GAGs, urine (g/mol CK) ERT naïve at dosing Post ERT Withdrawal ERT Single Patient IND Time on Study Majority of patients maintained low levels of total urine GAGs Phase I/II Trial data cut: January 17, 2023 Single Patient IND data cut: December 12, 2021 12

  13. Slide 13: Summary of Interim Results

    RGX-111 Phase I/II Trial and Single Patient IND Summary of Interim Results Safety: RGX-111 was well tolerated  8 participants were dosed in the Phase I/II trial and 1 in the single patient IND protocol  RGX-111 has been well tolerated with no SAEs related to study drug or administration procedure

  14. Slide 14: Acknowledgements

    Acknowledgements The RGX-111-002 Investigators REGENXBIO  Nidal Boulos  Caroline Mulatya  Can Ficicioglu, Children’s Hospital of Philadelphia  Jenna Burke  Laura Pisani  Roberto Giugliani, HCPA, Porto Alegre, Brazil  Yoonjin Cho  Dawn Phillips  Yair Anikster, Sheba Medical Center, Israel 

REGENXBIO — SSIEM 2023 on 6ix