Regenxbio Inc. · NASDAQ:RGNX

Regenxbio — SSIEM 2023

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

  1. Slide 1: RGX-121, An Investigational Gene Therapy for Severe MPS II

    RGX-121, An Investigational Gene Therapy for the Treatment of Severe Mucopolysaccharidosis Type II (MPS II) CAMPSIITE™ Phase I/II/III: A Clinical Study Update Paul Harmatz, MD Professor, Pediatrics UCSF Benioff Children’s Hospital, Oakland, CA SSIEM, Jerusalem Israel, August 30, 2023 1

  2. Slide 2: AAV Gene Therapy Has the Potential to Address Unmet Need in MPS II

    AAV Gene Therapy Has the Potential to Address Unmet Need in MPS II High Unmet Need in MPS II Potential of RGX-121 for MPS II Incidence of MPS II Prevalence AAV9 Vector + IDS Attenuated MPS II Severe Transgene 1 in 100,000 MPS II to ~25% ~75% 1 in 170,000 RGX-121, an  One-time administration investi

  3. Slide 3: RGX-121: CAMPSIITE Part 1, Phase I/II

    RGX-121: CAMPSIITE Part 1, Phase I/II NCT03566043 on ClinicalTrials.gov Participants Cohorts (dose levels) Data Genome copies/g brain mass Enrollment up to 16 Primary Endpoint: Safety severe MPS II partcipants RGX-121 (≥ 4 months to ˂ 5 years of age) AAV9 + IDS Secondary & Exploratory May be on Stan

  4. Slide 4: RGX-121 Phase I/II Cohorts

    RGX-121 Phase I/II Cohorts  15 participants dosed as of January 3, 2023  Age at dosing ranged from 5 months to 59 months  IDS Mutations among severe MPS II trial participants included deletion, frameshift, gene inversion, insertion, missense, splicing, and substitution  Study duration 104 weeks.

  5. Slide 5: CAMPSIITE Interim Safety Summary

    CAMPSIITE Interim Safety Summary No SAEs are considered related to RGX-121 or the administration procedure  12 serious adverse events (SAE; 8 in main study, 4 in LTFU) reported in 7 participants: SAEs reported in main study: HSV gingivostomatitis*, fever requiring SAE hospitalization, infection of

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

    Cerebrospinal Fluid (CSF) GAGs: Heparan Sulfate (HS) Cohort 1 n = 3 Cohort 2 n = 7 Cohorts (median†) Individual Participants Cohort 3 n = 4 % Reduction 1600 Week Week Week Cohort 8 24 48 -20.6% -33.5% 1400 - 29.5 n=2 n=3 1 1200 % CSF HS (ng/mL) n=3 -42.3% -36.4% -48.9% 1000 2 n=6 n=7 n=6 -58.7% -74.

  7. Slide 7: CSF GAGs: Durable Reductions in Heparan Sulfate in Cohort 3 up to 48 weeks

    Cerebrospinal Fluid (CSF) GAGs: Durable Reductions in Heparan Sulfate (HS) in Cohort 3 up to 48 weeks Cohort 1 n = 3 Cohort 2 n = 7 Cohorts (median†) Individual Participants Cohort 3 n = 4 % Reduction 1600 Week Week Week Cohort 8 24 48 -20.6% -33.5% 1400 - 29.5 n=2 n=3 1 1200 % CSF HS (ng/mL) n=3 -4

  8. Slide 8: HS D2S6 reduced over 80% in Cohort 3

    CSF GAGs: HS D2S6, a Trisulfated Disaccharide, reduced over 80% in Cohort 3 D2S6 is a Correlate of Neuropathology Phenotype in Severe MPS II1-3 Cohort 1 n = 3 Cohort 2 n = 7 Cohort 3 n = 4 CSF D2S6 (ng/mL) Maximum attenuated Time on Study (Weeks) • Week 48 CSF HS D2S6 measurements continued to show

  9. Slide 9: Neurodevelopment Assessments

    Neurodevelopment Assessments Bayley Scales of Infant and Toddler Development, 3rd Edition (BSID-III)  Participants were assessed using the BSID-III  Age Equivalent (AEq) data is presented for the BSID-III Cognitive, Expressive Language and Fine Motor subtests  BSID-III manual normative data were

  10. Slide 10: Neurodevelopmental Function: Baseline Cognitive Function > -2SD

    Neurodevelopmental Function Baseline BSID-III Cognitive Function > -2SD Cohort 1 Cohort 2 Cohort 3 Cognition Expressive Language Fine Motor +/- 1S D Age Equivalence (months) +/- 1S D +/- 1S D +/- 2S D +/- 2S D +/- 2S D Age (months) The majority of participants with baseline function >-2SD have devel

  11. Slide 11: Neurodevelopmental Function: Baseline Cognitive Function Below -2 SD

    Neurodevelopmental Function Baseline BSID-III Cognitive Function Below -2 SD Cognition Expressive Language Fine Motor Cohort 2 Cohort 3 Age Equivalence (months) Age (months) The majority of participants with baseline function below -2SD stabilized or had an increase of > 3 mo in AEq on cognitive, ex

  12. Slide 12: Vineland Adaptive Behavior Scales Second Edition (VABS-II)

    Vineland Adaptive Behavior Scales Second Edition (VABS-II) VABS measures adaptive behavior, defined as the personal and social skills for everyday living* Communication Daily Living Socialization The majority of participants demonstrated stabilization or ongoing skill acquisition on age-appropriate

  13. Slide 13: VABS-II Maladaptive Behavior Index

    VABS-II Maladaptive Behavior Index  Maladaptive behaviors, a measure of undesirable behaviors that interfere with daily functions, are associated with neurodegeneration Cohort 1  Participants are classified according to level of maladaptive behavior at baseline and compared to average performance

  14. Slide 14: RGX-121 CAMPSIITE Part 1 Summary of Interim Results

    RGX-121 CAMPSIITE Part 1, Phase I/II Summary of Interim Results Safety: RGX-121 was well tolerated  As of January 3, 2023, 15 participants have been dosed with RGX-121  RGX-121 has been well tolerated across 3 cohorts with no SAE related to study drug or administration procedure CNS: CSF GAGs and

  15. Slide 15: Acknowledgements

    Acknowledgements The RGX-121-101 Investigators REGENXBIO  Can Ficicioglu, Children’s Hospital of Philadelphia  Nidal Boulos  Caroline Mulatya  Roberto Giugliani, Hospital de Clinicas, Porto  Yoonjin Cho  Laura Pisani Alegre, Brazil  Paulo Falabella  Dawn Phillips  Paul Harmatz, UCSF Benioff

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