Duan 2018 — Systemic AAV Micro-dystrophin Gene Therapy for Duchenne Muscular Dystrophy

Citation: Duan D. (2018). “Systemic AAV Micro-dystrophin Gene Therapy for Duchenne Muscular Dystrophy.” Molecular Therapy, 26(10), 2337–2356.
DOI: 10.1016/j.ymthe.2018.07.011
PMC: PMC6171037
File: ~/BookLibrary/incoming/Duan_2018_Systemic-AAV-micro-dystrophin-DMD_MolTher.pdf

Why This Matters for STRC

Dystrophin (~11 kb) faces the same problem as STRC (~6.9 kb) — both exceed single AAV capacity (~4.7 kb). DMD gene therapy has moved furthest in clinical translation. Duan’s micro-dystrophin work is the template for how to handle oversized genes via AAV.

Key Findings

  • Micro-dystrophin approach: engineered miniaturized gene retaining critical functional domains
  • Fits in single AAV (unlike dual-vector)
  • Demonstrates systemic IV delivery is feasible for muscle
  • Key domains retained: actin-binding (N-terminal), spectrin-like repeats 1,2,3,24, CR domain, CT domain
  • Proof-of-concept for structural miniaturization as alternative to dual-vector splitting

Relevance to STRC

Two strategies for STRC oversized payload:

  1. Dual-vector split (Iranfar 2026 approach) — recombination in cochlea
  2. Mini-STRC — truncated but functional STRC, fits in single AAV

STRC functional domains: WD40 repeats (C-terminal, for TM attachment), N-terminal coiled-coil (for H-H links between stereocilia). A mini-STRC retaining these could work.

Clinical Translation Path

  • Duan’s micro-dystrophin → Mendell 2020 Phase 1/2 trial → FDA accelerated approval pathway
  • STRC likely follows same path: mouse model → NHP → IND → Phase 1/2
  • Timeline estimate: 5-8 years from strong mouse data to Phase 1

Connections