Slide 1: First clinical evidence for myocyte stem (satellite) cell targeting in DMD
First clinical evidence for myocyte stem (satellite) cell targeting in DMD: Results from Part A of a Phase 1b/2 study of WVE-N531 Kuldeep Singh, BVSc, MS, PhD, Diplomate ACVP Head of Pathology, Wave Life Science, Lexington, MA-02421, USA May 19, 2024 Presented at MENA 2024
Slide 2: Disclosures
Disclosures Kuldeep Singh, Laurent Servais, Craig Campbell, Michael Tillinger, Xiao Shelley Hu, Andrew Hart, Joseph A. Haegele, Jeanette Rheinhardt, Anamitra Ghosh, Fangjun Liu, Chandra Vargeese, Anne-Marie Li-Kwai-Cheung, Padma Narayanan • Kuldeep Singh is a full-time employee of Wave Life Sciences
Slide 3: Overview
Overview Phase 1b/2 Part A study design and results WVE-N531 uptake in myogenic stem (satellite) cells • Relevance of myogenic stem cell physiology and pathology in DMD • Selection and protocol optimization of stem cell marker Paired Box Protein 7 (PAX-7) IHC and ISH • Results and comments Conclusio
Slide 4: WVE-N531: An investigational PN-containing ASO for DMD amenable to exon 53 skipping
WVE-N531: An investigational phosphoryl guanidine (PN)-containing ASO being developed for patients with DMD amenable to exon 53 skipping Phase 1b/2 (Part A): First-in-human study results • High exon skipping and Tissue % Exon Dystrophin Tissue muscle concentrations after Patient Source concentration
Slide 5: Why assess stem cell uptake?
Why assess stem cell uptake? • Stem cells play a major role in muscle regeneration • Lack of dystrophin in stem cells results in stem cell dysfunction and impaired regeneration Normal Muscle Dystrophic Muscle • Stem cells use dystrophin, Mark2, and Pard3 to maintain polarity that is needed to underg
Slide 6: Experimental design: Myocyte stem cell uptake of WVE-N531
Experimental design: Myocyte stem cell uptake of WVE-N531 • The objective was to assess WVE-N531 uptake by skeletal muscle stem cells using biopsies from the 3 patients enrolled in Part A of the Phase 1b/2 study • Rationale: Skeletal muscles of DMD patients show impaired differentiation and regenera
Slide 7: Protocol optimization for PAX7 IHC: muscle from mdx mouse and healthy human
Protocol optimization for PAX7 IHC: muscle from mdx mouse and healthy human Anti PAX7 Antibody - NBP232894 Sections stained with PAX7 antibody Sections stained with IgG antibody (control) WVE-N531 WVE-N531 Treated Mouse Treated Mouse Healthy human Healthy human (WVE-N531 (WVE-N531 untreated) untreat
Slide 8: Results: Observation of stem cells in patient samples
Results: Observation of stem cells in patient samples Patient No. 1 Deltoid Muscle Location of Stem Cells in Myofibers PAX7 Positive Stem Cells (Arrows) 8 Background cytoplasmic signal in endothelial and smooth muscle cells.
Slide 9: Results: Observation of stem cells in patient samples
Results: Observation of stem cells in patient samples Patient 1 Patient 3 * ** Note degenerating myofibers (asterisks) and PAX7 positive nuclei (arrowheads) surrounding these myofibers PAX7 and RNAScope dualplex without probe 9 Controls: IgG for Pax7 – Negative, RNAScope Ubiquitin – Positive, & RNAS
Slide 10: WVE-N531 demonstrated clear uptake in myogenic stem cells
WVE-N531 demonstrated clear uptake in myogenic stem cells Patient 1 Patient 2 Patient 3 Red signal: WVE-N531 Brown signal: PAX7 Positive stem cells PAX7 and RNAScope dualplex 10 Controls: IgG for Pax7 – Negative, RNAScope Ubiquitin – Positive, & RNAScope DapB – Negative; Serial sections are not avai
Slide 11: Conclusions & next steps
Conclusions & next steps • WVE-N531 demonstrated clear uptake in myocyte stem cells in all three patients as evaluated by dual PAX7 (stem cell marker) immuno-histochemistry and WVE-N531 RNAscope chromogenic assay. • Stem cells were mostly associated with myofibers undergoing repair. • Confirmation i
Slide 12: Acknowledgements
Acknowledgements Silencing Silencing Thanks to all colleagues and contributors from Wave Life Sciences and our collaborators Study participants & families DMD Investigators • Laurent Servais Splicing RNA Editing • Craig Campbell • Muath AlQurashi • Mai Bader 12