Slide 1: Measuring Protein Expression in Cardiac Gene Therapy
Measuring Protein Expression in Cardiac Gene Therapy August 26, 2025
Slide 2: Today’s speakers
Today’s speakers Faraz Ali, MBA Kathy Ivey, Ph.D., Chief Executive Officer Senior Vice President, Research Guest Speaker: Michael Previs, Ph.D. Whit Tingley, M.D., PhD Associate Professor of Chief Medical Officer Cellular, Molecular, and Biomedical Sciences at the University of Vermont 2
Slide 3: Forward-looking statement
Forward-looking statement This presentation contains forward-looking statements within the meaning of Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended, that are based on our management’s beliefs and assumptions and on information currently availabl
Slide 4: Our purpose: transform and extend lives through potentially curative therapies
Our purpose: To transform and extend lives through the discovery, development and delivery of potentially curative therapies that target the underlying causes of heart disease. 4
Slide 5: Singular focus on the heart
Singular focus on the heart 3 clinical-stage programs Multiple near-term gene therapy data readouts Deep expertise in cardiology, genetics and rare disease drug development Foundational capabilities fuel innovation and first-in-class potential Track record of execution 5
Slide 6: Gene therapy pipeline coming into focus
Gene therapy pipeline coming into focus U.S. Development Program Modality Status Prevalence Stage Clinical-Stage Programs Cohort 1 enrolled MyPEAK -1 Phase 1b/2 TN-201 for MYBPC3+ HCM Cohort 2 enrolled • FDA Orphan Drug, Fast Track and Rare Pediatric Disease designations AAV9 gene > 120K(1) Complete
Slide 7: Agenda and speakers
Agenda and speakers • Introductory remarks Faraz Ali • Tenaya Gene Therapy Program Update Dr. Whit Tingley Today’s agenda • Measuring Protein Expression in Cardiac Gene Therapy Dr. Kathy Ivey in conversation with Dr. Michael Previs • Q&A Dr. Michael Previs, Ph.D. Associate Professor, Molecular Physi
Slide 8: Tenaya’s Cardiomyopathy Gene Therapy Programs – An Update
Tenaya’s Cardiomyopathy Gene Therapy Programs – An Update Whit Tingley
Slide 9: 1H’25 Scorecard: Important progress advancing our two lead gene therapy programs
1H’25 Scorecard: Important progress advancing our two lead gene therapy programs TN-201 for TN-401 for MYBPC3-associated HCM PKP2-associated ARVC MyPEAK-1 additional Cohort 1 data at ACC RIDGE Natural History study data presented at HRS MYBPC3+ HCM disease burden presented at ACC RIDGE-1 Coh
Slide 10: MYBPC3-associated HCM is estimated to affect 120,000 people in the U.S.
MYBPC3-associated HCM is estimated to affect 120,000 people in the U.S. alone(1) A severe and progressive autosomal dominant condition affecting adults, teens, children and infants HCM HEART ~57% of identified genetic variants underlying familial HCM are MYBPC3 mutations(2) Thickened left ventricle
Slide 11: TN-201 is the first gene therapy being developed for MYBPC3-associated HCM
TN-201 is the first gene therapy being developed for MYBPC3-associated HCM(1) MYBPC3+ Pathophysiology TN-201 Mechanism of Action • MyBP-C is an essential structural protein • TN-201 targets the • Addition of a MYBPC3 gene increases regulating cardiac contractility via underlying genetic cause of MyB
Slide 12: Q4’2025 TN-201 MyPEAK-1 readout: What to expect
Q4’2025 TN-201 MyPEAK-1 readout: What to expect Cohort 2 Cohort 1 Initial readout focused on safety and biopsy Longer-term (>=1 year) follow-up for 3 patients at results for the 3 patients at the 6E13 vg/kg dose the 3E13 vg/kg dose Looking for tolerability at the higher dose and Aiming for continuat
Slide 13: PKP2-associated ARVC is estimated to affect >70,000 people in the U.S.
PKP2-associated ARVC is estimated to affect >70,000 people in the U.S.(1) A severe and progressive genetic heart disease lacking therapeutic treatment options • Early symptoms include palpitations, lightheadedness, >15% of heart-related deaths in fainting (1) patients < 35 are due to ARVC(2) • Signi
Slide 14: TN-401 gene therapy for PKP2-associated ARVC
TN-401 gene therapy for PKP2-associated ARVC PKP2+ Pathophysiology TN-401 Mechanism of Action Desmosome and Gap Junctions in Treated with TN-401 PKP2-associated HCM Heart Missing PKP2 protein PKP2 Desmosome structural integrity Less PKP2 protein restored results in abnormal heart function • Mutation
Slide 15: Q4’2025 TN-401 Data Readout: What to Expect
Q4’2025 TN-401 Data Readout: What to Expect Cohort 1 Data release will include initial Cohort 1 (3E13 vg/kg) data focused on safety and biopsy results Readout will focus on tolerability and the presence of TN-401 DNA, TN-401 RNA and PKP2 protein level changes from baseline 15
Slide 16: Measuring Protein Expression in Cardiac Gene Therapy
Measuring Protein Expression in Cardiac Gene Therapy Dr. Kathy Ivey in conversation with Dr. Michael Previs
Slide 17: Biopsy measurements – What are we looking for?
Biopsy measurements – What are we looking for? Gene Therapy Mechanism of Action Gene Therapy 1 2 3 DELIVERY: EXPRESSION: EXPRESSION: upon Infusion Transduction (DNA) Transcription (RNA) Translation (Protein) Gene therapy enters The healthy gene is mRNA is then converted to the cardiomyocytes. The he
Slide 18: Cardiac biopsies are collected to quantify leading indicators of efficacy
Cardiac biopsies are collected to quantify these leading indicators of TN-201 or TN-401 efficacy Measurement assays Anticipated result over time TN-201 or TN-401 DNA is measured by • Total VCN initially decreases as TN-201 ddPCR or TN-401DNA is cleared from non-CM Quantifies the number of TN-201 vec
Slide 19: Why do methods matter?
Why do methods matter? Protein produced from gene therapy and protein produced by the patient’s one working gene are indistinguishable Post-dose biopsy mRNA Post-dose biopsy protein Slightly different RNAs Endogenous RNA Identical proteins Gene Therapy RNA Therefore, we needed a solution that was hi
Slide 20: Measuring Protein Expression in Cardiac Gene Therapy
Measuring Protein Expression in Cardiac Gene Therapy Dr. Kathy Ivey in conversation with Dr. Michael Previs
Slide 21: Role and function of MyBP-C protein in the sarcomere
Role and function of MyBP-C protein in the sarcomere MyBP-C modulates the force and speed of each contraction Actin MyBP-C Myosin protein head Myosin 21
Slide 22: MYBPC3-associated HCM is a disease of haploinsufficiency
MYBPC3-associated HCM is a disease of haploinsufficiency Range of MyBP-C protein levels in Relative abundance of MyBP-C in the individual HCM samples MYBPC3-associated HCM samples and when compared to the donor control group (1) normal controls(1) 0.11 0.1065 Blue dashed line indicates the group mea
Slide 23: Measuring Protein Expression in Cardiac Gene Therapy
Measuring Protein Expression in Cardiac Gene Therapy Dr. Kathy Ivey in conversation with Dr. Michael Previs
Slide 24: Variability in tissue sample quality happens
Variability in tissue sample quality happens Heart tissue in cardiomyopathy patients is heterogenous resulting in variability in biopsy quality and in the number of cardiomyocytes per sample. Mass spectrometry overcomes this challenge. Normal heart tissue ARVC donor heart tissue with fibrofatty repl
Slide 25: Measuring Protein Expression in Cardiac Gene Therapy
Measuring Protein Expression in Cardiac Gene Therapy Dr. Kathy Ivey in conversation with Dr. Michael Previs
Slide 26: Normalizing MyBP-C to myosin mitigates variability in measurements
Normalizing MyBP-C to myosin mitigates variability in measurements of MyBP-C expression MyBP-C levels are tightly regulated within cardiomyocytes present in biological replicates from donor control heart and MYBPC3-associated HCM samples(1) MyBP-C / MYH6-MYH7 1. O’Leary, et al; J Mol Cell Cardiol 20
Slide 27: Normalizing MyBP-C to other housekeeping proteins results in apparent variability
Normalizing MyBP-C to other “housekeeping” proteins results in apparent variability in MyBP-C expression When MyBP-C is normalized to GAPDH rather than myosin, MyBP-C expression seems highly variable. Myosin normalized GAPDH normalized / MYH6-MYH7 0.12 1.2 MyBP-C Common 0.10 1.0 MyBPC/GAPDH MyBPC/ M
Slide 28: Measuring Protein Expression in Cardiac Gene Therapy
Measuring Protein Expression in Cardiac Gene Therapy Dr. Kathy Ivey in conversation with Dr. Michael Previs
Slide 29: Variability for PKP2 within donors is lower than across donors
Variability for PKP2 within donors is lower than across donors Variability in PKP2 levels measured from independent pieces of the same donor control hearts is low and reproducible but the levels vary from donor control to donor control 0.013 0.013 0.0123 0.012 MYH6-MYH7 0.012 PKP2/ / MYH6-MYH7 0.011
Slide 30: Q&A Closing remarks
Q&A Closing remarks TENAYA THERAPEUTICS