FDMT Leerink Global… Presentation

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 2 Legal Disclaimer This Presentation contains forward looking statements that involve substantial risks and uncertainties. All statements, otherthan statements of historical facts, contained in this Presentation, including statements regarding our clinical development plans, strategy, future operations, future financial position, prospects, plans, objectives of management, and implied and express statements regarding the therapeutic potential, clinical benefits of and market potential of our product candidates are forward looking statements. The words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “target,” “should,” “would,” and similar expressions are intended to identify forward looking statements, although not all forward looking statements contain these identifying words. We may not actually achieve the plans, intentions, or expectations disclosed in these forward looking statements, and you should not place undue reliance on these forward looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in these forward looking statements. In addition, the forward looking statementsincluded in this Presentation represent our views as of the date of this Presentation. We anticipate that subsequent events and developments will cause our views to change. However,while we may elect to update these forward looking statements in the future, we specifically disclaim any obligation to do so. These forward looking statements should not be relied upon as representing our views as of any date subsequent to the date of this Presentation. This Presentation discusses our product candidates that are under preclinical study and in clinical trials, and which have not yet been approved for marketing by the U.S. Food and Drug Administration. No representation is made as to the safety or effectiveness of our product candidates for the therapeutic use for which they are being studied. This Presentation also contains estimates and other statistical data made by independent parties and by us relating to market size and other data about our industry. This data involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such data and estimates. In addition, projections, assumptions and estimates of our future performance and the future performance of the markets in which we operate are necessarily subject to a high degree of uncertainty and risk. This Presentation shall not constitute an offer to sell or the solicitation of an offer to buy securities.

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 4 4D-150: Phase 3 Therapeutic Designed to Disrupt the Global Market for Retinal Vascular Diseases & Improve Patient Outcomes 4D-150 Ease of Clinical & Commercial Adoption Backbone therapy with multi-year durability: Foundational therapy with paradigm-shifting treatment burden reduction & vision preservation Addresses Primary Clinical Unmet Need Predictable long-term safety: Clinically significant IOI rate in-line with blockbuster aflibercept; aflibercept protein safe in over 60M eyes treated Favorable Safety Profile $17B+ and growing global market Leveraging expression of validated blockbuster aflibercept Multi-Billion Dollar Annual Opportunity Readouts from both Phase 3 studies in 4FRONT global registration program expected in H2 2027 T opline Data from wet AMD Pivotal Trials in 2027 Single IVT injection: Seamless integration into retina clinic practice flow and buy & bill reimbursement model

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 5 4D-150: Phase 3 Therapeutic Designed to Disrupt the Global Market for Retinal Vascular Diseases & Improve Patient Outcomes 4D-150 Ease of Clinical & Commercial Adoption Backbone therapy with multi-year durability: Foundational therapy with paradigm-shifting treatment burden reduction & vision preservation Addresses Primary Clinical Unmet Need Predictable long-term safety: Clinically significant IOI rate in-line with blockbuster aflibercept; aflibercept protein safe in over 60M eyes treated Favorable Safety Profile $17B+ and growing global market Leveraging expression of validated blockbuster aflibercept Multi-Billion Dollar Annual Opportunity Readouts from both Phase 3 studies in 4FRONT global registration program expected in H2 2027 T opline Data from wet AMD Pivotal Trials in 2027 Single IVT injection: Seamless integration into retina clinic practice flow and buy & bill reimbursement model

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 6 T otal Branded Anti-VEGF Market Continues to Grow with Share Driven by Incremental Durability Improvements: Aflibercept Remains Market Leader Source: EvaluatePharma Historical and Consensus Estimates as of 3/7/2025. Note: Product sales reflect sales across manufacturers; Eylea sales include both Eylea and Eylea HD formulations $1.3B $11.4B $4.4B $0.4M $1.2M $1.8M $2.4M $3.0M $3.9M $5.0M $6.5M $7.7M $8.5M $9.5M $10.5M $11.9M $13.0M $13.0M $15.0M $15.3M $15.9M $17.1M 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 Vabysmo Eylea Lucentis

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 7 Incremental Durability Improvements Have Resulted in Accelerating Launch Performance 1. Lucentis package insert; 2. Real-World Evidence (TRUCKEE Study) Durability: ~30 Days1 Durability: ~44 Days2 Durability: ~57 Days2 (After 6 injections) $0.9B $2.1B $3.3B 2012A 2013A 2014A $0.4B $1.2B $1.8B 2006A 2007A 2008A $0.6B $2.6B $4.4B 2022A 2023A 2024A

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 8 4D-150: Phase 3 Therapeutic Designed to Disrupt the Global Market for Retinal Vascular Diseases & Improve Patient Outcomes 4D-150 Ease of Clinical & Commercial Adoption Backbone therapy with multi-year durability: Foundational therapy with paradigm-shifting treatment burden reduction & vision preservation Addresses Primary Clinical Unmet Need Predictable long-term safety: Clinically significant IOI rate in-line with blockbuster aflibercept; aflibercept protein safe in over 60M eyes treated Favorable Safety Profile $17B+ and growing global market Leveraging expression of validated blockbuster aflibercept Multi-Billion Dollar Annual Opportunity Readouts from both Phase 3 studies in 4FRONT global registration program expected in H2 2027 T opline Data from wet AMD Pivotal Trials in 2027 Single IVT injection: Seamless integration into retina clinic practice flow and buy & bill reimbursement model

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 9 Short Durability of Wet AMD Standard of Care Leads to Poor Vison Outcomes 1Guo et al. Ophthal Res 2023; 66:406-12. 2Evans et al. JAMA Ophtalmol 2020;138:1043-51. Current Standard of Care Central Retinal Thickness Durability Impact on Retinal Anatomy Vision Associated with greater vision loss1 & fibrosis2 Bolus loading doses, followed by… 4 weeks 4-8 weeks 8 weeks 8-12 weeks 8-12-16 weeks 8-16 weeks

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 10 Markedly Improving Outcomes with a Multi-year Backbone Therapy 1Guo et al. Ophthal Res 2023; 66:406-12. 2Evans et al. JAMA Ophtalmol 2020;138:1043-51. Current Standard of Care Solution: 4D-150 Backbone Therapy Central Retinal Thickness Goal Post 4D-150 Central Retinal Thickness Durability Impact on Retinal Anatomy Vision Multiple years Associated with greater vision loss1 & fibrosis2 4D-150 Low retinal variability to preserve vision Bolus loading doses, followed by… 4 weeks 4-8 weeks 8 weeks 8-12 weeks 8-12-16 weeks 8-16 weeks Bolus loading doses, followed by… Bolus supplement as needed

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 11 6.0 1.0 0.3 4D-150 Demonstrated Transformative Treatment Burden Reduction & Durability in Multiple Wet AMD Patient Populations 21% 2 injections 27% >2 injections Recently DiagnosedBroadPhase 1/2a Population: Severe, Recalcitrant Mean annual injections Post 4D-150 10.2 1.8 Projected Annual Labeled Q8W Regimen –83% –94%–83% Mean annual injections Post 4D-150 Injections in Prior 12 Months Phase 2b Populations:

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 12 4D-150: Phase 3 Therapeutic Designed to Disrupt the Global Market for Retinal Vascular Diseases & Improve Patient Outcomes 4D-150 Ease of Clinical & Commercial Adoption Backbone therapy with multi-year durability: Foundational therapy with paradigm-shifting treatment burden reduction & vision preservation Addresses Primary Clinical Unmet Need Predictable long-term safety: Clinically significant IOI rate in-line with blockbuster aflibercept; aflibercept protein safe in over 60M eyes treated Favorable Safety Profile $17B+ and growing global market Leveraging expression of validated blockbuster aflibercept Multi-Billion Dollar Annual Opportunity Readouts from both Phase 3 studies in 4FRONT global registration program expected in H2 2027 T opline Data from wet AMD Pivotal Trials in 2027 Single IVT injection: Seamless integration into retina clinic practice flow and buy & bill reimbursement model

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 13  No 4D-150–related serious adverse events  No 4D-150–related hypotony, endophthalmitis, occlusive/non-occlusive retinal vasculitis, or choroidal effusions  Treatment-related 1+ vitreous cells at a single timepoint observed in 2 of 71 (2.8%)  99% (70 of 71) completed prophylactic topical steroid taper on schedule  99% (70 of 71) remain completely off steroids Highest SUN/NEI Score† 4D-150 3E10 vg/eye (N=71)* 4D-150 Has Been Well T olerated in Broad Wet AMD Population: Safety In-Line With Aflibercept Protein to Date *Duration of follow up, ≤3 years. †4D-150–related. VC, Vitreous cell; NEI, National Eye Institute; SUN, Standardization of Uveitis Nomenclature. None 1+ 3+ 4+ 2+ 97.2% 2.8% Wet AMD

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 14 4D-150 Has Been Well T olerated in DME Patients: No Intraocular Inflammation at Any Timepoint at Any Dose Level Data cutoff date, December 13, 2024. *Excludes patient with early termination due to death. The subject had a prior history of hepatic cirrhosis and died prior to any study visits due to liver failure (assessed by PI as unrelated to 4D-150). NEI, National Eye Institute; SUN, Standardization of Uveitis Nomenclature; X, missed visit. One of the subjects missed three consecutive study visits due to recovery from foot surgery. Anterior Chamber Cells Vitreous Cells X X X X 0 2 8 12 16 20 24 28 32 X X X X 0 2 8 12 16 20 24 28 32Week X 0 (none) 1+ 3+ 4+ 2+ 5E9 vg/eye Topical Corticosteroid NEI/SUN Score 3E10 vg/eye (N=9) 1E10 vg/eye* (N=11) Missed Visit  All patients completed the 16- week topical steroid taper on schedule and remained completely off steroids  No hypotony, endophthalmitis, vasculitis, choroidal effusions or retinal artery occlusions DME

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 15 4D-150: Phase 3 Therapeutic Designed to Disrupt the Global Market for Retinal Vascular Diseases & Improve Patient Outcomes 4D-150 Ease of Clinical & Commercial Adoption Backbone therapy with multi-year durability: Foundational therapy with paradigm-shifting treatment burden reduction & vision preservation Addresses Primary Clinical Unmet Need Predictable long-term safety: Clinically significant IOI rate in-line with blockbuster aflibercept; aflibercept protein safe in over 60M eyes treated Favorable Safety Profile $17B+ and growing global market Leveraging expression of validated blockbuster aflibercept Multi-Billion Dollar Annual Opportunity Readouts from both Phase 3 studies in 4FRONT global registration program expected in H2 2027 T opline Data from wet AMD Pivotal Trials in 2027 Single IVT injection: Seamless integration into retina clinic practice flow and buy & bill reimbursement model

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 16 Clinics Payors Potential to Improve Economic Value for Payors and Clinics with 4D-150  IVT dosing with seamlessly adoption into current practice flow  Seamless integration into current distribution networks & clinic storage  Improved cash flow & clinic capacity, esp with Buy & Bill reimbursement model  Adherence by design, leading to long term preservation of vision  Reduction in treatment burden, leading to patient freedom and quality-of-life  Preservation of vision, leading to socio-economic benefit  Low expected COGS, leading to pricing flexibility

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 17 4D-150: Phase 3 Therapeutic Designed to Disrupt the Global Market for Retinal Vascular Diseases & Improve Patient Outcomes 4D-150 Ease of Clinical & Commercial Adoption Backbone therapy with multi-year durability: Foundational therapy with paradigm-shifting treatment burden reduction & vision preservation Addresses Primary Clinical Unmet Need Predictable long-term safety: Clinically significant IOI rate in-line with blockbuster aflibercept; aflibercept protein safe in over 60M eyes treated Favorable Safety Profile $17B+ and growing global market Leveraging expression of validated blockbuster aflibercept Multi-Billion Dollar Annual Opportunity Readouts from both Phase 3 studies in 4FRONT global registration program expected in H2 2027 T opline Data from wet AMD Pivotal Trials in 2027 Single IVT injection: Seamless integration into retina clinic practice flow and buy & bill reimbursement model

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 18 *Determined by SD-OCT and confirmed by an independent Reading Center. †PI discretion not allowed. Noninferiority Trials to Enable Global Registration in Wet AMD Global 4FRONT Phase 3 Trial Design Primary endpoint Durezol® taper (both arms) starting Day -3 Baseline Response Week -5 -1 D1 4 8 12 16 20 24 28 32 36 40 44 48 52 104 4D-150 3E10 vg/eye (n=200)                 Aflibercept 2 mg (n=200)                   4D-150  Aflibercept Sham injection Randomize Global, Multicenter, Randomized, Double Masked, Aflibercept Q8W Comparator Controlled Studies ≥15% reduction in CST or complete resolution of intraretinal and/or subretinal fluid*  Randomizing strong aflibercept responders to reduce variability

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 19 *Determined by SD-OCT and confirmed by an independent Reading Center. †PI discretion not allowed. Noninferiority Trials to Enable Global Registration in Wet AMD Global 4FRONT Phase 3 Trial Design Primary endpoint Durezol® taper (both arms) starting Day -3 Baseline Response Week -5 -1 D1 4 8 12 16 20 24 28 32 36 40 44 48 52 104 4D-150 3E10 vg/eye (n=200)                 Aflibercept 2 mg (n=200)                   4D-150  Aflibercept Sham injection Randomize Global, Multicenter, Randomized, Double Masked, Aflibercept Q8W Comparator Controlled Studies Reference Values: BCVA: Average of Week 4 & 8 CST: Week 8 Disease Activity (if any criteria are met)†: Vision & Anatomy: ≥5 letter loss in BCVA AND ≥50 µm increase in CST Vision: ≥10 letter loss in BCVA Anatomy: ≥100 µm increase in CST New vision-threatening hemorrhage Supplemental Aflibercept Criteria (Both arms)  Optimized for primary endpoint success & demonstrating clinically meaningful treatment burden reduction ≥15% reduction in CST or complete resolution of intraretinal and/or subretinal fluid*

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 20 Global North American 4D-150 Wet AMD Phase 3 Expected Milestones Q1 25 Q2 25 Q3 25 Q4 25 H1 26 H2 26 H1 27 H2 27 March 2025 First Patients Enrolled 2026 Fully Randomized H2 2027 Topline Data Q3 2025 Initiation 2026 Fully Randomized H2 2027 Topline Data

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 21 THERAPEUTIC AREA VECTOR ROUTE OF ADMIN PRODUCT CANDIDATE INDICATION ESTIMATED PREVALENCE PHASE 1 PHASE 2 PIVOTAL STATUS LARGE MARKET OPHTHALMOLOGY R100 Intravitreal 4D-150 Wet AMD ~3M U.S./EUMM  PRISM Ph2b 52-week interim data: Feb 10, 2025  4FRONT-1 Initiation: Mar 2025  4FRONT-2 Initiation: Q3 2025  PRISM Ph1/2a 2-year & Ph2b 1.5- year data: Q4 2025  4FRONT-1 & -2 topline data: H2 2027 DME ~5M U.S./EUMM Part 1:  32-week interim data  52-week interim data: Q3 2025 PULMONOLOGY A101 Aerosol 4D-710 CF lung disease (mod. ineligible/ intolerant) ~15K WW  Interim data: H2 2025 Pipeline Focused on Large Market Indications with High Unmet Need $505M cash as of December 31, 2024; Runway into 2028

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© 2025 4D Molecular Therapeutics. All Rights Reserved. © 2025 4D Molecular Therapeutics. All Rights Reserved. THANK YOU 5858 Horton Street, Suite 455 | Emeryville, California 94608 (510) 505-2680 | Investor.Relations@4DMT.com IR.4DMT.com | LinkedIn

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 23 4D-150 Wet AMD Summary Results & Phase 3 Plans 23% 2 injections 70% 0-1 Injections 57% Injection free13% 1 injection 7% >2 injections 13% 2 injections 87% 0-1 Injections 80% Injection free 7% 1 injection 21% 2 injections 52% 0-1 Injections 44% Injection free 8% 1 injection 27% >2 injections Recently DiagnosedBroadSevere, Recalcitrant Phase 1/2 Topline 1-year data for both studies expected in H2 2027 Phase 3 Treatment Naïve & Recently Diagnosed 3E10 vg/eye (Phase 3 Dose): Supplemental Injections Required Over 52 Weeks After 4D-150

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 24 *28-day taper. †Endobronchial biopsy (4D-710 transgene and protein expression), 2nd biopsy allowed beyond 12 months. ppFEV1, percent predicted forced expiratory volume in 1 second; SRT, Safety Review Team. Generate Safety, Biomarker & Clinical Activity Data to Inform Selection of Phase 2 & 3 Dose(s) Phase 1/2 Designed to Identify Doses for Late-Stage Development 1E15 vg (n=3) 2E15 vg (n=4) SRT Review Phase 1 (Dose Exploration) Phase 2 (Dose Expansion)  Phase 1: Dose ranging to characterize safety & biomarkers  Phase 2: Expand in selected dose to confirm clinical activity for Phase 3 Other doses (Pending) 5E14 vg (n=3) 2.5E14 vg (n=3-6) Scheduled study assessment Bronchoscopy†4D-710 40 mg oral prednisone D1 1 2 3 6 9 12 15 18 21 24 Month * Long-term follow up (Inc. Bronchoscopy†) Key Endpoints: Primary Objectives:  Safety & tolerability  Lung biomarkers  Clinical activity 1E15 vg (Cleared) Enrolling

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 25 Dose-dependent CFTR∆R RNA Expression Following 4D-710 Administration Best available data as of May 24, 2024. Quantification by Visiopharm® AI Machine Learning Analysis. Number shown below each group indicates the number of lung samples. *Attempts to genotype commercial CF samples yielded results for 13/35 samples; of these, a majority were ΔF508 homozygous mutations. CFTR, cystic fibrosis transmembrane conductance regulator; ISH, in situ hybridization. CFTR∆R RNA (ISH): mean % (+) airway epithelial cells  Dose-dependent CFTR∆R mRNA expression in bronchial epithelial cells  No CFTR∆R mRNA expression observed in commercial non-CF and CF lung samples  Commercial non-CF samples positive for endogenous CFTR mRNA expression 53 40 27 14 (0) (0) 0 20 40 60 80 Mean % (+) epithelial cells 2E15 vg (n=8) 1E15 vg (n=5) 5E14 vg (n=2) 2.5E14 vg (n=1) Non-CF (n=10) CF lung* (n=35) 4D-710 Controls

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 26 Widespread 4D-710–Mediated CFTR Protein Expression at All Doses and in All Participants Best available data as of May 24, 2024. Quantification by Visiopharm AI Machine Learning Analysis. Number shown below each group indicates the number of lung samples. *H-score. †Attempts to genotype commercial CF samples yielded results for 13/35 samples; of these, a majority were ΔF508 homozygous mutations. IHC, immunohistochemistry. CFTR (+) Epithelial Cells (IHC) CFTR Staining Intensity (IHC)* 99.3 98.3 100 94 44.2 18.4 0 20 40 60 80 100Mean % (+) epithelial cells 224.9 204.9 277 150 47 19 0 50 100 150 200 250 300 Mean intensity score* Non-CF (n=10) CF lung† (n=35) 4D-710 Controls 4D-710 Controls 2E15 vg (n=8) 1E15 vg (n=5) 5E14 vg (n=2) 2.5E14 vg (n=1) Non-CF (n=10) CF lung† (n=35) 2E15 vg (n=8) 1E15 vg (n=5) 5E14 vg (n=2) 2.5E14 vg (n=1)

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 27 Widespread & Consistent CFTR Protein Expression: 100% of Samples Best available data as of May 24, 2024. *Representative images, endobronchial biopsy samples obtained from the left secondary carina (row 1) and right middle lobe (row 2). †Endobronchial biopsy performed at Week 8. CF Lung 2E15 vg Participant 1 Participant 2† Participant 3 Participant 4 Pending Pending Non-CF Lung Non-treated Controls 1E15 vg Participant 1 Participant 2† Participant 3 Not sampled 5E14 vg Participant 1 2.5E14 vg Participant 1 Not sampled 4D-710 Treated Interstitial staining at highest dose

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 28 Best available data as of May 24, 2024. *Image from 1E15 vg participant. †Images from 2E15 vg participants. CFTR, cystic fibrosis transmembrane conductance regulator. IHC, immunohistochemistry. CFTR Protein Expression (IHC) Following Administration of 4D-710: Secretory, Ciliated & Basal Cells CFTR Protein Expression Observed in Multiple Airway Cell Types (1) Basal cells (2) Goblet cells (3) Columnar ciliated cells Longitudinal Cross section Localization to Apical Region†CFTR Protein Expressed in Multiple Cell Types*

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 29 T wo of Three Participants with Mild to Moderate ppFEV1 Impairment at Baseline Showed Improvement at 12 Months Best available data as of May 24, 2024. 4D-710 (2x1015 vg) Respiratory-related adverse events*: Pulmonary exacerbation Viral respiratory infection Pneumonitis 40 50 60 70 80 90 D1 3 6 9 12 ppFEV1 Month 2x1015 vg Participant 2 2x1015 vg Participant 3 1x1015 vg Participant 2 Prednisone Expected Transgene expression +5 +6 –5 56 80 51 86 69 74  Three participants had a baseline ppFEV1 ≤80% and >6 months of follow up  T wo showed improvement in ppFEV1 at 12 months o 2E15 vg (n=1): +6% o 1E15 vg (n=1): +5% 2E15 vg (Pt 2) 2E15 vg (Pt 3) 1E15 vg (Pt 2)

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 30 4D-710 (1E15 vg): Durable Improvement in CFQ-R-R Score Best available data as of May 24, 2024. *Respiratory-related adverse event within 21 days of assessment. †All enrolled participants (n=3). ‡Excludes participants with a respiratory-related event within 21 days of assessment. CFQ-R-R, Cystic Fibrosis Questionnaire-Revised (respiratory symptoms scale). Scores range from 0 to 100, with higher scores indicating better health. MCID=4 points [1]. 1. Quittner AL et al. Chest 2009;135:1610–18. 72 61 83 78 72 78 83 56 89 72 83 83 78 72 89 20 30 40 50 60 70 80 90 100 CFQ-R Respiratory Symptom Score Month 3 96 120 Participant 1 Participant 2 Participant 3 * * * * 3 96 1203 96 120 CFQ-R Respiratory Symptom Score Mean Change in CFQ-R-R Score 8.4 8.4 11.1 8.4 7.4 0 2 4 6 8 10 12 14 3 6 9 12 12 Mean change in CFQ-R Respiratory Symptom Score Evaluable, n‡ 2 222 Month † MCID1

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© 2025 4D Molecular Therapeutics. All Rights Reserved. 31 T otality of Clinical & Biomarker Data T o-date Supports 1E15 vg as Intended Phase 2 Expansion Dose, 5E14 vg Dose Pending Additional Follow-Up Best available data as of May 24, 2024. *Both events reported by one study participant (Participant 2) 1. Dannhoffer L et al. Am J Respir Cell Mol Biol 2009; 40:717–23. 2. Bell S et al. Lancet Resp Med 2020; 8:65–124. Dose Selection Criteria: T arget Profile 2E15 vg (n=4) 1E15 vg (n=3) 5E14 vg (n=1) 2.5E14 vg (n=1) Expression CFTR∆R RNA expression (ISH) ≥15% cells1,2     CFTR protein expression (IHC) ≥15% cells1,2     Cell types transduced Basal cells & secretory cells     No/limited expression in interstitial cells     Pre-existing A101 Immunity No effect on expression    Pending Safety & T olerability Safety & tolerability No ≥Grade 3 related AEs, No related SAEs     Clinical Activity ppFEV1 (at 6-12 months) >4.5% change from baseline   Pending Pending CFQ-R-R (at 6-12 months) >4 points change from baseline Not interpretable  Pending Pending Cleared Pending

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