
Non-Viral Genetic Medicine Virtual KOL Event: Emerging NMIBC Market Insights August 11, 2026

Disclaimers Cautionary Statement Regarding Forward-Looking Statements This Presentation contains certain forward-looking statements within the meaning of the federal securities laws and "forward-looking information" within the meaning of Canadian securities laws (collectively, "forward-looking statements"). Forward-looking statements may be identified by the use of the words such as “forecast”, “intend”, “develop”, “expect”, “anticipate”, “become”, “believe”, “continue”, “could”, “estimate”, “goal”, “intends”, “may”, “might”, “plan”, “possible”, “project”, “should”, “strategy”, “future”, “potential”, “opportunity”, “target”, “term”, “will”, “would”, “will be” or similar expressions that predict or indicate future events or trends or that are not statements of historical matters. These forward-looking statements include, but are not limited to, statements regarding detalimogene’s potential efficacy, durability, safety, tolerability and ease of use profile, our current views and market research on the non-muscle invasive bladder cancer market, the depth, breadth and quality of our market research, our conclusions, implications or take-aways from the results of our market research, estimates, projections or forecasts of payer coverage of therapies, projected revenues for detalimogene at pricing parity with new therapies, the size of the addressable BCG unresponsive population, our expectations regarding the frequency or manner in which healthcare providers may use detalimogene, potential growth of the potential patient population, sequencing of products the development of detalimogene, the potential benefits of detalimogene, plans regarding regulatory interactions and potential biologics license application (“BLA”) submission for detalimogene, plans regarding updates on the LEGEND study, including clinical data and engagement with the FDA, the development of detalimogene, projections of market opportunity and market share, and the anticipated market acceptance of detalimogene, if approved, the potential benefits of combining a surfactant bladder wash with detalimogene, including the potential for increased efficacy and durability, estimates and forecasts of financial and performance metrics, projections of market opportunity and market share, the anticipated market acceptance of detalimogene, expectations and timing related to regulatory submissions and commercial product launches and the prospects for regulatory approval of detalimogene. These forward-looking statements are based on various estimates and assumptions, whether or not identified in this presentation, and on the current expectations of the management of enGene Therapeutics Inc. ("enGene"), are not predictions of actual performance, and are subject to risks and uncertainties. Such statements are subject to numerous important factors, risks and uncertainties, many of which are beyond enGene's control, that may cause actual events or results to differ materially from enGene's current expectations. For example, there can be no guarantee that detalimogene will successfully complete necessary clinical development phases, including achieving positive results in the pivotal cohort of the LEGEND study, or that those results or any feedback from regulatory authorities will ultimately lead to a BLA submission for, and the approval of, detalimogene. Management's expectations and, therefore, any forward-looking statements in this presentation could also be affected by risks, uncertainties and assumptions relating to a number of other factors, which could cause the Company’s actual results, performance or achievements to differ materially from those expressed or implied by the forward-looking statements, including, without limitation, the inability of preliminary clinical data to predict the final results of the trial; changes in the results from enGene’s clinical trials, including due to new data collected from the ongoing LEGEND study or future studies, subsequent analysis of existing data, and audit and verification procedures; the content and timing of decisions made by the FDA and other regulatory authorities; the Company’s ability to recruit and retain qualified scientific and management personnel, establish clinical trial sites and enroll patients in its clinical trials, execute on the Company’s clinical development plans, and secure regulatory approval on anticipated timelines; and other risks and uncertainties detailed in filings with Canadian securities regulators on SEDAR+ and with the U.S. Securities and Exchange Commission (“SEC”) on EDGAR, including those described in the “Risk Factors” section of the Company’s Annual Report on Form 10-K for the fiscal year ended October 31, 2025 (copies of which may be obtained at www.sedarplus.ca or www.sec.gov). You should carefully consider the risks and uncertainties described in the “Risk Factors” section of such Annual Report, as well as other documents if and when filed by enGene from time to time with the SEC and Canadian securities regulators. If any of these risks materialize or our assumptions prove incorrect, actual events and results could differ materially from those contained in the forward-looking statements. There may be additional risks that enGene does not presently know or that enGene currently believes are immaterial that could also cause actual events and results to differ. In addition, forward-looking statements reflect enGene’s expectations, plans, or forecasts of future events and views as of the date of this presentation. enGene anticipates that subsequent events and developments will cause enGene’s assessments to change. While enGene may elect to update these forward-looking statements at some point in the future, enGene specifically disclaims any obligation to do so, unless required by applicable law. These forward-looking statements should not be relied upon as representing enGene’s assessments as of any date subsequent to the date of this presentation. Accordingly, undue reliance should not be placed upon the forward-looking statements contained herein. Intellectual Property This Presentation contains trademarks, service marks, trade names, copyrights, and products of enGene and other companies, which are the property of their respective owners. The use or display of third parties’ trademarks, service marks, trade names, copyrights, or products in this Presentation is not intended to, and does not, imply a relationship with enGene, or an endorsement of or sponsorship by enGene. Solely for convenience, the trademarks, service marks, and trade names referred to in this Presentation may appear without the ®, TM or SM symbols, but such references are not intended to indicate, in any way, that enGene will not assert, to the fullest extent permitted under applicable law, its rights or the rights of the applicable licensor in such trademarks, service marks and trade names. Industry and Market Data This Presentation relies on and refers to certain information and statistics based on estimates by enGene’s management and/or obtained from third party sources which enGene believes to be reliable. enGene has not independently verified the accuracy or completeness of any such third party information, which involves elements of subjective judgment and analysis that may or may not prove to be accurate. None enGene, or its affiliates or any third parties that provide information to enGene or its affiliates, such as market research firms, guarantees the accuracy, completeness, timeliness, or availability of any information. Neither enGene nor its affiliates nor any third parties that provide information to enGene and its affiliates, such as market research firms, is responsible for any errors or omissions (negligent or otherwise), regardless of the cause, or the results obtained from the use of such content. enGene may have supplemented such information where necessary, taking into account publicly available information about other industry participants and enGene management’s best view as to information that is not publicly available. Neither enGene nor its affiliates give any express or implied warranties with respect to the information included herein, including, but not limited to, any warranties regarding its accuracy or of merchantability or fitness for a particular purpose or use, and they expressly disclaim any responsibility or liability for direct, indirect, incidental, exemplary, compensatory, punitive, special, or consequential damages, costs, expenses, legal fees, or losses (including lost income or profits and opportunity costs) in connection with the use of the information herein. Lead Program (detalimogene voraplasmid) The lead program described herein is an investigational drug therapy that has not been subject to testing designed to demonstrate that the therapy is effective in humans or to provide a basis to predict in advance whether an adequate level of efficacy in humans will be demonstrated in further testing. Although the FDA has indicated that the Phase 2 portion of the current LEGEND study may potentially support BLA approval, that outcome will depend entirely on the final results of Phase 2 clinical testing. Corporate Presentation July 2026

Agenda Subject Presenter Welcome Ron Cooper, Chief Executive Officer NMIBC Market Insights Amy Pott, Chief Global Commercialization Officer Community Urologist KOL Dr. Neal Shore Medical Director, START-Carolinas Research Q&A Ron Cooper, Chief Executive Officer NMIBC Market Insights Event August 2026

Detalimogene: Non-Viral Gene Therapy with Local Immune ActivationSynergistic Stimulation of Specific Innate and Adaptive Immune Responses 1. Gao J, et al, inventors; enGene, Inc., assignee. US patent WO 2013/138930 A1. September 26, 2013. 2. Joshi S, et al. Presented at: 2025 ASCO GU Cancers Symposium; February 13-15, 2025; San Francisco, CA. Abstract TPS886. 3. Narayan VM, et al. Poster presented at: 2025 ASCO GU Cancers Symposium; February 13-15, 2025; San Francisco, CA. Abstract 826. 4. Taylor J, et al. Presented at: 2025 ASCO GU Cancers Symposium; February 13-15, 2025; San Francisco, CA. Abstract 802. 5. Steinberg JD, et al. Presented at: 2023 SUO; November 28-December 1, 2023; Washington, DC. Abstract 112 Detalimogene delivers plasmid DNA encoding 3 genes that activate the RIG-I pathway and drive expression of IL-12 RIG-I activation triggers innate immune signaling and recruitment of antitumor NK and T cells Localized IL-12 expression drives Th1 polarization of tumor-infiltrating –cells, antitumor cytokine production, and immune memory formation VA1 (RIG-I agonist dsRNA) IL-12 eRNA11a (RIG-I agonist dsRNA) Detalimogene Voraplasmid Detalimogene Plasmid nanoparticle NMIBC Market Insights Event August 2026

Multiple LEGEND Cohorts Maximize Detalimogene’s Potential *These additional non-pivotal Phase 2 cohorts of the LEGEND study provide further opportunity to demonstrate the potential use of detalimogene in clinical settings with unmet need. Progress as of October 24, 2025. All cohorts are currently in Phase 2 clinical trials. All NMIBC cohorts refer to high-risk NMIBC unless otherwise specified Expected data update, timelines, enrollment targets, and anticipated milestones reflect enGene management's current estimate and are subject to change Completed Active Corporate Presentation July 2026 Cohort / NMIBC Indication Pre-Clinical Phase 1 Pivotal Status Enrollment Complete: 12-Month Data Update Expected 2H 2026 First Patients Enrolled: Ongoing Enrollment Complete N=30 N=46 N=47 Pivotal Cohort 1: BCG-Unresponsive /w CIS Surfactant Bladder Rinse Cohort: BCG-Unresponsive NMIBC CIS Cohort 2a: BCG-Naïve /w CIS* Cohort 2b: BCG-Exposed /w CIS* Cohort 3: BCG-Unresponsive /w Papillary Only*

Detalimogene: Investigational Next-Generation Therapy for NMIBC * Reflective of interim data presented as of as of 21 April 2026 TRAEs = treatment-related adverse events, CR = complete response, NMIBC = non-muscle-invasive bladder cancer, BLA = biologics license applications, PI = product information. NMIBC Market is Growing Compelling Clinical Profile* Unique Non-Viral Offering Enhancement with Surfactant More treatment options are expected to increase sequencing Sequencing expands the treatable patient population over time Market growth creates opportunity for multiple therapies 54% CR at any time (primary endpoint) within the range observed from approved products Potential best-in-class tolerability with low rates of TRAEs leading to treatment interruptions or discontinuations Simplified storage and handling designed to support broad community adoption Readily available low-cost components supporting scalable manufacturing CDRP supports BLA readiness Potential future opportunity to improve CR any time and durability with surfactant bladder rinse Potential to decrease dwell of detalimogene from 60-minutes to 30-minutes with surfactant $285M in Cash; Pivotal Cohort 12-month Data and Filing of BLA Expected in 2H 2026 NMIBC Market Insights Event August 2026

Emerging NMIBC Market Insights

Market Research: Stakeholder Interviews, Surveys, and Claims Data >65 Urologist & Uro-Oncologist Interviews >15 Payer Interviews >2,000 NMIBC Patient Claims 2 x 100 Urologist & Uro-Oncologist Surveys 20+ clinical literature articles NMIBC Market Insights Event August 2026

Framing the US NMIBC BCG-Unresponsive Commercial Opportunity Inputs Estimates Source 90,000 Literature, Claims 80% Literature 30% Literature, Market Insights Evolving Market Insights Evolving Market Insights Evolving Market Insights Evolving Market Insights Source: enGene market research, SEER database; Knowles et al., Nat Rev Cancer 15, 25–41 (2015); Isharwal and Konety, Indian Journal of Urology, 2015; TNM Classification, 8th Edition; Tan et al., Eur Urol Oncol (2022): https://doi.org/10.1016/j.euo.2022.05.005, Nielson et al. Cancer. 2013 Oct 10;120(1):86–95. doi: 10.1002/cncr.28397, Aldousari and Kassouf, Can Urol Assoc J. 2010 Feb;4(1):56-64. doi:10.5489/cuaj.777, Minato et al., Cancer Diagn Progn. 2026 Jan;6(1):135-143. doi:10.21873/cdp.10514, Hjort et al., BJU Int. (2026). doi:10.1111/bju.70267, Boorjian, Mayo Clinic (2021). High-risk nonmuscle invasive bladder cancer, Bedke et al., Urol Oncol. 2023 Dec;41(12):461-475. doi:10.1016/j.urolonc.2023.10.004, Anastasiadis and de Reijke, Ther Adv Urol. 2012 Feb;4(1):13-32. doi:10.1177/1756287211431976, MyBladderCancerTeam. High-Risk Non-Muscle-Invasive Bladder Cancer: 5 Facts. Updated Dec 29, 2025, Lee C. SCS AUA 2024: High Risk NMIBC Treatment: The Case for Bladder Sparing Therapy. UroToday (2024), Zlotta, Fleshner, and Jewett, Can Urol Assoc J. 2009 Dec;3(6 Suppl 4):S199-S205. doi:10.5489/cuaj.1196 New Bladder Cancer % NMIBC % High Risk % CIS % BCG-Unresponsive % Drug Market Share Annual Price NMIBC Market Insights Event August 2026

High-Risk NMIBC Splits into Two Segments: CIS ± Papillary & Papillary Only % NMIBC % BCG-Unresponsive % Drug Market Share Annual Price New Bladder Cancer % High Risk % CIS Source: American Cancer Society “What Is Bladder Cancer?” May 2024, Bladder Cancer Advocacy Network “Bladder Cancer Carcinoma In-Situ (CIS): What Does A Diagnosis Mean?” Oct 2025. NMIBC Market Insights Event August 2026 CIS: flat lesion confined to bladder lining, often multifocal and hard to fully resect Papillary (Ta/T1): exophytic tumors projecting into bladder cavity, more visible/resectable Both CIS and papillary are non-muscle-invasive and the two can coexist in the same patient

Papillary-Only Patients Are Managed and Reimbursed like CIS Patients % NMIBC % BCG-Unresponsive % Drug Market Share Annual Price New Bladder Cancer % High Risk % CIS Note: Interviewed n=13 payers. All NCCN recommendations are category 2A unless otherwise indicated. While papillary only population is included in NCCN guidelines it is not a promotable population. Keytruda®, Adstiladrin®, Anktiva®, Inlexzo® are trademarks of their respective owners Source: NCCN Guidelines Bladder Cancer V 01.2026, enGene market research. All interviewed payers indicated they will cover NMIBC BCG-Unresponsive therapies broadly with 2A+ NCCN recommendation Therapies with 2A Recommendation for Papillary Only 2A Drugs Multi-Chemo Size of Study 48 72 52 Retrospective The National Comprehensive Cancer Network (NCCN) — an alliance of leading U.S. cancer centers — sets consensus treatment standards that clinicians follow to guide care and payers use to determine coverage Category 2A reflects uniform NCCN consensus that the treatment is appropriate based on the available evidence — the highest recommendation level short of Category 1 Papillary NMIBC Market Insights Event August 2026

Y0 Y1 Y2 Eligible Patient Pool Exceeds the Annual BCG-Unresponsive IncidencePatients will Sequence Therapies Creating a Compounding Effect on the Eligible Pool % NMIBC Annual Price New Bladder Cancer % High Risk % CIS % Drug Market Share % BCG-Unresponsive Note: Interviews n=22 urologists. The rate of patients requiring a 3L/4L therapy could be anywhere from 75% - 35% depending on which therapy they receive and rate of radical cystectomy. Source: enGene market research (interviews, surveys, and claims data), other NMIBC company estimates, Harris Poll NMIBC Patient Preference Survey (November 2025, n=200). All interviewed urologists will sequence patients through 3-4L of therapy before radical cystectomy 89% (n=200) patients would try anything to avoid radical cystectomy Illustration of Patient Sequencing =10,000 pts + 5,000 pts + 2,500 pts 2L 3L 4L 2L ~50% ~50% ~50% Patients will need a new therapy by EOY = 10,000 pts = 10,000 pts + 5,000 pts 3L 2L New Incident Patients NMIBC Market Insights Event August 2026 Patients who respond to 2L treatment in Y1 may fail in later years and require sequencing through therapies reflecting an additional potential +3,000 – 5,000 patients

Private Practice: Segmented by Resources & Economic Philosophy % NMIBC % BCG-Unresponsive Annual Price New Bladder Cancer % High Risk % CIS % Drug Market Share Note: Resource-Limited, Workflow-Constrained, Economics-Focused, and Clinical-Excellence all represent urology private practice. Source: enGene market research (third party claims analysis of real-world data of >2,000 patient claims). Academic Medical Center-Owned Practice Health System / Hospital-Owned Practice Large Urology Group Practice Small Private Practice ~75% Incident NMIBC BCG-Unresponsive Patients Treated in the Community Private Practice Clinical Excellence Practices Economics-Focused Practices Workflow-Constrained Practices Resource-Limited Practices NMIBC Market Insights Event August 2026

~40% of Patients Are Treated in Practices Balancing a Wide Range of Needs Practices Balance Resources, Economics, and Efficacy % NMIBC % BCG-Unresponsive Annual Price New Bladder Cancer % High Risk % CIS % Drug Market Share Urology Segment NMIBC Patients Considerations Resource-Limited Practices 19% (~3,800) Upfront acquisition cost is the gating factor; practices cannot administer viral therapies Workflow-Constrained Practices 11% (~2,200) Logistical burden is gating; practices cannot administer viral therapies Economics-Focused Practices 11% (~2,200) Net-cost-recovery drives treatment selection balanced with efficacy Clinical Excellence Practices 6% (~1,200) Hospital / Health System 29% (~5,800) Academic Medical Center 24% (~4,800) Note: Assumes ~20,000 addressable NMIBC BCG-unresponsive patients. Resource-Limited, Workflow-Constrained, Economics-Focused, and Clinical-Excellence all represent urology private practice. Source: enGene market research (third party claims analysis of real-world data of >2,000 patient claims). Academic Medical Center Health System / Hospital Clinical Excellence Practices Economics-Focused Practices Workflow-Constrained Practices Resource-Limited Practices Efficacy and safety are prioritized in treatment selection; these settings have the logistical capabilities to handle all therapies NMIBC Market Insights Event August 2026

Detalimogene Profile is Attractive for Private Practice Urologists % NMIBC % BCG-Unresponsive Annual Price New Bladder Cancer % High Risk % CIS % Drug Market Share * Reflects total addressable NMIBC BCG-Unresponsive patients. Assumes ~20,000 total addressable NMIBC BCG-unresponsive patients split between different practice settings. Note: Resource-Limited, Workflow-Constrained, Economics-Focused, and Clinical-Excellence all represent urology private practice. Source: enGene market research (third party claims analysis of real-world data of >2,000 patient claims; urologist interviews). Urology Segment Total NMIBC Patients* Detalimogene 2L/3L+ Use Resource-Limited Practices 19% (~3,800) Workflow-Constrained Practices 11% (~2,200) Economics-Focused Practices 11% (~2,200) Clinical Excellence Practices 6% (~1,200) Hospital / Health System 29% (~5,800) Academic Medical Center 24% (~4,800) Academic Medical Center Health System / Hospital Clinical Excellence Practices Economics-Focused Practices Workflow-Constrained Practices Resource-Limited Practices Meaningful Interest Limited Interest NMIBC Market Insights Event August 2026

Buy-and-Bill is the Predominant Model Used to Acquire NMIBC Therapies % NMIBC New Bladder Cancer % High Risk % CIS % Drug Market Share % BCG-Unresponsive Annual Price Source: enGene market research (survey n=100 urologists / uro-oncologists). Private practice urologists highlight that net cost recovery is critical for building practice infrastructure Academic Medical Center-owned Health system / Hospital-owned Private Practice Drug Acquisition Channel Used by HCPs for NMIBC Therapies Buy-and-Bill Spec Pharma Both Unsure NMIBC Market Insights Event August 2026

Efficacy Is One of Several Pricing Inputs, Not the Deciding OneRecent Launches Have Reached Pricing Parity Despite Efficacy Differences % NMIBC New Bladder Cancer % High Risk % CIS % Drug Market Share % BCG-Unresponsive Annual Price * Assume durability is defined by duration of response (DOR) of ≥ 12-Months. Inlexzo was 51% and Anktiva was 58%. Note: Gilenya®, Aubagio®, Stelara®, Otezla®, Dupixent®, Adbry®, Tepezza®, and Lumova® are trademarks of their respective owners. Source: enGene market research, Inlexzo USPI, Anktiva USPI. NMIBC Market Insights Event August 2026 Pricing Considerations CR at Any Time Durability Safety Competitor Pricing Inlexzo launched at a higher price despite Inlexzo’s lower durability of response* compared to Anktiva Examples of Pricing Parity Drugs Despite Efficacy Differences

Benchmark Market Price for NMIBC Therapies has Moved Up Annual WAC has moved from $220K/year up to $690K/year % NMIBC New Bladder Cancer % High Risk % CIS % Drug Market Share % BCG-Unresponsive Annual Price *Y2 for first j-code year. WAC = wholesale acquisition cost. Note: Keytruda®, Adstiladrin®, Anktiva®, Inlexzo® are trademarks of their respective owners. Source: enGene market research. Annual WAC ($ USD) Launch Year New Price Benchmark Interviewed payers will cover therapies at parity assuming NCCN guideline category 2A NMIBC Market Insights Event August 2026

Illustration of an Approved NMIBC Product Net Sales if Pricing ParityPricing Parity of 2025 Benchmark % NMIBC New Bladder Cancer % High Risk % CIS % Drug Market Share % BCG-Unresponsive Annual Price *Pricing parity assumes price of ~$650K-$700K/per patient per year. Patient count calculations assume gross-to-net discount of 21% and therefore a net price of $545,000 per year. Source: enGene market research, NMIBC company 2025 Annual Report. J-Code Year Treated Patients Est.* N/A N/A ~2,000 pts Approved NMIBC Product US Net Sales, 2024-2025 NMIBC Market Insights Event August 2026 $200 $500 $1,000

Framing the US NMIBC BCG-Unresponsive Commercial Opportunity New Bladder Cancer % NMIBC % High Risk % CIS % BCG-Unresponsive % Drug Market Share Annual Price Inputs Estimates 90,000 80% 30% Likely include papillary Compounding effect of sequencing Differential market share by practice types New Benchmark $690K * High Risk NMIBC BCG-Unresponsive Papillary only is not a promotional indication. Intended to reflect payer coverage dynamics for therapies included in NCCN guidelines. Source: enGene market research. NMIBC Market Insights Event August 2026

Community Urologist Dr. Neal Shore Dr. Neal Shore is the Medical Director for START-Carolinas Research in Myrtle Beach, SC and the Global Director of Genitourinary Oncology for START Cancer Research. He has conducted over 500 clinical trials and is actively involved with the Society for Immunotherapy of Cancer (SITC) Guidelines Committee for Bladder Cancer and has served on the board of the Bladder Cancer Advocacy Network.

Q&A
