Delivering on the promise of Prime Editing Corporate Presentation January 2026 1 Forward Looking Statements This presentation contains forward-looking statements of Prime Medicine, Inc. ("Prime", "we" or "our") within the meaning of the Private Securities Litigation Reform Act of 1995, as amended. These forward-looking statements contain information about our current and future prospects and our operations, which are based on currently available information. All statements other than statements of historica ...

Summary of Prime Medicine Conference Call on Wilson Disease Company Overview - **Company**: Prime Medicine - **Focus**: Development of prime editing technology for genetic diseases, specifically targeting Wilson disease and other liver-related conditions [3][6][11] Industry Context - **Disease**: Wilson disease, a genetic disorder caused by mutations in the ATP7B gene, leading to copper accumulation in the body [21][24] - **Current Treatments**: Existing therapies include chronic chelation therapy and dietary restrictions, which are burdensome and often ineffective [30][37] Key Points and Arguments 1. **Strategic Focus**: Prime Medicine is concentrating on Wilson disease due to its high unmet medical need and the absence of curative therapies [8][10] 2. **Prime Editing Technology**: This next-generation gene editing technology allows precise and permanent correction of genetic mutations, offering the potential for durable cures [11][12][38] 3. **Preclinical Data**: Recent preclinical studies demonstrate that prime editing can revert Wilson disease to a normal phenotype, showcasing the technology's transformative potential [9][40][46] 4. **Market Opportunity**: The global market for Wilson disease treatments is estimated to exceed $20 billion, with potential to reach $40 billion, given the prevalence of the disease in the U.S., Europe, and Japan [20][21] 5. **Patient Population**: Approximately 25,000 patients in the U.S., Europe, and Japan are considered addressable for prime editing therapies, with a focus on the most prevalent mutations (H1069Q and R778L) [18][19] 6. **Clinical Development Plans**: Prime Medicine plans to file an IND for Wilson disease in 2026, with initial human data expected in 2027 [16][48] 7. **Safety and Efficacy**: Preclinical studies indicate a favorable safety profile with no off-target effects and high editing efficiency, achieving over 80% correction in animal models [39][42][41] 8. **Long-term Vision**: The company aims to transition from managing symptoms to providing a one-time curative treatment, fundamentally changing patient care for Wilson disease [37][50] Additional Important Insights - **Challenges in Current Treatments**: Current therapies have significant non-adherence rates (30-50%) and can lead to severe side effects, highlighting the need for a more effective solution [31][78] - **Potential for Broader Applications**: The modular nature of prime editing technology allows for rapid expansion into other liver diseases and genetic disorders, enhancing the company's pipeline [15][54] - **Regulatory Considerations**: The company is preparing for regulatory filings and is focused on establishing safety and efficacy benchmarks for accelerated approval [91][92] This summary encapsulates the critical insights from the conference call, emphasizing Prime Medicine's innovative approach to treating Wilson disease and the broader implications for genetic therapies.

Core Insights - Prime Medicine is advancing its pipeline with new preclinical data for PM577 in Wilson's Disease (WD) to be presented at AASLD, with plans to file an IND and/or CTA in the first half of 2026 and initial clinical data expected in 2027 [1][4][5] - The company has nominated PM647 as a development candidate for Alpha-1 Antitrypsin Deficiency (AATD), also on track to file an IND and/or CTA in mid-2026, with initial clinical data anticipated in 2027 [1][5] - The leadership team has been strengthened with the appointment of Matthew Hawryluk, Ph.D., M.B.A. as Chief Business Officer [1][4] Pipeline Developments - Prime Medicine is focused on in vivo programs targeting Wilson's Disease and Alpha-1 Antitrypsin Deficiency, with IND and/or CTA filings expected in 2026 and initial clinical data in 2027 [5][6] - The company is also advancing a Cystic Fibrosis program supported by the Cystic Fibrosis Foundation and developing Prime Edited CAR-T products in partnership with Bristol Myers Squibb [6] Financial Performance - For the quarter ended September 30, 2025, R&D expenses were $44.0 million, up from $40.3 million in the same period of 2024, primarily due to license and intellectual property costs [10][12] - General and Administrative expenses decreased to $11.2 million from $14.1 million year-over-year, attributed to reduced personnel costs [10][12] - The net loss for the quarter was $50.6 million, compared to a net loss of $52.5 million in the prior year [10][12] Cash Position - As of September 30, 2025, the company reported cash, cash equivalents, and investments totaling $213.3 million, which is expected to fund operations into 2027 [10][21]

Core Insights - Prime Medicine is advancing its pipeline with new preclinical data for PM577 in Wilson's Disease and has nominated PM647 for Alpha-1 Antitrypsin Deficiency, with both expected to file IND and/or CTA applications in the coming years [1][2][3] Pipeline Developments - The company is focused on liver-targeted programs for Wilson's Disease and Alpha-1 Antitrypsin Deficiency, with IND filings anticipated in H1 2026 for AATD and H1 2027 for WD, and initial clinical data expected in 2027 [3][4] - Prime Medicine is also developing a Cystic Fibrosis program and exploring collaborations, including a partnership with Bristol Myers Squibb for Prime Edited CAR-T products [4][11] Leadership and Corporate Updates - Matthew Hawryluk, Ph.D., M.B.A., has been appointed as Chief Business Officer to enhance business development and strategic collaborations [1][10] - A virtual KOL event is scheduled for November 12, 2025, to discuss the company's strategy for Wilson's Disease [1][10] Financial Performance - For Q3 2025, Prime Medicine reported R&D expenses of $44.0 million, up from $40.3 million in Q3 2024, primarily due to increased license and intellectual property costs [10][20] - General and Administrative expenses decreased to $11.2 million from $14.1 million year-over-year, attributed to workforce reductions [10][20] - The net loss for Q3 2025 was $50.6 million, slightly improved from a net loss of $52.5 million in Q3 2024 [10][20] - As of September 30, 2025, the company had cash and investments totaling $213.3 million, sufficient to fund operations into 2027 [8][18]

Core Insights - Prime Medicine, Inc. is set to host a virtual event on November 12, 2025, to discuss its liver disease franchise, particularly focusing on Wilson's Disease [1][2] - The company plans to file an investigational new drug (IND) and/or clinical trial application (CTA) for PM577, targeting H1069Q-driven Wilson's Disease, in the first half of 2026, with initial clinical data expected in 2027 [1][8] Company Overview - Prime Medicine is a biotechnology company focused on developing a new class of one-time curative genetic therapies using its proprietary Prime Editing platform, which allows precise and efficient gene editing [4][5] - The company is advancing a diversified portfolio of investigational therapeutic programs in core areas such as liver, lung, immunology, and oncology, targeting diseases with well-understood biology [5] Strategic Focus - The upcoming event will feature presentations from the management team and Dr. Michael Schilsky, highlighting the treatment landscape for Wilson's Disease, which currently lacks a curative therapy [2][8] - Prime Medicine aims to leverage the modularity of its Prime Editing platform to accelerate the development of multiple Prime Editors for Wilson's Disease and potentially other diseases [8][9] Market Opportunity - The company identifies a significant global market opportunity for Wilson's Disease treatment, noting that current standard-of-care options are limited by compliance, cost, and tolerability [8] - Prime Editing technology has the potential to provide durable cures by precisely addressing the genetic causes of Wilson's Disease, which could impact millions of patients [8][9]

Core Insights - Prime Medicine, Inc. is set to host a virtual event on November 12, 2025, to discuss its liver disease franchise, particularly focusing on Wilson's Disease [1][2] - The company plans to file an investigational new drug (IND) and/or clinical trial application (CTA) for PM577, targeting H1069Q-driven Wilson's Disease, in the first half of 2026, with initial clinical data expected in 2027 [1][9] Company Overview - Prime Medicine is a biotechnology company focused on developing one-time curative genetic therapies using its proprietary Prime Editing platform, which allows precise and efficient gene editing [4][5] - The company aims to address a range of genetic mutations across various tissues and diseases, potentially unlocking thousands of indications [4][5] Strategic Focus - Prime Medicine is concentrating on high-value programs in liver, lung, and immunology and oncology, with a clear clinical development path for each [5] - The company intends to leverage the modularity of its Prime Editing platform to accelerate the development of therapies for Wilson's Disease and other genetic conditions [8][9] Market Opportunity - There is currently no curative therapy for Wilson's Disease, and existing treatments face challenges related to compliance, cost, and tolerability [8] - Prime Editing has the potential to provide a durable cure for Wilson's Disease by precisely addressing its genetic causes [8][9]