CRISPR Therapeutics : Phase 1/2 CTX001™ Investor Update Presentation

CTX001TM INVESTOR EVENT

DECEMBER 9, 2020

©2020 Vertex Pharmaceuticals Incorporated and ©2020 CRISPR Therapeutics

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AGENDA

Reshma Kewalramani, M.D.,

Vertex CEO and President

Haydar Frangoul, M.D., Medical Director of Pediatric Hematology and Oncology at Sarah Cannon Research Institute, HCA Healthcare's TriStar Centennial Medical Center

Samarth Kulkarni, Ph.D.,

CRISPR Therapeutics CEO

Q&A

Scientific Achievements and Recent Progress for CTX001

CTX001 Data Presentation from ASH Conference

Commercial Opportunity and Future Outlook for CTX001

David Altshuler, M.D., Ph.D.,

Vertex's EVP, Global Research, and

Chief Scientific Officer

©2020 Vertex Pharmaceuticals Incorporated and ©2020 CRISPR Therapeutics

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FORWARD-LOOKING STATEMENTS

VERTEX: This presentation contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995, including, without limitation, the information provided regarding longer duration and additional patient CTX001 data, and statements regarding (i) anticipated regulatory filings and data submissions, (ii) the development plan and timelines, including expectations for available data, for product candidates including collaborations, (iii) anticipated potential benefits and commercial potential of CRISPR/Cas9 gene-editing technologies and therapies, including CTX001, (iv) anticipated patient populations that may be served by CRISPR/Cas9 gene-editing technologies and therapies, including CTX001, and (v) anticipated benefits of the Vertex and CRISPR collaboration. While Vertex believes the forward-looking statements contained in this presentation are accurate, these forward-looking statements represent the company's beliefs only as of the date of this presentation and there are a number of risks and uncertainties that could cause actual events or results to differ materially from those expressed or implied by such forward-looking statements. Those risks and uncertainties include, among other things, that data from a limited number of patients may not to be indicative of final clinical trial results, that future CTX001 data may not be favorable, that COVID-19 may have different or more significant impacts on the collaboration or final outcome of the clinical trials than currently expected, that data from the company's development programs may not be available on expected timelines, or at all, support registration or further development of its potential medicines due to safety, efficacy or other reasons, and other risks listed under "Risk Factors" in Vertex's most recent annual report and subsequent quarterly reports filed with the Securities and Exchange Commission at www.sec.gov and available through the company's website at www.vrtx.com. You should not place undue reliance on these statements or the data presented. Vertex disclaims any obligation to update the information contained in this presentation as new information becomes available.

CRISPR THERAPEUTICS: This presentation may contain a number of "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including

statements regarding CRISPR Therapeutics' expectations about any or all of the following: (i) the safety, efficacy and clinical progress of CRISPR Therapeutics' various clinical programs including CTX001, CTX110™, CTX120™ and CTX130™; (ii) the status of clinical trials and expectations regarding the data that are being presented; and (iii) the therapeutic value, development, and commercial potential of CRISPR/Cas9 gene editing technologies and therapies. Although CRISPR Therapeutics believes that such statements are based on reasonable assumptions within the bounds of its knowledge of its business and operations, existing and prospective investors are cautioned that forward-looking statements are inherently uncertain and not to place undue reliance on such statements, which speak only as of the date they are made. Actual performance and results may differ materially from those projected or suggested in the forward-looking statements due to various risks and uncertainties. These risks and uncertainties include, among others: the potential that preliminary data from any clinical trial not to be indicative of final trial results; the potential that clinical trial results may not support registration or further development; potential impacts due to the coronavirus pandemic, such as the timing and progress of clinical trials; that future competitive or other market factors may adversely affect the commercial potential for CRISPR Therapeutics' product candidates; uncertainties regarding the intellectual property protection for CRISPR Therapeutics' technology; and those risks and uncertainties described under the heading "Risk Factors" in CRISPR Therapeutics' most recent annual report on Form 10-K, quarterly report on Form 10-Q, and in any other subsequent filings made by CRISPR Therapeutics with the U.S. Securities and Exchange Commission, which are available on the SEC's website at www.sec.gov. CRISPR Therapeutics disclaims any obligation or undertaking to update or revise any forward-looking statements contained in this presentation, other than to the extent required by law.

CRISPR THERAPEUTICS® standard character mark and design logo, CTX001™, CTX110™, CTX120™, and CTX130™ are trademarks and registered trademarks of CRISPR Therapeutics AG. All other trademarks and registered trademarks are the property of their respective owners.

©2020 Vertex Pharmaceuticals Incorporated and ©2020 CRISPR Therapeutics

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RESHMA KEWALRAMANI, M.D., VERTEX CEO AND PRESIDENT

Scientific Achievements and Recent Progress for CTX001

©2020 Vertex Pharmaceuticals Incorporated and ©2020 CRISPR Therapeutics

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