Editas Medicine : Corporate Governance Presentation

Governance

Engagement

Presentation

May 2021

Forward Looking Statements

This presentation contains forward-looking statements and information within the meaning of The Private Securities Litigation Reform Act of 1995. 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. The Company 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 as a result of various factors, including: uncertainties inherent in the initiation and completion of preclinical studies and clinical trials and clinical development of the Company's product candidates; availability and timing of results from preclinical studies and clinical trials; whether interim results from a clinical trial will be predictive of the final results of the trial or the results of future trials; expectations for regulatory approvals to conduct trials or to market products and availability of funding sufficient for the Company's foreseeable and unforeseeable operating expenses and capital expenditure requirements. These and other risks are described in greater detail under the caption "Risk Factors" included in the Company's most recent Annual Report on Form 10-K, which is on file with the Securities and Exchange Commission, and in other filings that the Company may make with the Securities and Exchange Commission in the future. Any forward-looking statements contained in this presentation speak only as of the date hereof, and the Company expressly disclaims any obligation to update any forward-looking statements, whether because of new information, future events or otherwise.

© 2021 Editas Medicine 2

A Message From Our CEO

Editas was founded in 2013 with the mission to discover and develop a novel class of genome editing therapeutics. Specifically, our focus is to create therapeutics that enable precise and corrective molecular modification to treat the underlying cause of a broad range of diseases at the genetic level. There are well over 6,000 known genetic disorders, with new genetic disorders regularly being identified in medical literature. Our long-term vision at Editas is to bring medicines to patients with limited therapeutic options to help them overcome the disorders that are inhibiting their lives.

We've made tremendous progress towards achieving this vision and overcoming the numerous technical challenges of transforming gene editing technology into clinically practical and important therapeutics. We, along with everyone else, had to contend with the COVID-19 global pandemic. It was incredibly humbling seeing many of our peer companies work in unison to find viable solutions.

Biotechnology companies were suddenly essential to our social health. If there is any silver lining to the pandemic, I hope this encourages more students of under-represented minorities to pursue careers in the life sciences. I have personally been involved in expanding career opportunities, mentoring, and financial support for minorities pursuing education and careers in life sciences through my work on the board of the Biomedical Sciences Career Program for over 20 years.

Addressing the widening biotechnology skills gap to ensuring equitable access to things like education, laboratories, safety equipment, and online literature is absolutely critical. Actively seeking and providing opportunities to diverse candidates is necessary and something we embrace. Attraction, retention and development of talent is our most important responsibility in our quest to develop breakthrough therapies for important diseases.

How we balance the interests of shareholders, employees, patients, and our communities is constantly evaluated by management and directors. We are constantly refining and updating our practices to better align with all stakeholders, including making recent meaningful changes to our workforce diversity disclosures, committing to board diversity, and shifting to a performance-based CEO compensation program. Many of the amendments to our governance practices are direct responses to the feedback we received from you, our shareholders.

At Editas, our responsibilities and values are embedded in our everyday principles as we strive to reach our highest potential for all our stakeholders. Our leadership team and board remain committed to delivering new, innovative medicines to patients while facilitating a safe, inclusive, and collaborative culture. I look forward to updating you on our continued progress.

James Mullen

Chairman & CEO

© 2021 Editas Medicine 3

Editas is

Transforming

Medicine

Harnessing the power and potential of gene editing to develop medicines for people living with serious

diseases around the world

Striving to discover, develop, manufacture, and commercialize transformative, durable

genomic medicines

© 2021 Editas Medicine 4

Three Platforms of Medicine Development

Built on a Powerful Gene Editing Engine and a Talented Team

In Vivo

Global leader in in vivo gene editing medicines, starting with LCA10, moving into other inherited retinal diseases, and eventually into different tissues

Cell Therapy

Gene edited iPSC NK cells to revolutionize cancer treatments for multiple tumor types

Transformative

Medicines,

Changing Lives

Ex Vivo

Differentiated approach for treating sickle cell and beta thalassemia

The Engine: best-in-class

gene editing platform, broad intellectual

property, flexible and robust manufacturing capabilities

The People: seasoned executive team supported by world-class scientists

© 2021 Editas Medicine 5