Editas Medicine Announces Third Quarter 2016 Results and Update

Editas Medicine Announces Third Quarter 2016 Results and Update

Further strengthened leadership team with appointments of Charles Albright, Ph.D., as Chief Scientific Officer, and Gerald Cox, M.D., Ph.D., as Chief Medical Officer

CAMBRIDGE, Mass., November 7, 2016 Editas Medicine, Inc. (NASDAQ: EDIT), a leading genome editing company, today reported financial results for the third quarter ended September 30, 2016, and provided an update on recent accomplishments and upcoming events.

We made important progress in the third quarter of 2016 across all three of our key strategic objectives, said Katrine Bosley, President and Chief Executive Officer of Editas Medicine. Most notably, the addition of Charlie Albright and Gerry Cox to lead our scientific and clinical teams further reinforces our belief that we have the right team and platform to advance CRISPR medicines broadly.

multiple patients. Edited HSPCs were viable, retained ex vivo hematopoietic activity, and supported blood reconstitution following transplantation in mice. Importantly, similar levels of gene editing were observed in HSPCs before and after transplantation, and edited cells transplanted into secondary recipients' reconstituted human blood for up to 26 weeks.

Poster Title: Highly Efficient CRISPR/Cas9 Mediated Gene Editing in Long-Term Engrafting Human Hematopoietic Stem/Progenitor Cells

Authors: J. M. Heath, A. Chalishazar, C.S. Lee, W. Selleck, C. Cotta-Ramusino, D. Bumcrot, J.L. Gori

Session Name: Gene Therapy and Transfer: Poster I

Time: Saturday, December 3, 2016, 5:30-7:30 p.m.

Location: San Diego Convention Center, Hall GH

Third Quarter 2016 Financial Results

Cash and cash equivalents at September 30, 2016, were $199.9 million, compared to $143.2 million at December 31, 2015.

For the three months ended September 30, 2016, net loss attributable to common stockholders was $21.0 million, or $0.59 per share, compared to $7.5 million, or $2.57 per share, for the same period in 2015.

process and platform development expenses due to increased research activity, a $1.1 million increase in facility-related costs resulting from additional office and laboratory space, and a $0.8 million increase in certain license fees and expenses.

The Editas management team will host a conference call and webcast today at 5:00 p.m. ET to provide and discuss a corporate update and third quarter 2016 financial results. To access the call, please dial 877-809-6321 (domestic) or 615-247-0223 (international) and provide the passcode 8708082. A live webcast of the call will be available on the Investors & Media section of the Editas website at www.editasmedicine.com and a replay will be available approximately two hours after its completion.

About Editas Medicine

Editas Medicine is a leading genome editing company dedicated to treating patients with genetically-defined diseases by correcting their disease-causing genes. The Company was founded by world leaders in genome editing, and its mission is to translate the promise of genome editing science into a broad class of transformative genomic medicines to benefit the greatest number of patients.

Forward-Looking Statements

This press release 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 Quarterly Report on Form 10-Q, 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 press release speak only as of the date hereof, and the Company expressly disclaims any obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.

EDITAS MEDICINE, INC.

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