Agios Highlights 2021 Milestones to Accelerate and Expand Its Genetically Defined Disease Portfolio and Drive Near- and Long-Term Value Creation Company Expects to File for Regulatory Approval for Mitapivat for the Treat

Agios Highlights 2021 Milestones to Accelerate and Expand Its Genetically Defined Disease Portfolio and

Drive Near- and Long-Term Value Creation

Company Expects to File for Regulatory Approval for Mitapivat for the Treatment of

Adults with Pyruvate Kinase (PK) Deficiency in the U.S. in Q2 2021 and in the EU in Mid-2021

Pivotal Trials for Mitapivat in Thalassemia on Track for Initiation in 2H 2021 and in Sickle Cell Disease by Year-End

Sale of Oncology Portfolio to Servier Expected to Close in Q2 2021,

Enabling Agios to Focus on Genetically Defined Diseases

Company s 2025 Strategic Vision Includes

Commercialization of Mitapivat in 3 Indications, 5+ Molecules in Clinical Development across 10+ Indications, an Investigational New Drug Every 12-24 Months and a Cash-Flow Positive Business

CAMBRIDGE, Mass., January 11, 2021 Agios Pharmaceuticals, Inc. (NASDAQ: AGIO), a leader in the field of cellular metabolism

to treat cancer and genetically defined diseases, today announced its key 2021 milestones that will drive its recently announced strategic pivot to focus on developing and commercializing innovative treatments for genetically defined

diseases, as well as its five-year vision for the company. Agios will present at the virtual 39th Annual J.P. Morgan Healthcare Conference on Monday, January 11 at 10:50 a.m. ET, and a live webcast will be available at investor.agios.com.

Agios is at an exciting inflection point as we prepare to move forward with a singular focus on genetically defined diseases, said Jackie Fouse,

Ph.D., chief executive officer of Agios. 2021 will be a year of significant momentum and further evidence of our potential to meaningfully impact the lives of patients with unmet needs in pyruvate kinanse deficiency, thalassemia, sickle cell

disease and other genetically defined diseases. This year, we expect to file for the approval of mitapivat in pyruvate kinase deficiency, which currently has no disease-modifying treatment options, and to initiate pivotal development programs in

thalassemia and sickle cell disease. We also expect to further unlock the potential of PK activation across a range of genetically defined diseases by advancing our rich and sustainable research pipeline. As we reimagine the future of Agios, we look

forward to building on our core values and pioneering leadership in cellular metabolism to expand and accelerate our work on behalf of patients.

Anticipated 2021 Key Milestones

Agios expects to achieve

the following key milestones in 2021:

Genetically Defined Disease Program Milestones

Genetically Defined Disease Data Presentations

Oncology Milestones & Data Presentations

Agios 2025 Strategic Vision

The Agios 2025 strategic vision reflects the company s expected evolution over the next five years in light of its singular focus on genetically defined

diseases. As part of this vision, Agios expects to achieve the following milestones by the end of 2025:

2020 Year-End Cash and Guidance Agios ended 2020 with approximately $670.5 million of cash, cash

equivalents and marketable securities. The company expects that its cash, cash equivalents and marketable securities as of December 31, 2020, together with anticipated product and royalty revenue, interest income and expense reimbursements

under our collaboration agreements, but excluding any additional program-specific milestone payments, will enable the company to fund its planned operating expenses and capital expenditure requirements to the end of 2022. Following the completion of

the transaction with Servier and the subsequent shareholder returns, Agios expects its cash runway to extend to cash-flow positivity in 2025.

Presentation at 39th Annual J.P. Morgan Healthcare

Conference Agios will webcast its corporate presentation from the virtual 39th Annual J.P. Morgan Healthcare Conference on Monday, January 11, 2021 at 10:50 a.m.

ET (7:50 a.m. PT). A live webcast of the presentation can be accessed under Events & Presentations in the Investors section of the company s website at agios.com. A replay of the webcast will be archived on the Agios

website for at least two weeks following the presentation.

Agios is focused on discovering and developing novel investigational medicines to treat malignant hematology, solid tumors and genetically defined diseases

through scientific leadership in the field of cellular metabolism. In addition to an active research and discovery pipeline across these three therapeutic areas, Agios has two approved oncology precision medicines and multiple first-in-class investigational therapies in clinical and/or preclinical development. For more information, please visit the company s website at www.agios.com.

Cautionary Note Regarding Forward-Looking Statements

This press release contains forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Such forward-looking

statements include those regarding Agios plans, strategies and expectations for the preclinical, clinical and commercial advancement of its drug development programs; the potential benefits of Agios products and product candidates;

Agios key milestones and guidance for 2021 and strategic vision for 2025; its financial guidance regarding the period in which it will have capital available to fund its operations; expectations regarding the sale of Agios oncology

portfolio and associated return of capital to shareholders; and the potential benefits of Agios s strategic plans and focus. The words anticipate, expect, goal, hope, milestone,

plan, potential, possible, strategy, will, vision, and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements

contain these identifying words. Such statements are subject to numerous important factors, risks and uncertainties that may cause actual events or results to differ materially from Agios current expectations and beliefs. Management s

expectations and, therefore, any forward-looking statements in this press release could also be affected by risks and uncertainties relating to a number of other important factors, including, without limitation risks and uncertainties related to:

(i) Agios s sale of its oncology portfolio, including the occurrence of any event, change or other circumstance that could give rise to the termination of the purchase and sale agreement; the failure of Agios to obtain stockholder approval

for the proposed transaction or the failure to satisfy any of the other conditions to the completion of the proposed transaction; the effect of the announcement of the proposed transaction on the ability of Agios to retain and hire key personnel and

maintain relationships with its customers, suppliers, advertisers, partners and others with whom it does business, or on its operating results and businesses generally; risks associated with the disruption of management s attention from ongoing

business operations due to the proposed transaction; the ability to meet expectations regarding the timing and completion of the proposed transaction, including with respect to receipt of required regulatory approvals; the failure of Agios to

receive milestone or royalty payments under the purchase and sale agreement and the uncertainty of the timing of any receipt of any such payments; and the uncertainty of the results and effectiveness of the use of proceeds from

the proposed transaction; (ii) the impact of the COVID-19 pandemic to Agios business, operations, strategy, goals and anticipated milestones, including its ongoing and planned research activities,

ability to conduct ongoing and planned clinical trials, clinical supply of current or future drug candidates, commercial supply of current or future approved products, and launching, marketing and selling current or future approved products;

(iii) Agios results of clinical trials and preclinical studies, including subsequent analysis of existing data and new data received from ongoing and future studies; (iv) the content and timing of decisions made by

the U.S. FDA, the EMA or other regulatory authorities, investigational review boards at clinical trial sites and publication review bodies; (v) Agios ability to obtain and maintain requisite regulatory approvals and to enroll

patients in its planned clinical trials; (vi) unplanned cash requirements and expenditures and competitive factors; (vii) Agios ability to obtain, maintain and enforce patent and other intellectual property protection for any product

candidates it is developing; (viii) Agios ability to maintain key collaborations; and (ix) general economic and market conditions. These and other risks are described in greater detail under the caption Risk Factors

included in Agios public filings with the Securities and Exchange Commission. Any forward-looking statements contained in this press release speak only as of the date hereof, and Agios expressly disclaims any obligation to update any

forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

Additional Information and Where to Find It

This communication relates to the proposed transaction involving the sale by Agios Pharmaceuticals, Inc. ( Agios ) of its oncology business to

Servier Pharmaceuticals, LLC. In connection with the proposed transaction, Agios will file relevant materials with the U.S. Securities and Exchange Commission (the SEC ), including Agios proxy statement on Schedule 14A (the

Proxy Statement ). This communication is not a substitute for the Proxy Statement or any other document that Agios may file with the SEC or send to its stockholders in connection with the proposed transaction. BEFORE MAKING ANY VOTING

DECISION, STOCKHOLDERS OF AGIOS ARE URGED TO READ ALL RELEVANT DOCUMENTS FILED WITH THE SEC, INCLUDING THE PROXY STATEMENT, WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION. Investors and

security holders will be able to obtain the documents (when available) free of charge at the SEC s website, at http://www.sec.gov, and Agios s website, at www.agios.com. In addition, the documents (when available) may be

obtained free of charge by accessing Agios s website at www.agios.com under the heading Investors or, alternatively, directing a request to Holly Manning by email at holly.manning@agios.com or by calling 617-649-8600.

Participants in the Solicitation

Agios and its directors and executive officers may be deemed to be participants in the solicitation of proxies from the holders of Agios common stock in

respect of the proposed transaction. Information about the directors and executive officers of Agios is set forth in the proxy statement for Agios 2020 annual meeting of stockholders, which was filed with the SEC on April 16, 2020, and in

other documents filed by Agios with the SEC. Other information regarding the participants in the proxy solicitation and a description of their direct and indirect interests, by security holdings or otherwise, will be contained in the Proxy Statement

and other relevant materials to be filed with the SEC in respect of the proposed transaction when they become available.

Director, Investor Relations

Jessica Rennekamp, 857-209-3286

Associate Director, Corporate Communications