Agios Provides Business Update on Discovery Research Strategy and Pipeline, Progress on Clinical Programs, Commercial Launch Preparations and Reports First Quarter 2018 Financial Results at Investor Day Commercial Infras

Agios Provides Business Update on Discovery Research Strategy and Pipeline, Progress on Clinical

Programs, Commercial Launch Preparations and Reports First Quarter 2018 Financial Results at Investor Day

Infrastructure In Place Ahead of August 21, 2018 PDUFA Action Date for TIBSOVO (Ivosidenib) for IDH1m R/R AML

Clinical Portfolio Advancing with Four Compounds in Development and Five Pivotal Trials Ongoing or Planned Across Three Distinct

Drug Discovery Platform Poised to Deliver New Research Programs with Next IND Expected in Q4 2018;

Three Rare Genetic Disease Programs Unveiled

Company in a Strong Financial Position to Launch TIBSOVO (Ivosidenib) and Execute Research and Clinical Plans with Q1 2018 Ending Cash, Cash Equivalents and Marketable Securities of $995M

CAMBRIDGE, Mass., May 4, 2018 Agios Pharmaceuticals, Inc. (NASDAQ: AGIO), a leader in the field of cellular metabolism

to treat cancer and rare genetic diseases, is hosting an Investor Day in New York City today. During the event, the company will provide a comprehensive business update and report financial results for the first quarter ended March 31, 2018.

The presentations will highlight how Agios drug discovery platform and broad clinical portfolio set Agios on the path to become a sustainable, multi-product biopharmaceutical company. The event will be webcast today starting at 8:00 a.m. ET at

As we prepare to launch our second Agios-discovered and first wholly owned medicine later this year, we continue to invest in

our productive drug discovery engine and advance a robust pipeline of first-in-class medicines, said David Schenkein, M.D., chief executive officer at Agios.

Our first quarter progress against that objective was highlighted by the NDA acceptance of TIBSOVO in IDH1m relapsed or refractory AML and multiple clinical trial initiations,

including dosing the first patient with our MAT2A inhibitor AG-270 and the start of our AG-348 pivotal program in PK deficiency.

HIGHLIGHTS FROM INVESTOR DAY PRESENTATIONS

FIRST QUARTER 2018 HIGHLIGHTS & RECENT PROGRESS

UPCOMING 2018 MILESTONES & EXPECTED DATA PRESENTATIONS

The company expects to achieve the following additional milestones in 2018:

Rare Genetic Diseases:

FIRST QUARTER 2018 FINANCIAL RESULTS & CASH GUIDANCE

Revenue for the quarter ended March 31, 2018 was $8.8 million, which includes $7.4 million of collaboration revenue and

$1.4 million of royalty revenue from net sales of IDHIFA . Revenue for the quarter ended March 31, 2017 was $10.5 million and consisted solely of collaboration revenue. The

decrease in collaboration revenue recognized for the quarter ended March 31, 2018 compared to the comparable period in 2017 was primarily driven by adoption of the new revenue recognition standard.

Research and development (R&D) expenses were $78.2 million, including $8.6 million of

stock-based compensation expense, for the quarter ended March 31, 2018, compared to $62.7 million, including $7.0 million in stock-based compensation expense, for the comparable period in 2017. The increase in R&D

expense was primarily attributable to start-up costs for the AG-348 pivotal program in PK deficiency, including the initiation of the

ACTIVATE-T trial. R&D expense also increased as a result of the initiation of a Phase 1 dose-escalation study of AG-270, our first-in-class MAT2A inhibitor, and IND enabling activities for AG-636, our DHODH inhibitor.

General and administrative (G&A) expenses were $24.6 million, including $5.9 million of stock-based compensation expense, for the

quarter ended March 31, 2018, compared to $14.8 million, including $3.7 million of stock-based compensation expense, for the quarter ended March 31, 2017. The increase in G&A expense was primarily attributable

to the growth in our U.S. commercial organization in order to support the expected launch of TIBSOVO (ivosidenib) in the third quarter of

Net loss for the quarter ended March 31, 2018 was $90.8 million, compared to a net loss of $66.2 million for the

quarter ended March 31, 2017.

Cash, cash equivalents and marketable securities as of March 31, 2018 were $994.7 million, compared to

$567.8 million as of December 31, 2017. The increase in cash was driven by the net proceeds of $516.2 million from the January follow on offering, $4.4 million of cost reimbursements under our collaboration agreements with

Celgene and $12.3 million received from employee stock transactions. This was offset by expenditures to fund operations of $104.8 million during the quarter ended March 31, 2018.

The company expects that its cash, cash equivalents and marketable securities as of March 31, 2018, together with the anticipated product and royalty

revenue, anticipated interest income, and anticipated expense reimbursements, but excluding any additional program-specific milestone payments, will enable the company to fund its anticipated operating expenses and capital expenditure requirements

through at least the end of 2020.

The live webcast from today s event can be accessed under Events & Presentations in the Investors section of the company s

website at www.agios.com. The archived webcast will be available on the company s website after the event.

Agios is focused on discovering and developing novel investigational medicines to treat cancer and rare genetic diseases through scientific leadership in the

field of cellular metabolism. In addition to an active research and discovery pipeline across both therapeutic areas, Agios has an approved oncology precision medicine and multiple

first-in-class investigational therapies in

clinical and/or preclinical development. All Agios programs focus on genetically identified patient populations, leveraging our knowledge of metabolism, biology and genomics. For more

information, please visit the company s website at www.agios.com.

About Agios/Celgene Collaboration

IDHIFA (enasidenib) and AG-881 are part of Agios global

strategic collaboration with Celgene Corporation focused on cancer metabolism. Under the terms of the 2010 collaboration agreement, Celgene has worldwide development and commercialization rights for

IDHIFA . Agios continues to conduct certain clinical development activities within the IDHIFA development program and is eligible to

receive reimbursement for those development activities and up to $95 million in remaining payments assuming achievement of certain milestones, and royalties on any net sales. Celgene and Agios are currently

co-commercializing IDHIFA in the U.S. Celgene will reimburse Agios for costs incurred for its

co-commercialization efforts. For AG-881, the companies have a joint worldwide development and 50/50 profit share collaboration, and Agios is eligible to receive

regulatory milestone payments of up to $70 million. AG-270 is part of a 2016 global research collaboration agreement with Celgene. Through Phase 1 dose escalation, Celgene has the option,

for a fee of at least $30 million, to participate in a worldwide cost and profit share with Agios. Upon exercise of the option the parties will share all development costs, subject to specified exceptions, and any profits on net sales

and Agios will be eligible for up to $169 million in clinical and regulatory milestone payments for the program.

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 its and its collaborator s preclinical, clinical and commercial advancement of its drug development programs including IDHIFA , TIBSOVO (ivosidenib), AG-881, AG-348, AG-270 and AG-636; the potential benefits of Agios product candidates; its key milestones for 2018; its plans regarding future data presentations; its financial guidance regarding the period in which it will have capital

available to fund its operations; and the potential benefit of its strategic plans and focus. The words anticipate, believe, could, estimate, expect, hope, intend,

may, milestone, path , plan, possible, potential, predict, prepare , project, strategy, will, would,

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. For example, there can be no guarantee that any product candidate Agios or its collaborator, Celgene, is developing will successfully

commence or complete necessary preclinical and clinical development phases, or that development of any of Agios product candidates will successfully continue. There can be no guarantee that any positive developments in Agios business

will result in stock price appreciation. 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: Agios results of clinical trials and preclinical studies, including

subsequent analysis of existing data and new data received from ongoing and future studies; the content and timing of decisions made by the U.S. FDA and other regulatory authorities,

investigational review boards at clinical trial sites and publication review bodies; Agios ability to obtain and maintain requisite regulatory approvals and to enroll patients in its planned clinical trials; unplanned cash requirements and

expenditures; competitive factors; Agios ability to obtain, maintain and enforce patent and other intellectual property protection for any product candidates it is developing; Agios ability to maintain key collaborations, such as its

agreements with Celgene; and 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.

Consolidated Balance Sheet Data

Consolidated Statements of Operations Data

(in thousands, except share and per share data)

Renee Leck, 617-649-8299

Senior Manager, Investor Relations

Holly Manning, 617-844-6630

Associate Director, Corporate Communications