Agios Reports Second Quarter 2018 Financial Results TIBSOVO Launch Underway Post FDA Approval for IDH1m R/R AML; Second Medicine Approved from Agios Discovery Platform in 12 Months Entered License Agreement with CStone P

Agios Reports Second Quarter 2018 Financial Results

TIBSOVO Launch Underway Post FDA Approval for IDH1m R/R AML; Second

Medicine Approved from Agios Discovery Platform in 12 Months

Entered License Agreement with CStone

Pharmaceuticals to Develop and Commercialize Ivosidenib in Greater China

(AG-348) Pivotal Program (ACTIVATE and ACTIVATE-T) Initiated for Pyruvate Kinase Deficiency

Company in Strong Financial Position with Q2 2018 Ending Cash, Cash Equivalents and Marketable Securities of $937 Million

CAMBRIDGE, Mass., August 2, 2018 Agios Pharmaceuticals, Inc. (NASDAQ: AGIO), a leader in the field of cellular

metabolism to treat cancer and rare genetic diseases, today reported business highlights and financial results for the second quarter ended June 30, 2018. In addition, Agios highlighted select corporate milestones and clinical data from its

development programs.

The first half of 2018 has been productive across all aspects of our business, culminating in the recent approval and launch

of our second internally discovered medicine, said David Schenkein, M.D., chief executive officer at Agios. This achievement sets us well on the path to becoming a sustainable, multiproduct company with a thriving research engine on

track to submit its 7th IND and a broad clinical development program with multiple trials planned or underway to expand our oncology and rare genetic disease portfolios.

SECOND QUARTER 2018 HIGHLIGHTS & RECENT PROGRESS

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

Rare Genetic Diseases:

EXPECTED FOURTH QUARTER CLINICAL DATA PRESENTATIONS

SECOND QUARTER 2018 FINANCIAL RESULTS

Revenue for the quarter ended June 30, 2018 was $40.4 million, which includes $26.4 million of collaboration revenue and $1.6 million of

royalty revenue from net U.S. sales of IDHIFA under our collaboration agreements with Celgene, and $12.4 million of collaboration revenue under our agreement with CStone. Revenue for the

quarter ended June 30, 2017 was $11.3 million and consisted solely of collaboration revenue under our agreements with Celgene. The year over year increase in collaboration revenue for the second quarter was primarily driven by the

$15.0 million milestone related to Celgene s filing of an MAA to the EMA for IDHIFA and $12.4 million related to the delivery of the license under the CStone Agreement.

Research and development (R&D) expenses were $86.7 million, including $9.7 million of stock-based compensation expense, for the

quarter ended June 30, 2018, compared to $79.8 million, including $8.2 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 mitapivat (AG-348) pivotal program in PK deficiency, including the initiation of the ACTIVATE-T trial. R&D

expense also increased as a result of IND enabling activities for AG-636, our DHODH inhibitor.

administrative (G&A) expenses were $26.6 million, including $6.8 million of stock-based compensation expense, for the quarter ended June 30, 2018, compared to $16.1 million,

including $4.0 million of stock-based compensation expense, for the quarter ended June 30, 2017. The increase in G&A expense was primarily attributable to the growth in our U.S. commercial organization to support the launch

Net loss for the quarter ended June 30, 2018 was $68.7 million,

compared to a net loss of $83.1 million for the quarter ended June 30, 2017.

Cash, cash equivalents and marketable securities as of

June 30, 2018 were $936.6 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, $8.9 million of cost

reimbursements under our collaboration agreements with Celgene and $22.0 million received from employee stock transactions. This was offset by expenditures to fund operations of $178.1 million during the six months ended June 30,

The company expects that its cash, cash equivalents and marketable securities as of June 30, 2018, together with anticipated product and

royalty revenue, anticipated interest income, and anticipated expense reimbursements under our collaboration and license agreements, 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.

CONFERENCE CALL INFORMATION

Agios will host a conference call and live webcast with slides today at 8:00 a.m. ET to discuss second quarter 2018 financial results and recent business

activities. To participate in the conference call, please dial 1-877-377-7098 (domestic) or 1-631-291-4547 (international) and referring to conference ID 1497883. The live webcast 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 beginning approximately two hours 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

two approved oncology precision medicines 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 TIBSOVO (ivosidenib)

TIBSOVO (ivosidenib) is an isocitrate dehydrogenase-1 (IDH1)

inhibitor indicated for the treatment of adult patients with relapsed or refractory acute myeloid leukemia (AML) with a susceptible IDH1 mutation as detected by an FDA-approved test. For more information,

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 (enasidenib). Agios continues to conduct certain clinical development activities within the

IDHIFA (enasidenib) development program and is eligible to receive reimbursement for those development activities and up to $95 million in remaining milestone payments, and royalties on

any net sales. Celgene and Agios are currently co-commercializing IDHIFA (enasidenib) 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. The program focused on MTAP (methylthioadenosine phosphorylase)-deleted cancers is part of a 2016 global co-development and co-commercialization agreement with Celgene focused on metabolic immuno-oncology. Celgene has the option to participate in a worldwide 50/50 cost and profit share with Agios, under which Agios is 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 (enasidenib), TIBSOVO (ivosidenib), AG-881, mitapivat

(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 CStone Pharmaceuticals; 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