Agios Reports Third Quarter 2018 Financial Results Supplemental New Drug Application Submission for Single Agent TIBSOVO (ivosidenib) in Newly Diagnosed IDH1m AML Patients Not Eligible for Standard Treatment Planned by t

Agios Reports Third Quarter 2018 Financial Results

Supplemental New Drug Application Submission for Single Agent TIBSOVO

(ivosidenib) in Newly Diagnosed IDH1m AML Patients Not Eligible for Standard Treatment Planned by the End of January 2019

Enrollment for Phase 3 AGILE Trial of Ivosidenib Combination with Azacitidine in Newly Diagnosed AML Patients Not Eligible for

Intensive Chemotherapy Expected to Complete in 2020 with Revised Primary Endpoint

Mitapivat Pivotal Trials ACTIVATE

and ACTIVATE-T in Adults with PK Deficiency Expected to Complete Enrollment in 2019

TIBSOVO Launch in R/R IDH1m AML

Reported Revenue of $4.5M in First Partial Quarter of Launch

CAMBRIDGE, Mass., November 1, 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 third quarter ended September 30, 2018.

On the heels of the third quarter U.S. approval of TIBSOVO , our first wholly owned precision

medicine, we remain focused on executing on our remaining 2018 milestones and continuing to create value from our portfolio, said David Schenkein, M.D., chief executive officer at Agios. Based on regulatory discussions, we are

accelerating our frontline strategy in IDH1m AML with the planned submission of an sNDA expanding TIBSOVO s label to newly diagnosed AML patients not eligible for standard treatment and

a shorter enrollment timeline for the Phase 3 AGILE trial. In addition, we continue to activate new sites globally for our pivotal PK deficiency program and accrue patients in the dose-escalation portion of the Phase 1 study in MTAP-deleted tumors.

We believe these programs coupled with our robust preclinical pipeline, support our next phase of growth toward becoming a fully integrated, sustainable biopharmaceutical company.

THIRD QUARTER & RECENT 2018 HIGHLIGHTS

KEY UPCOMING MILESTONES

The company expects to achieve

the following near-term milestones:

Rare Genetic Diseases:

FOURTH QUARTER CLINICAL DATA PRESENTATIONS

THIRD QUARTER 2018 FINANCIAL RESULTS

Revenue for the quarter ended September 30, 2018 was $15.2 million, which includes $4.5 million of net product revenue from U.S. sales of

TIBSOVO , $8.7 million of collaboration revenue and $2.0 million of royalty revenue from net global sales of IDHIFA under

our collaboration agreements with Celgene. Revenue for the quarter ended September 30, 2017 was $11.4 million and consisted of $10.6 million of collaboration revenue and $0.7 million of royalty revenue under our agreements with

Celgene. The year-over-year increase in total revenue for the third quarter was primarily driven by U.S. sales of TIBSOVO and royalty revenue from U.S. sales of IDHIFA , offset by a decrease in collaboration revenue recognized during the quarter.

Cost of sales for the

quarter ended September 30, 2018 were $0.7 million and relate to manufacturing costs associated with TIBSOVO sales.

Research and development (R&D) expenses were $82.6 million, including $13.4 million of stock-based compensation expense, for the

quarter ended September 30, 2018, compared to $72.9 million, including $7.6 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 and IND enabling activities for AG-636, our DHODH inhibitor.

R&D expense also increased as a result of ongoing research efforts across our discovery platform programs.

Sales, general and administrative

(SG&A) expenses were $31.1 million, including $10.8 million of stock-based compensation expense, for the quarter ended September 30, 2018, compared to $17.5 million,

including $4.6 million of stock-based compensation expense, for the quarter ended September 30, 2017. The increase in SG&A expense was primarily attributable to the growth in our U.S. commercial organization to support

the launch of TIBSOVO and personnel costs related to increased headcount.

Net loss for the quarter ended September 30, 2018 was $94.7 million, compared to a net loss

of $77.1 million for the quarter ended September 30, 2017.

Cash, cash equivalents and marketable securities as of September 30,

2018 were $878.4 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,

$14.8 million of cost reimbursements and royalty payments under our collaboration agreements with Celgene, $12.0 million under our collaboration agreement with CStone and $29.2 million received from employee stock transactions. This

was offset by expenditures to fund operations of $263.0 million during the nine months ended September 30, 2018.

The company expects that its

cash, cash equivalents and marketable securities as of September 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 third 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 5285068. 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.

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. Please see full Prescribing Information including Boxed Warning at TIBSOVO.com.

About Agios/Celgene Collaboration

IDHIFA (enasidenib) and AG-270 are part of our collaboration with Celgene Corporation. Under the terms of our 2010 collaboration agreement focused on cancer metabolism, 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 $80 million in remaining milestone payments, 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. AG-270 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-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

Associate Director, Investor Relations

Holly Manning, 617-844-6630

Associate Director, Corporate Communications