Sage Therapeutics Announces Third Quarter 2016 Financial Results and Provides SRSE European Update Positive Scientific Advice From European Medicines Agency on Development of SAGE-547 in SRSE Provides Regulatory Path in

Sage Therapeutics Announces Third Quarter 2016 Financial Results and Provides

SRSE European Update

Positive Scientific Advice From European Medicines Agency on Development of SAGE-547 in

SRSE Provides Regulatory Path in E.U.

Ongoing Phase 3 STATUS Trial Expected to be Sufficient to Support a European Marketing

Authorization Application for SAGE-547 in SRSE

Eight Clinical Trials Across Pipeline Expected to Generate Top-Line Data in 2017

Moving into Next Strategic Phase - a Multi-Product, Neuropsych Development Portfolio

Conference Call Today at 8:00 AM ET

CAMBRIDGE, Mass., November 3, 2016 Sage Therapeutics, Inc. (NASDAQ: SAGE) today reported financial results for the third quarter ended

September 30, 2016 and an update on its corporate strategy. Sage recently received positive Scientific Advice from the European Medicines Agency (EMA) on the development of SAGE-547 in the treatment of patients with super-refractory status

epilepticus (SRSE). Based on the Scientific Advice from the EMA, Sage believes its current Phase 3 program, if successful, will be sufficient to support a European Marketing Authorization Application (MAA) to the EMA for the SRSE indication.

Scientific Advice is a procedure offered by the EMA to stakeholders for clarification of questions arising during development of medicinal products and focuses on development strategies rather than pre-evaluation of data to support an MAA.

The recent EMA Scientific Advice provides Sage with a clear regulatory path forward in SRSE in the E.U. and is important for Sage as we plan for

top-line results from the Phase 3 STATUS Trial in SRSE, expected in the first half of next year, while continuing to lay the groundwork for a potential near-term commercial launch of SAGE-547, said Jeff Jonas, M.D., Chief Executive

Officer of Sage. Building on our recent clinical and regulatory accomplishments, including FDA Breakthrough Therapy Designation for SAGE-547 in postpartum depression (PPD), we continue to transform Sage. We are now poised to drive our strategy

to the next phase - a multi-product, neuropsych development portfolio across three distinct disease areas: neurology with SRSE, mood disorders with PPD and major depressive disorder (MDD), and movement disorders with essential tremor and

Parkinson s. As we continue to explore the potential applications of our novel compounds through deliberate and stepwise development, Sage is now well-positioned to produce eight important data readouts throughout 2017.

Sage is advancing a portfolio of

multiple, novel central nervous system (CNS) product candidates targeting the GABAA and NMDA receptor systems. Dysfunction in these systems are known to be at the core of numerous psychiatric

and neurological disorders. Sage is employing an innovative development approach focused on indications where patient populations are easily identified, clinical endpoints are well-defined, and development pathways are feasible.

Expected Near-Term Clinical Milestones

Financial Results for the Third Quarter of 2016

Expected Upcoming Events and Presentations

Conference Call Information

Sage will host a conference call and webcast today at 8:00 AM ET to discuss its third quarter 2016 financial results and recent

business updates. The live webcast can be accessed on the investor page of Sage s website at investor.sagerx.com. The conference call can be accessed by dialing 1-866-450-8683 (toll-free domestic) or 1-281-542-4847 (international) and

using the conference ID 4543484. A replay of the webcast will be available on Sage s website approximately two hours after the completion of the event and will be archived for up to 30 days.

About Sage Therapeutics

Sage Therapeutics is

a clinical-stage biopharmaceutical company committed to developing novel medicines to transform the lives of patients with life-altering central nervous system (CNS) disorders. Sage has a portfolio of novel product candidates targeting critical CNS

receptor systems, GABA and NMDA. Sage s lead program, SAGE-547, is in Phase 3 clinical development for super-refractory status epilepticus, a rare and severe seizure disorder, and is being developed for postpartum depression. Sage is

developing its next generation modulators, including SAGE-217 and SAGE-718, with a focus on acute and chronic CNS disorders. For more information, please visit www.sagerx.com.

Forward-Looking Statements

in this release concern Sage s future expectations, plans and prospects, including without limitation: our expectations regarding development of our product candidates and their potential in the treatment of various CNS disorders; the expected

timing of initiation

and completion of clinical trials; the expected timing of IND-enabling activities; the anticipated availability and announcement of data and results from clinical trials of our product

candidates; our plans for evaluation of new indications and new compounds; our expectations regarding the regulatory pathway for SAGE-547 in the treatment of SRSE in the E.U., and our belief that the results of the current development program for

SAGE-547 in SRSE, if successful, will be sufficient for an MAA filing in the EU; our expectations regarding a potential future NDA filing and commercial launch of SAGE-547, if successfully developed and approved; and our expectations with respect to

future cash use and cash needs. These forward-looking statements are neither promises nor guarantees of future performance, and are subject to a variety of risks and uncertainties, many of which are beyond our control, which could cause actual

results to differ materially from those contemplated in these forward-looking statements, including the risks that: we may continue to experience slower than expected enrollment and randomization of evaluable patients in the STATUS trial or slower

than expected clinical site initiation and enrollment in our other clinical trials, or the potential need for additional analysis or data or the need to enroll additional patients, leading to possible delays in completion of trials or in the

availability of data; we may not be able to generate supportive non-clinical data or to successfully demonstrate the efficacy and safety of our product candidates at each stage of development; success in our non-clinical studies or in earlier

stage clinical trials may not be repeated or observed in ongoing or future studies involving the same compound or other product candidates, and ongoing and future pre-clinical and clinical results may not support further development of product

candidates or be sufficient to gain regulatory approval to market any product; decisions or actions of regulatory agencies may affect the initiation, timing, progress and cost of clinical trials, and our ability to proceed with further clinical

studies of a product candidate or to obtain marketing approval, including the risk that the EMA may, despite scientific advice, decide that the data from our Phase 3 trial in SRSE are not sufficient to support approval; the internal and external

costs required for our activities, and to build our organization in connection with such activities, and the resulting use of cash, may be higher than expected, or we may conduct additional clinical trials or pre-clinical studies or engage in new

activities, requiring additional expenditures and using cash more quickly than anticipated; and we may encounter technical and other unexpected hurdles in the development and manufacture of our products which may delay our timing or increase

our expenses and use of cash, as well as those risks more fully discussed in the section entitled Risk Factors in our most recent Quarterly Report on Form 10-Q, as well as discussions of potential risks, uncertainties, and other

important factors in our subsequent filings with the Securities and Exchange Commission. In addition, any forward-looking statements represent our views only as of today, and should not be relied upon as representing our views as of any

subsequent date. We explicitly disclaim any obligation to update any forward-looking statements.

Paul Cox, Sage Therapeutics

Maureen L. Suda, Suda Communications LLC

Sage Therapeutics, Inc. and Subsidiaries

Condensed Consolidated Balance Sheets

Sage Therapeutics, Inc. and Subsidiaries

Condensed Consolidated Statements of Operations

(in thousands, except share and per share data)