Sage Therapeutics Announces First Quarter 2020 Financial Results and Highlights Pipeline and Business Progress Expected initiation of three new short-term zuranolone clinical studies in 2020, with the potential for three

Sage Therapeutics Announces First Quarter 2020 Financial Results and Highlights Pipeline and Business Progress

Expected initiation of three new short-term zuranolone clinical studies in 2020, with the potential for three distinct indications

April restructuring to advance corporate strategy and pipeline expected to result in approximate annualized cost savings of

$170M, with significant portion related to ZULRESSO commercial and G&A support

Progress continues in neurology and neuropsychiatry franchises with planned initiation of Phase 2 clinical trials of SAGE-324

in 1H and SAGE-718 in 2H, 2020

Mike Cloonan elevated to chief operating officer

Conference call today at 4:30 p.m. ET

CAMBRIDGE, Mass. May 7, 2020 Today, Sage Therapeutics, Inc. (NASDAQ: SAGE), a biopharmaceutical company committed to developing novel

therapies with the potential to transform the lives of people with debilitating disorders of the brain, reported business highlights and financial results for the first quarter ended March 31, 2020. The Company also announced the promotion of Mike

Cloonan to chief operating officer; he will continue to report into Jeff Jonas, Sage s chief executive officer. In the newly created role, Mr. Cloonan will strategically align the business functions to support the ongoing development and

commercialization of Sage s brain health portfolio.

I want to take a moment to acknowledge the challenges resulting from the global COVID-19 pandemic. I m proud of the way our employees, partners, and the community have responded in this unprecedented time, said Jeff Jonas, M.D., chief executive officer at Sage Therapeutics. The

teams at Sage are handling virtual work well, and progress across our pipeline remains strong. Our mission is more important than ever as mental health issues are coming to the forefront and will continue to have significant impact even after the

current phase of the COVID-19 pandemic is over. The strategic decisions we made in the first quarter, and the promotion of Mike to chief operating officer, have us on the right track, we believe, to continue

developing medicines that matter for people with brain health disorders.

Sage is advancing a portfolio of novel and differentiated product candidates designed to improve brain health by targeting the GABAA and NMDA receptor systems. Dysfunction in these systems is thought to be at the core of numerous neurological and neuropsychiatric disorders.

Depression Franchise

The Depression Franchise

includes zuranolone (SAGE-217), Sage s next-generation positive allosteric modulator (PAM) of GABAA receptors, being evaluated in clinical

development as a treatment for various affective disorders, and ZULRESSO (brexanolone) CIV injection, the first treatment approved by the U.S. Food and Drug Administration (FDA) specifically

for postpartum depression (PPD). Zuranolone has received breakthrough therapy designation from the FDA for the treatment of major depressive disorder (MDD).

Ongoing study updates:

SAGE-324, a next-generation PAM of GABAA receptors and

Sage s lead neurology asset, is in development as a potential oral therapy for neurological conditions, such as essential tremor (ET), epilepsy and Parkinson s disease.

Neuropsychiatry Franchise

SAGE-718, Sage s first-in-class NMDA receptor PAM and lead neuropsychiatric drug candidate, is in development as a potential oral

therapy for cognitive disorders associated with NMDA receptor dysfunction, including Huntington s disease (HD).

Anticipated Upcoming Milestones and Potential Impact of COVID-19

Sage has implemented business continuity policies and practices intended to safeguard employees and help reduce the spread of COVID-19, including initiating a work from home policy for all employees. Sage is working closely with clinical development teams to develop strategies to help mitigate potential disruptions caused by COVID-19 and at this time the Company does not anticipate there will be a significant impact to timelines for its planned or ongoing clinical programs.

Financial Results for the First Quarter 2020

Conference Call Information

Sage will host a conference call and webcast today, Thursday, May 7, 2020, at 4:30 p.m. ET to discuss its first quarter 2020 financial results and

recent corporate updates. The live webcast can be accessed on the investor page of Sage s website at investor.sagerx.com. 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 biopharmaceutical company committed to developing novel therapies with the potential to transform the lives of people with

debilitating disorders of the brain. We are pursuing new pathways with the goal of improving brain health, and our depression, neurology and neuropsychiatry franchise programs aim to change how brain disorders are thought about and treated. Our

mission is to make medicines that matter so people can get better, sooner. 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 views and expectations regarding revenues from sales of ZULRESSO and factors that may impact revenues, including the expected impact of

the COVID-19 pandemic on ZULRESSO revenues; our clinical development plans and expected timelines, including our belief as to our ability to mitigate the possible impact of the

COVID-19 pandemic on our clinical development timelines; the amount of the expected one-time cost associated with our restructuring; expected reductions in external

expenses; our expectations with respect to 2020 operating expenses and year-end cash; our belief that existing cash will support operations into 2022; our belief in the potential of our product candidates in

various indications; the potential profile and benefit of our product candidates; and the goals, opportunity and potential for our business. These statements constitute forward-looking

statements as that term is defined in the Private Securities Litigation Reform Act of 1995. 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 never be able

to generate meaningful revenues from sales of ZULRESSO or to generate revenues at levels necessary to justify our investment; the impact of the COVID-19 pandemic on sales of ZULRESSO may last longer than we

expect or may reoccur in waves; our post-restructuring focus on geographies where there are existing, active ZULRESSO treating sites may not be sufficient for us to achieve success from the sale of ZULRESSO or to generate revenues at meaningful

levels or at levels necessary to justify our investment even after the impact of the COVID-19 pandemic lessens; we may not be able to overcome the barriers to treatment with ZULRESSO or we may continue to

encounter other issues or challenges in commercializing ZULRESSO which could further limit the potential of ZULRESSO and the timing and amount of future revenues; results achieved with use of ZULRESSO in the treatment of PPD in commercial use may be

different than observed in clinical trials, and may vary among patients; the number of women with PPD or the unmet need for additional treatment options may be significantly smaller than we expect; we may not realize expected cost savings from our

restructuring, including the anticipated decrease in external spend, at the levels we expect; we may encounter delays in initiation or conduct of our planned clinical trials, including slower than expected site initiation or enrollment, that may

impact our ability to meet our expected time-lines and increase our costs; we may not be able to mitigate the impact of COVID-19 on our clinical development timelines and the impact may be more significant

than we expect and may negatively impact expected site initiation or enrollment in our clinical trials, or cause us to pause trials or not be able to use data, in each case which may significantly impact our ability to meet our expected time-lines

or may significantly impact the integrity or sufficiency of the data from our trials or increase our costs or cause us to have to change our plans; the internal and external costs required for our ongoing and planned activities, and the resulting

impact on expense and use of cash, may be higher than expected which may cause us to use cash more quickly than we expect or change or curtail some of our plans or both; our expectations as to expenses,

year-end cash and cash needs may prove not to be correct for other reasons such as changes in plans or actual events being different than our assumptions; we may be opportunistic in our future financing plans

even if available cash is sufficient; we may not be successful in our development of any of our product candidates in any indication we are currently pursuing or may in the future pursue; success in our

non-clinical studies or in earlier clinical trials may not be repeated or observed in ongoing or future studies, and ongoing and future non-clinical and clinical results

may not meet their primary or key secondary endpoints or be sufficient to file for or gain regulatory approval to market the product without further development work or may not support further development at all; we may encounter adverse events at

any stage of development that negatively impact further development or that require additional nonclinical and clinical work which may not yield positive results; we may encounter different or more severe adverse events at the higher doses we are

planning to study in new trials; we may encounter issues with the efficacy or durability of short-term treatment, or co-initiated treatment with zuranolone or safety and efficacy concerns with respect to

retreatment that require additional studies be conducted; the FDA may ultimately decide that the design or results of our completed and planned clinical trials for any of our product candidates, even if positive, are not sufficient for regulatory

approval in the indications that are the focus of our development plan; other decisions or actions of the FDA or other regulatory agencies may affect the initiation, timing, design, size, progress and cost of clinical trials and our ability to

proceed with further development; we may encounter technical and other unexpected hurdles in the development and manufacture of our product candidates which may delay our timing or change our plans or increase our costs; as well as those risks more

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.

Inc. and Subsidiaries

Condensed Consolidated Statements of Operations

(in thousands, except share and per share data)

Sage Therapeutics, Inc. and Subsidiaries

Condensed Consolidated Balance Sheets

About ZULRESSO (brexanolone) CIV injection

ZULRESSO, the first medicine specifically approved by the U.S. Food and Drug Administration (FDA) for the treatment of postpartum depression (PPD) in

adults, is a positive allosteric modulator of both synaptic and extrasynaptic GABAA receptors. Allosteric modulation of neurotransmitter receptor activity results in varying degrees of desired activity rather than complete activation or inhibition

IMPORTANT SAFETY INFORMATION

What is the most important information I should know about ZULRESSO?

ZULRESSO can cause serious side effects, including:

Before receiving ZULRESSO, tell your healthcare provider

about all your medical conditions, including if you:

Tell your healthcare

provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

ZULRESSO and some medicines may interact with each other and cause serious side effects.

Especially tell your healthcare provider if you take other antidepressants, opioids, or Central Nervous System (CNS) depressants (such as

Know the medicines you take. Keep a list of them to show your healthcare provider and pharmacist when you

get a new medicine. Your healthcare provider will decide if other medicines can be taken with ZULRESSO.

How will I receive ZULRESSO?

ZULRESSO is given to you by continuous intravenous (IV) infusion into your vein. The infusion will last for a total of 60 hours (2.5 days).

What should I avoid while receiving ZULRESSO?

What are the possible side effects of ZULRESSO?

ZULRESSO can cause serious side effects, including:

How can I watch for and try to prevent suicidal thoughts and actions?

healthcare provider right away if you have any of the following symptoms, especially if they are new, worse, or worry you:

The most common side effects of ZULRESSO include:

These are not all the side effects of ZULRESSO.

doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.