Sage Therapeutics Announces Third Quarter 2024 Financial Results and Highlights Pipeline and Business Updates Achieved $11 million in ZURZUVAE (zuranolone) collaboration revenue during the third quarter of 2024 (50% of t

Sage Therapeutics Announces Third Quarter 2024 Financial Results and Highlights Pipeline

and Business Updates

Achieved $11 million in ZURZUVAE (zuranolone)

collaboration revenue during the third quarter of 2024 (50% of the net revenue recorded by Biogen), representing 49% growth from the second quarter

Sage and Biogen will not pursue further development of zuranolone in major depressive disorder (MDD) in the U.S.

Topline data from the DIMENSION Study in Huntington s Disease (HD) expected late 2024

Cash, cash equivalents and marketable securities of $569 million as of September 30, 2024

CAMBRIDGE, Mass. October 29, 2024 Sage Therapeutics, Inc. (Nasdaq: SAGE), today reported business highlights and

financial results for the third quarter ended September 30, 2024.

We are committed to harnessing the full potential of ZURZUVAE as a

transformative treatment for women with postpartum depression. Our encouraging third quarter results, highlighted by continued growth in revenue and shipments, brings us one step closer to our goal of establishing ZURZUVAE as the standard of care to

help more women suffering from this debilitating condition, said Barry Greene. Looking forward, we believe that our strategic decisions, including the recent reorganization, will best-position Sage to foster long-term growth and support

our mission of better brain health for patients.

Third Quarter 2024 Portfolio Updates

Sage and its collaborator, Biogen, are

focused on the goal of establishing ZURZUVAE as the first line therapy and standard of care for women with postpartum depression (PPD). As of the third quarter ended September 30, 2024, the following results had been achieved:

Related to payor coverage, as of September 30, 2024:

In terms of prescriber trends:

Zuranolone Business Update

August 2023, the FDA issued a Complete Response Letter for the New Drug Application for zuranolone in the treatment of adults with MDD. Sage and Biogen will not pursue further development of zuranolone as a treatment for MDD in the U.S. based on the

significant new investment and time we expect would be needed to conduct additional studies. Sage plans to prioritize its resources on supporting the PPD patient community.

Sage plans to sunset ZULRESSO (brexanolone) as a part of its strategic shift to further focus on the commercialization of ZURZUVAE for the treatment of women with PPD. ZULRESSO will be commercially available until

Dalzanemdor (SAGE-718)

Sage recently announced results from the Phase 2 LIGHTWAVE Study in the treatment of mild cognitive impairment and mild dementia in Alzheimer s Disease

(AD). The LIGHTWAVE Study did not demonstrate a statistically significant difference from baseline in participants treated with dalzanemdor versus placebo on the Wechsler Adult Intelligence Scale Fourth Edition

(WAIS-IV) Coding Test at Day 84, the primary endpoint. Dalzanemdor was generally well-tolerated and no new safety signals were observed. The majority of treatment emergent adverse events were mild to moderate

in severity. Based on these data, the Company does not plan further clinical development of dalzanemdor in AD.

Ongoing studies in the dalzanemdor

clinical program include:

expects to report topline data from the Phase 2 DIMENSION Study of dalzanemdor in cognitive impairment associated with HD later this year.

In September, Sage announced that Biogen terminated its rights under the collaboration and license

agreement with Sage specific to the SAGE-324 program. The companies previously announced negative results from the Phase 2 KINETIC 2 Study of investigational SAGE-324

for the chronic treatment of essential tremor (ET) and discontinued further clinical development of SAGE-324 in ET. Under the terms of the collaboration and license agreement, the termination will be effective

on February 17, 2025, and Sage will resume full ownership of SAGE-324 at that time. Sage is continuing to evaluate other potential indications, if any, for

Recent Period Business Update

In October, Sage announced a strategic reorganization of its business operations to support the ongoing launch of ZURZUVAE in PPD and focus pipeline

development efforts ahead of the clinical study readout for dalzanemdor in HD expected later this year. The reorganization is intended to enable Sage to strengthen its balance sheet, extend cash runway, and position the company for long-term growth

potential and is planned to be substantially completed by the end of the fourth quarter of 2024.

FINANCIAL RESULTS FOR THE THIRD QUARTER 2024

Sage will host a conference call and webcast today, October 29, 2024, at 4:30 p.m. ET to review its third quarter 2024 financial

results and discuss 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 following the completion of

the event and will be archived for up to 30 days.

About Sage Therapeutics

Sage Therapeutics (Nasdaq: SAGE) is a biopharmaceutical company committed to our mission of pioneering solutions to deliver life-changing brain health

medicines, so every person can thrive. Sage developed the only two FDA-approved treatments indicated for postpartum depression and is advancing a robust pipeline to target unmet needs in brain health. Sage was

founded in 2010 and is headquartered in Cambridge, Mass. Find out more at www.sagerx.com or engage with us on Facebook, LinkedIn, Instagram, and X.

Forward-Looking Statements

Various statements in

this release concern Sage s future expectations, plans and prospects, including without limitation our statements regarding: our plans, expectations and goals for commercialization of ZURZUVAE as a treatment for women with PPD, including our

goal to establish ZURZUVAE as the first line therapy and standard of care in this indication; our beliefs that our strategic decisions, including implementation of the October 2024 reorganization, will reduce our operating expenses, foster long-term

growth and support our mission; our belief in the potential for ZURZUVAE and that ZURZUVAE will be successful as a transformative treatment in helping women with PPD; anticipated timelines for completion of enrollment in clinical trials and

reporting of results with respect to certain of our other programs, including the expected timing of readout of the DIMENSION Study of dalzanemdor in HD; our plans to not pursue further development of zuranolone as a treatment for MDD and

discontinue commercial availability of ZULRESSO as of December 31, 2024, and our strategic shift to further focus on commercialization of ZURZUVAE for the treatment of women with PPD; our expectations regarding expenses and our cash runway,

including our plans to update our cash runway guidance in the near future; our plans to evaluate next steps, if any, for the SAGE-324 program; our expectations related to the October 2024 reorganization,

including timing, cost savings, and our goals to position the company for long-term growth and focus pipeline development efforts; our belief in the potential profile and benefit of our product candidates, potential indications for our product

candidates, the potential for success of our programs, and the opportunity to help patients in various indications; our belief as to the key catalysts for our business and potential value creation; and the mission and goals 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 not realize cost savings

from the October 2024 reorganization at the levels we expect, and as a result, the reorganization may not strengthen our balance sheet, foster long-term growth, or enable us to extend our cash runway; our launch and

commercialization efforts in the U.S. with respect to ZURZUVAE for the treatment of women with PPD may not be successful, and we may be unable to generate revenues from sales of ZURZUVAE at the

levels or on the timing we expect or at levels or on the timing necessary to support our goals; early positive signs from launch or from our engagements with healthcare professionals, patients and payors related to ZURZUVAE may not be a signal of

the potential for future success; the number of women with PPD, the unmet need for additional treatment options, and the potential market for ZURZUVAE in women with PPD, may be significantly smaller than we expect; ZURZUVAE may not achieve the

clinical benefit, clinical use or level of market acceptance from healthcare professionals, patients or payors in the treatment of PPD we expect or we may encounter reimbursement-related or other market-related issues, including competition in the

market, or issues with our distribution network that impact the success of our commercialization efforts, including our ability to achieve access goals; ZURZUVAE may never become the first line treatment and standard of care for women with PPD; we

may encounter delays in initiation, conduct, completion of enrollment or completion and reporting of data with respect to any of our ongoing clinical trials, such as our plans disclose the results of the DIMENSION Study, including as a result of

slower than expected site initiation, slower than expected enrollment, the need or decision to expand the trials or other changes, that may impact our ability to meet our expected timelines and may increase our costs; success in earlier clinical

trials of any of our product candidates may not be repeated or observed in ongoing or future studies, and ongoing and future clinical trials may not meet their primary or key secondary endpoints, which may substantially impair development;

unexpected concerns may arise from additional data, analysis or results from any of our completed studies; decisions or actions of the FDA or the timing of meetings with the FDA may affect the timing, design, size, progress and cost of clinical

trials or the timing of data read-outs or our ability to proceed with further development or may impair the potential for successful development or the timing or success of filing for and gaining regulatory approval; we may encounter adverse events

at any stage that negatively impact further development and the potential for approval of our product candidates or the potential for successful commercialization of any our products or that require additional nonclinical and clinical work, which

may not yield positive results; the need to align with our collaborators may hamper or delay our development and commercialization efforts for the products or product candidates that are part of the collaboration or increase our costs; the

anticipated benefits of our ongoing collaborations, including the receipt of payments or the successful development or commercialization of products and generation of revenue, may never be achieved at the levels or timing we expect or at all; our

business may be adversely affected and our costs may increase if any of our key collaborators fails to perform its obligations or terminates our collaboration; 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 change or curtail some of our plans or both; we may not be successful in our efforts to gain regulatory approval of products beyond ZURZUVAE and

ZULRESSO; we may not achieve revenues from our products that may be successfully developed in the future, at levels we expect; additional funding may not be available on acceptable terms when we need it, which could hamper our development and

commercialization activities; any of the foregoing events could impair the value creation opportunities for our business; and we may encounter technical and other unexpected hurdles in the development and manufacture of our product candidates or the

commercialization of any current or future marketed product, which may delay our timing or change our plans, increase our costs or otherwise negatively impact our business; as well as those risks more fully discussed in the section entitled

Risk Factors in our most recent annual or quarterly report filed with the Securities and Exchange Commission, 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.

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)

SELECT IMPORTANT SAFETY INFORMATION FOR ZURZUVAE

ZURZUVAE (zuranolone) CIV, is a neuroactive steroid gamma-aminobutyric acid (GABA) A receptor positive modulator indicated for the treatment of postpartum

depression in adults.

This does not include all the information needed to use ZURZUVAE safely and effectively. See full prescribing information for

ZURZUVAE may cause serious side effects, including decreased awareness and alertness, which can affect your ability to drive safely or safely

do other dangerous activities. Do not drive, operate machinery, or do other dangerous activities until at least 12 hours after taking each dose. You may not be able to tell on your own if you can drive safely or tell how much ZURZUVAE is affecting

you. ZURZUVAE may cause central nervous system (CNS) depressant effects including sleepiness, drowsiness, slow thinking, dizziness, confusion, and trouble walking. Taking alcohol, other medicines that cause CNS depressant

effects such as benzodiazepines, or opioids while taking ZURZUVAE can make these symptoms worse and may also cause trouble breathing. ZURZUVAE is a federally controlled substance schedule IV

because it contains zuranolone, which can be abused or lead to dependence. Tell your healthcare provider right away if you become pregnant or plan to become pregnant during treatment with ZURZUVAE. You should use effective birth control

(contraception) during treatment with ZURZUVAE and for 1 week after the final dose. ZURZUVAE and other antidepressant medicines may increase the risk of suicidal thoughts and actions in people 24 years of age and younger. ZURZUVAE is not for use in

children. The most common side effects of ZURZUVAE include sleepiness or drowsiness, dizziness, common cold, diarrhea, feeling tired, weak, or having no energy, and urinary tract infection.

SELECT IMPORTANT SAFETY INFORMATION for ZULRESSO

ZULRESSO (brexanolone) CIV, is a neuroactive steroid gamma-aminobutyric acid (GABA) A receptor positive modulator indicated for the treatment of postpartum