Sage Therapeutics Prices Public Offering of Common Stock

CAMBRIDGE, Mass.–(BUSINESS WIRE)–Sage Therapeutics (Nasdaq: SAGE), a clinical-stage biopharmaceutical
company developing novel medicines to treat life-altering central
nervous system (CNS) disorders, today announced the pricing of an
underwritten public offering of 3,529,411 shares of its common stock at
a public offering price of $85.00 per share. The gross proceeds to Sage
Therapeutics from the offering, before deducting the underwriting
discounts and commissions and other estimated offering expenses, are
expected to be approximately $300.0 million. The offering is expected to
close on or about November 17, 2017, subject to the satisfaction of
customary closing conditions. In addition, Sage has granted the
underwriters a 30-day option to purchase up to an additional 529,411
shares of its common stock.

J.P. Morgan Securities LLC, Goldman Sachs & Co. LLC and Morgan Stanley
are acting as joint book-running managers for the offering. Cowen and
Company, LLC and Leerink Partners LLC are serving as lead managers. The
offering is subject to market and other conditions, and there can be no
assurance as to whether or when the offering may be completed, or as to
the actual size or terms of the offering.

The shares are being offered by Sage pursuant to an automatically
effective shelf registration statement on Form S-3 that was previously
filed with the Securities and Exchange Commission (SEC). A preliminary
prospectus supplement relating to and describing the terms of the
offering was filed with the SEC on November 13, 2017. The final
prospectus supplement relating to the offering will be filed with the
SEC and will be available on the SEC’s web site at www.sec.gov.

When available, copies of the final prospectus supplement and the
accompanying prospectus relating to these securities may also be
obtained by contacting one of the following: J.P. Morgan Securities LLC,
c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood,
New York 11717 or by telephone at 866-803-9204; Goldman Sachs & Co. LLC
at Prospectus Department, 200 West Street, New York, New York 10282, by
telephone at 866-471-2526, by facsimile at 212-902-9316 or by e-mail at prospectusgroup-ny@ny.email.gs.com;
or Morgan Stanley & Co. LLC at Prospectus Department, 180 Varick Street,
2nd Floor, New York, NY 10014.

This press release shall not constitute an offer to sell or the
solicitation of an offer to buy, nor shall there be any sale of, these
securities in any state or jurisdiction in which such offer,
solicitation or sale would be unlawful prior to the registration or
qualification under the securities laws of such state or jurisdiction.

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, a proprietary IV
formulation of brexanolone (SAGE-547), has completed two Phase 3
clinical trials in postpartum depression. Sage is developing its next
generation modulators, including SAGE-217 and SAGE-718, in various CNS
disorders.

Forward-Looking Statements

Various statements in this release concerning Sage’s future
expectations, plans and prospects, including without limitation, Sage’s
expectations regarding the timing and completion of its proposed public
offering of its common stock, and Sage’s plans with respect to its
product candidates and other activities, constitute forward-looking
statements for the purposes of the safe harbor provisions under 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 Sage’s control, which could cause actual results to differ
materially from those indicated by these forward-looking statements,
including, without limitation: the uncertainties related to market
conditions and Sage’s ability to complete the public offering on
accepted terms or at all; the risk that Sage may not be able to satisfy
the customary closing conditions related to the proposed offering; the
potential that Sage’s completed, ongoing and future clinical and
non-clinical data may not be sufficient to file for or gain regulatory
approval to launch and commercialize its product candidates; the
potential that future pre-clinical and clinical results may be negative
or may not support further development of Sage’s product candidates or
that Sage may not be able to successfully demonstrate the efficacy and
safety of its product candidates at each stage of development in a
manner sufficient to obtain approval; the risk that actions or decisions
of regulatory agencies may affect the initiation, timing and progress of
clinical trials; the potential for unexpected adverse events in the
conduct of one of Sage’s clinical trials to impact its ability to
continue the clinical trial or further development of a product
candidate; the risk that Sage may encounter other unexpected hurdles or
issues in the development and manufacture of its product candidates that
may impact its timing or progress, as well as those risks more fully
discussed in the section entitled “Risk Factors” in Sage’s most recent
quarterly report on Form 10-Q, as well as discussions of potential
risks, uncertainties, and other important factors in Sage’s subsequent
filings with the Securities and Exchange Commission. In addition, any
forward-looking statements represent Sage’s views only as of today and
should not be relied upon as representing its views as of any subsequent
date. Sage explicitly disclaims any obligation to update any
forward-looking statements.

Contacts

Investor Contact:
Sage Therapeutics
Paul Cox,
617-299-8377
paul.cox@sagerx.com
or
Media
Contact:

Suda Communications LLC
Maureen L. Suda,
585-355-1134
maureen.suda@sagerx.com