Filing Details

Daniel Radden

c/o Armistice Capital, LLC

510 Madison Avenue

7^th Floor

New York, NY 10022

Telephone Number: (212) 231-4930

(Name, Address and Telephone Number of Person Authorized to Receive

Notices and Communications)

The name of the issuer is Tetraphase Pharmaceuticals, Inc., a Delaware corporation (the "Issuer"). The address of the Issuer's principal executive offices is 480 Arsenal Way, Watertown, Massachusetts 02472. This Schedule 13D relates to the Issuer's Common Stock, $0.001 par value (collectively, the "Shares").

Armistice Capital is an investment adviser registered with the Securities and Exchange Commission (the “SEC”) that is principally engaged in the business of providing investment management services to private investment vehicles, including the Master Fund. The principal business address of Armistice Capital is 510 Madison Avenue, 7^th Floor, New York, New York 10022.

The Master Fund is principally engaged in the business of investing in securities. The principal business address of the Master Fund is c/o dms Corporate Services Ltd., 20 Genesis Close, P.O. Box 314, Grand Cayman KY1-1104, Cayman Islands. The board of directors of the Master Fund consists of Steven Boyd, Kevin A. Phillip and Gregory S. Bennett.

Steven Boyd is the managing member of Armistice Capital and a director of the Master Fund. Mr. Boyd’s business address is 510 Madison Avenue, 7^th Floor, New York, New York 10022.

The funds for the purchase of the 1,419,507 Shares beneficially owned by the Reporting Persons came from the working capital of the Master Fund. No borrowed funds were used to purchase the Shares, other than any borrowed funds used for working capital purposes (including certain leverage arrangements) in the ordinary course of business.

On January 22, 2020, the Master Fund entered into a private investment in public equity agreement with the Issuer (the "PIPE Agreement"), pursuant to which the Issuer agreed to issue and sell to the Master Fund (i) 1,270,000 Shares; (ii) pre-funded warrants to purchase 2,063,334 Shares (the “Unregistered Pre-Funded Warrants”); and (iii) unregistered common warrants to purchase 3,333,334 Shares (the “Unregistered Common Warrants”). The Unregistered Pre-Funded Warrants will be exercisable at an exercise price of $0.001 per Share and have no expiration. The Unregistered Common Warrants will be exercisable at an exercise price of $2.87 per share and expire five years from the date of issuance. The Master Fund may not exercise all or any portion of such warrants if, upon giving effect to such exercise the aggregate number of Shares beneficially owned by Master Fund would exceed 9.99% of the outstanding Shares

The total amount paid by the Reporting Persons for the warrants and shares acquired pursuant to the PIPE Agreement is $10,000,002.

Pursuant to the PIPE Agreement, the Issuer also appointed Mr. Boyd and Keith Maher, a Managing Director at Armistice Capital, to its board of directors (the “Board”) effective immediately.

In connection with the PIPE Agreement, the Issuer and the Master Fund also entered into a Registration Rights Agreement dated January 22, 2020 (the “Registration Rights Agreement”) pursuant to which the Issuer has agreed to file a registration statement (“Registration Statement”) covering the resale by the Master Fund of the (i) Shares  acquired by the Master Fund pursuant to the PIPE Agreement and (ii) the shares of the Issuer’s common stock issuable upon exercise of the Unregistered Pre-Funded Warrants and the Unregistered Common Warrants pursuant to the PIPE Agreement (the “Unregistered Warrant Shares”) on the later of 30 days following the date of the Registration Rights Agreement or the second trading day following the date the Issuer files its Annual Report on Form 10-K for the fiscal year ended December 31, 2019 with the SEC. The Issuer also agreed to use commercially reasonable efforts to cause such Registration Statement to become effective and to keep such Registration Statement effective until the date the Shares acquired by the Master Fund pursuant to the PIPE Agreement and Unregistered Warrant Shares covered by such Registration Statement have been sold or may be resold pursuant to Rule 144 without restriction.

The foregoing was a summary of certain material terms of the (i) PIPE Agreement; (ii) Form of Unregistered Pre-Funded Warrant; (iii) Form of Unregistered Common Warrant; and (iv) Registration Rights Agreement. The foregoing descriptions are not, and do not purport to be, complete and are qualified in their entirety by reference to the full text of the forms of these documents, which have been filed as Exhibit C, D, E and F, respectively, hereto, and are incorporated herein by reference.

The Reporting Persons purchased the Shares for investment in the ordinary course of their investment activities based on the Reporting Persons’ belief that the Shares, when purchased, were undervalued and represented an attractive investment opportunity. The Reporting Persons intend to review their investment in the Issuer on a continuing basis. Depending on various factors including, without limitation, the Issuer’s financial position, the price levels of the Shares, conditions in the securities markets and general economic and industry conditions, the Reporting Persons may in the future take such actions with respect to their investment in the Issuer as they deem appropriate including, without limitation, engaging in communications with management and/or the Board, engaging in discussions with stockholders of the Issuer and others about the Issuer and the Reporting Persons’ investment, reshaping the Issuer's corporate strategy, revitalizing the Issuer’s promising Research and Development pipeline, restructuring the Issuer’s expense base, recommending business development transactions including mergers and acquisitions, proposing changes to management, operations and the structure of the Board (including the composition of the Board), purchasing additional Shares, selling some or all of their Shares, engaging in short selling of or any hedging or similar transaction with respect to the Shares, or changing their intention with respect to any and all matters referred to in subparagraphs (a) - (j) of Item 4 of Schedule 13D.

Except as otherwise set forth herein, the Reporting Persons do not have any present plans or proposals which would relate to, or result in, the matters set forth in subparagraphs (a) – (j) of Item 4 of Schedule 13D. However, subject to market conditions and in compliance with applicable securities laws, the Reporting Persons reserve the right, at a later date, to effect one or more of such changes or transactions in the number of Shares they may be deemed to beneficially own in open-market or privately negotiated transactions, on such terms and at such times as the Reporting Persons may deem advisable.

As of the date hereof, each of the Reporting Persons may be deemed to be the beneficial owner of 1,419,507 Shares, constituting 19.9% of the Shares, based upon 7,116,163 Shares outstanding as of the date hereof, as adjusted for warrants of the Issuer beneficially owned by the Reporting Persons. Each of the Reporting Persons has the sole power to vote or direct the vote of 0 Shares and the shared power to vote or direct the vote of 1,419,507 Shares. Each of the Reporting Persons has the sole power to dispose or direct the disposition of 0 Shares and the shared power to dispose or direct the disposition of 1,419,507Shares.

The material terms of the PIPE Agreement are described in Item 4 above and incorporated by reference herein. The other transactions in the Shares by the Reporting Persons during the past sixty days are set forth on Exhibit B. Each reported transaction on Exhibit B was an open-market transaction. There have been no other transactions in the Shares by the Reporting Persons during the past sixty days.

(e)

N/A

The information set forth in Item 4 above is incorporated by reference in its entirety in this Item 6. In addition, prior to entering into the PIPE Agreement, the Master Fund held (i) 1,430,493 pre-funded warrants of the Issuer, subject to a blocker provision that prevents the Master Fund from exercising the warrants if it would be more than a 9.99% beneficial owner of the Shares following such exercise; and (ii) 2,130,493 warrant shares of the Issuer, subject to a blocker provision that prevents the Master Fund from exercising the warrants if it would be more than a 4.99% beneficial owner of the Shares following such exercise.

Except as set forth herein, the Reporting Persons do not have any contract, arrangement, understanding or relationship with any person with respect to securities of the Issuer that is not described in this Schedule 13D and/or incorporated by reference herein.

Exhibit F:

Name: Steven Boyd

Title: Managing Member

Name: Steven Boyd

Title: Director

Name: Steven Boyd

Title: Managing Member

Name: Steven Boyd

Title: Director