On June 24, 2020, Tetraphase Pharmaceuticals, Inc. (Tetraphase or the Company)
issued a press release announcing the execution of an Agreement and Plan of Merger (the Merger Agreement) with La Jolla Pharmaceutical Company, a California corporation (La Jolla or the Parent), and TTP Merger
Sub, Inc., a Delaware corporation and a wholly-owned subsidiary of La Jolla (the Purchaser). The Merger Agreement provides for the acquisition of Tetraphase by La Jolla through a cash tender offer (the Offer) by the Purchaser
for all of Tetraphases outstanding shares of common stock (Common Stock), for (1) $2.00 per share of Common Stock, and (2) one contingent value right per share representing the right to receive certain consideration based on
the achievement of net sales milestones, in an aggregate amount of up to $16.0 million. Upon completion of the Offer, and subject to the satisfaction or waiver of the conditions set forth in the Merger Agreement, Purchaser will be merged with
and into Tetraphase, with Tetraphase surviving as a wholly-owned subsidiary of La Jolla (the Merger).
A copy of the press release was filed
as Exhibit 99.1 to Tetraphases Current Report on Form 8-K filed with the Securities and Exchange Commission (the SEC) on June 24, 2020, and is incorporated herein by reference.
Additional Information
The tender offer for the
outstanding shares of the Company referenced in this document has not yet commenced. This document is for informational purposes only and is neither an offer to purchase nor a solicitation of an offer to sell any securities, nor is it a substitute
for the tender offer materials that La Jolla and its subsidiary will file with the SEC. At the time the tender offer is commenced, the Parent will file with the SEC a Tender Offer Statement on Schedule TO, and thereafter the Company will file a
Solicitation/Recommendation Statement with the SEC on Schedule 14D-9 with respect to the tender offer. The Companys stockholders and other investors are strongly advised to read the tender offer
materials (including the Offer to Purchase, the related Letter of Transmittal and certain other tender offer documents that have yet to be filed) and the Solicitation/Recommendation Statement because they will contain important information that
should be read carefully before any decision is made with respect to the tender offer. The Tender Offer Statement and the Solicitation/Recommendation Statement will be available for free at the SECs website at www.sec.gov. Free copies of these
materials and other tender offer documents will be made available by the information agent for the tender offer.
In addition to the Offer to Purchase,
the related Letter of Transmittal and certain other tender offer documents, the Company and the Parent file annual, quarterly and special reports, proxy statements and other information with the SEC. The Companys filings with the SEC are
available to the public from the website maintained by the SEC at www.sec.gov. Additional copies of the tender offer materials may be obtained for free by contacting La Jolla Pharmaceutical Company at 4550 Towne Centre Court, San Diego,
California 92121, Attention: Chief Financial Officer.
Forward-Looking Statements
Any statements in this document regarding the proposed transaction between the Parent and the Company, the expected timetable for completing the transaction,
future financial and operating results, benefits and synergies of the transaction, future opportunities for the combined company and any other statements about the Company managements future expectations, beliefs, goals, plans or prospectus
constitute forward-looking statements. Any statements that are not statements of historical fact (including statements containing believes, anticipates, plans, expects, may,
will, would, intends, estimates, and similar expressions), should also be considered to be forward-looking statements. There are a number of important factors that could cause actual results or events
to differ materially from those indicated by such forward-looking statements, including the risk that the proposed Offer and Merger may not be completed in a timely manner, or at all, which may adversely affect the Companys business and the
price of its Common Stock; risks as to the percentage of the Companys stockholders tendering their shares in the Offer; the possibility that competing offers will be made; the failure to satisfy all of the closing conditions of the Offer
and/or the Merger; the occurrence of any event, change or other circumstance that could give rise to the termination of the Merger Agreement, the Offer and/or the other proposed transactions; the effect of the announcement or pendency of the Offer,
Merger or other proposed transactions on the Companys business, operating results, and relationships with customers, suppliers, competitors and others; risks that the Offer, Merger or other proposed transactions may disrupt the Companys
current plans and business operations; potential difficulties retaining employees as a result of the proposed transactions; risks related to the diverting of managements attention from the Companys ongoing business operations; the
outcome of any legal proceedings