Cubist Pharmaceuticals to Acquire Optimer Pharmaceuticals For $10.75 In Cash

Cubist Pharmaceuticals, Inc.

and Optimer Pharmaceuticals, Inc.

today announced that they have signed a merger agreement under which Cubist will acquire all of the outstanding shares of Optimer common stock for $10.75 per share in cash, or approximately $535 million on a fully diluted basis. In addition to the upfront cash payment, each stockholder of Optimer will receive a Contingent Value Right (CVR), which is expected to be publicly traded, entitling the holder to receive an additional one-time cash payment of up to $5.00 for each share they own if certain net sales of DIFICID®(fidaxomicin) are achieved, or a total transaction value of up to $801 million on a fully diluted basis. The transaction has been approved by the Boards of Directors of both companies. Cubist will host a conference call and webcast today at 6:00 p.m. ET (details below). Optimer received U.S. Food and Drug Administration approval in May 2011 for DIFICID, the first antibacterial drug approved in more than 25 years to treat Clostridium difficile-associated diarrhea (CDAD) in adults 18 years of age or older. In two large Phase 3 clinical studies, DIFICID 200 mg twice daily was non-inferior to oral vancomycin 125 mg four times daily in clinical response at the end of 10 days of treatment, and was superior to vancomycin in sustained clinical response through 25 days beyond the end of treatment. The CDAD market is large, with over 700,000 cases annually in the U.S. alone and a high recurrence rate at 20-30%. Hospital stays related to CDAD increased four-fold from 1993 to 2009 and, according to the U.S. Centers for Disease Control and Prevention, the disease is estimated to be responsible for approximately 14,000 deaths per year in the U.S. DIFICID was launched in the U.S. in July 2011. In April 2011, Cubist and Optimer entered into a two-year agreement under which Cubist has been co-promoting DIFICID to physicians, hospitals, and other healthcare institutions in the U.S. Concurrently with the merger agreement, the companies have agreed to extend the co-promotion agreement for up to one year. Michael Bonney, Chief Executive Officer of Cubist, said, “Optimer is a natural fit for Cubist given our co-promotion of DIFICID and focus on the acute care and hospital environments. The transaction meets our strict criteria for acquisitions and is well aligned with our strategic goals – the Building Blocks of Growth. There is a significant and rising need for DIFICID as CDAD infections continue to be a growing clinical and economic burden globally. Given Cubist's outstanding hospital-based commercial infrastructure and our first-hand experience co-promoting DIFICID in the U.S., we are uniquely positioned to maximize DIFICID's full potential for the benefits of patients, hospitals and our shareholders. We expect a very smooth transition, and we look forward to its contributions to creating shareholder value for many years to come.” "I am pleased that we were able to successfully conclude our strategic review process with a transaction with Cubist. After a long and extensive process considering a range of alternatives with a number of parties, the Board of Optimer has determined that this transaction provides the best opportunity to optimize value for our stockholders by delivering an immediate upfront cash payment and a meaningful opportunity to participate in the future upside of DIFICID through the CVR,” said Dr. Hank McKinnell, Chairman and CEO of Optimer. “Cubist, a premier acute care and hospital commercialization organization, is well equipped to bring the benefits of DIFICID to patients. Extending our existing co-promote agreement with Cubist allows the continuation of Cubist's commitment to DIFICID and, in doing so, facilitates sustained DIFICID growth toward the achievement of the CVR.” Transaction Terms and Financial Highlights Terms of the contingent value right (CVR) call for an additional one-time cash payment of up to $5.00 per share based on cumulative net sales of DIFICID in the U.S. and Canada between July 1, 2013 and December 31, 2015. The CVR payment will be $3.00 if cumulative net sales exceed $250 million, $4.00 if cumulative net sales exceed $275 million and $5.00 if cumulative net sales exceed $300 million. It is expected that the CVR will be listed on the Nasdaq Stock Market. In addition, Cubist has committed to purchase $25 million of non-voting preferred stock of Optimer per quarter, commencing September 15, 2013, to address Optimer's near-term cash needs prior to closing. The transaction is expected to be accretive to Cubist's earnings in the first year post closing. The companies' expectation is to close the transaction later this year, subject to required regulatory approvals and other customary closing conditions, including stockholder approval. Morgan Stanley & Co. LLC is acting as the exclusive financial advisor to Cubist, and Ropes & Gray LLP is serving as legal counsel. J.P. Morgan Securities LLC and Centerview Partners LLC are acting as financial advisors to Optimer, and Sullivan & Cromwell LLP is serving as legal counsel. Optimer Second Quarter Financial Results Highlights Optimer's previously scheduled second quarter financial results conference call for August 1, 2013 has been cancelled. Optimer's unaudited financial results for the second quarter ended June 30, 2013 are the following: Second quarter 2013 DIFICID net product sales in the U.S. and Canada of $19.0 million, compared to $15.2 million in the corresponding quarter in 2012 and up 13% from $16.8 million in the first quarter of 2013 Second quarter 2013 total net revenues of $20.1 million Cash, cash equivalents and short-term investments at June 30, 2013 totaled $77.5 million 2013 net loss for the second quarter was $26.9 million, or $0.55 per share Optimer will report its complete unaudited financial results for the second quarter ended June 30, 2013, on August 1, 2013. Cubist Conference Call Information *********************CONFERENCE CALL & WEBCAST INFORMATION*********************** Tuesday, July 30, 2013 at 6:00 pm ET U.S./Canada Attendee Dial-in: (866) 706-4759 International Attendee Dial-in: (484) 756-4327 Attendee Passcode: 073013 24-HOUR REPLAY U.S./CANADA: (855) 859-2056 24-HOUR REPLAY INTERNATIONAL: (404) 537-3406 Conference ID: 26269970 CALL WILL ALSO BE BROADCAST LIVE, LISTEN ONLY, VIA THE WEB AT: https://cubist.webex.com/cubist/onstage/g.php?t=a&d=628926950 Attendee Password: 073013 Replay will be available for 90 days at www.cubist.com ********************************************************************************* Important Safety Information for DIFICID DIFICID is contraindicated in patients with hypersensitivity to fidaxomicin. DIFICID should not be used for systemic infections. Acute hypersensitivity reactions (angioedema, dyspnea, pruritus, and rash) have been reported. In the event of a severe reaction, discontinue DIFICID. Only use DIFICID for infection proven or strongly suspected to be caused by C. difficile. Prescribing DIFICID in the absence of a proven or strongly suspected C. difficile infection is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria. The most common adverse reactions reported in clinical trials are nausea (11%), vomiting (7%), abdominal pain (6%), gastrointestinal hemorrhage (4%), anemia (2%), and neutropenia (2%). About Cubist Cubist Pharmaceuticals, Inc. is a biopharmaceutical company focused on the research, development, and commercialization of pharmaceutical products that address significant unmet medical needs in the acute care environment. Cubist is headquartered in Lexington, Mass. Additional information can be found at Cubist's web site at www.cubist.com. About Optimer Optimer Pharmaceuticals, Inc is a global biopharmaceutical company currently focused on commercializing our antibiotic product DIFICID® (fidaxomicin) tablets in the United States and Canada, and developing other fidaxomicin products in the United States and worldwide, both independently and in our conjunction with partners and licensees. DIFICID, a macrolide antibacterial drug, was approved by the U.S. Food and Drug Administration on May 27, 2011, for the treatment of Clostridium difficile-associated diarrhea, or CDAD, in adults 18 years of age and older. Fidaxomicin has also received marketing authorization in other jurisdictions, including the European Union, where it is marketed under the trade name DIFICLIR™ by our licensee, Astellas Pharma Europe. CDAD is the most common symptom of Clostridium difficile infection, or CDI. Additional information can be found at http://www.optimerpharma.com.