Clostridium difficile Infection 'Epidemic' Leads to Calls for Emerging Next-Generation Therapies

World Experts Present on Challenges, Diagnosis and Treatment Strategies

BARCELONA, 21 April 2008 – Leading world experts in infectious disease have warned that the rapid spread of Clostridium difficile infection (CDI) has given rise to an epidemic, making it an urgent health priority.

The symposium, sponsored by Optimer Pharmaceuticals, Inc. (Nasdaq: OPTR), at the 18^th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) in Barcelona, Spain, highlighted the increasing prevalence of CDI. Dr. Ed. J. Kuijper, Medical Microbiologist at the Leiden University Medical Center, the Netherlands, said that the hyper-virulent NAP1/027 strain of Clostridium difficile was largely responsible for this emerging epidemic along with routine antibiotic use, and a lack of facilities for isolating infected patients.

“Epidemics involving type NAP1/027 have affected more than 250 hospitals in 17 European countries. This underlines the importance of continuous surveillance to observe changes in the epidemiology of individual C. difficile strains,” said Dr Kuijper.

The symposium, titled ‘Clostridium difficile-Associated Disease: Current Treatments and Challenges’ attracted over 400 clinical practitioners involved in the battle against infectious diseases. The meeting was co-chaired by John Bartlett, M.D., Professor of Medicine at the Johns Hopkins University of School of Medicine in Baltimore, Maryland and Carl-Erik Nord, M.D., Professor of Clinical Microbiology from the Department of Laboratory Medicine at the Karolinska University Hospital of the Karolinska Institute in Stockholm, Sweden.

CDI, responsible for  the most common form of hospital-acquired diarrhea, affects over 500,000 people in the United States[1] and one out of every 1,000 patients hospitalized in Europe.[2]  Higher incidence and severity of CDI, increased treatment failures with standard therapies[3], and the emergence of the highly virulent epidemic strain have combined to create a significant concern among public health officials, infectious diseases physicians, gastroenterologists, microbiologists and epidemiologists.

Patients who have been treated with broad spectrum antibiotics (those that affect a wide range of bacteria, including intestinal bacteria) are at greatest risk of CDI.  Many of the patients affected are elderly with serious underlying illnesses. Most infections occur in hospitals but can also occur in primary care settings.

“Important milestones in meeting the CDI challenge include developing next-generation therapies to improve clinical outcomes and also finding ways to enhance the body’s immunity to this infection,” said Dr. Mark Miller, M.D., FRCPC., Chair of Infection Prevention and Control, Chief of the Division of Clinical Microbiology and Head of the Division of Infectious Diseases at the Jewish General Hospital, Montreal, Canada.

“The most-commonly used available treatment, metronidazole, is now recognized to be inadequate for patients with moderate to severe CDI, leaving us with only one other option: the antibiotic vancomycin, which also has limitations. Newer and more efficacious treatments are desperately needed for this life-threatening illness.  Companies developing new CDI therapies should focus on three goals: speed up the time to recovery, prevent relapsing disease after the end of therapy, and eliminate death and disability from this infection.” 

Optimer is currently conducting phase 3 clinical trials in North America and Europe for its lead drug candidate, OPT-80 (formerly known as PAR-101 or Difimicin), a first-in-class macrocyclic antibiotic for the treatment of CDI.

OPT-80, which has been granted Fast Track status by the US Food and Drug Administration, provides a narrow spectrum of activity that is bactericidal against Clostridia and does not disturb normal intestinal microbes. It has shown no cross resistance with other anti-infectives. If approved, Optimer believes OPT-80 will address many of the problems of existing treatments by accelerating time to clinical cure, reducing rates of recurrence, and decreasing daily dose requirements.

-ENDS-

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About Optimer

Optimer Pharmaceuticals, Inc. is a biopharmaceutical company focused on discovering, developing and commercializing innovative anti-infective products for the treatment of serious infections. Optimer has two late-stage anti-infective product candidates in Phase 3 clinical trials.  Additional information regarding Optimer can be found at http://www.optimerpharma.com.

Forward-looking Statements

Statements included in this press release that are not a description of historical facts are forward-looking statements, including without limitation all statements related to incidence of CDI  and the ability of OPT-80 to address current treatment limitations. Words such as "believes," "anticipates," "plans," "expects," "intend," "will," "goal" and similar expressions are intended to identify forward-looking statements. The inclusion of forward-looking statements should not be regarded as a representation by Optimer that any of its plans will be achieved. Actual results may differ materially from those set forth in this release due to the risks and uncertainties inherent in Optimer's business including, without limitation, risks relating to: the timing, progress and likelihood of success of its product research and development programs, the timing and status of its preclinical and clinical development of potential drugs and other risks detailed in Optimer's filings with the Securities and Exchange Commission.