Optimer Pharmaceuticals Presents Results From Fidaxomicin Phase 3 Study for the Treatment...

Sun May 17, 2009 3:30am EDT

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Optimer Pharmaceuticals Presents Results From Fidaxomicin Phase 3 Study for
the Treatment of Clostridium difficile Infection

Positive data from subgroup analysis presented at 19th annual European
Congress of Clinical Microbiology and Infectious Diseases (ECCMID) meeting in
Helsinki, Finland

SAN DIEGO, May 17 /PRNewswire-FirstCall/ -- Optimer Pharmaceuticals, Inc.
(Nasdaq: OPTR) announced that the results from its North American Phase 3
clinical study of fidaxomicin in patients with Clostridium difficile infection
(CDI) were presented today by clinical investigator Thomas J. Louie, M.D. for
the first time in an oral presentation at the 19th annual European Congress of
Clinical Microbiology and Infectious Diseases (ECCMID) in Helsinki, Finland.

(Logo:  http://www.newscom.com/cgi-bin/prnh/20090413/LA97352LOGO)

Dr. Louie presented the positive top-line results that the Company had
previously announced in November 2008.  The trial met its primary endpoint
with fidaxomicin achieving clinical cure compared to Vancocin(R). In addition,
patients treated with fidaxomicin experienced a reduction in CDI recurrence
compared to Vancocin (p=0.004) and had a higher global cure (cure with no
recurrence within four weeks) compared to Vancocin (p=0.006).

"This study showed that fidaxomicin is as effective as vancomycin for
treatment of C. Difficile diarrhea, including treatment of infection by the
hyper virulent NAP1/ribotype 027 outbreak strain. Moreover, compared to
vancomycin, recurrence of CDI is significantly less likely to occur following
fidaxomicin therapy. Combining cure of CDI and freedom from recurrence,
fidaxomicin is superior to vancomycin as treatment for this serious and common
cause of infectious diarrhea," said Thomas J. Louie, M.D., Medical Director,
Infection Prevention and Control for the Calgary Health Region and professor
in the Departments of Medicine and Microbiology-Infectious Diseases,
University of Calgary. "These findings indicate that fidaxomicin offers both
highly effective but more selective therapy that is less damaging to the
normal intestinal bacteria that protect against recurrence of CDI." 

Additional findings also presented for the first time include a subgroup
analysis of clinical cure and recurrence rates for fidaxomicin compared to
Vancocin, as well as baseline demographic and disease characteristics.
Clinical cure rates for fidaxomicin and Vancocin were similar in each of the
following subgroups: patient status (in-patient/out-patient), age (under/over
65) and strain type (BI/NAP1/027). Most notably, fidaxomicin showed a
reduction across several subgroups in recurrence rates compared to Vancocin in
both out-patient and in-patient settings, as well as in patients both over and
under the age of 65.  The recurrence rates in the BI/NAP1/027 subgroup were
similar between fidaxomicin and Vancocin. 

    Per Protocol                          Fidaxomicin     Vancocin(R) capsules
    (microbiologically evaluable)         (200mg bid)         (125mg qid)

    Recurrence Rates by Subgroup
    Patient Status
      In-patient                          17.9% (19/106)      26.1% (29/111)
      Out-patient                          8.6% (9/105)       21.8% (24/110)

      < 65                                 9.5% (12/126)      18.6% (22/118)
      >/= 65                              18.8% (16/85)       30.1% (31/103)

    Strain Type
     BI (NAP1/027)                        25.0% (11/44)       24.1% (13/54)
    Overall                               13.3% (28/211)      24.0% (53/221)

Baseline demographic and disease characteristics of study participants were
similar between the fidaxomicin and Vancocin arms.  The BI/NAP1/027 hyper
virulent strain of C. difficile was present in 36% of patients in the study.
46% of the patients were over the age of 65, 56% were in-patients, 17% had a
prior episode of CDI and study participants had an average of 8.3 bowel
movements per day. 

The incidence of adverse events and serious adverse events between the
fidaxomicin and Vancocin arms was similar.

Additional detailed data from the study will be presented at medical
conferences throughout the year.

Fidaxomicin Clinical Study Design

629 adult subjects were enrolled in this multi-center, randomized,
double-blind Phase 3 clinical trial, which was the largest such trial for the
treatment of CDI.  Subjects with confirmed CDI received either 200 mg
fidaxomicin dosed orally twice daily or 125 mg Vancocin dosed orally four
times daily. This study was conducted in more than 100 clinical sites
throughout North America.  The objective of the study was to show that a
10-day course of fidaxomicin was at least as efficacious (non-inferior) and
safe as a 10-day course of Vancocin (vancomycin hydrochloride capsules, USP)
for the treatment of CDI.  

The primary endpoint of the study was clinical cure defined as patients
requiring no further CDI therapy two days after completion of study
medication, as determined by the investigator.  The secondary endpoint
evaluated CDI recurrence up to four weeks post therapy with recurrence defined
as the return of diarrhea associated with CDI confirmed by a positive toxin
test.  Global cure was defined as patients who were cured and did not have a

About Clostridium Difficile Infection

CDI has become a growing problem in hospitals, long-term care facilities and
in the community.  It is a serious illness caused by infection of the inner
lining of the colon by C. difficile bacteria, which produce toxins that cause
inflammation of the colon, severe diarrhea and, in the most serious cases,
death.  CDI typically develops from the use of broad-spectrum antibiotics that
disrupt normal gastrointestinal (gut) flora, allowing C. difficile bacteria to

Current therapeutic options for CDI include metronidazole and oral vancomycin.
 However, approximately 20% to 30% of CDI patients who initially respond to
these treatments experience a clinical recurrence following cessation of
antibiotic administration.

Primary risk factors for CDI include broad-spectrum antibiotic use, advanced
age (over 65), emerging hyper-virulent strains (NAP1/027, 078, 001) of C.
difficile, and previous exposure to CDI that lead to recurrence. Higher
incidence, increased treatment failures, and recurrence with standard
therapies have resulted in greater awareness and concern of CDI among medical
professionals and public health officials. 

About Fidaxomicin

Fidaxomicin is the first in a new class of antibiotics called macrocyclics,
which inhibit the bacterial enzyme RNA polymerase, resulting in the death of
Clostridium difficile. The narrow spectrum profile of fidaxomicin may
eradicate Clostridium difficile selectively with minimal disruption to the
normal intestinal flora. This may facilitate the return of the normal
physiological conditions in the colon and reduce the probability of CDI

About Optimer Pharmaceuticals

Optimer Pharmaceuticals, Inc. is a biopharmaceutical company focused on
discovering, developing and commercializing innovative anti-infective products
to treat serious infections and address unmet medical needs. Optimer has two
late-stage anti-infective product candidates under development. Fidaxomicin,
formerly known as OPT-80, is the only antibiotic therapy currently in Phase 3
worldwide clinical development for Clostridium difficile infection. 
Prulifloxacin is an antibiotic which has completed two Phase 3 clinical trials
for the treatment of travelers' diarrhea, a form of infectious diarrhea. 
Additional information 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 fidaxomicin to
treat CDI and 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
fidaxomicin research and development efforts, the timing and status of its
clinical development of fidaxomicin, including the fact that prior clinical
results may not predict future results, and other risks detailed in Optimer's
filings with the Securities and Exchange Commission. 


    Optimer Pharmaceuticals, Inc.
    John Prunty, CFO & VP, Finance
    Christina Donaghy, Corporate Communications Manager

    Porter Novelli Life Sciences
    Jason I. Spark, Vice President

SOURCE  Optimer Pharmaceuticals, Inc.

John Prunty, CFO & VP, Finance, or Christina Donaghy, Corporate Communications
Manager, both of Optimer Pharmaceuticals, Inc., +1-858-909-0736; or Jason I.
Spark, Vice President of Porter Novelli Life Sciences +1-619-849-6005, for
Optimer Pharmaceuticals, Inc.
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