SAN DIEGO, Calif., Nov 10, 2008 / Optimer Pharmaceuticals, Inc. (Nasdaq: OPTR) today released positive top-line results from a pivotal Phase 3 clinical study of the Company’s lead anti-infective drug candidate, OPT-80, in patients with Clostridium difficile Infection (CDI).   

 

92.1% of patients treated with OPT-80 (per protocol population) achieved clinical cure vs. 89.8% for Vancocin.  In addition, only 13.3% of patients treated with OPT-80 experienced a recurrence vs. 24.0% for Vancocin (p = 0.004).

Patients treated with OPT-80 had a global cure (cure with no recurrence within four weeks) of 77.7%, which was greater than Vancocin at 67.1% (p = 0.006). OPT-80 was well-tolerated.

The OPT-80 clinical trial (Protocol 101.1.C.003) is the largest single comparative study ever conducted against Vancocin. The detailed data from the study will be presented at a medical conference in the near future. Top-line trial results are summarized in the table below. 

Per Protocol                     OPT-80                              Vancocin(R) capsules                  p-value          95% Confidence Interval
(microbiologically evaluable)    (200mg bid)                         (125mg qid)
Clinical Cure                    92.1% (244/265 patients)            89.8% (254/283 patients)            NA               (-2.6, )(a)
Recurrence                       13.3          % (28/211)            24.0          % (53/221)            0.004            (-17.9, -3.3  )
Global Cure                      77.7          % (206/265)           67.1          % (190/283)           0.006            (3.1, 17.9    )

modified Intent-to-Treat (mITT)  OPT-80                              Vancocin(R) capsules                  p-value          95% Confidence Interval
                                 (200mg bid)                         (125mg qid)
Clinical Cure                    88.2% (253/287 patients)            85.8% (265/309 patients)            NA               (-3.1, )(a)
Recurrence                       15.4          % (39/253)            25.3          % (67/265)            0.005            (-16.6, -2.9  )
Global Cure                      74.6          % (214/287)           64.1          % (198/309)           0.006            (3.1, 17.7    )

(a) one-sided 97.5% CI
NA= Not Applicable (trial met non-inferiority endpoint)

The Per Protocol (Microbiologically Evaluable) Population is the
patient group with CDI confirmed by diarrhea with a positive toxin
assay, met all inclusion/exclusion criteria, and received at least
3 days of therapy and were considered a failure or at least 8 days
of therapy and were considered a cure.

The Modified Intent-to-Treat Population is the patient group with
CDI confirmed by diarrheawith a positive toxin assay and
received at least one dose of study medication.

 

In this multi-center, randomized, double-blind Phase 3 clinical trial, 629 adult subjects were enrolled. Subjects with confirmed CDI received either 200 mg OPT-80 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 OPT-80 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, an exploratory endpoint, was defined as patients who were cured and did not have a recurrence.

 

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 flourish.

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.

Higher incidence and severity of CDI, increased treatment failures with standard therapies and the emergence of the hypervirulent BI (NAP1/027) strain of C. difficile have combined to result in greater awareness of CDI and growing concern among medical professionals and public health officials.

 

OPT-80 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 OPT-80 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 recurrence.

 

 

 

 

 

 

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 OPT-80, the incidence and anticipated effects of CDI, the efficacy of current CDI treatments and OPT-80 and the timing of clinical trials and anticipated results thereof. Words such as "believes", "anticipates", "plans", "expects", “may”, "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 research and development and clinical trial programs, the timing and status of its preclinical and clinical development of potential drugs, the development of alternative treatments for CDI, and other risks detailed in Optimer's filings with the Securities and Exchange Commission.

 

 

Optimer Pharmaceuticals, Inc.

Christina Donaghy, Corporate Communications Manager

John D. Prunty, Chief Financial Officer & VP Finance

858-909-0736

 

Porter Novelli Life Sciences

Jason I. Spark, Vice President

619-849-6005