SAN DIEGO, Sept. 14 /PRNewswire-FirstCall/ -- Optimer Pharmaceuticals, Inc. (Nasdaq: OPTR) announced that new data from its North American and European fidaxomicin Phase 3 clinical trials in patients with Clostridium difficile infection (CDI) was presented at the 50th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Boston.
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“Patients with CDI often have persistent infections or develop new infections during the course of CDI treatment and are often administered concomitant antibiotics. Although clinically necessary the use of concomitant antibiotics has a deleterious effect on outcomes of cure, recurrence and global cure. Compared to vancomycin therapy, fidaxomicin blunts these negative effects by significantly lowering recurrences and increasing global cure of patients,” said Pedro Lichtinger, Optimer’s President and Chief Executive Officer. “The additional data presented suggest fidaxomicin has the potential to become the product of choice for CDI, if approved.”
Kathleen M. Mullane, D.O., Pharm. D., an investigator from the University of Chicago, Department of Medicine, Section of Infectious Diseases, in Illinois, presented combined data from Optimer’s two Phase 3 trials indicating that the use of concomitant antibiotics is a significant risk factor for a negative CDI treatment outcome. Many patients with CDI have persistent infections or develop new infections during the course of CDI treatment making concomitant antibiotics clinically necessary and common. Overall, 34% of subjects received antibiotics in addition to fidaxomicin and vancomycin for intervening infections during the study. The data indicated fidaxomicin was a superior therapy to vancomycin in preventing recurrence and in promoting global cure in patients requiring concomitant antibiotics. The analysis from the Phase 3 trials indicated that in patients receiving concomitant antibiotics, those treated with fidaxomicin versus vancomycin had a significantly lower CDI recurrence rate (17% vs. 28%, p=0.039) and had a significantly improved global cure rate (73% vs. 60%, p=0.013). At the same time, among subjects who received no concomitant antibiotics, recurrence in vancomycin-treated subjects was double that of fidaxomicin-treated subjects (23% vs. 11.5%, p<0.001).
Ellie J. Goldstein, M.D., from the R.M. Alden Research Laboratory in Santa Monica, CA, presented data on the antimicrobial susceptibilities of C. difficile isolates to fidaxomicin, vancomycin, metronidazole, and rifaximin cultured from fecal specimens collected from patients at study entry and at failure/recurrence in Optimer’s second Phase 3 clinical trial. The data showed that there was no relationship between MICs of baseline CDI isolates and clinical outcome for fidaxomicin but there was a one dilution difference for vancomycin between cure and failure. The MIC90s were generally low for fidaxomicin, vancomycin, and metronidazole but the BI isolates generally had higher MICs for the four drugs tested than the BK, CF, DH, G, J, and Y group isolates. No resistance to either fidaxomicin or vancomycin developed during the 10-day treatment in this or in the first Phase 3 trial. Rifaximin resistant strains, 8.1% of all strains, were isolated in both treatment groups with MIC90s higher in treatment failures than cures.
In an oral presentation, Dale N. Gerding, M.D., an investigator from the Hines VA Hospital in Chicago, IL, presented data on the C. difficile strain types isolated in Optimer’s two fidaxomicin Phase 3 trials and their relationship to outcome. These data show that the cure rate among patients harboring BI isolates was significantly lower than those with non-BI strains (86.5% vs. 94.3%, p=0.0006) and that the recurrence rate was significantly higher for those with the BI strain versus the non-BI strains (27.3% vs. 16.6%, p=0.003). In the trials, the BI strain of Clostridium difficile was the major strain type (39%) in North America but the BI strain was not nearly as frequent in Europe (10%). In the non-BI group recurrence rates were significantly lower in patients treated with fidaxomicin versus patients treated with vancomcyin (8.4% vs. 25.3%, p<0.001). In the BI group fidaxomicin showed a clinically meaningful 25% reduction in recurrence rates compared to vancomycin (23.3% vs 31.2%).
Clinical investigator, Mark A. Miller, M.D., head of the Division of Infectious Diseases, Chair of the Infection Prevention and Control Unit at the Jewish General Hospital in Montreal, Quebec, Canada, presented analyses on a bedside scoring system for assessing CDI risk factors. There is currently no validated bedside risk assessment tool to categorize patients or predict CDI cure or recurrence. Using data from Optimer’s first fidaxomicin Phase 3 trial, researchers evaluated a scoring system composed of five simple patient risk factors: Age, Temperature (T), Leukocytosis (WBC), Albumin (Alb), and Concomitant Systemic Antibiotics (SA). These five bedside risk factors were combined to correlate with CDI cure, recurrence, and global cure. Dr. Miller recommended that this scoring system should be validated on other databases of CDI patients in order to assist in predicting CDI cure, recurrence, morbidity, and mortality.
For a complete list of posters, please visit the Resources page on our website at: www.optimerpharma.com
Fidaxomicin Clinical Studies
The two fidaxomicin Phase 3 clinical studies were multi-center, randomized, double-blind trials, which enrolled a total of 1,164 adult subjects. Subjects with confirmed CDI received either fidaxomicin (200 mg q12h) or Vancocin® (125 mg q6h), the only FDA approved product for the treatment of CDI. These studies were designed to evaluate safety and compare the response to treatment in subjects during and after a 10-day course of therapy. The primary endpoint was non-inferiority compared to Vancocin in clinical cure (defined as patients requiring no further CDI therapy two days after completion of study medication, as determined by the investigator). If cured, subjects were monitored for a subsequent four-week period to evaluate recurrence, which was a secondary endpoint. Global cure, also a secondary endpoint, was defined as patients who were cured and did not have a recurrence during this subsequent four-week period. In both of these studies, fidaxomicin achieved its primary endpoint of non-inferiority compared to Vancocin. Fidaxomicin was also statistically superior to Vancocin in global cure rate and in reducing recurrences of CDI.
About Clostridium difficile Infection
CDI has become a significant medical 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 produces toxins that cause inflammation of the colon, severe diarrhea and, in the most serious cases, death. Patients typically develop CDI from the use of broad-spectrum antibiotics that disrupt normal gastrointestinal (gut) flora, and thus allowing C. difficile bacteria to flourish.
Current therapeutic options for CDI include the off-label use of metronidazole and oral vancomycin, the only FDA-approved treatment. 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 (such as cephalosporins and fluoroquinolones), advanced age (over 65) and exposure to emerging hyper-virulent strains (BI/NAP1/027, 078, 001) of C. difficile. Increasing incidence, higher treatment failures and recurrence with current 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 macrocycles, which inhibit the bacterial enzyme RNA polymerase, resulting in the death of C. difficile. The narrow-spectrum profile of fidaxomicin may eradicate C. difficile selectively with minimal disruption to the normal intestinal flora, while the alternative antibiotics to treat CDI, metronidazole and vancomycin, disrupt the flora. Fidaxomicin may facilitate the return of normal physiological conditions in the colon which may be responsible for reducing CDI recurrence.
About Optimer Pharmaceuticals
Optimer Pharmaceuticals, Inc. is a biopharmaceutical company focused on discovering, developing and commercializing hospital specialty products to treat serious infections and address unmet medical needs. Optimer has two anti-infective product candidates in development. Fidaxomicin is a narrow spectrum antibiotic being developed for the treatment of Clostridium difficile infection (CDI). Optimer has completed two Phase 3 trials of fidaxomicin for the treatment of CDI, demonstrating that fidaxomicin was statistically superior to vancomycin in global cure rate (defined as cure with no recurrence within four weeks of completing therapy) as well as statistically superior in reducing recurrences of CDI by up to 50% when compared with vancomycin, the only FDA approved product for CDI. Optimer has also successfully completed two Phase 3 trials of Pruvel a prodrug in the fluoroquinolone class of antibiotics being developed as a treatment for 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 the ability of fidaxomicin to treat CDI and address current treatment limitations and the potential for fidaxomicin to be a treatment of choice for CDI. 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, the development of alternative treatments for or means of preventing CDI, whether regulatory authorities will review or approve Optimer’s applications for marketing approval, the timing of any marketing approvals, Optimer’s ability to complete its NDA submission in a timely manner, Optimer’s ability to commercialize any products for which it receives marketing approval, whether healthcare professionals will prescribe fidaxomicin, if approved, whether fidaxomicin will receive reimbursement coverage from healthcare payors and government agencies and other risks detailed in Optimer’s filings with the Securities and Exchange Commission.
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SOURCE Optimer Pharmaceuticals, Inc.
