Two DIFICID Phase 3 study data in C. difficile presented at ECCMID conference

Optimer Pharmaceuticals, Inc. (NASDAQ: OPTR) today announced the presentation of two abstracts at the 21st European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) conference in Milan, Italy highlighting additional analyses of the Phase 3 data of DIFICID™ (fidaxomicin) for the treatment of Clostridium difficile infection (CDI). The data resulted from analysis of specific risk factors associated with negative outcomes in patients with CDI, including immunosuppression and alcohol abuse.

The first study analyzed pooled data from two Phase 3 clinical trials of DIFICID for the treatment of CDI and determined that immunosuppression is associated with higher death and lower CDI cure rates. The analysis also demonstrated that the rate of CDI recurrence remained substantially lower among immunosuppressed patients treated with DIFICID vs.vancomycin (16% vs. 27%; p < 0.01).  Independent of treatment regimen, mortality was higher among patients with a net state of immunosuppression (11% vs. 3%; p < 0.01), patients receiving immunosuppressive medications (9% vs. 6%; p < 0.04), patients receiving systemic steroids (14% vs. 5%; p < 0.01) or moderate or high-dose steroids (25% vs. 5%; p < 0.01), and patients with neutropenia (16% vs. 6%; p < 0.01).  Independent of treatment regimen, cure rates were lower among immunosuppressed patients, particularly those receiving moderate or high-dose steroids (75% vs. 88%; p < 0.01). In a multivariate analysis, immunosuppression was independently associated with a higher mortality rate from CDI and a lower cure rate, but was not associated with a higher recurrence rate. The study, titled "Immunosuppression and the risk of death, cure rates and disease recurrence among patients with Clostridium difficile infection (CDI)," was featured in an oral presentation on May 10.

"Any number of variables can cause a patient to have a less effective immune system, including the use of certain medicines, neutropenia or background illness, and each of these variables is significantly associated with an increase in death and a lower cure rate in patients with C. difficile," noted Sherwood L. Gorbach, M.D., Chief Scientific Officer for Optimer. "Notably, regardless of patients' level of immunosuppression, the rate of CDI recurrence remained substantially lower among patients treated with DIFICID."

The second study, titled "Clostridium difficile recurrence (CDR), alcohol consumption, and the effect of fidaxomicin vs. vancomycin," analyzed 794 patients from the same two Phase 3 clinical trials. Independent of treatment regimen, the study determined that alcohol abuse, defined as consumption of more than two alcoholic drinks a day, is associated with a higher rate of CDI recurrence (33.3% vs. 17.9%; p < 0.01), and particularly recurrence that occurs one to 15 days after stopping an antibiotic treatment regimen (26.1% vs. 12.1%; p < 0.01). Compared to vancomycin, DIFICID was associated with lower recurrence rates regardless of alcohol consumption.