Chart: Fighting C. difficile: Beyond Optimer's Fidaxomicin

Optimer released positive data Feb. 4 from its second pivotal Phase III trial of fidaxomicin, raising hopes that hospitals will soon have a new weapon for fighting new deadly strains of Clostridium difficile, a bacterium that occurs naturally in the gut and is ordinarily benign. Problems arise, however, when antibiotics used to treat hospital-acquired infections eliminate other resident flora, allowing novel and toxic strains of C. diff to proliferate. Outbreaks of the disease, typified by diarrhea, nausea and in severe cases, colitis, sepsis and death, have made headlines in the United Kingdom and Canada. Vancomycin and metronidazole are the current standards of care, but relapse rates with those drugs are 20 to 30 percent, and resistance is a growing worry. Optimer's data shows fidaxomicin has a slightly better cure rate and much lower recurrence rate than vancomycin, though the recurrence rate is no different among patients with a severe form of C. diff infection. Are these factors enough to sway hospitals to use fidaxomicin if approved instead of vacomycin, especially if generic versions come to market? An FDA advisory committee endorsed a generic vancomycin pathway last August ("The Pink Sheet," Aug. 10, 2009).