Optimer Pharmaceuticals Inc. (OPTR), said Tuesday that a committee of the U.S. Food and Drug Administration has recommended approval of the company's investigational antibiotic Dificid for treating Clostridium difficile infection. While the recommendation made by the committee is considered by the FDA, it is not mandatory for the agency to accept it and does not ensure an automatic approval. Nevertheless, the news failed to cheer investors, and the stock lost nearly 3 percent in extended trade.
In a unanimous 13-0 decision, the FDA's Anti-Infective Drugs Advisory Committee found that the clinical evidence submitted by Optimer showed the drug to be efficacious in treating CDI, compared with standard care vancomycin.
Clostridium difficile infection, or CDI is a bacterial infection in the lining of the gut that can cause severe diarrhea, colitis and in some cases death. In the U.S. alone, CDI is said to infect 700,000 people each year.
Optimer's Dificid is a new antibiotic with a novel mechanism of action, which inhibits the bacterial enzyme RNA polymerase, resulting in the rapid killing of C. difficile.
Current therapeutic options for CDI include the off-label use of metronidazole and oral vancomycin, the latter being the only FDA-approved treatment, though 20 percent to 30 percent of patients who initially respond to these treatments report a resurgence in the disease after treatment has ceased.
Optimer's New Drug Application for Dificid was filed in November last year. The FDA accepted the NDA filing and granted a six-month Priority Review in January 2011, assigning a Prescription Drug User Fee Act goal date of May 30, 2011.
The recommendation by the FDA committee was based partly on late stage studies that showed Dificid to be as effective compared with vancomycin in clinical cure, and superior to vancomycin in global cure - defined as cure without a recurrence after 4 weeks of therapy.
The objective of both studies was to show that a 10-day course of Dificid was at least as efficacious and safe as a 10-day course of vancomycin.
Dificid also met the primary endpoint of non-inferiority of clinical cure - defined as patients requiring no further CDI therapy two days after completion of study medication compared to vancomycin.
OPTR closed Tuesday's regular trade at $13.80 on the Nasdaq. In after hours, the stock lost $0.40 or 2.90%.
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