Clostridium difficile, a gram-positive anaerobic bacterium, is one of the most common hospital infections around the world. The C difficile infection, or CDI for short, results in inflammation of the colon, severe diarrhea and, in extreme cases, death and is a serious problem facing the U.S. healthcare system.
The deadly infection is currently treated by a generic drug called metronidazole or ViroPharma Inc's (VPHM) Vancocin (oral form Vancomycin), and the latter being the only FDA-approved treatment. The dosing regimen of both metronidazole and Vancocin is every six hours for a minimum of seven days.
A new treatment for CDI developed by San Diego-based Optimer Pharmaceuticals Inc.(OPTR) is under regulatory review. The company's investigational antibiotic for CDI, Fidaxomicin, faces an expert FDA panel on April 5.
Fidaxomicin is the first in a new class of antibiotics called macrocycles, which inhibit the bacterial enzyme RNA polymerase, resulting in the rapid killing of C. difficile. Fidaxomicin was granted Fast Track designation by the FDA in 2003 for the treatment of CDI, which allowed the company to initiate a rolling NDA submission.
Optimer Pharma completed submission of the New Drug Application for Fidaxomicin last November. Fidaxomicin also has a priority review status and we should know by May 30 if it will win the FDA approval. The drug is also under review by the European Medicines Agency.
Fidaxomicin was studied in two phase III clinical studies, which enrolled a total of 1,164 adult patients with confirmed CDI. In the late-stage trials, the patients were treated with either Fidaxomicin or Vancocin. In both the studies, Fidaxomicin not only met the primary endpoint of non-inferiority of clinical cure compared to Vancocin, but has also been found to be statistically superior to Vancocin in reducing recurrences of CDI and in *global cure rate. (*defined as cure with no recurrence within four weeks of completing therapy)
It is estimated that more than 700,000 people are afflicted with CDI each year in the U.S. The total annual costs associated with hospital cases of CDI in United States are estimated at $3.2 billion and the total estimated annual cost for treating the disease in Europe is approximately $3.8 billion.
According to Optimer, the current treatment options of metronidazole and Vancocin have the shortcomings of limited efficacy, high recurrence rate, bacterial resistance and inconvenient dosing and difficult compliance. Sales of Vancocin, which were $232.3 million in 2008, declined to $213.1 million in 2009. For the nine months ended September 30, 2010 sales of the drug were up 19 percent to $191.7 million. (Full-year 2010 Vancocin sales results to be reported on Feb.24)
Fidaxomicin with a twice daily dosing regimen is believed to offer some advantages, including, a high potency activity against C. difficile, favorable safety profile, superiority to Vancocin in treating a CDI recurrence and cost effectiveness as a result of lower rate of recurrence.
Market research firm Datamonitor foresees sales of Fidaxomicin to reach $265 million across the seven major markets of the US, Japan, France, Germany, Spain, and the UK in 2019.
Apart from the tablet form of Fidaxomicin, Optimer is also developing an oral suspension formulation for use in pediatric CDI patients. Last December, the FDA granted orphan drug designation for the treatment of pediatric CDI. The company is also evaluating the development of an oral formulation for patients in intensive care units and elderly patients who cannot swallow tablets.
Optimer has no products approved for commercial sale and, to date, has not generated any revenues from product sales. Fidaxomicin will be the company's first marketed drug if it successfully crosses the regulatory finish line.
The company funded its operations through December 31, 2010 from the sale of roughly $256.2 million of its securities and through research funding pursuant to collaborations with partners or government grants. The company has incurred operating losses since its inception in 1998. As of September 30, 2010, accumulated deficit totaled about $210.9 million.
Earlier this month, Japan-based Astellas Pharma purchased the marketing rights to develop and commercialize Fidaxomicin in Europe and certain other countries in the Middle East, Africa and the CIS in a deal that could be worth over $220 million to Optimer. In all other regions of the world, including the U.S., Optimer owns the rights to Fidaxomicin.
On February 16, Optimer completed a public offering of 6.9 million shares of its common stock for a price of $11.25 per share, which fetched aggregate gross proceeds of $77.6 million.
Optimer has a lot riding on Fidaxomicin's approval. The company's shares have gained nearly 50% in the past 6 months. The stock has thus far hit a 52-week low of $7.68 and a 52-week high of $13.80. OPTR closed Friday's trading at $12.10, up 0.83% on an above-average volume of 310,599 shares.
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