SAN DIEGO (

TheStreet

) --

Optimer Pharmaceuticals

(OPTR)

will launch its newly approved antibiotic Dificid later this summer, pricing the drug at twice the cost of its main competitor, company executives announced Monday.

U.S. regulators approved Dificid late Friday as the first new treatment in 25 years for Clostridium difficile, or C. diff, a bacterial infection often contracted by patients while they're in the hospital that attacks the lining of the intestines and can cause severe, sometimes fatal, diarrhea.

Shares of Optimer were up 6% to $13.73 in Monday trading.

Optimer will price a 10-day course of Dificid at $2,800, or about twice the price tag of

Viropharma's

(VPHM)

Vancocin, a competing antibiotic also used to treat the intestinal bug.

On a conference call Monday, Optimer CEO Pedro Lichtinger said premium pricing is justified because Dificid is better at preventing the recurrence of C. diff infection than Vancocin. C. diff re-infection is dangerous for patients and costly to hospitals, which are forced to prolong patient stays.

Even though Dificid costs more, hospitals will save money because of lower re-infection rates compared to treating patients with Vancocin, which often has to be used more often and at higher doses, Lichtinger said.

Approximately 450,000 cases of C. diff are reported every year in the U.S., with about 70% of the infections in "high risk" patients such as the elderly or those with impaired kidney function, according to Optimer.

Optimer has partnered with

Cubist Pharmaceuticals

(CBST)

to sell Dificid in the U.S., while

Astellas

will help sell the drug in Europe, where it is still not approved. Analysts, on average, have forecasted U.S. sales of Dificid could reach $217 million, according to Bloomberg. European and international sales could double that peak revenue total.

One question mark left unanswered as Dificid nears launch is how quickly doctors will turn to Dificid. Optimer argues that a majority of patients should be treated with Dificid first, even though the drug costs more. However, some doctors may choose to treat patients with less expensive Vancocin first and then re-treat with Dificid if patients suffer a relapse.

Further complicating the treatment dynamic is the looming threat of generic vancomycin, the active ingredient in Vancocin. A generic version of Vancocin could give hospitals and doctors even more incentive to push back use of the higher priced Dificid.

Optimer, on its call Monday, said it fully anticipated the entry of generic vancomycin when it decided on pricing for Dificid. Based on contacts with insurers and hospitals, Optimer doesn't believe a cheaper, generic competitor will impact Dificid's use.

Optimer executives, however, declined to offer sales guidance for Dificid, choosing to wait to see how the drug lauches before offering investors a specific forecast.

--Written by Adam Feuerstein in Boston.

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