In early trials, torezolid was shown to be more potent and faster-acting than Zyvox, Stein said. While both are so-called oxazolidinones, the Trius drug has a different chemical structure that leaves it unaffected by a mutation that can enable bacteria to resist Zyvox, Sanchez said.
Optimer gained 22 cents, or 1.6 percent, to $13.65 at 4 p.m. in Nasdaq Stock Market composite trading. Cubist gained 22 cents, less than 1 percent, to $34.39. Trius dropped 33 cents, or 4 percent, to $7.95.
A visit to the skin infections clinic at San Francisco General Hospital shows the need for new drugs.
On a recent morning, David Young, the clinic's director, was involved in a case in which the patient had a red, swollen abscess on his cheek. The patient, whom Young couldn't identify because of federal privacy laws, previously had infections on his chest, neck and face, Young said.
While the man's infections respond to the clindamycin, an oral generic antibiotic, "the bacteria will grow back" after each treatment, Young said. It becomes infected with any break in the skin, from a spider bite to a shaving nick, he said.
"It is akin to pulling all the weeds out of a field," he said. "When you stop weeding, the weeds will always return."
20% Won't Heal
Today, about 20 percent of patients won't heal with clindamycin or Bactrim, another antibiotic, Young said. For them, the hospital faces a choice: a 10-day course of Pfizer's Zyvox at a cost of about $1,000, or use of an intravenous drug, vancomycin, which requires a hospital stay.
Cubist expects to start final trials by year's end for CXA- 201, which targets pneumonia, abdominal and urinary tract infections caused by gram-negative bacteria, said Steve Gilman, executive vice president for research and development.
Durata Therapeutics, a two-year-old closely held company, is testing dalbavancin, one of two so-called lipoglycopeptides in late-stage trials. The drugs are modified versions of an older class of antibiotic that breaks down the cell walls and membranes of bacteria.