Trius Therapeutics, the San Diego-based biotech company, has passed an important milestone in its quest to develop a more convenient, more effective antibiotic against deadly MRSA bacterial infections that people tend to get in the hospital.
Trius released results today from a study in which 188 patients with severe skin infections were randomly assigned to get a low, mid-range, or high dose of its experimental antibiotic, torezolid (TR-701). The study found the once-daily pill, given for five to seven days, helped 98 percent of patients on the lowest dose achieve what’s considered a clinical cure. There were no clinical relapses at follow-up visits three to four weeks after treatment.
“The nature of such infections usually warrants use of an IV antibiotic, but the trial results indicate that oral torezolid successfully treated these severe infections quickly and effectively,” said Joseph Surber, chief medical officer of Southwest Regional Research Group, and a clinical investigator on the study, in a company statement.
Biotech and pharmaceutical companies have been pushing hard for several years—without much success—to develop new antibiotics that can kill tough bugs like the MRSA pathogen that are becoming increasingly resistant to standard treatments. An estimated 19,000 people in the U.S. die from bacterial infections each year, more than die from HIV, Trius CEO Jeff Stein told me back in October. Two other companies trying to crack this market—South San Francisco-based Theravance, and Cambridge, MA-based Targanta Therapeutics—ran into various roadblocks and delays after applying to the FDA for market approval.
Trius’s goal is to develop a drug from the same chemical family, but with a superior profile compared to Pfizer’s linezolid (Zyvox), one of the fastest-growing antibiotics.
Antibiotics in this class are potent killers of drug-resistant bacteria, like MRSA. The Trius candidate appears to be more potent in animal tests than linezolid, meaning it can be taken at a much lower dose—which could offer fewer side effects and lower manufacturing costs. It also could be given once a day instead of twice a day, Stein has said. Both Pfizer’s drug and Trius’s can be taken as oral pills, but the added convenience of less-frequent dosing could be important, because antibiotic resistance thrives when patients fail to take all their required meds. Giving them a once-daily pill option may increase the odds that patients will stay in compliance with doctors’ orders.
The Trius therapy was considered well-tolerated, and 92 percent of the side effects considered possibly drug-related were graded as mild, researchers said. No patients dropped out because of adverse events. The least number of side effects were reported on the lowest dose, of 200 milligrams, Trius said.
The trial results have given Trius enough information to pick the lowest dose, 200 milligrams once a day, for the next step in development, a Phase III pivotal clinical trial in patients with severe skin infections. The company plans to complete an early-stage trial of an intravenous form of the drug later this year, and to merge the IV and oral development programs in Phase III trials early next year, Trius said in a statement.
