Trius Therapeutics, Developer of Antibiotic Against MRSA, Taking On Pfizer’s Zyvox

Whenever headline writers get whipped up about another wave of MRSA or other drug-resistant bacteria sweeping the land, a venture capitalist somewhere starts thinking about creating new antibiotics to stop it. Jeff Stein was in that position a couple years ago at Sofinnova Ventures, and he found an experimental drug he liked so much that he left that gig in 2007 to be founding CEO of San Diego-based Trius Therapeutics.

This company has some serious backing, raising $50 million in venture capital in its first two years from the likes of Sofinnova, Kleiner Perkins Caufield & Byers, FinTech Global Capital, InterWest Partners, Prism VentureWorks, and Versant Ventures.

So why are the investors so excited? First, an estimated 19,000 people in the U.S. die from bacterial infections each year, more than die from HIV, Stein says. Everyone in public health from the Centers for Disease Control and Prevention on down says that antibiotic resistance is a growing problem. And the investor syndicate is betting Trius will do nothing less than offer a superior alternative to one of the fastest-growing antibiotics sold by the world’s largest drugmaker; Trius is developing TR-701, an antibiotic that is in the same family as Pfizer’s linezolid (marketed as Zyvox), which is on track to eclipse $1 billion in sales this year.

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 says. Both Pfizer’s drug and Trius’ 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.

Data on this compound from an early-stage clinical trial will be included when Trius is featured this week among a hefty slate of presentations at the Interscience Conference on Antimicrobial Agents and Chemotherapy in Washington, D.C. It’s the biggest anti-infection scientific meeting of the year, drawing thousands of researchers from around the world.

Trius started its Phase I trial in January. It was designed to enroll 88 patients at a variety of doses, and, in an unusual twist for such an early study, it will compare the effects of TR-701 with those of linezolid. Stein wouldn’t say much about the results, because he wants to get maximum bang by saving the scoop for the ICAAC conference, but he said that researchers found the Trius drug had a more steady concentration in the blood than linezolid. The results were also good enough for Trius to go ahead with a mid-stage trial of 180 patients, which began last month, looking at the effectiveness of once-daily doses over a five-to-seven day course of therapy. This trial recruited its first 11 patients in one week, and expects to wrap up enrollment by the end of 2008, Stein says.

The Trius drug did knock down patients’ platelet cell counts in the blood, and platelets are important agents of clotting, although the reductions weren’t severe, Stein says. Final data from the mid-stage study should be available by June, which will pave the way for partnership talks with a larger drugmaker who could help usher this candidate through the final stage of testing, Stein says.

Plenty of other companies are vying for a piece of the growing antibiotic market, including Cambridge, MA-based Targanta Therapeutics, which plans to present data soon on oritavancin, which may kill drug-resistant bacteria with a single shot. Lexington, MA-based Cubist Pharmaceuticals reported last week that sales of its daptomycin (Cubicin) rose 45 percent to $110 million in the quarter ending on September 30.

Cost could be one way Trius separates itself, Stein says. Linezolid generally costs $100 a day, which runs about $1,400 for a course of therapy, so insurance companies often make hospitals jump through hoops to get reimbursed for it, Stein says. Since the Trius candidate will likely be given in one-sixth the dose, it will be cheaper to make because it requires less of the active ingredient. He didn’t disclose what his drug’s price will be, but suggested it could end up costing the health system less than linezolid.

“Zyvox is a very expensive drug,” Stein says. “We could have a big pharmacoeconomic advantage.”

We’ll stay posted for details coming out of ICAAC. There haven’t been many headlines about MRSA lately, so the reporting may be a bit more muted this year, but you can bet that pharma company dealmakers will be looking for interesting candidates, and they’ll be going over Trius’ clinical trial results with a fine-tooth comb.

Author: Luke Timmerman

Luke is an award-winning journalist specializing in life sciences. He has served as national biotechnology editor for Xconomy and national biotechnology reporter for Bloomberg News. Luke got started covering life sciences at The Seattle Times, where he was the lead reporter on an investigation of doctors who leaked confidential information about clinical trials to investors. The story won the Scripps Howard National Journalism Award and several other national prizes. Luke holds a bachelor’s degree in journalism from the University of Wisconsin-Madison, and during the 2005-2006 academic year, he was a Knight Science Journalism Fellow at MIT.