this drug is potent against gram-negative bacteria, in contrast to many other antibiotic companies—Theravance, Trius Therapeutics, Rib-X Pharmaceuticals—which tend to focus on gram-positive bugs, like the dreaded MRSA.
Tetraphase’s compound has passed an initial study in healthy volunteers, which showed it can be given in a convenient once-daily form, at a safe dose. Now comes the hard part. In about three to six months, Tetraphase it plans to study TP-434 in 250 to 300 patients, probably with complicated abdominal infections, Macdonald says. This study will randomly assign patients to the Tetraphase drug or to standard treatment, he says. Results ought to be available in about 18 months.
“We’re going to do a meaningful study,” Macdonald says.
That’s also going to be an expensive study, but one of the nice things about raising $45 million is that Macdonald doesn’t have to put all his eggs in one basket. A little further behind in the pipeline, Tetraphase has two different candidates it is preparing for their initial-phase clinical trials. Both of them are made as oral pills, and each of them is designed to be narrowly effective against a specific bug, Macdonald says. That’s desirable for physicians when they know exactly what kind of infection a patient has, which enables them to keep a broad-spectrum antibiotic in reserve just in case resistance develops to the narrower drug, Macdonald says.
One of these specific candidates is for complicated urinary tract infections, and the other is for community-acquired bacterial pneumonia—one of the most common infections doctors have to deal with.
These last two drugs only emerged during the last year, Macdonald says. They were so compelling that Tetraphase curtailed a Series B financing plan that was built around the lead asset, and came up with new term sheets for this $45 million Series C to finance all three programs. Obviously, if Tetraphase can prove in clinical trials that it truly has a product-discovery engine, and is not just a one-drug company, then it could have “really good M&A opportunities” in a couple years, Macdonald says.
“Nobody else out there now can do what we do,” he says.
