to kill the pathogens, and then square that up with an initial phase human study that looked at how much people could tolerate. The Pfizer drug that’s on the market sometimes has limited use because it can cause nausea, Macdonald says, and it is given in a twice-daily dose. What’s important to Tetraphase is that it has shown the once-daily dose can kill the bugs, and that it should have a flexible enough dosing range to be made into an oral pill that people can take conveniently when they start feeling well enough to leave the hospital.
“With difficult-to-treat ESKAPE pathogens, you sometimes can’t get enough drug into the patient because of the safety profile. We think we’ve shown in the Phase I we’ll get more drug into people with a better tolerability profile,” Macdonald says.
This is all still very early in the development process, and the big test is yet to begin. Tetraphase is now gearing up to start enrolling the first of 200 to 250 patients with appendicitis, who will be randomly assigned to the new IV drug or the standard treatment, carbapenum. That study should start enrolling by year’s end, Macdonald says. And while that’s happening, Tetraphase is working on an oral pill form of the same drug that can be given on an outpatient basis, and also getting ready to begin clinical trials of two other antibiotic candidates in the first half of 2011.
It’s still early to talk about those programs, but Macdonald stressed that they are a key part of the Tetraphase strategy. Only about one-fourth to one-third of the $45 million financing is being funneled into the lead drug candidate’s clinical trials, while the rest is going toward the oral formulation work, and a pipeline of more antibiotics to come.
“We’re not a one product company,” Macdonald says. “We have a platform that can develop novel and diverse profiles of antibiotics. It’s a potential franchise.”
