Tetraphase Pharmaceuticals raised a big $45 million venture round back in June, and now scientists can see more clearly why it’s been able to raise all that dough.
The Watertown, MA-based company made a series of 10 different poster presentations over the past few days at the biggest antibiotics meeting of the year, the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Boston. Tetraphase showed that its lead tetracycline drug in development was effective against all but one of the major bugs it sought to kill in animals; it was well-tolerated in a convenient once-daily intravenous dose; the drug can be made into an oral pill; and that its chemistry platform has potential to generate more than just one drug.
“People are always looking for new antibiotic products, and there’s not enough in development,” says Tetraphase CEO Guy Macdonald. “People are excited about the spectrum of activity we have shown and our oral potential. We’re not a one product company. We have a platform that can develop novel and diverse profiles of antibiotics.”
Tetraphase, born in 2006 with technology from Harvard University, is setting out to custom-build new tetracycline antibiotics with properties that couldn’t be engineered via conventional fermentation methods. Tetraphase has used its new technique to synthesize antibiotics that can kill a broad variety of bugs from the two major classes of bacteria (gram positive and gram negative), and also more narrowly focused and potent drugs to kill specific bugs. While public health officials regularly sound alarm bells about antibiotic overuse contributing to the rise of drug-resistant “superbugs,” the biotech industry hasn’t developed much in the way of innovative new antibiotics versatile enough to kill a wide variety of the pathogens. Pfizer’s tigecycline (Tygacil) is the only new member of the tetracycline class approved by the FDA in the past 40 years, so Tetraphase is betting that if it can navigate the clinical trial process, it will be able to fulfill a real market need.
Many of the other venture-backed companies in the antibiotic market—San Diego’s Trius Therapeutics, New Haven, CT-based Rib-X Pharmaceuticals, and South San Francisco-based Achoagen—are largely focused on antibiotics that work against a specific type of bug or a certain property, which makes many of their compounds what scientists call “narrow spectrum” antibiotics. (Update and clarification 1:30 pm ET, Sept. 16): While one of Rib-X’s lead drugs, radezolid, fits this category, another advanced candidate, delafloxacin, is a “broad spectrum” antibiotic).
Tetraphase is attempting to develop its lead compound, TP-434, as a “broad spectrum” antibiotic that’s supposed to kill a whole range of bugs that resist other treatments, whether they have surface properties that make them classified as gram-negative or gram-positive pathogens. That’s thought to be especially useful for physicians seeking to treat the most severe infections people sometimes get in hospital intensive-care units, and for when physicians don’t yet have lab results to tell them exactly what kind of bug has infected the patient.
Tetraphase presented data from a series of animal studies at the ICAAC conference that suggests its new antibiotic ought to work against five of the six major bugs that cause most infections in hospitals and that are hard to treat. The list of so-called ESKAPE pathogens includes Enterococcus faecium, Staphylococcus aureus, Klebsiella species, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species. Only one of those bugs, pseudomonas aeruginosa, was able to resist the Tetraphase drug in animal tests, Macdonald says.
Part of the Tetraphase R&D program looked at the lowest possible dose required
