With plans to file for regulatory approval of its lead product, a broad-spectrum antibiotic for Gram-positive infections, Targanta Therapeutics pulled in $70 million in Series C financing.

It's the largest venture round to date for the Cambridge, Mass.-based company, which previously raised about $40 million since its 1997 inception as PhageTech Inc. The latest funding is "a nice capstone for us," said Targanta President and CEO Mark Leuchtenberger, adding that it should provide "a good strong runway."

The venture round was led by Greenwich, Conn.-based Brookside Capital, Palo Alto, Calif.-based Skyline Ventures, and New York-based firms Radius Ventures and OrbiMed Advisors. Existing investors Seaflower Ventures, of Waltham, Mass., along with VenGrowth Advanced Life Sciences Fund, of Toronto, and the Canadian Medical Discoveries Fund also participated.

The money "will allow us to advance the pipeline and get ready for filing a [new drug application] for oritavancin, which we're targeting for the second half of this year," Leuchtenberger told BioWorld Today. The NDA will seek approval of the drug in complicated skin and skin structure infections (cSSSI).

Oritavancin is a once-daily, glycopeptide antibiotic aimed at Gram-positive infections, including pathogens resistant to vancomycin. While Targanta's product is similar to vancomycin, "the mechanism of action suggests that it's less likely to engender resistance," he said. That could make oritavancin "a very competitive product," in the Gram-positive infection market.

In addition to vancomycin, that market already includes Cubicin (daptomycin for injection) from Lexington, Mass.-based Cubist Pharmaceuticals, which is approved in the U.S. for cSSSI and bacteremia. Another antibiotic, Theravance Inc.'s telavancin, is pending FDA review in cSSSI. Theravance, of South San Francisco, anticipates a decision in the second half of this year. (See BioWorld Today, Dec. 11, 2006.)

Oritavancin initially was developed by Indianapolis-based Eli Lilly & Co., which took the product through its first Phase III study before licensing it to InterMune Inc. After completing a second Phase III trial, Brisbane, Calif.-based InterMune refocused its pipeline, divesting oritavancin to Targanta in exchange for $9 million in up-front and milestone payments and a convertible promissory note worth up to $25 million. (See BioWorld Today, Dec. 28, 2005.)

Now that the product is in Targanta's hands, it's heading toward regulatory filing. Leuchtenberger said the company has had "three successful meetings with the FDA that basically confirm the roadmap to the NDA."

The filing will include data from the Phase III studies conducted by Lilly and InterMune, showing that oritavancin met its primary endpoints in providing treatment as effective as a standard regimen of vancomycin followed by cephalexin. If all goes as planned, oritavancin could hit the market in the summer of 2008, Leuchtenberger said.

Targanta anticipates commercializing the product in the U.S. itself, and likely will seek additional funding for pre-launch activities. Money from the Series C round should "get us through the early part of next year, including the PFUFA date for oritavancin," he said.

The company also plans to expand development of oritavancin in additional indications, and expects to initiate trials this summer in pneumonia, bacteremia and single-dose treatment of cSSSI. Down the road, the company also hopes to move Clostridium difficile-based infections and possibly an anthrax treatment.

Beyond oritavancin, the remainder of Targanta's pipeline is in early stage development. The most advanced is a preclinical bone-seeking antibiotic program aimed at treating and preventing osteomyelitis.

But right now, the focus is on getting oritavancin to market, Leuchtenberger said. "Then we'll build out the other indications."