Third Rock leads $30M round for antibody upstart

Designing a better antibody is one of the hottest strategies driving start-up biotechs in the U.S. And one recent entry in the field has picked up a pair of powerhouse venture backers.

This morning CytomX Therapeutics announced that it banked $30 million from a Series B led by Third Rock Ventures and joined by Roche Venture Fund. The money, which comes on top of the $5 million in angel capital that helped the company launch in 2008, will be used to beef up its staff, relocate from Santa Barbara to the Bay Area biotech hotbed and drive several next-gen antibody programs to the clinic.

CytomX is building its pipeline on a platform technology that uses disease enzymes to turn antibodies on right at the site where they're needed. "Many antibody therapeutics are successful drugs," CEO Nancy Stagliano tells FierceBiotech. But a "good subset" is also plagued with toxicity issues. CytomX believes its technology, which originated from work done by CytomX scientific founder Patrick Daugherty at UC-Santa Barbara, can not only resolve some of those toxicity issues, it can also be used to target diseases that antibodies currently can't touch.

Aside from noting that the company has a couple of preclinical oncology programs under way, Stagliano is keeping her early-stage work under wraps for now. "We anticipate entering clinical trials in 2013," she adds. And like a number of start-up antibody developers, CytomX will look to start partnering at an early point--a factor that is likely to influence when the biotech will need to look for more cash.

At $30 million, the round hits right in Third Rock's sweet spot, giving it a significant stake in a company with some big upside while providing the cash needed to put its science to the test. It also marks Third Rock's recent decision to set up a West Coast office, branching out of the Boston area as it winds down its first fund and prepares to start investing its second. Stagliano--a veteran of Millennium, where she got to know some of the partners who launched Third Rock--says that CytomX now has the resources to add about 10 workers to its staff of eight.

- here's the CytomX press release for more info