CytomX Therapeutics Adds $11M For Antibody Drugs

Xconomy San Francisco — 

South San Francisco-based CytomX Therapeutics has an ambitious plan to make an antibody drug that can beat existing products from Eli Lilly and Amgen. Now it has some more money to pursue the goal.

CytomX said today it has expanded its Series B venture round to a total of $41 million, after previously announcing the B round brought in $30 million in September 2010. Canaan Partners led the financing, and was joined by CytomX’s existing investors Third Rock Ventures and Roche Venture Fund.

The company, which I profiled here in March, is developing technology to make a more potent targeted antibody against the EGF receptor that Lilly’s cetuximab (Erbitux) and Amgen’s panitumumab (Vectibix) are designed to hit. CytomX’s bet is that its new drug will be potent enough to work for about 40 percent of colon cancer patients who don’t respond to the existing drugs because they have a mutant form of the KRAS gene, without causing any nasty skin rashes. CytomX is also hoping to extend its antibody engineering techniques to other products in development.