Amgen, VC groups pump $16.5M into Sutro Biopharma

Sutro Biopharma has reeled in more capital to back work on next-generation protein drugs. Skyline Ventures led the second $16.5 million closing of the San Francisco-based startup's Series C round, which included backing from Amgen Ventures, Lilly Ventures, Alta Partners and SV Life Sciences.

The VC units of Amgen ($AMGN) and Lilly ($LLY) joined Alta and SV in the first $20 million closing of the $36.5 million third-round financing in November 2010. Sutro, founded in 2003, says it has landed almost $60 million from investors, and the company is among of bevy of biotech startups benefitting from pharma companies' growing role the venture game.

Sutro is working on antibody-drug conjugates and bi-specific antibodies with the company's protein drug platform. Last year the company landed a research pact with Pfizer ($PFE), agreeing to work on peptide-based drugs for the drug giant. Sutro aims to land more collaboration deals with biopharma partners as well as pursue its own drug programs, according to the company's release.

"Although we generally remain cautious, especially when investing in earlier stage companies, we see the tremendous potential for antibody drug conjugates and bispecific antibodies for drug development, particularly in cancer therapy," Skyline partner Leon Chen said in a statement. "We believe that Sutro's biochemical protein synthesis platform provides a unique opportunity to rapidly identify and develop next generation therapeutics that can be manufactured utilizing the same platform in accordance with current good manufacturing practices."

- here's the release