UPDATED: Big Biopharmas help fuel a $26M round for Sutro's immunotherapy work

Amgen, Celgene and Eli Lilly joined forces with some prominent venture players to back a $26 million round for Sutro Biopharma, a San Francisco-based biotech which has been garnering some careful scrutiny for its work on antibodies. Over the past 10 years Sutro has now raised more than $90 million, concentrating its development work on "armed" conjugates and now bispecific antibodies.

Alta Partners, Skyline Ventures and SV Life Sciences chipped in part of the latest round along with the corporate investors ($AMG, $CELG, $LLY). Their money has been augmented with some significant partnering activities at Sutro, which believes it has a next-gen approach to antibody-drug conjugates that can significantly outperform the first generation of armed antibodies to make it to the market.

The new round gives Sutro enough money to ramp up a fresh effort in one of the hottest fields in cancer R&D: immunotherapy, specifically using the checkpoint strategy that stole the show at ASCO last summer. CEO Bill Newell says that the company plans to quickly whip up bispecific antibodies that can mix and match the PD-1 and PD-L1 checkpoint approach with other cancer targets.

"We think we have the ability to take the data sets developed by Bristol-Myers, Merck and MedImmune and really take it to the next level," says Newell, who has a very high opinion of the company's platform technology, which promises to slice as much as 18 months off of the development process in a drive to the clinic.

Sutro execs are staying quiet for now on how they plan to mix cancer targets with immunotherapy, but Jeremy Bender, the chief business officer, compared it to the Bristol-Myers Squibb ($BMY) combo of Yervoy and its PD-1 drug, which has created a sensation in the biotech field. And Newell adds that the current staff of 65--who cover everything from research to manufacturing--will be able to handle the bulk of the new work on bispecifics, with only a few new hires needed to broaden the company's scope.

Celgene signed up for a $500 million partnership with Sutro a year ago, and Sanofi ($SNY) followed up a few weeks later with a vaccine development pact. Today Newell promised at least one more collaboration to come in the first half of 2014, adding a new injection of cash to further spur its efforts.

"Our ability to accelerate the development of our immuno-oncology portfolio is now in hand. This successful financing further demonstrates the enthusiasm of our investors in Sutro and is a tremendous validation of our emerging product pipeline together with our broad technology platform. Sutro is an emerging leader in the rapid development of novel and differentiated products targeting immuno-oncology pathways," Newell said in a statement. "We will continue to advance candidates that leverage the immune system's natural ability to fight cancer, with the goal of establishing next generation immuno-oncology products that will transform cancer therapy for physicians and patients."

- here's the release