All in on IL-11, Frazier unveils latest startup with dual focus on fibrosis and cancer
In late 2017, a team of Singaporean scientists published a Nature paper highlighting what they call a “groundbreaking” and “outstanding” new target for fibrosis. Interleukin-11, a cytokine downstream of the well-known TGFβ1 pathway, had been overlooked but actually plays an even more central role in the fibrotic process, they wrote.
“The discovery that IL11 is a critical fibrotic factor is the type of breakthrough that the scientists and pharmaceutical companies have been searching for,” Stuart Cook, a senior author and the director of the National Heart Research Institute Singapore, said then.
Cook and Sebastian Schäfer, a co-author, had founded a biotech named Enleofen that would go on to score a major alliance with Boehringer Ingelheim. Now, Frazier Healthcare is debuting its own effort to drug the target — aiming not just at various types of fibrosis but also cancer.

With Mark Barrett, Sanofi Genzyme vet and now Frazier entrepreneur-in-residence, at the helm, Lassen Therapeutics has $31 million to find out which indications they’d like to start with and reach IND next year.
The Nature paper had piqued their interest in IL-11, Barrett told Endpoints News, just as he and co-founder David King were searching for a new concept that would play to King’s expertise in antibody discovery and development.
“We believed that there’s such a great proliferation of really high-quality and high-capability antibody generation technologies available that a biotech company today can be highly successful leveraging those technologies for the right applications,” he said.
King, who had had a company creation exercise with Frazier at AnaptysBio, brought over a few scientists to the founding team and built it out to a group of 10 based out of San Diego. Barrett remains in Boston, where he’s been based for the past decade — not that it had made a difference for the last few months as his West Coast colleagues found themselves chatting with him and one another over video calls amid a statewide shutdown.

They began by scouring the patent literature on IL-11 blockade and discovered an IP estate that CSL had created around a suite of antibodies hitting the IL-11 receptor. The Australian pharma giant had done some work with them in COPD and asthma but it was, after all, not a great fit for their core plasma and vaccines business.
“They had worked on the program but had kind of parked it at the stage where it needed more focus and investment,” Barrett said. “We happened to come in at just the right moment” last year to license it all.
Through the deal CSL became an equity holder in Lassen alongside Frazier (with its latest, $617 million fund), Alta Partners and Longwood Fund. Andrew Nash, the SVP of research at CSL, is also joining the biotech’s scientific advisory board.
Barrett has been around long enough to remember that IL-11 does have a past in oncology. Cambridge, MA-based Genetics Institute had ushered a recombinant IL-11 to the market as a support therapeutic to chemotherapy before getting acquired by Wyeth, which in time rolled up into Pfizer.
“But the further biology in terms of its role in fibrosis or cancer just wasn’t well enough understood, I guess, for people to be successful to develop blocking therapeutics like IL-6, although IL-11 and IL-6 are in the same family of cytokines,” he said. “It’s just one of those things; biology is hard. Figuring out the right application takes time — decades, sometimes.”
Lassen now has its foot on the gas pedal, looking to accelerate the R&D work by partnering with both academic investigators and Fujifilm Diosynth, which will manufacture clinical-grade material for them once they decide on the fibrotic context and organ system to target first.
There’s plenty of room for both Boehringer and Lassen to bring forth new treatments in the broad space, Barrett added, especially as “we may diverge in the way we focus.”