Treeline Biosciences Treeline Biosciences

October 2022

An update from our founders

"Homo sapiens is a storytelling animal that thinks in stories rather than in numbers or graphs, and believes that the universe itself works like a story, replete with heroes and villains, conflicts and resolutions, climaxes and happy endings."

— Yuval Noah Harari, 21 Lessons for the 21st Century

Last year, we provided a founders’ letter that told a story. 15 months into the Treeline journey, we find ourselves in between story and “numbers and graphs.” While we’ve made significant progress in building the pipeline we envisioned at company formation, we are a team that wants our data to do the talking. We are excited for the day when we provide scientific disclosure that has clear implications for patients with cancer and other serious diseases. That day is not today. Nevertheless, a new and exciting financing deserves mention.

KKR has led an expansion of our existing investor syndicate, with a significant capital commitment from its Health Care Strategic Growth Fund II, a fund dedicated to investing in high-growth health care-related companies to which KKR can be a unique and strategic partner in helping reach scale. Other investors in the Series A round included Rock Springs Capital, ARCH Venture Partners, GV, OrbiMed, Access Industries, funds and accounts advised by T. Rowe Price Associates, Inc., Ajax Health/Zeus, Casdin Capital and Aisling Capital.

The implications for our approach to portfolio construction and team building are profound. The size and structure of our funding ensures that Treeline has the runway to work on long lead time projects as well as near-term opportunities. We are also able to work on exploratory programs with the expectation of attrition and replacement.

We have built a stellar team of over 130 people across three sites (San Diego, Stamford and Watertown) and at large. Our internal R&D team is equally weighted across biology, chemistry, protein sciences and computation. We are privileged to have an extremely capable internal IP team and G&A colleagues who are fully integrated into our drug discovery programs. Recruiting against a five-year plan has had a healthy impact on culture. We’ve been able to attract folks who make long-term commitments to their projects and would have not otherwise considered the biotech model as well as seasoned biotech veterans. Like most companies, we also use external CROs for greater scale and certain capabilities we do not yet possess internally. However, we suspect that our investment in internal infrastructure and talent is atypical. In a world that is rapidly deglobalizing, we expect this push to continue.

We remain humbled and honored by the budget mandate we have been given, and by the faith expressed by our team members who have joined us in this effort. We look forward to the work ahead.


Josh and Jeff


April 2021

A message from our founders

We have started a new biotech company called Treeline Biosciences. The name is meant to connote the outer edge of scientific possibility, where conditions are challenging but the metaphorical trees still grow.

The company will prioritize molecular targets in oncology that are validated but difficult to drug. If successful, we believe that our approaches could apply to other therapeutic areas as well.

Some proteins, such as kinases and other enzymes, have obvious footholds for pharmacologic inhibition, while others conceal the mechanics of how they mediate their biologic effects. Inventing small molecules that successfully alter the function of these next-generation targets requires a drug discovery plan that is scientifically and operationally complex.

Our efforts will incorporate both established and emerging technologies, across disciplines, including biology (big data genetics, CRISPR, cell biology), chemistry (covalent modifiers, molecular glue and heterobifunctional degraders, allosteric approaches), structural biology (NMR, X-ray crystallography, Cryo EM) and computation (in silico docking, molecular dynamics, machine learning/AI). Many components of this toolbox did not exist even 5 years ago, and our industry is only beginning to integrate these capabilities into the routine drug discovery cascade.

However, we believe that human behavior, more than technology, will be critical to success. A startup offers certain advantages: an organizational blank page, programmatic focus and survivalist urgency. Culturally, we are committed to a “company of equals” model. The various scientific disciplines named above should interact with the others on equal footing; titles and reporting hierarchies should not drive the workflow or scientific decision making.

We are very fortunate to partner with a group of leading life sciences investors who share our vision. We recently closed a tranched Series A financing led by ARCH Venture Partners, GV and OrbiMed. Other investors include Access Industries, Ajax Health/Zeus, Casdin Capital, funds and accounts advised by T. Rowe Price Associates, Inc., and Aisling Capital. The financing was designed to provide the company with significant operating runway across many programs. Our lab operations will be based in Watertown, MA and San Diego, CA and there will be a corporate presence in Stamford, CT.

There is a ton of work to do, both in building a team and launching the science. Please forgive us in advance for keeping a low profile. We’ll report back from the tree line once we’ve marked some new trails.


Josh Bilenker, M.D. and Jeff Engelman M.D., Ph.D.