Third Rock launches Rheos, puts $60M behind immunometabolism player

Interim CEO Abbie Celniker, Ph.D. (Rheos Medicines)(Third Rock Ventures / Rheos)

Third Rock Ventures unwrapped its latest biotech baby this morning. The new company—Rheos Medicines—is focused on the emerging field of immunometabolism and makes its debut with $60 million in first-round funding.

Rheos’ approach to immunometabolism is to try to identify metabolic pathways in immune cells that are associated with disease and “tune” them to change their behavior. It’s very different from the one-size-fits-all approach of many current treatments for autoimmune and inflammatory diseases, according to the new company’s chief scientific officer Laurence Turka, M.D., a regulatory T-cell specialist formerly at Mass General and Harvard.

“With today’s antibody drugs that treat diseases, they also turn off the beneficial effects of the immune cells they target,” he tells FierceBiotech. “In contrast, at Rheos, our approach for tuning metabolic pathways will bring an immune cell back to a healthy state, thereby preserving the cell's beneficial functions.”

At the moment, Rheos’ programs are all in the drug discovery phase, and it is focusing initially on two cell types—CD4 and CD8—which are involved in a range of diseases such as inflammatory bowel disease, psoriasis and vitiligo and could also have immuno-oncology applications.

Its initial focus is on autoimmune and inflammatory disease, but for now it’s not discussing specific indications, says interim CEO Abbie Celniker, Ph.D., who is also a Third Rock partner.

“When we say ‘immunometabolism,’ we define it as the understanding of the physiology of immune cells and how their metabolic pathways differ in healthy versus diseases states,” she tells us. “At Rheos, we are pioneering a new approach to tune these metabolic pathways with novel medicines, in order to restore balance.”

The primary task in that effort is to develop what the biotech calls its Immune Cell Encyclopedia (ICE), a catalog of the metabolic pathways involved in immune cell function—in health and disease—that has been developed in part from patient cell samples.

“With ICE, we are able to gain knowledge and insights to generate both novel drug targets and biomarkers … that allow us to understand patient subsets within these highly heterogeneous diseases,” says Celniker. “We are identifying novel biomarkers that will translate into ‘metabolic signatures’ that will allow us to understand which patients should be treated with our medicines. “

The idea for Rheos came from Third Rock partner Craig Muir, who ran over the concept with Ed Driggers, Ph.D., a metabolomics specialist and founder of General Metabolics (GMet)—now appointed chief technology officer of the startup.

“They became very excited about the prospect of translating this new science into novel drug discovery,” according to Celniker, and decided to reach out to Turka to gauge his interest in becoming Rheos’ first scientific founder. With Turka on board, they then assembled a team of leading academic researchers in immunometabolism and recruited ex-Takeda executive Ryan Cohlhepp to lead the R&D effort. The company was incorporated last summer in Cambridge, Massachusetts, and currently has 15 employees.

Now out of stealth mode, Rheos will use the series A proceeds to continue to build its product engine and advance early targets in drug discovery based on research and insights from its founders into a pipeline of drug candidates.