Third Rock-founded Rheos Medicines launches to tackle immunometabolism

Tapping into the blossoming field of immunometabolism, Rheos Medicines has come out of stealth with $60 million in funding from Third Rock Ventures. The Cambridge, Mass.-based biotech firm will initially develop small molecules to treat autoimmune diseases such as inflammatory bowel disease, vitiligo, and lupus.

While many areas of drug development are moving toward personalized medicine—most notably in cancer, where targeted therapy has proliferated—immunologists still rely on one-size-fits-all treatments for their patients.

Rheos hopes to change that. Starting last summer, the company assembled a drug discovery platform based on findings from its academic founders, whose work focuses on how a cell’s metabolic pathways can control its fate.

Cells, like people, get their energy from different sources, explains Rheos’ chief scientific officer, Laurence Turka. “You know how you feel different if you have two slices of pizza for lunch instead of a salad? You behave differently.” Cells are no different, he says. They can use different metabolic pathways depending on their state.

Rheos wants to tune those metabolic pathways to alter the behavior of cells. “Immune cells are not inherently bad or deficient, but in disease states they’re just not doing what we want them to do,” CEO Abbie Celniker says. Currently-available antibody drugs target immune cells themselves, treating disease, but also turning off the beneficial effects of those cells. Rheos hopes its tuning approach will instead bring immune cells back to a healthy state, preserving their useful functions.

The company’s technology is intended to identify drug targets along the various metabolic pathways. That work should also reveal related metabolites that can be used as biomarkers to find patients who will respond to the drugs.

Although Rheos will initially focus on autoimmune diseases, it expects to later find targets relevant to immuno-oncology.

Checkpoint inhibitors—antibodies that allow immune cells to see and destroy cancer cells—work remarkably for some, but not all, cancer patients, and their effect can wear off over time. “We now know that one of the reasons they may become ineffective is because exhausted cells, or cells that need to be re-awakened, alter their metabolism,” Turka says. The Rheos platform could identify targets that get around that barrier, he adds.