Cytokines control nearly all aspects of the immune system. As drugs, though, they have limited potential because of inherent drawbacks. Simcha Therapeutics is engineering versions of cytokines to activate various immune cells in the fight against cancer. Simcha’s most advanced program, ST-067, is the first in a new class of interleukin-18 based immunotherapies designed to overcome a key defense mechanism that the tumor microenvironment produces to prevent Interleukin-18 from doing its work. We spoke to Sanuj Ravindran, CEO of Simcha Therapeutics, about the company’s engineered cytokines, how they work, and why they may represent a powerful addition to the immunotherapy arsenal.