Obsidian Therapeutics, Inc. is a clinical-stage biopharmaceutical company harnessing novel protein-regulation technology to develop engineered TIL cell therapies for the treatment of patients with solid tumors. Its proprietary cytoDRiVE technology is designed to regulate the timing and level of protein function by using FDA-approved small-molecule drugs. Its lead clinical program, OBX-115, is an investigational TIL cell therapy engineered to express membrane-bound IL15 (mbIL15), which is designed to support TIL activity. Its cytoDRiVE discovery platform has identified a library of internally discovered drug-responsive domains (DRDs) of varying sizes and intended purposes and enables rapid optimization of regulatable and functional proteins in any cell type. It has developed a synthetic biology engineering toolkit that supports the design and optimization of a range of therapeutic proteins, including but not limited to type I/II membrane proteins, and membrane-bound cytokines.