858 Therapeutics is a clinical-stage biotechnology company in San Diego building small-molecule cancer drugs aimed at novel targets in DNA damage response, RNA modulation, and innate immunity. Its lead candidate, the oral PARG inhibitor ETX-19477, is in a first-in-human Phase 1/2 trial for advanced solid tumors and has won FDA Fast Track designation for BRCA-mutated, platinum-resistant ovarian cancer. Founded in 2019 by a serial team of San Diego drug developers, the company has raised $110 million across Series A and B financings.
Jeffrey Stafford is the CEO and co-founder of 858 Therapeutics, a San Diego clinical-stage biotech developing small-molecule cancer drugs against novel targets in DNA-damage repair, innate immunity and RNA epigenetics. A chemist by training, he has spent three decades turning molecules into medicines: his discovery teams contributed to three FDA-approved drugs, and he previously led Jecure Therapeutics (acquired by Genentech in 2018) and co-founded Quanticel Pharmaceuticals (acquired by Celgene in 2015). 858's lead asset, the PARG inhibitor ETX-19477, won FDA Fast Track status and posted a 57% response rate in BRCA-mutated ovarian cancer at ASCO 2026.