Atossa Therapeutics, Inc. is a clinical-stage biopharmaceutical company that develops medicines for areas of significant unmet medical need in oncology in the United States. Its lead drug candidate is oral (Z)-endoxifen, a selective estrogen receptor modulator and selective estrogen receptor degrader, currently in Phase 2 clinical development for the treatment and risk reduction of breast cancer, as well as in other therapeutic areas. The company was formerly known as Atossa Genetics Inc. and changed its name to Atossa Therapeutics, Inc. in January 2020. Founded in 2008, it is based in Seattle, Washington.