Seattle-based Atossa Therapeutics, Inc. (Nasdaq: ATOS) announced a registered direct offering of up to USD 16.5 million in total potential gross proceeds, structured to provide USD 4.5 million in immediate capital while retaining the possibility of an additional USD 12 million contingent on warrant exercises. For a clinical-stage company carrying a USD 34.8 million net loss in 2025 against a year-end cash balance of approximately USD 41.3 million, the offering represents a measured effort to extend runway as the company advances (Z)-endoxifen across oncology and rare disease programs, including Duchenne Muscular Dystrophy and McCune-Albright Syndrome.
The financing provides Atossa with USD 4.5 million in upfront gross proceeds through a registered direct sale of common stock to institutional investors, with the potential to raise an additional USD 12 million if accompanying warrants are exercised. The warrants become exercisable six months after issuance and include both longer- and shorter-dated tranches. Rodman & Renshaw acted as exclusive placement agent. Atossa said the proceeds will support clinical development of (Z)-endoxifen and other pipeline programs, as well as general corporate purposes.
Company overview and pipeline
Atossa is a clinical-stage biopharmaceutical company focused on developing (Z)-endoxifen, a potent selective estrogen receptor modulator and degrader (SERM/D) with additional PKC-β1 inhibitory activity. Unlike tamoxifen, which requires metabolic conversion via CYP2D6, (Z)-endoxifen delivers direct pharmacological activity independent of that enzyme, providing more consistent systemic exposure across patient populations with variable CYP2D6 metabolism.
The company is evaluating (Z)-endoxifen across multiple clinical settings. In breast cancer, Atossa is conducting the EVANGELINE study in collaboration with the Mayo Clinic, with enrollment expected to conclude by mid-2026 and preliminary data anticipated later that year. A separate arm within the I-SPY 2 adaptive trial, pairing (Z)-endoxifen with Eli Lilly's abemaciclib (Verzenio) in ER+/HER2- early breast cancer, dosed its first patient in August 2024.