ATOS · Atossa Therapeutics, Inc.

Atossa Therapeutics reported a widened Q1 2026 net loss of $9.6 million, or ($1.11) per share, compared to $6.7 million, or ($0.78) per share, in the prior-year quarter, reflecting accelerated investment in its lead asset (Z)-endoxifen. Total operating expenses climbed 33% to $9.9 million, with R&D up 15% to $4.8 million driven by a $1.0 million increase in clinical and pre-clinical trial costs for (Z)-endoxifen, including drug development expenses. Compensation rose modestly due to stock-based awards, offset by lower regulatory consulting fees. G&A expenses more than doubled to $5.1 million, propelled by $1.8 million in legal fees from patent litigation—now settled—and intellectual property management, despite reduced headcount. Interest income fell to $0.3 million from lower cash balances. Balance sheet shows cash at $31.7 million as of March 31, 2026, down from $41.3 million at year-end, supporting ongoing clinical execution. CEO Dr. Steven Quay highlighted progress in (Z)-endoxifen for breast cancer and rare diseases, including FDA Orphan Drug Designation for DMD in January 2026, prior RPD for DMD, and new RPD for McCune-Albright Syndrome in May 2026, potentially unlocking Priority Review Vouchers valued historically at $100–$205 million. Pre-clinical DMD data presented March 11, 2026, demonstrated improved muscle strength and reduced damage markers in mouse models, supporting clinical advancement. Leadership bolstered with hires of Kathy Puyana Theall, M.D., as Medical Director - Breast Oncology, and Adebola Giwa, M.D., as Medical Director - Rare Diseases to drive milestones.