Business Description

1. Description of Business Organization LeonaBio, Inc. (the "Company") was incorporated as M3 Biotechnology, Inc. in the state of Washington on March 31, 2011 and reincorporated in the state of Delaware on October 27, 2015 . In April 2019, the Company changed its name to Athira Pharma, Inc and in January 2026 the Company changed its name to LeonaBio, Inc. The Company currently has office and laboratory space in Bothell, Washington. The Company is a clinical-stage biopharmaceutical company dedicated to the development of novel therapeutics for high unmet medical needs, including treatment-resistant metastatic breast cancer and amyotrophic lateral sclerosis. Liquidity and Capital Resources Since the Company’s inception, it has funded its operations primarily with proceeds from the sale and issuance of common stock, convertible preferred stock, common stock warrants, prefunded common stock warrants, and convertible notes, and to a lesser extent from grant income and stock option exercises. From the Company’s inception through December 31, 2025, it has raised aggregate net cash proceeds of $ 489.8 million primarily from the issuance of its common stock (excluding option exercises), convertible preferred stock, common stock warrants, prefunded common stock warrants and convertible notes. In December 2025, the Company raised approximately $ 90 million in a Private Placement (as defined below), excluding placement agent fees and offering expenses. See Note 9 for more information. As of December 31, 2025, the Company had cash, cash equivalents and investments of $ 88.3 million. The Company’s net loss for the year ended December 31, 2025 was $ 105.6 million and cash used in operations for the year ended December 31, 2025 was $ 45.7 million. Since the Company’s inception, it has devoted substantially all of its resources to its research and development efforts such as small molecule compound discovery, nonclinical studies and clinical trials, as well as manufacturing activities, establishing and maintaining the Company’s intellectual property portfolio, hiring personnel, raising capital, and providing general and administrative support for these operations. Based upon the Company’s current operating plan, it estimates that its $ 88.3 million of cash, cash equivalents and investments at December 31, 2025 will be sufficient to fund its operating expenses and capital expenditure requirements through at least the next 12 months following the date of the Company’s Annual Report on Form 10-K. Historically, the Company has incurred net losses from continuing operations and negative operating cash flows. The Company has not yet established an ongoing source of revenue sufficient to cover its operating costs; therefore, the Company expects it will need to continue to raise additional capital to accomplish its operating plan. The Company has a sales agreement in place with Cantor Fitzgerald & Co. and BTIG, LLC for an “at the market” equity offering facility through which it may offer and sell shares of its common stock, however, the Company is currently unable to offer and sell shares under this facility due to its ineligibility to use a Registration Statement on Form S-3 through December 2026. The Company has no t sold any securities pursuant to this ATM offering. Should it be determined to be strategically advantageous, the Company could pursue public and private offerings of its equity securities similar to those the Company has previously completed, debt financings, or other strategic transactions, which could include income from collaboration, licensing or similar arrangements with third parties, or receiving research contributions, or grants.