0001620463 dei:BusinessContactMember 2026-01-01 2026-03-31 0001620463 2026-01-01 2026-03-31 true 0001620463 S-1/A WA WA LeonaBio, Inc. DE 2836 45-3368487 18706 North Creek Parkway Suite 104 Bothell 98011 425 620-8501 Mark Litton 18706 North Creek Parkway Suite 104 Bothell 98011 425 620-8501 Non-accelerated Filer true false This Pre-Effective Amendment No. 1 to Form S-3 on Form S-1 is being filed by LeonaBio, Inc. (the “Company”) to convert the Registration Statement on Form S-3 (File No. 333-292826) filed by the Company with the Securities and Exchange Commission on January 20, 2026, into a registration statement on Form S-1.