LeonaBio Raises $90M, Secures Phase 3 Lasofoxifene Rights with $146M Upside
LeonaBio secured a license for lasofoxifene’s Phase 3 program for ER+ ESR1-mutated breast cancer and raised $90 million financing with warrants unlocking up to $146 million. The company plans enrollment completion in 4Q 2026 with topline data in 2H 2027 and schedules a Phase 2 ALS study in 2H 2026.
1. Financial Update
LeonaBio reported full year 2025 results and bolstered its balance sheet with a $90 million private placement financing. The company issued cash-exercisable warrants that could provide up to an additional $146 million upon exercise, funding key clinical and regulatory milestones through 2027.
2. Lasofoxifene Phase 3 Program
In December 2025, LeonaBio obtained an exclusive global license (excluding Asia and select Middle Eastern countries) from Sermonix Pharmaceuticals for lasofoxifene, a novel SERM targeting ESR1 mutations in ER+ breast cancer. The ongoing ELAINE-3 Phase 3 trial, combining lasofoxifene with abemaciclib, has been amended to enroll up to 600 patients with enrollment expected to finish in 4Q 2026 and topline progression-free survival data due in 2H 2027.
3. ATH-1105 ALS Program
ATH-1105 is a brain-penetrant small molecule modulating the neurotrophic HGF system for neurodegenerative diseases including ALS. Phase 1 data in healthy volunteers demonstrated favorable safety, dose-proportional pharmacokinetics and CNS penetration, and the company plans to initiate a Phase 2 proof-of-concept study in ALS patients in the second half of 2026.