LeonaBio, Inc. Reports Transformational 2025 Financial Results and Business Update

Key Highlights for Investors

• Acquisition of Lasofoxifene License: LeonaBio acquired an exclusive global license (excluding Asia and certain Middle East countries) for the late-stage drug candidate, lasofoxifene, from Sermonix Pharmaceuticals. This positions the company to target the multi-billion dollar market for ER-positive, HER2-negative, ESR1-mutated metastatic breast cancer, a patient group with significant unmet medical need.
• Major Private Placement Financing: The company secured \$90 million in gross proceeds through a private placement of common stock and warrants, with cash-exercisable warrants that could provide up to an additional \$146 million to support further development and key milestones of lasofoxifene.
• Advanced Clinical Pipeline: Enrollment for the pivotal Phase 3 ELAINE-3 clinical trial of lasofoxifene is expected to complete in Q4 2026, with topline data anticipated in the second half of 2027. LeonaBio is also on track to initiate a Phase 2 proof-of-concept study of ATH-1105 for ALS in 2H 2026.
• Corporate Transformation: The company rebranded from Athira Pharma to LeonaBio in January 2026, reflecting a strategic shift to a more focused, diversified biopharma entity with two clinical-stage programs and a strengthened leadership team.
• Strong Financial Position: Cash, cash equivalents, and investments were \$88.3 million as of December 31, 2025, up from \$51.3 million a year earlier, supporting the company’s ability to fund ongoing R&D and clinical activities.

Detailed Business and Pipeline Update

Lasofoxifene – Pivotal Oncology Asset

• Lasofoxifene is a novel, nonsteroidal selective estrogen receptor modulator (SERM) with a unique binding profile designed for potent activity against both wild-type and mutant estrogen receptors, including ESR1 mutations that confer resistance to standard endocrine therapy.
• The ongoing Phase 3 ELAINE-3 trial (NCT05696626) evaluates lasofoxifene in combination with abemaciclib, a CDK4/6 inhibitor, as a targeted therapy for a genetically-defined subset of breast cancer patients. The study’s primary endpoint is progression-free survival (PFS), assessed by blinded, independent central review.
• LeonaBio is amending the ELAINE-3 protocol to increase the sample size from 500 to 600 participants, aiming to ensure robust statistical power for disease progression events.
• Prior Phase 2 studies (ELAINE-1 and ELAINE-2) demonstrated clinical benefit in heavily pretreated ESR1-mutated, ER+, HER2-negative metastatic breast cancer:
  • ELAINE-1: Lasofoxifene monotherapy showed improved median PFS (5.6 vs. 3.7 months), higher objective response rates (13.3% vs. 2.9%), and a durable complete response over 2.5 years compared to fulvestrant, with a favorable safety profile.
  • ELAINE-2: Combination with abemaciclib yielded a median PFS of ~13 months, an objective response rate of 56%, and a clinical benefit rate of 65.5%, with mostly low-grade adverse events.

ATH-1105 – Neurodegeneration Pipeline Progress

• ATH-1105 is an orally available, brain-penetrant, next-generation small molecule designed to modulate the neurotrophic HGF system. It is being developed for amyotrophic lateral sclerosis (ALS), with potential in Alzheimer’s and Parkinson’s disease.
• Results from a Phase 1 trial in healthy volunteers presented in August 2025 showed a favorable safety and tolerability profile, dose-proportional pharmacokinetics, and CNS penetration.
• Preclinical evidence supports statistically significant improvements in nerve and motor function, reduction of biomarkers of inflammation and neurodegeneration, and increased survival in ALS models.
• First-in-human Phase 1 trial (completed November 2024) enrolled 80 healthy volunteers, confirming ATH-1105’s profile and supporting a planned Phase 2 proof-of-concept trial in ALS patients in 2H 2026.

Corporate Updates

• Mark F. Kubik was appointed Chief Business Officer in February 2026, overseeing licensing, partnership strategy, and corporate development.
• The corporate rebranding to LeonaBio follows the transformative lasofoxifene license, underlining the company’s commitment to leadership and innovation in oncology and neurodegeneration.

Financial Summary (2025)

• Cash Position: \$88.3 million in cash, cash equivalents, and investments as of December 31, 2025, versus \$51.3 million in 2024.
• Net Cash Used in Operations: \$45.7 million for 2025, a significant improvement from \$97.2 million in 2024.
• R&D Expenses: Increased to \$85.6 million (from \$70.7 million in 2024), driven by acquired in-process R&D costs relating to lasofoxifene.
• G&A Expenses: Decreased to \$16.7 million (from \$26.1 million in 2024), reflecting cost efficiencies.
• Net Loss: \$105.6 million (\$24.70 per share), compared to \$96.9 million (\$25.19 per share) in 2024.
• Weighted-Average Shares Outstanding: 4,275,762 (basic and diluted).
• Balance sheet includes new liabilities related to the Sermonix pre-funded warrant (\$37.5 million) and milestone liabilities (\$15.1 million).

Potential Share Price Drivers & Investor Considerations

• Late-stage Lasofoxifene Asset: The acquisition and advancement of lasofoxifene into a pivotal Phase 3 trial for a well-defined, high-value oncology market represent a significant potential value inflection point.
• Substantial Capital Infusion: The \$90 million financing, with up to \$146 million more available via warrants, provides a strong runway through key upcoming clinical milestones.
• Clinical Milestones Ahead: Completion of ELAINE-3 trial enrollment and topline data in 2027, plus initiation of Phase 2 ALS trial for ATH-1105, are major upcoming catalysts.
• Pipeline Diversification: With two clinical-stage candidates targeting high unmet need in oncology and neurodegeneration, LeonaBio is well-positioned for multiple shots on goal.
• Reduced G&A Expenses: Improved cost structure could enhance operating leverage if pipeline advances deliver positive data.
• Risks: Execution risk remains, including successful trial enrollment, meeting regulatory endpoints, and realizing anticipated clinical and commercial value from the pipeline. The company’s financial position is strong but contingent on timely warrant exercises and successful trial outcomes.

About LeonaBio

LeonaBio is a clinical-stage biopharmaceutical company based near Seattle, WA, focused on developing novel therapeutics for treatment-resistant metastatic breast cancer and neurodegenerative diseases such as ALS. Lead assets include lasofoxifene, a SERM for ESR1-mutated metastatic breast cancer, and ATH-1105 for ALS, both with the potential to transform patient outcomes in areas of high unmet need.

For further information: www.leonabio.com

Disclaimer

This article contains forward-looking statements reflecting management’s current expectations, estimates, and projections about future events and financial trends that may affect LeonaBio, Inc. These statements involve risks and uncertainties that could cause actual results to differ materially from those anticipated. Investors should review all risks, including those detailed in LeonaBio’s SEC filings, and should not place undue reliance on these forward-looking statements. This content is for informational purposes only and does not constitute investment advice.

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