On March 26, 2026 LeonaBio, Inc. (NASDAQ: LONA), a clinical-stage biopharmaceutical company dedicated to the development of novel therapeutics for diseases with high unmet medical needs, reported financial results for the year ended December 31, 2025, and provided recent pipeline and business updates.

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"2025 was a truly transformational year for LeonaBio. With our license for lasofoxifene, we added a late-stage drug candidate that has the potential to become the endocrine therapy of choice in the multi-billion-dollar second line metastatic breast cancer setting" stated Mark Litton, Ph.D., President and Chief Executive Officer of LeonaBio. "Coupled with our successful $90 million fundraise with the potential for $146 million in additional capital available through warrant exercises, we enter 2026 with the financial resources needed to advance both our oncology and neurodegeneration programs with confidence."

"Our transition from Athira Pharma to LeonaBio reflects far more than a name change; it represents our evolution into a more focused, diversified, and opportunity-driven biopharmaceutical company. We now have two clinical-stage programs and an experienced team aligned around focused execution. As we look ahead to meaningful clinical milestones in 2026 — including the anticipated completion of enrollment of the Phase 3 ELAINE-3 clinical trial and initiation of patient dosing in our ATH-1105 ALS program — we are energized by what lies ahead. We are building a company that we believe has the potential to change the treatment landscape for patients who urgently need better options, and I couldn’t be more optimistic about the momentum we carry into 2026 and beyond," concluded Dr. Litton.

Clinical Development & Pipeline Programs

Lasofoxifene – A novel, nonsteroidal selective estrogen receptor modulator (SERM) with a unique binding profile, designed to confer potent activity against both wild-type and mutant estrogen receptors, including the clinically significant ESR1 mutations commonly associated with resistance to endocrine therapy in metastatic breast cancer.

In December 2025, LeonaBio acquired an exclusive global license (excluding Asia and certain countries in the Middle East) from Sermonix Pharmaceuticals, Inc. for rights to develop and commercialize lasofoxifene.

Lasofoxifene is being advanced in a Phase 3 clinical trial (NCT05696626) in combination with abemaciclib, a CDK4/6 inhibitor, as a targeted therapy for estrogen receptor-positive (ER+), HER2-negative, ESR1-mutated metastatic breast cancer, a population with limited treatment options following progression on aromatase inhibitors and CDK4/6 inhibitors. The primary endpoint of the study is statistically significant improvement in progression free survival (PFS) as determined by blinded, independent central review (BICR). The ongoing Phase 3 trial aims to establish a new standard of care for this genetically defined patient group.
LeonaBio is amending the ELAINE-3 trial protocol to increase the sample size from 500 participants to up to 600 participants. The primary goal of the amendment is to help ensure that the trial will have the appropriate number of disease progression events. The Company expects to complete enrollment of the Phase 3 ELAINE-3 clinical trial in the fourth quarter of 2026 and to have topline data in the second half of 2027.
Lasofoxifene was previously evaluated in two Phase 2 studies in patients with ER+, HER2-negative locally advanced or metastatic breast cancer expressing an ESR1 mutation, ELAINE-1 and ELAINE-2
ELAINE-1, an open-label, randomized trial comparing lasofoxifene to fulvestrant, showed improved outcomes for lasofoxifene as a potential monotherapy. Although the trial was not powered, results included longer median progression-free survival (5.6 vs. 3.7 months), higher objective response rates (13.3% vs. 2.9%) and a durable complete response lasting more than 2.5 years. The treatment was well-tolerated with patients reporting quality-of-life benefits.
ELAINE-2, an open-label study evaluating lasofoxifene in combination with abemaciclib, demonstrated clinical benefits in heavily pretreated patients, with a median progression-free survival of approximately 13 months, an objective response rate of 56% and a clinical benefit rate of 65.5%. The combination was generally well-tolerated with most adverse events being low grade.
ATH-1105 – A novel, orally available, brain-penetrant, next-generation small molecule drug candidate designed to positively modulate the neurotrophic HGF system for potential treatment of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), Alzheimer’s disease, and Parkinson’s disease. ATH-1105 is currently being developed for the potential treatment of ALS.

In August 2025, LeonaBio presented results from the first-in-human Phase 1 clinical trial (NCT 06432647) of ATH-1105 in healthy volunteers at the ALS Nexus 2025 conference.
Results from the Phase 1 trial demonstrated a favorable safety and tolerability profile as well as dose-proportional pharmacokinetics and CNS penetration.
Previously, the Company presented data from the Phase 1 clinical trial of ATH-1105 at the 4th Annual ALS Drug Development Summit. Key highlights from the presentation included:
ATH-1105 showed a favorable safety profile and was well tolerated in both single and multiple ascending dose studies in healthy volunteers
ATH-1105 showed dose proportional pharmacokinetics and central nervous system (CNS) penetration
ATH-1105 demonstrated consistent and robust beneficial effects in preclinical models of ALS
LeonaBio conducted the first-in-human Phase 1 double-blind, placebo-controlled clinical trial that enrolled 80 healthy volunteers to evaluate single and multiple oral ascending doses of ATH-1105. The study was completed in November 2024 and evaluated the safety and tolerability of ATH-1105 and included measurements of pharmacokinetic outcomes.
ATH-1105’s potential is supported by a body of preclinical evidence demonstrating statistically significant improvements in nerve and motor function, biomarkers of inflammation and neurodegeneration, including neurofilament light chain and survival in various models of ALS.
LeonaBio is on track to dose ALS patients in a Phase 2 proof-of-concept clinical trial in the second half of 2026.
Corporate Updates

In February 2026, Mark F. Kubik was appointed as Chief Business Officer of LeonaBio, with responsibility for licensing, partnership strategy and corporate development initiatives.
In January 2026, LeonaBio changed its name from Athira Pharma to align with the Company’s transformative acquisition of rights to develop and commercialize lasofoxifene as a treatment for metastatic breast cancer and better reflect its commitment to continued leadership, resilience and innovation.
In December 2026, the Company acquired an exclusive global license (excluding Asia and certain countries in the Middle East) from Sermonix Pharmaceuticals, Inc. for rights to develop and commercialize lasofoxifene, a selective estrogen receptor modulator (SERM) for the potential treatment of metastatic breast cancer.
In conjunction with the Sermonix license agreement, LeonaBio announced a $90 million private placement financing of common stock and warrants, with the warrants providing, if exercised, up to an additional $146 million to support development through key clinical and regulatory milestones.
Financial Results

Cash Position. Cash, cash equivalents and investments were $88.3 million as of December 31, 2025, compared to $51.3 million as of December 31, 2024. Net cash used in operations was $45.7 million for the year ended December 31, 2025, compared to $97.2 million for the year ended December 31, 2024.
Research and Development (R&D) Expenses. R&D expenses were $85.6 million for the year ended December 31, 2025, compared to $70.7 million for the year ended December 31, 2024. The increase was driven primarily by acquired in-process research and development costs related to our license of lasofoxifene.
General and Administrative (G&A) Expenses. G&A expenses were $16.7 million for the year ended December 31, 2025, compared to $26.1 million for the year ended December 31, 2024. The decrease was driven primarily by a realization of cost efficiencies in 2025 as we pursued our strategic alternatives.
Net Loss. Net loss was $105.6 million, or $24.70 per share, for the year ended December 31, 2025, compared to a net loss of $96.9 million, or $25.19 per share, for the year ended December 31, 2024.

(Press release, LeonaBio, MAR 26, 2026, View Source [SID1234663961])