LeonaBio to Host Virtual Key Opinion Leader Event Highlighting Potential of Lasofoxifene in Treatment-Resistant ER+/HER2-, ESR1-Mutated Metastatic Breast Cancer
Management to be Joined by Two Clinical Leaders in the Breast Cancer Field
Expected to Complete Enrollment in Ongoing ELAINE-3 Phase 3 Registrational Study of Lasofoxifene in Metastatic Breast Cancer in 4Q26 with Data Expected in 2H27
Webinar Event on Wednesday, April 29, 2026, at 12:00 p.m. ET
BOTHELL, Wash., April 23, 2026 (GLOBE NEWSWIRE) -- LeonaBio, Inc. (NASDAQ:LONA), a clinical-stage biopharmaceutical company dedicated to the development of novel therapeutics for diseases with high unmet medical needs, today announced that it will host a virtual Key Opinion Leader event with two leading physician experts in the breast cancer field to discuss the current and evolving treatment landscape in metastatic breast cancer and the potential for lasofoxifene to transform the standard of care for patients with treatment-resistant estrogen receptor-positive (ER+), HER2-negative, ESR1-mutated metastatic breast cancer.
The event titled, "Modulation and Combination: the Potential for Lasofoxifene to Transform the Standard-of-Care in Metastatic Breast Cancer," will take place on Wednesday, April 29, 2026, beginning at 12:00 p.m. ET. To participate in the event, register here.
"As we look toward completing enrollment in ELAINE-3 later this year, with data expected in the second half of 2027, we are pleased to be joined by two leading voices in the breast cancer field to discuss the evolving treatment landscape in metastatic disease," said Mark Litton, Ph.D., President and Chief Executive Officer of LeonaBio. "This conversation will highlight the persistent gaps in care, particularly for genetically defined populations, and the potential for lasofoxifene to address a critical unmet need in patients with treatment-resistant ER+, HER2-, ESR1-mutated metastatic breast cancer."
The webcast event will feature a discussion with David Portman, M.D., Chief Executive Officer of Sermonix Pharmaceuticals and an oncology consultant to LeonaBio, along with two physician experts in the breast cancer field:
- Matthew P. Goetz, M.D., Erivan K. Haub Family Professor of Cancer Research Honoring Richard F. Emslander, M.D, Mayo Clinic, Principal investigator and director, Breast Cancer Specialized Program of Research Excellence (SPORE), Mayo Clinic Comprehensive Cancer Center and Enterprise Deputy Director, Translational Research, Mayo Clinic Comprehensive Cancer Center.
- Seth Wander, M.D., Ph.D., Director of Precision Medicine, Termeer Center for Targeted Therapies, Director of Translational Research, Breast Oncology Program, Mass General Brigham Cancer Institute, Assistant Professor of Medicine, Harvard Medical School.
In addition to the live webinar, the event will be archived on the LeonaBio website under Events in the Investor Relations here.
About Metastatic Breast Cancer
Metastatic breast cancer (MBC) occurs when cancer spreads from the breast to other parts of the body—such as bones, lungs, liver, or brain. While approximately two-thirds of breast cancers are diagnosed at a localized stage, a notable proportion either present as metastatic at diagnosis or progress to that stage over time. From 2001 to 2021, approximately 4.65 million new cases of female breast cancer were reported in the United States, with approximately 260,000 (5.6%) diagnosed as distant (metastatic) stage at initial diagnosis. The metastatic breast cancer treatment market represents a sizable and rapidly expanding global opportunity with a global market of $17.1 billion in 2021, expected to expand to $41.7 billion by 2030, with a compound annual growth rate (CAGR) of approximately 10.4%. These projections reflect a market rich with innovation—from chemotherapy and hormone therapies to biologics, targeted agents and emerging personalized medicine. Growth is driven by the persistent incidence of metastatic disease, regulatory and clinical advances and evolving treatment landscapes.
About Lasofoxifene
Lasofoxifene is 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. Two Phase 2 studies—ELAINE-1 and ELAINE-2—have demonstrated its potential to address a critical unmet need in this patient population.
ELAINE-1, a randomized trial comparing lasofoxifene to fulvestrant, showed improved outcomes for lasofoxifene, including 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. Patients also reported quality-of-life benefits and the treatment was well tolerated.
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.
Lasofoxifene is being advanced in a Phase 3 clinical trial 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 ongoing ELAINE-3 trial (NCT05696626) is evaluating lasofoxifene in combination with the CDK4/6 inhibitor, abemaciclib, and is aiming to establish a new standard of care for this genetically defined patient group.
About LeonaBio
LeonaBio, headquartered in the Seattle, Washington area, is a clinical-stage biopharmaceutical company dedicated to the development of novel therapeutics for diseases with high unmet medical needs, including treatment-resistant metastatic breast cancer and amyotrophic lateral sclerosis (ALS), with the goal of improving patients' lives. Our lead drug candidates, lasofoxifene and ATH-1105, are novel, small molecule therapies with the potential to address devastating diseases where current treatment options are limited or ineffective. With a strong commitment to scientific excellence and patient-centered innovation, we are dedicated to developing meaningful new therapies for those who need them most.
For more information, visit www.leonabio.com.
Forward-Looking Statements
This communication contains "forward-looking statements" within the meaning of Section 27A of the Securities Act, Section 21E of the Securities Exchange Act of 1934 and the Private Securities Litigation Reform Act of 1995. These forward-looking statements are not based on historical fact and include statements regarding: the beneficial characteristics, safety and efficacy of LeonaBio's drug candidates; the potential of any subsequent clinical trials to show the beneficial characteristics, safety and efficacy of LeonaBio's drug candidates; LeonaBio's drug candidates as potential treatments for metastatic breast cancer and other diseases; anticipated development milestone timelines, such as the completion of enrollment of clinical trials and the timing of data releases, and LeonaBio's ability to meet such timelines; the potential of LeonaBio to complete the Phase 3 ELAINE-3 clinical trial for lasofoxifene and to meet the trial endpoints; LeonaBio's ability to obtain regulatory approval for any of its product candidates and to successfully commercialize any approved products; the rate and degree of market acceptance of LeonaBio's drug candidates, if approved for commercial use; the size and growth potential of the markets for LeonaBio's drug candidates, if approved for commercial use, and LeonaBio's ability to serve those markets; and the potential for lasofoxifene to be a new standard of care in its target genetically defined patient group. Forward-looking statements generally include statements that are predictive in nature and depend upon or refer to future events or conditions, and include words such as "may," "will," "should," "on track," "would," "expect," "plan," "believe," "intend," "pursue," "continue," "suggest," "potential," "target" and similar expressions. Any forward-looking statements are based on management's current expectations of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to, risks associated with the possible failure to realize certain anticipated benefits of the license relating to lasofoxifene and the recent private placement financing, including with respect to future financial and operating results; the data from nonclinical and clinical trials may not support the safety, efficacy and tolerability of LeonaBio's drug candidates; development of drug candidates may cease or be delayed; regulatory authorities could object to protocols, amendments and other submissions; future potential regulatory milestones for drug candidates, including those related to current and planned clinical studies, may be insufficient to support regulatory submissions or approval; whether LeonaBio's trials are sufficiently powered to meet the planned endpoints; LeonaBio may not be able to recruit sufficient patients for its clinical trials; the outcome of legal proceedings that may in the future be instituted against LeonaBio, its directors and officers; possible negative interactions of LeonaBio's drug candidates with other treatments; FDA regulatory delays and uncertainty and new policies, including executive orders, changes in the leadership of federal agencies such as the FDA and SEC, staff layoffs, budget cuts to agency programs and research and changes in drug pricing controls; LeonaBio's assumptions regarding its financial condition and the sufficiency of its cash, cash equivalents and investments to fund its planned operations may be incorrect; adverse conditions in the general domestic and global economic markets, including as a result of tariffs; the impact of competition; the impact of drug candidate development and clinical activities on operating expenses; the impact of new or changing laws and regulations; as well as the other risks detailed in LeonaBio's filings with the SEC from time to time. These forward-looking statements speak only as of the date hereof and LeonaBio undertakes no obligation to update forward-looking statements. LeonaBio may not actually achieve the plans, intentions or expectations disclosed in its forward-looking statements, and you should not place undue reliance on the forward-looking statements.
Investor & Media Contact:
Julie Rathbun
LeonaBio
Julie.rathburn@leonabio.com
206-769-9219
