On Track to Complete Enrollment of Phase 3 ELAINE-3 Clinical Trial of Lasofoxifene in ER-positive (ER+), HER2-negative, ESR1-mutated Metastatic Breast Cancer in 4Q 2026 with Topline Data Expected in 2H 2027
BOTHELL, Wash., Aug. 14, 2026 (GLOBE NEWSWIRE) -- LeonaBio, Inc. $(LONA)$, a clinical-stage biopharmaceutical company dedicated to the development of novel therapeutics for diseases with high unmet medical needs, today reported financial results for the quarter ended June 30, 2026, and provided recent pipeline and business updates.
"We enter the second half of 2026 with a clear focus on executing our Phase 3 ELAINE-3 trial and advancing lasofoxifene toward what we believe could be a transformative treatment option for patients with ESR1-mutated metastatic breast cancer," said Mark Litton, Ph.D., President and Chief Executive Officer of LeonaBio. "We have enrolled 495 patients and remain on track to complete enrollment of ELAINE-3 in the fourth quarter of 2026 with topline data expected in the second half of 2027. As the treatment landscape for metastatic breast cancer continues to evolve, we believe the differentiated profile of lasofoxifene positions it to address a significant unmet need as a potential endocrine therapy partner and create opportunities beyond ELAINE-3, including additional combination strategies and future label expansions. The body of clinical and scientific evidence behind lasofoxifene supports our confidence in its potential to greatly benefit patients battling this difficult-to-treat form of breast cancer."
"As we approach the completion of enrollment in this Phase 3 registrational trial, we are investing today in critical CMC, regulatory, and commercial readiness activities to ensure we are well-positioned to bring this therapy to patients as quickly as possible, if approved. With our talented team and the potential to add up to an additional $146 million upon exercise of cash-exercisable warrants issued in our December 2025 financing, we believe LeonaBio is well-positioned to deliver on multiple value-creating milestones in the years ahead," added Dr. Litton.
Clinical Development & Pipeline Programs
Lasofoxifene -- A third generation 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 ELAINE-3, 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, following progression on aromatase
inhibitors and CDK4/6 inhibitors. The primary endpoint of the study is a
statistically significant improvement in progression free survival $(PFS)$,
as determined by blinded, independent central review (BICR). ELAINE-3
aims to establish a new standard of care for this genetically defined
patient group with limited treatment options.
-- The Company expects to complete enrollment of 600 participants in 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.
-- In April 2026, LeonaBio hosted a virtual Key Opinion Leader event with
two leading physicians 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 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," featured 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. A replay of the event is available on
the LeonaBio website under "Events & Presentations" in the
"Investor Relations" section here.
Brelgometon (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. Brelgometon is currently in clinical development for the potential treatment of ALS.
-- LeonaBio's first-in-human Phase 1 double-blind, placebo-controlled
clinical trial (NCT06432647) enrolled 80 healthy volunteers to evaluate
single and multiple oral ascending doses of brelgometon, demonstrating a
favorable safety and tolerability profile as well as dose-proportional
pharmacokinetics and CNS penetration and supporting its advancement into
a Phase 2 proof-of-concept trial.
-- The Company expects to provide an update on the timing of a proposed
Phase 2 proof-of-concept clinical trial following completion of
enrollment of the Phase 3 ELAINE-3 clinical trial as it continues to
focus on its lasofoxifene program.
Corporate Updates
LeonaBio announced the appointment of Fred Callori, J.D., Natalie Holles and Peter B. Silverman, J.D. to its Board of Directors, effective as of May 5, 2026. The company also announced that John Fluke, Jr., who served on the Board since 2014, retired effective May 4, 2026.
-- Fred Callori, J.D., has served as a Partner and Managing Director at
Perceptive Advisors LLC, an investment firm that specializes in investing
in biotechnology stocks, since January 2018.
-- Natalie Holles has served as the Chief Executive Officer and member of
the Board of Directors of Aura Biosciences, a clinical-stage
biotechnology company, since April 2026. Ms. Holles served as the Chief
Executive Officer of Third Harmonic Bio, a biopharmaceutical company,
from August 2021 to December 2025.
-- Peter B. Silverman, J.D., served as Chief Operating Officer of Merus N.V.
(formerly, Nasdaq: MRUS), a biotechnology company, from January 2023
until its acquisition by Genmab A/S in December 2025, and prior to that,
Mr. Silverman held several leadership roles at Merus. Mr. Silverman has
served as a member of the board of directors of Kinaset Therapeutics, a
biopharmaceutical company, since January 2026.
Financial Results
-- Cash Position. Cash, cash equivalents and investments were $51.1 million
as of June 30, 2026, compared to $88.3 million as of December 31, 2025.
Net cash used in operations was $37.9 million for the quarter ended June
30, 2026, compared to $21.7 million for the quarter ended June 30, 2025.
In conjunction with the December 2025 Sermonix license agreement,
LeonaBio announced a $90 million private placement financing of common
stock and warrants, with the Series A warrants providing, if exercised in
full, up to an additional $146 million to support development through key
clinical and regulatory milestones.
-- Research and Development (R&D) Expenses. R&D expenses were $12.9 million
for the quarter ended June 30, 2026, compared to $3.7 million for the
quarter ended June 30, 2025. The increase was driven primarily by
clinical trial spend related to the ELAINE-3 trial for lasofoxifene.
-- General and Administrative (G&A) Expenses. G&A expenses were $6.6 million
for the quarter ended June 30, 2026, compared to $3.6 million for the
quarter ended June 30, 2025. The increase was driven primarily by
personnel-related expenses, including stock-based compensation and
professional service fees.
-- Net Loss. Net loss was $19.0 million, or $0.80 per share, for the quarter
ended June 30, 2026, compared to a net loss of $7.0 million, or $1.78 per
share, for the quarter ended June 30, 2025.
About LeonaBio