BOTHELL, Wash., August 12, 2026
LeonaBio, Inc. announced that its lead investigational therapy lasofoxifene will be featured in multiple presentations at DAVA Oncology’s 4th Summit on Breast Cancer, taking place August 18–22, 2026, in Kona, Hawaii. The presentations will highlight clinical and scientific evidence supporting lasofoxifene as a potential treatment for patients with ER-positive (ER+), HER2-negative, ESR1-mutated metastatic breast cancer, an area where acquired resistance can limit the effectiveness of endocrine therapies. LeonaBio is advancing lasofoxifene in combination with the CDK4/6 inhibitor abemaciclib in the pivotal Phase 3 ELAINE-3 clinical trial. The company said enrollment remains on track for completion in the fourth quarter of 2026, with topline results expected in the second half of 2027. The upcoming summit presentations are intended to provide breast cancer specialists with additional insight into the clinical development strategy and potential role of lasofoxifene in treatment-resistant metastatic disease.
Lasofoxifene Featured in Phase 3 ELAINE-3 Program
Lasofoxifene will be discussed during a presentation led by Jessica Tao, M.D., a breast cancer medical oncologist at Johns Hopkins Sidney Kimmel Comprehensive Cancer Center. The presentation, scheduled for August 19, will include information on the Phase 3 ELAINE-3 trial, which is evaluating lasofoxifene in combination with abemaciclib for patients with ER+/HER2-negative, ESR1-mutated metastatic breast cancer. ESR1 mutations are an important mechanism of endocrine treatment resistance and can contribute to disease progression despite previous hormone-directed therapy. LeonaBio believes lasofoxifene’s differentiated pharmacological profile could potentially provide another treatment approach for patients whose disease has developed resistance. The company is also expected to highlight the broader clinical development rationale for combining lasofoxifene with CDK4/6 inhibition, a therapeutic strategy that could potentially address both hormone receptor signaling and cell-cycle progression. However, ELAINE-3 remains an ongoing investigational study, and the clinical benefit of the combination will ultimately depend on the results of the Phase 3 trial.
Breast Cancer Experts to Review Clinical Development Strategy
A second presentation will be delivered by David Portman, M.D., Founder and Chief Executive Officer of Sermonix and a consultant to LeonaBio, during an industry lunch presentation on August 20. The session will focus on the development of lasofoxifene and its potential application in metastatic breast cancer. LeonaBio is positioning the candidate as a potential therapy for patients facing limited options as treatment resistance emerges. The company said successful development of ELAINE-3 could potentially support the use of lasofoxifene alongside CDK4/6 inhibition and provide a foundation for evaluating additional combination strategies and breast cancer settings. The upcoming scientific discussions come as the company moves toward completion of enrollment in its pivotal trial. Importantly, presentation of clinical evidence at a medical meeting does not establish efficacy or regulatory approval, and the significance of lasofoxifene will depend on the eventual randomized Phase 3 results and subsequent regulatory review.
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LeonaBio Targets Treatment-Resistant Metastatic Disease
The advancement of ELAINE-3 toward its enrollment milestone represents a key development stage for LeonaBio’s oncology pipeline. The company expects to complete enrollment during Q4 2026 and currently anticipates topline data in H2 2027, creating a significant future clinical catalyst for lasofoxifene. LeonaBio is focused on developing therapies for diseases with high unmet medical needs, including treatment-resistant metastatic breast cancer and amyotrophic lateral sclerosis (ALS). Its lead development programs include lasofoxifene and brelgometon (ATH-1105), both novel small-molecule candidates being investigated for serious diseases with limited treatment options. For lasofoxifene, the immediate focus remains the Phase 3 ELAINE-3 study and determining whether the candidate can demonstrate clinically meaningful benefit in ESR1-mutated metastatic breast cancer. If the study produces positive results, the data could support further regulatory discussions and potentially expand development of lasofoxifene into additional breast cancer treatment strategies.
Source:LeonaBio, press release
