December 08, 2020

Cambridge, MA — H3 Biomedicine, Inc. (H3), a U.S.-based precision medicine research & development subsidiary of Eisai Co., Ltd., today announced the presentation of three posters at the 2020 San Antonio Breast Cancer Symposium (SABCS). The presentations include interim data from H3’s ongoing Phase 1/2 clinical development program, H3B-6545, a potential first-in-class, orally available Selective ERα Covalent Antagonist (SERCA), in women with ER-positive, HER2-negative breast cancer.
“Our ongoing evaluation of H3B-6545 underscores our mission to work to develop new oncology therapeutics by unlocking cancer genomics, real-world patient data and biomarkers,” said Antonio Gualberto, MD, PhD, Chief Medical Officer of H3. “H3B-6545 is part of a new class of endocrine therapies that target normal or mutated versions of the ER-alpha protein and we look forward to showcasing its progress and potential at SABCS 2020.”


Abstract Number: 1142
Title: Phase I/II Trial of H3B-6545, a Novel Selective Estrogen Receptor Covalent Antagonist (SERCA), in Estrogen Receptor Positive (ER+), Human Epidermal Growth Factor Receptor 2 Negative (HER2-) Advanced Breast Cancer
Session: PD8-06
Date and Time: Thursday, December 10, 2020, 2:15pm – 3:30pm CT
Presenter: Erika P. Hamilton, Sarah Cannon Research Institute, Tennessee Oncology

Abstract Number: 1268
Title: Pharmacokinetics of H3B-6545 in Patients with Locally Advanced or Metastatic Estrogen Receptor-Positive HER2 Negative Breast Cancer (ER+ and HER2- BC)
Session: PS12-15
Date and Time: Wednesday, December 9, 2020, 8:00am CT
Presenter: Oneeb Majid, Eisai Ltd.

Abstract Number: 918
Title: Development of H3B-6545, a First-in-Class Oral Selective ER Covalent Antagonist (SERCA), for the Treatment of ERWT and ERMUT Breast Cancer
Session: PS12-23
Date and Time: Wednesday, December 9, 2020, 8:00am CT
Presenter: Manav Korpal, H3 Biomedicine, Inc.

About H3B-6545
Estrogen receptor alpha (ERα) plays an important oncogenic role in the genesis and progression of luminal breast cancers and historically has been a target of endocrine therapies. However, recently, hotspot mutations in ERα have been detected in nearly 30% of endocrine-therapy resistant metastases. Functional studies have shown that these ERα mutations can confer ligand-independent activation of the ERα pathway and can promote partial resistance to existing classes of ER-directed therapies. H3B-6545, a first-in-class small molecule selective estrogen receptor covalent antagonist (SERCA) demonstrates activity in tumor models that harbor wild-type or mutant ERα. H3B-6545 activity against ERα mutants resistant to standard therapy provides an opportunity to target a currently unmet medical need both as a single agent and in combination with other breast cancer therapies.

This release discusses investigational uses of agents in development and is not intended to convey conclusions about efficacy or safety. There is no guarantee that such investigational agents will successfully complete clinical development or gain health authority approval.

About H3 Biomedicine, Inc.
H3 Biomedicine, Inc., the U.S.-based precision oncology research and development subsidiary of Eisai Co., Ltd., is solely focused on advancing drugs from bench to bedside. Uniquely positioned to integrate real-world clinical evidence with the latest advances in cancer genomics, H3 is developing a pipeline of highly targeted, breakthrough medicines that have the potential to impact the future of cancer care and treatment.

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