Sermonix Pharmaceuticals Completes Enrollment of Phase 2 I-SPY 2 Arm Evaluating Lasofoxifene in Neoadjuvant Breast Cancer Setting

COLUMBUS, Ohio and SAN FRANCISCO, Aug. 27, 2024 (GLOBE NEWSWIRE) — Sermonix Pharmaceuticals Inc., a privately held biopharmaceutical company developing innovative therapeutics to specifically treat metastatic breast cancers (mBC), and Quantum Leap Healthcare Collaborative™ today announced Sermonix completed enrollment of its Phase 2 clinical trial evaluating lasofoxifene, its lead investigational drug, as a neoadjuvant endocrine therapy (NET) in molecularly selected HR+/HER2-, locally advanced breast cancer.

The open-label, randomized, multicenter trial is an arm of the Endocrine Optimization Pilot Protocol (EOP), a sub-study of Quantum Leap’s ongoing I-SPY 2 TRIAL (Investigation of Serial studies to Predict Your Therapeutic Response with Imaging And moLecular analysis 2). Twenty patients (10 pre- and nine postmenopausal women, and one male) were enrolled in the lasofoxifene arm of the study.

“Sermonix is delighted to have quickly completed enrollment of this I-SPY 2 EOP study of lasofoxifene as a neoadjuvant endocrine therapy, complementing our ongoing ELAINE-3 Phase 3 combination study of lasofoxifene with abemaciclib in the ESR1-mutated metastatic breast cancer setting,” said Dr. David Portman, Sermonix founder and chief executive officer. “With a recent preclinical study also suggesting lasofoxifene could be an effective therapy for all hormone treatment-resistant breast tumors, and other data suggesting beneficial effects of lasofoxifene on genitourinary syndrome of menopause and bone health, we are focused on exploring the drug’s broad potential as a therapy for people confronted with breast cancer – and one that does so while potentially offering unique quality of life benefits across the treatment continuum.”

NET can downstage breast tumors and may facilitate breast conservation as does neoadjuvant chemotherapy in women with locally advanced HR+/HER2- breast cancer, but with lower toxicity. Aromatase inhibition is the standard NET for HR+/HER2- breast cancer. However, the toxicity profile of AIs causes poor tolerance. Lasofoxifene is a next-generation selective estrogen receptor modulator (SERM) that has shown efficacy and a favorable toxicity profile in women with HR+/HER2- mBC.

“We are pleased to complete enrollment of this I-SPY 2 EOP arm,” said Dr. Jo Chien, principal investigator of the sub-study. “Aromatase inhibitors can be difficult for our patients to tolerate. Based on prior data, lasofoxifene has a more favorable tolerability profile, particularly as it relates to vaginal and sexual health. Tolerance is a vital concern and quality-of-life preservation is an important element of successful cancer treatment. We look forward to gaining greater understanding of lasofoxifene’s potential in the neoadjuvant setting.”

The EOP study has a primary objective of determining the feasibility of enrolling and treating molecularly selected patients with early-stage HR+ breast cancer in a randomized neoadjuvant trial using novel endocrine therapy. Feasibility is defined as ≥75% of enrolled patients completing at least 75% of protocol-defined study therapy. Secondary objectives include safety and tolerability of 5 mg daily lasofoxifene; assessment of efficacy: Ki-67, PEPI score, residual cancer burden at time of surgery, change in tumor volume by dynamic contrast enhanced MRI, rates of breast conservation; 3/5/10-year relapse-free survival and overall survival. Patient-reported outcomes will be assessed as well.

Quantum Leap partners with a consortium that includes the U.S. Food and Drug Administration (FDA), industry, patient advocates, philanthropic sponsors, and clinicians from 41 major U.S. cancer research centers.

A poster reviewing the study’s background, objectives and design is available: EOP Trial in Progress.