Sermonix Pharmaceuticals Completes Enrollment of Phase 2 ELAINE 1 Randomized Clinical Trial Assessing Efficacy of Oral Lasofoxifene Versus Intramuscular Fulvestrant

In In The News by Barbara Jacoby

Source: Sermonix Pharmaceuticals LLC


The study enrolled 100 patients who have ER+/HER2- breast cancer with an ESR1 mutation, with topline data expected in first half of 2022

Sermonix Pharmaceuticals Inc., a privately held biopharmaceutical company developing innovative therapeutics to treat ESR1-mutated metastatic breast and gynecological cancers, today announced that it has completed enrollment in its Phase 2 randomized clinical trial studying the efficacy of its lead investigational drug, lasofoxifene, versus fulvestrant for the treatment of ER+/HER2- breast cancer in patients with an ESR1 mutation. Sermonix expects data from the trial to be reported in the first half of 2022.

The open-label, multi-center Evaluation of Lasofoxifene in ESR1 Mutations (ELAINE 1, NCT03781063) study is evaluating the efficacy of oral lasofoxifene versus intramuscular fulvestrant for the treatment of 100 postmenopausal women with locally advanced or metastatic estrogen receptor-positive ER+/HER2- breast cancer with an ESR1 mutation and progression-free survival as the primary endpoint.

“The completion of ELAINE 1 enrollment marks an important milestone in our efforts to develop lasofoxifene as a meaningful advancement over current endocrine therapies, which are limited and confer poor prognosis and resistance,” said David Portman, M.D., Sermonix founder and chief executive officer. “Efficacy and tolerability remain a trade-off, suggesting that a significant unmet need exists in this patient population, particularly as mBC patients live longer and quality of life becomes increasingly important.

“Lasofoxifene has been extensively studied across a range of doses in multiple late-stage non-oncology trials and the safety and tolerability in the non-oncology setting has been well characterized. Given the oncology community’s renewed focus on identifying lower doses that are both efficacious and tolerable, lasofoxifene’s unique features may represent a differentiated approach to the treatment of breast cancer.

“We thank the participants, investigators and everyone involved in accelerating this important Phase 2 study despite the ongoing impact of the COVID-19 pandemic, and we look forward to data which, if positive, will inform an efficient late-stage clinical development plan.”

Lasofoxifene is the only oral SERM currently in development and the only endocrine therapy solely focused on increasingly prevalent ESR1 mutations.

The ELAINE 1 study was the first and only of its kind to select all patients prospectively based on ESR1 mutation status. Assessment of ESR1 mutations using tissue biopsies of multiple tumor sites is difficult in patients with advanced disease. Tissue biopsies are often impractical, painful and sometimes dangerous for patients. To address this challenge, Sermonix utilized a liquid biopsy blood test to identify for inclusion appropriate ELAINE 1 study participants.

“Up to 40% of breast cancer patients develop ESR1 mutations following first-line therapy, and this troubling trend is accelerating due to widespread use of aromatase inhibitors in a first-line setting,” said Stephanie Graff, M.D., director of breast oncology at Lifespan Cancer Institute at Brown Medicine and investigator in the ELAINE 1 study. “Lasofoxifene, with its mechanism of action and clinical data to date, holds great potential as a targeted, third-generation oral SERM with a differentiated profile from ER degraders also in development. I am pleased to be a part of this important study and look forward to results early next year.”

ELAINE 2, a separate multicenter trial of lasofoxifene in combination with Eli Lilly and Company’s approved CDK4 and 6 inhibitor Verzenio (abemaciclib), also recently completed enrollment, with top-line data expected in the first half of 2022. The ELAINE studies will provide data on lasofoxifene monotherapy as well as a part of potential combination strategies to address resistant ESR mutations that have developed on other endocrine therapies.

For more information about the ELAINE studies, visit

About Lasofoxifene
Lasofoxifene is an investigational, nonsteroidal selective estrogen receptor modulator (SERM), which Sermonix licensed globally from Ligand Pharmaceuticals Inc. (NASDAQ: LGND) and has been studied in previous comprehensive Phase 1-3 non-oncology clinical trials in more than 15,000 postmenopausal women worldwide. Lasofoxifene’s bioavailability and activity in mutations of the estrogen receptor could potentially hold promise for patients who have acquired endocrine resistance due to ESR1 mutations, a common finding in the metastatic setting and an area of high unmet medical need. Lasofoxifene’s novel activity in ESR1 mutations was discovered at Duke University and Sermonix has exclusive rights to develop and commercialize the product in this area. Lasofoxifene, a potent, oral SERM could, if approved, play a critical role in the targeted precision medicine treatment of advanced ER+ breast cancer.

About Sermonix
Sermonix Pharmaceuticals Inc. is a privately held biopharmaceutical company focused on the development of female-specific oncology products and is currently undertaking two Phase 2 clinical studies of lasofoxifene, its lead investigational drug. Sermonix Pharmaceuticals was founded in 2014 by David Portman, M.D., a leading clinical researcher and expert in women’s health, menopause and selective estrogen receptor modulator (SERM) therapy. The Sermonix management team, led by Dr. Portman, has significant experience in all stages of the drug development and regulatory process. Paul Plourde, M.D., vice president of oncology clinical development, has many decades of experience in the oncology drug development arena. Barry Komm, Ph.D., chief scientific officer, is recognized for his expertise in SERM biology. Miriam Portman, M.D., is chief operating officer. Elizabeth Attias, M.M.Sc., Sc.D., chief strategy and development officer, has extensive experience in pharmaceutical drug commercialization. Simon Jenkins, Ph.D., vice president of operations, has over 30 years of experience in global drug development leadership. Sermonix non-executive chairman of the board is Anthony Wild, Ph.D., former president of both Parke-Davis Pharmaceuticals and Warner-Lambert’s Pharmaceutical Division.