Sermonix to Present Four Posters During the 2022 San Antonio Breast Cancer Symposium

Results of a novel anticancer drug specifically designed to treat ESR1-mutated metastatic breast and gynecological cancers, will be presented in four different posters during the 2022 San Antonio Breast Cancer Symposium (SABCS), which will be held Dec. 6-10 at the Henry B. Gonzalez Convention Center in San Antonio, Tx.

Two of the posters address the evaluation of circulating tumor DNA (ctDNA) to determine levels of mutant ESR1 in patients who participated in each of Sermonix’s Evaluation of Lasofoxifene in ESR1 Mutations (ELAINE) Phase 2 studies.

• The ELAINE 1 study assessed the efficacy and safety of Sermonix’s lead development candidate, oral lasofoxifene, versus the current standard of care, intramuscular fulvestrant, in postmenopausal women with locally advanced or metastatic ER+/HER2- breast cancer (mBC) and an ESR1 mutation.
• The ELAINE 2 study evaluated lasofoxifene in combination with the CDK4/6 inhibitor abemaciclib in a heavily pre-treated ESR1 mutation positive patient population. [1]

Lasofoxifene, which is being developed by Sermonix Pharmaceuticals, is an investigational targeted endocrine treatment and next-generation nonsteroidal selective estrogen receptor modulator (SERM). The investigational agent, which Sermonix licensed globally from Ligand Pharmaceuticals, 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.

“We are excited to share details around the impact lasofoxifene, our ESR1 mutation-targeted endocrine therapy, has – alone and in combination – on mutant allele fraction (MAF), and how molecular response relates to clinical outcomes in our two Phase 2 ELAINE studies,” noted David Portman, M.D., chief executive officer of Sermonix Pharmaceuticals.

“We look forward to further exploring the unmet need in ESR1 mutation-positive breast cancer during our upcoming Phase 3 program set to launch in early 2023,” Portman added.

The two other posters address the results of Sermonix’s “ELAINE ESR1 and Quality of Life Survey (EQUALS),” created to help inform practicing oncologists about patients’ understanding of ESR1 mutations and the quality of life of metastatic breast cancer patients. One poster focuses on quality of life, while the other focuses on patient understanding of genomic testing and ESR1 mutations.

Clinical trials
Evaluation of Lasofoxifene Versus Fulvestrant in Advanced or Metastatic ER+/HER2- Breast Cancer With an ESR1 Mutation – NCT03781063
Evaluation of Lasofoxifene Combined With Abemaciclib in Advanced or Metastatic ER+/HER2- Breast Cancer With an ESR1 Mutation (ELAINEII) – NCT04432454

Reference
[1] Lainé M, Fanning SW, Chang YF, Green B, Greene ME, Komm B, Kurleto JD, Phung L, Greene GL. Lasofoxifene as a potential treatment for therapy-resistant ER-positive metastatic breast cancer. Breast Cancer Res. 2021 May 12;23(1):54. doi: 10.1186/s13058-021-01431-w. PMID: 33980285; PMCID: PMC8117302.

Featured image: 2019 San Antonio Breast Cancer Symposium (SABCS) – Photo Courtesy: 2019 © AACR/Todd Buchanan. Used with permission.