Sermonix Pharmaceuticals announces new results on lasofoxifene

Sermonix Pharmaceuticals announced that its lead drug candidate, lasofoxifene, which Sermonix licensed globally from Ligand Pharmaceuticals, improved vaginal/vulvar symptoms while fulvestrant worsened them in a study of postmenopausal women with locally advanced or metastatic estrogen receptor-positive (ER+)/HER2- breast cancer with an ESR1 mutation. The results, derived from the open-label randomized Evaluation of Lasofoxifene in ESR1 Mutations study, were shared March 4 in an e-poster presentation at the International Society for the Study of Women’s Sexual Health Annual Meeting 2023 in St. Louis. Top-line data for ELAINE 1, which began enrollment in September 2019, were shared in September at the European Society for Medical Oncology Congress 2022. This secondary analysis aimed to investigate changes in vaginal/vulvar symptoms with lasofoxifene versus fulvestrant, as lasofoxifene improved symptoms of vulvovaginal atrophy in two previous Phase 3 studies among postmenopausal women with moderate to severe VVA. Among patients who completed the VAS/VuAS at baseline, the mean composite VAS/VuAS score decreased from baseline to week 16 by 74% in lasofoxifene patients, but increased by 36% in fulvestrant patients. In the subgroup of patients with greater than or equal to1 moderate/severe symptom at baseline, mean composite VAS/VuAS score decreased from baseline to week 16 by 72% with lasofoxifene, in contrast to an increase of 32% with fulvestrant. The mean score for the most bothersome symptom decreased from baseline to week 16 by 65% with lasofoxifene versus 5% with fulvestrant. Of 103 enrolled patients, 75% of lasofoxifene patients and 65% of fulvestrant patients completed the VAS/VuAS at baseline; among them, 23% and 30% had greater than or equal to1 moderate/severe symptom, respectively. Women who completed the VAS/VuAS at baseline had a median age of 61.5 years "Sermonix is pleased with the results of this study, which when combined with the primary ELAINE 1 findings as well as lasofoxifene’s well-researched history of improving vulvovaginal atrophy in postmenopausal women, demonstrate its potential as a novel therapy that clearly fills an unmet medical need," said Dr. David Portman, Sermonix founder and chief executive officer. "We look forward to further investigating lasofoxifene’s efficacy, as a treatment for metastatic breast cancer with fewer negative side effects that greatly impact patients’ quality of life."