Dr. Sammons on Research Efforts Examining Lasofoxifene in ESR1-Mutant Breast Cancer

Sarah Sammons, MD, an assistant professor of medicine in the Department of Medicine and member of the Duke Cancer Institute at Duke University School of Medicine, discusses clinical trials examining lasofoxifene in patients with ESR1-mutant breast cancer.

The selective estrogen receptor modulator (SERM) lasofoxifene is a compound that appears to show preclinical activity in patients with ESR1-mutant breast cancer, says Sammons. This agent is currently under investigation in the phase 2 ELAINE trial (NCT03781063), where its activity will be compared with that of fulvestrant (Faslodex) in pre- and postmenopausal patients with locally advanced or metastatic ESR1-mutated breast cancer who have progressed following a CDK4/6 inhibitor and endocrine therapy. To be eligible for enrollment, patients could not have previously received treatment with fulvestrant. The results of this ongoing trial are anticipated to be of interest, according to Sammons.

Moreover, the ELAINE-2 study (NCT04432454) will examine the use of lasofoxifene in combination with abemaciclib (Verzenio) within a similar patient population to that of the ELAINE trial.

To determine the optimal treatment for patients with ESR1-mutant breast cancer, there is still much work to do and research that will need to be conducted, says Sammons. Currently, oral selective estrogen receptor degraders and some SERMs, like lasofoxifene, appear to be promising options for this population, Sammons concludes.