Bayer’s investigational nonhormonal therapy, elinzanetant, has demonstrated significant efficacy in reducing moderate to severe vasomotor symptoms (VMS), commonly known as hot flashes, in women undergoing endocrine therapy for hormone receptor-positive (HR+) breast cancer.
The findings from the Phase III OASIS-4 trial (NCT05587296) were presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting that took place from 30 May to 3 June in Chicago (US). The results were also published in the New England Journal of Medicine (NEJM).
Hot flashes and sleep disturbances are common vasomotor symptoms that often happen during menopause. But these symptoms can also affect nearly 90% of women with early breast cancer who take endocrine therapy. The side effects can be so severe that some breast cancer patients may stop treatment, which can impact the disease’s progression and, ultimately, their survival.
OASIS-4 Trial Results
The Phase III OASIS-4 trial evaluated elinzanetant for the treatment of moderate to severe VMS associated with endocrine therapy for the treatment or prevention of HR+ breast cancer.
The study found that elinzanetant significantly reduced the frequency of moderate to severe VMS from baseline to weeks 4 and 12 compared to placebo, the trial’s primary endpoint. At week 4, the mean reduction in VMS frequency was 6.5 episodes per day with elinzanetant versus 3.0 with placebo. By week 12, reductions were 7.8 and 4.2 episodes per day, respectively. The least squares mean difference at week 12 was -3.4.
Secondary endpoints showed significant improvements in sleep disturbances and menopause-related quality of life at week 12. The safety profile over 52 weeks was consistent with previous studies, with no new safety signals observed.
Elinzanetant Clinical Development Program
Elinzanetant is a dual neurokinin-1 and neurokinin-3 receptor antagonist administered orally once daily. The drug is being evaluated as part of the OASIS clinical program includes four Phase III trials—OASIS-1 (NCT05042362), OASIS-2 (NCT05099159), OASIS-3 (NCT05030584), and OASIS-4—each contributing to the understanding of elinzanetant’s efficacy and safety across different populations.
The OASIS-1 and OASIS-2 trials focused on postmenopausal women experiencing moderate to severe VMS. Both studies met all primary endpoints, demonstrating significant reductions in the frequency and severity of VMS at weeks 4 and 12 compared to placebo. For instance, in OASIS-1, elinzanetant reduced VMS frequency by an average of 3.3 episodes per day at week 4 and 3.2 at week 12. Severity scores also improved significantly.
Secondary endpoints revealed improvements in sleep disturbances and menopause-related quality of life. The safety profiles in both trials were favorable, with headache and fatigue being the most common adverse events.
OASIS-3 extended the evaluation to a 52-week period, confirming the long-term efficacy and safety of elinzanetant. Participants reported sustained reductions in VMS frequency and severity, along with continued improvements in sleep quality and overall well-being.
