Elinzanetant significantly reduces frequency of moderate to severe vasomotor symptoms associated with endocrine therapy for breast cancer in Phase III OASIS-4 study

Data from Phase III OASIS-4 study to be presented for the first time at 2025 ASCO Annual Meeting:
 

• In the Phase III OASIS-4 study conducted outside of the U.S., the investigational compound elinzanetant significantly reduced the frequency of moderate to severe vasomotor symptoms (VMS, also known as hot flashes) from baseline to weeks 4 and 12, versus placebo, in women taking endocrine therapy for treatment or prevention of hormone receptor (HR+) breast cancer. 
• Elinzanetant has also shown in key secondary endpoints statistically significant improvements in sleep disturbances and menopause-related quality of life from baseline to week 12 versus placebo.  
• Further secondary endpoints showed a reduction in VMS frequency at week 1 and in VMS severity at weeks 4 and 12 versus placebo.
• The safety profile over 52 weeks observed in the OASIS-4 study is generally consistent with previously conducted studies and published data on elinzanetant in postmenopausal women with VMS. 
• Elinzanetant is the first dual neurokinin targeted therapy, antagonizing NK-1 and NK-3 receptors, in late-stage clinical development globally for the treatment of moderate to severe VMS due to menopause or associated with endocrine therapy for breast cancer, administered orally once daily.
• This international study represents the fourth Phase III study in the clinical OASIS program and results are being presented at the American Society of Clinical Oncology (ASCO) Annual Meeting and have been simultaneously published in the New England Journal of Medicine (NEJM).

Berlin, June 2, 2025 – Detailed results from the Phase III OASIS-4 study found that the investigational compound elinzanetant showed a statistically significant reduction in the frequency of moderate to severe vasomotor symptoms (VMS, also known as hot flashes) from baseline to weeks 4 and 12 compared to placebo, in women taking endocrine therapy for treatment or prevention of hormone receptor (HR+) breast cancer. Key secondary endpoints showed statistically significant improvement of sleep disturbances and menopause-related quality of life from baseline to week 12 versus placebo. Additional secondary endpoints showed a reduction in VMS frequency at week 1 and improvements in VMS severity at weeks 4 and 12 versus placebo. These data are being presented at the American Society of Clinical Oncology (ASCO) Annual Meeting, taking place from May 30 – June 3 in Chicago, IL, USA, and have been simultaneously published in the New England Journal of Medicine (NEJM). OASIS-4 is the first pivotal international Phase III study to assess the safety and efficacy of elinzanetant for the treatment of moderate to severe VMS associated with endocrine therapy for the treatment or prevention of HR+ breast cancer. 

In OASIS-4, elinzanetant showed statistically significant mean reductions in frequency of VMS compared to placebo from baseline to week 4 with −6.5 (95% confidence interval [CI], −7.2 to −5.8) with elinzanetant and −3.0 (95% CI, −3.9 to −2.2) with placebo, with statistical significance between elinzanetant and placebo (least squares [LS] mean difference [95% CI]: −3.5 [−4.4, −2.6]; p<0.001). At week 12, reductions in VMS frequency were −7.8 (95% CI, −8.5 to −7.1) with elinzanetant and −4.2 (95% CI, −5.2 to −3.2) with placebo, with statistical significance between elinzanetant and placebo (LS mean difference [95% CI]: −3.4 [−4.2, −2.5]; p<0.001). The safety profile over 52 weeks observed in the OASIS-4 study is generally consistent with previously conducted studies and published data1,2,3 on elinzanetant in postmenopausal women with VMS, with fatigue, somnolence and diarrhea being the most frequent treatment emergent adverse events (TEAEs) in the elinzanetant group.
The mean change in the PROMIS SD SF 8b total T score from baseline to week 12 was −10.6 points (95% CI, −11.5 to −9.6) in the elinzanetant group and −4.1 points (95% CI, −5.3 to −2.9) in the placebo (LS mean difference between the trial groups, −6.1 points; 95% CI, −7.5 to −4.8; p<0.001). The mean change in the MENQOL total score from baseline to week 12 was −1.3 points (95% CI, −1.4 to −1.2) in the elinzanetant group and −0.5 points (95% CI, −0.7 to −0.3) in the placebo group (LS mean difference between the trial groups, −0.7 points; 95% CI, −0.9 to −0.5; p<0.001). Additional secondary endpoints showed a reduction in VMS frequency at week 1 and in VMS severity at weeks 4 and 12 with elinzanetant versus placebo.

“The results from OASIS-4 represent a potential advancement in addressing a need for women undergoing breast cancer treatment. Vasomotor symptoms associated with endocrine therapy can impact patients’ quality of life and may impact their ability to adhere to other treatments,” said Dr. Christian Rommel, member of the Executive Committee of Bayer AG’s Pharmaceutical Division and Global Head of Research and Development. “Advancing elinzanetant as an investigational, hormone-free treatment option for these patients reaffirms our commitment at Bayer to bring forward innovative treatments for the different health needs of women.”

Breast cancer is the most commonly diagnosed cancer in women globally with 2.3 million new cases in 2020, and nearly 70% of tumors being hormone-receptor positive. Adjuvant endocrine therapy is well established in guidelines worldwide and routinely prescribed to all women with hormone-positive breast cancer. Treatment with adjuvant endocrine therapy (such as tamoxifen) for up to 10 years substantially reduces the breast cancer mortality rate throughout the two decades after diagnosis.4 Endocrine therapy can also be used as primary prevention, in women at high risk of developing breast cancer. Side effects of endocrine therapy, such as VMS (also referred to as hot flashes), may affect quality of life and treatment compliance, with potential impact on recurrence5. Currently, there are no approved treatment options available. There is an unmet medical need for an effective hormone-free treatment for VMS associated with endocrine therapy.

Elinzanetant is the first dual neurokinin targeted therapy, antagonizing NK-1 and NK-3 receptors, in late-stage clinical development globally for the treatment of moderate to severe VMS due to menopause or associated with endocrine therapy for breast cancer, administered orally once daily. Data from OASIS-1 and -2 were published in the Journal of the American Medical Association (JAMA)3 in August 2024. Detailed results of the Phase III study OASIS-3 providing additional efficacy and safety data over 52 weeks were presented at The Menopause Society (TMS) annual meeting in September 2024. Based on the positive results from the Phase III clinical development program, submissions for marketing authorizations for elinzanetant are ongoing in the US, EU and other markets around the world.

About the Elinzanetant Clinical Development Program
The Phase III clinical development program of elinzanetant, OASIS, currently comprises four Phase III studies: OASIS-1, -2, -3 and -4. OASIS-1 and -2 investigated the efficacy and safety of elinzanetant administered orally once daily in women with moderate to severe VMS associated with menopause over 26 weeks and randomized 396 and 400 postmenopausal women between 40 and 65 years across 184 sites in 15 countries. Patients in the elinzanetant arm received a 120 mg dose of elinzanetant once daily for 26 weeks and patients in the control arm received a matching placebo once daily for 12 weeks, followed by elinzanetant 120 mg dose for 14 weeks. OASIS-3 investigated the efficacy and safety of elinzanetant for the treatment of VMS due to menopause over 52 weeks and randomized 628 postmenopausal women between 40 and 65 years across 83 sites in 9 countries. OASIS-4 is a double-blind, randomized, placebo-controlled multicenter study to investigate the efficacy and safety of elinzanetant for the treatment of VMS associated with endocrine therapy for treatment or prevention of HR+ breast cancer over 52 weeks and optionally for an additional 2 years in women taking endocrine therapy, for treatment of breast cancer. 474 patients at 90 centers in 16 countries (excluding the US) were randomized.

About Elinzanetant
Elinzanetant is the first dual neurokinin targeted therapy, antagonizing NK-1 and NK-3 receptors, in late-stage clinical development globally for the treatment of moderate to severe VMS due to menopause or associated with endocrine therapy for breast cancer, administered orally once daily. Elinzanetant may address moderate to severe VMS by modulating a group of estrogen sensitive neurons in the hypothalamus region of the brain (the KNDy neurons) which, with the decrease of estrogen, become hypertrophic and lead to a hyperactivation of the thermoregulatory pathway, consequently disrupting body heat control mechanisms resulting in VMS.

About Vasomotor Symptoms
Vasomotor symptoms (VMS; also referred to as hot flashes) result from hyperactivation of the thermoregulatory pathway mediated by hypertrophy of the KNDy neurons. This is due to a decrease of estrogen, which can result from the progressive reduction of ovarian function due to natural menopause or medical intervention by bilateral oophorectomy or endocrine therapy.

VMS are reported by up to 80% of women at some point during the menopausal transition and are one of the leading causes for seeking medical attention during this phase of a woman’s life. Over one-third of menopausal women report severe symptoms, which can last 10 years or more after the last menstrual period, with relevant impact on quality of life.

VMS may also be caused by endocrine therapy, for the treatment or prevention of breast cancer, impacting quality of life and treatment adherence. For these women, there are currently no approved treatment options.

About Menopause
By 2030, the global population of women experiencing menopause is projected to increase to 1.2 billion, with 47 million women entering this phase each year. Menopause is a transitional phase in women’s lives, related to the progressive decline of ovarian function. It usually occurs in women during their 40s or early 50s. It can also be the result of surgical or medical treatment, such as breast cancer treatment. The hormonal decline can lead to various symptoms which can substantially affect a woman’s health, quality of life, healthcare utilization and work productivity. The most frequently reported and disruptive symptoms during the menopausal transition are VMS, sleep disturbances and mood changes. Addressing these symptoms is key to maintaining functional ability and quality of life in menopause, which is highly relevant from both a healthcare and socio-economic perspective.

About Women’s Healthcare at Bayer
Women’s Health is in Bayer’s DNA. As a global leader in women’s healthcare, Bayer has a long-standing commitment to delivering science for a better life by advancing a portfolio of innovative treatments. Bayer offers a wide range of effective short- and long-acting birth control methods as well as therapies for menopause management and gynecological diseases. Bayer is also focusing on innovative options to address the unmet medical needs of women worldwide and to broadening treatment choices such as in menopause. Additionally, Bayer intends to provide 100 million women per year in low-and-middle income countries by 2030 with access to family planning by funding multi-stakeholder aid programs for capacity building and by ensuring the supply of affordable modern contraceptives. This is part of the comprehensive sustainability measures and commitments from 2020 onwards and in line with the Sustainable Development Goals of the United Nations.

About Bayer
Bayer is a global enterprise with core competencies in the life science fields of health care and nutrition. In line with its mission, “Health for all, Hunger for none,” the company’s products and services are designed to help people, and the planet thrive by supporting efforts to master the major challenges presented by a growing and aging global population. Bayer is committed to driving sustainable development and generating a positive impact with its businesses. At the same time, the Group aims to increase its earning power and create value through innovation and growth. The Bayer brand stands for trust, reliability and quality throughout the world. In fiscal 2024, the Group employed around 93,000 people and had sales of 46.6 billion euros. R&D expenses amounted to 6.2 billion euros. 

Contact for global media inquiries:
Katja Wiggers, phone +49 30 221541614
Email: katja.wiggers@bayer.com

Contact for US media inquiries:
Colleen Murphy, phone +1 904.631.0442 
Email: colleen.murphy.ext@bayer.com

Contact for investor inquiries:
Bayer Investor Relations Team, phone +49 214 30-72704
Email: ir@bayer.com 
www.bayer.com/en/investors/ir-team

Forward-Looking Statements 
This release may contain forward-looking statements based on current assumptions and forecasts made by Bayer management. Various known and unknown risks, uncertainties and other factors could lead to material differences between the actual future results, financial situation, development or performance of the company and the estimates given here. These factors include those discussed in Bayer’s public reports which are available on the Bayer website at www.bayer.com. The company assumes no liability whatsoever to update these forward-looking statements or to conform them to future events or developments.

References

<sup>1. Simon JA, Anderson RA, Ballantyne E, Bolognese J, Caetano C, Joffe H, Kerr M, Panay N, Seitz C, Seymore S, Trower M, Zuurman L, Pawsey S. Efficacy and safety of elinzanetant, a selective neurokinin-1,3 receptor antagonist for vasomotor symptoms: a dose-finding clinical trial (SWITCH-1). Menopause. 2023 Mar 1;30(3):239-246.
2. Trower M, et al. Effects of NT-814, a dual neurokinin 1 and 3 receptor antagonist, on vasomotor symptoms in postmenopausal women: a placebo-controlled, randomized trial. Menopause: The Journal of The North American Menopause Society. 2020; 27 (5): 498-505.
3. https://jamanetwork.com/journals/jama/fullarticle/2822766
4. Davies C, et al. Long-term effects of continuing adjuvant tamoxifen to 10 years versus stopping at 5 years after diagnosis of oestrogen receptor-positive breast cancer: ATLAS, a randomised trial. The Lancet. 2013 Mar 9;381(9869):805-16.
5 Smith, K.L., Verma, N., Blackford, A.L. et al. Association of treatment-emergent symptoms identified by patient-reported outcomes with adjuvant endocrine therapy discontinuation. npj Breast Cancer 8, 53 (2022). https://doi.org/10.1038/s41523-022-00414-0</sup>