FDA Grants Priority Review For Elinzanetant Hot Flash Treatment
The FDA has granted priority review to elinzanetant for treating hot flashes in women undergoing endocrine therapy for HR+ breast cancer.
The FDA has accepted Bayer’s supplemental New Drug Application for elinzanetant and granted priority review for treating vasomotor symptoms in women on endocrine therapy for HR+ breast cancer. On September 28, 2026, the agency accepted the application for elinzanetant, marketed as Lynkuet, to treat moderate to severe hot flashes caused by endocrine therapy for hormone receptor-positive breast cancer or its prevention. This priority review designation signals the FDA's assessment of potential clinical benefit but does not guarantee final approval.
Elinzanetant’s mechanism and prior approval
Elinzanetant is a non-hormonal, dual neurokinin receptor antagonist targeting both the NK-1 and NK-3 receptors. The drug was first approved by the U.S. FDA in October 2025 for the treatment of moderate to severe hot flashes due to menopause, under the brand name Lynkuet. That initial approval was based on data from three Phase III trials-OASIS-1, OASIS-2, and OASIS-3-which involved 1,420 women. The new supplemental application seeks to expand its use to a distinct patient population: those experiencing symptoms as a side effect of cancer treatment.
OASIS-4 trial design and results
The supplemental application is based on the Phase III OASIS-4 study. This 52-week, double-blind, randomized, placebo-controlled trial was conducted at 90 sites outside the United States. It enrolled 474 women aged 18 to 70 who were experiencing moderate to severe vasomotor symptoms due to adjuvant endocrine therapy for HR-positive breast cancer or for prevention in high-risk individuals. Participants were required to have at least 35 moderate-to-severe hot flashes per week at baseline.
Patients were randomized in a 2:1 ratio to receive either elinzanetant or a placebo for 12 weeks, after which those on placebo switched to elinzanetant for the remaining 40 weeks of the core study. An optional two-year extension period followed. The trial met its co-primary endpoints, showing statistically significant reductions in the frequency of moderate to severe hot flashes at both week 4 and week 12 compared to placebo. Key efficacy data from the study is shown below.
| Measure | Elinzanetant Arm | Placebo Arm | Difference (95% CI) | P-value |
|---|---|---|---|---|
| Baseline Mean Daily VMS Events | 11.4 | 11.5 | , | , |
| Mean Reduction at Week 4 | 6.51 events | 3.04 events | -3.5 (-4.4 to -2.6) | <.0001 |
| Mean Reduction at Week 12 | 7.76 events | 4.20 events | -3.4 (-4.2 to -2.5) | <.0001 |
All secondary endpoints were also achieved. These included reductions in symptom severity at weeks 4 and 12, a reduction in frequency as early as week 1, and improvements in sleep disturbances and menopause-related quality of life. The effects were maintained over the 52-week study period. The key findings were presented at the American Society of Clinical Oncology 2025 Annual Meeting and published in the New England Journal of Medicine. Fatima Cardoso, MD, FESMO, the trial's primary investigator, noted the significance of addressing this side effect. "Endocrine therapy is a standard of care for many women facing HR+ breast cancer, which can commonly cause side effects such as vasomotor symptoms," Cardoso said.
Safety and tolerability
During the initial 12-week placebo-controlled period, certain side effects were reported more frequently with elinzanetant than with placebo. These included somnolence, fatigue, and diarrhea. The common adverse events observed were consistent with the drug's known profile and included headache, fatigue, and somnolence.
Clinical context and unmet need
Hot flashes are among the most commonly reported and disruptive side effects of endocrine therapy, which is a standard adjuvant treatment for HR-positive breast cancer. Current guidelines recommend a minimum treatment duration of five years, with potential extension to ten years based on individual risk. HR-positive subtypes comprise roughly 70% of all breast cancer cases, which itself accounts for about 30% of all cancers diagnosed in women in the United States. These vasomotor symptoms represent a leading cause of early treatment discontinuation, creating a critical need for effective non-hormonal management options. The FDA’s priority review decision is expected to be followed by a final approval determination, which would expand elinzanetant’s indication to treat vasomotor symptoms due to endocrine therapy in HR-positive breast cancer patients.
