Elinzanetant, a non-hormonal pill that acts on the brain’s temperature control centre, is under fast-track review in the US for hot flushes caused by breast cancer therapy. Regulators in the UK, the EU, Switzerland and Canada have already approved it for this use.
The hypothalamus, a small region at the base of the brain, helps control body temperature. Nerve cells there called KNDy neurons carry two receptors, known as NK-1 and NK-3. When oestrogen activity falls, at menopause or during some breast cancer treatments, these cells become overactive and can set off hot flushes and night sweats, the drugmaker Bayer says.
Elinzanetant, a Bayer drug, blocks both receptors, and the company calls it the first dual neurokinin-targeted therapy. On 28 September 2026, Bayer said the US Food and Drug Administration (FDA) had granted it priority review for a new use. The application covers hot flushes caused by endocrine therapy in women with hormone receptor-positive breast cancer. It also covers women taking these drugs to prevent the disease.
Elinzanetant, sold as Lynkuet, is a once-daily pill without hormones. The FDA approved it in October 2025 for hot flushes caused by menopause. Under priority review, the FDA’s goal is to act on an application within six months, compared with 10 months under standard review. Bayer gave no date for a ruling.
Why women on endocrine therapy can’t usually take HRT
Tamoxifen and aromatase inhibitors are endocrine treatments for hormone receptor-positive breast cancer. They reduce the chance of these cancers returning by nearly half, according to the World Health Organization. Women take them for several years, and they can cause menopause symptoms.
The UK’s National Institute for Health and Care Excellence (NICE) advises clinicians to stop hormone replacement therapy (HRT) when a woman is diagnosed with breast cancer. It says HRT should not routinely be offered to women with a history of the disease and should be used only in exceptional circumstances. The guideline also notes that HRT in this group is off-label and contraindicated.
Breast cancer is the most common cancer in women in 164 of 186 countries, the WHO says. In 2024, an estimated 2.4 million women were diagnosed worldwide, and 694,000 women died.
Results from 474 women in the OASIS-4 trial
The application rests on OASIS-4, a phase III trial of 474 women aged 18 to 70 at 90 sites outside the US. Women were assigned at random to elinzanetant or a placebo, in a ratio of two to one. Those on placebo switched to the drug after 12 weeks, and the trial ran for 52 weeks.
Women started with about 11.4 moderate to severe hot flushes a day. By week 12, women on elinzanetant had 7.8 fewer a day, compared with 4.2 fewer on placebo, the results in the New England Journal of Medicine show. The trial met all its secondary goals, including better sleep and menopause-related quality of life.
Side effects were reported by 69.8% of women on the drug and 62.0% on placebo over the first 12 weeks. Serious adverse events affected 2.5% on elinzanetant and 0.6% on placebo. Sleepiness was more common with the drug, at 10.8% against 3.8%, the ASCO Post reported. Bayer funded the trial.
Options to raise with a cancer team now
NICE suggests clinicians consider a class of antidepressants called SSRIs for hot flushes in women with breast cancer, though not in women taking tamoxifen. This use is also off-label. The US National Cancer Institute says some antidepressants can affect how tamoxifen works, so the choice of medicine needs a clinician’s input.
Cognitive behavioural therapy, relaxation techniques or hypnosis may help hot flushes, the institute says, and work best alongside drug treatment. If one medicine doesn’t ease symptoms, switching to another may help. It advises women to tell their care team about any supplements they take and to talk to a doctor before trying plant-based products.
Already licensed in the UK, the EU, Switzerland and Canada
The European Commission authorised elinzanetant on 17 November 2025. Its EU approval covers hot flushes from menopause and from endocrine therapy for breast cancer. Bayer says Switzerland and Canada have also approved it for this use, and that submissions in further countries are under way.
The UK’s Medicines and Healthcare products Regulatory Agency has extended its licence to cover women on endocrine therapy. The British Menopause Society said elinzanetant is the first medicine licensed specifically for this use in the UK. NICE has not yet assessed it, the society added, so it isn’t yet available on the NHS.
This article is for information only and does not replace advice from a qualified health professional.
Header image: Phạm Trần Hoàn Thịnh on Unsplash