For Women on Breast Cancer Hormone Therapy, a Nonhormonal Pill Eased Hot Flashes

CATEGORY: WOMEN’S HEALTH

A woman on hormone-blocking treatment after breast cancer often counts her hot flashes by the hour. In a yearlong randomized trial of 474 women whose hot flashes and night sweats came from that treatment, a once-daily nonhormonal pill called elinzanetant reduced those episodes by 7.8 per day at week 12, while placebo reduced them by 4.2, a difference of 3.4 episodes every day.¹ The women began at about 11 episodes daily. That’s close to one for every waking hour. Relief appeared by week 4 and held.

Why the Usual Relief Is Off the Table

Drugs like tamoxifen and aromatase inhibitors guard against the return of hormone-sensitive breast cancer by blocking estrogen or draining it away. The protection is real. So is the cost: estrogen’s sudden absence can set off flushing and sweating around the clock, and the standard remedy for such symptoms, hormone therapy, is generally avoided in women who’ve had a hormone-sensitive tumor. Elinzanetant takes a different route. It blocks two signals in the brain’s temperature-control center (neurokinin-1 and neurokinin-3) that misfire when estrogen disappears, so it doesn’t touch the hormones the cancer treatment is working to suppress.

A Year of Counting Every Flash

The trial enrolled women having moderate to severe hot flashes while taking endocrine therapy, which means hormone-blocking medicine, either to treat breast cancer or to prevent it. Two of every three women received elinzanetant and one in three got an identical placebo. A random draw made that split, and neither the women nor their doctors knew who had which.¹ Each woman logged her episodes daily. After week 12, everyone was moved onto the real drug so safety could be watched for a full 52 weeks. Side effects stayed mostly mild. About 70% of women on elinzanetant reported some adverse event, against 62% on placebo, and serious events were uncommon in both groups, at 2.5% versus 0.6%.

The Menopause Test Came First

This wasn’t the drug’s first exam. In two earlier randomized trials in menopausal women, elinzanetant reduced hot flashes and improved sleep, and the FDA approved it in October 2025 under the name Lynkuet.² The new trial asked a harder question: does it still work when the symptoms come from cancer treatment rather than natural menopause, in women with far fewer choices? The answer was yes, with a similar safety picture. What the trial can’t tell us is anything past one year, or whether easing these symptoms helps more women stay on treatment that protects their lives. Nobody has run that study yet.

Key Takeaways

• Elinzanetant cut hot flashes and night sweats by 7.8 daily episodes at week 12 in women on breast cancer endocrine therapy; placebo cut them by 4.2. The gap opened within four weeks.
• Hormone-based relief is generally avoided after hormone-sensitive breast cancer, so this group has had few tested options for a symptom that can strike hourly.
• The drug already carries FDA approval for menopausal hot flashes; this trial tested it in a different setting, and side effects over a year were mostly mild.

References

1. Cardoso F, Parke S, Brennan DJ, et al. Elinzanetant for Vasomotor Symptoms from Endocrine Therapy for Breast Cancer. New England Journal of Medicine. 2025;393(8):753-763. link
2. Pinkerton JV, Simon JA, Joffe H, et al. Elinzanetant for the Treatment of Vasomotor Symptoms Associated with Menopause: OASIS 1 and 2 Randomized Clinical Trials. JAMA. 2024;332:1343-1354. link