What to know
- Health Canada has authorized Lynkuet as the first treatment in Canada specifically for moderate to severe hot flashes and night sweats caused by breast cancer endocrine therapy.
- Breast medical oncologist Dr. Ellen Warner says treatment-induced menopause can affect patients suddenly and severely, sometimes causing them to pause or stop the therapy intended to reduce their risk of recurrence.
- Dr. Warner says Lynkuet could provide another option when lifestyle changes, venlafaxine or gabapentin do not work or cause intolerable side effects, although questions about long-term safety and improved treatment adherence remain unanswered.
- Lynkuet is not currently publicly funded in Canada. Dr. Warner warns that it may initially be limited to wealthier patients or those with private drug coverage.
Breast cancer patients in Canada may now have access to a new non-hormonal treatment aimed at reducing and helping some of the most disruptive side effects of cancer therapy.
Health Canada has expanded its authorization of elinzanetant, sold under the brand name Lynkuet, to treat moderate to severe hot flashes and night sweats caused by adjuvant endocrine therapy for breast cancer, Bayer announced Monday.
The once-daily oral medication was first authorized in Canada in July 2025 for vasomotor symptoms associated with menopause. According to Bayer, it is now the first treatment approved in Canada specifically for patients experiencing these symptoms because of breast cancer endocrine therapy.
“For women receiving endocrine therapy for breast cancer, hot flashes, night sweats and sleep disruption can have a profound impact on daily life and treatment experience,” Viktoria Friedrich, country president and general manager of Bayer’s pharmaceutical division in Canada, said in the release.
Why breast cancer treatment can cause menopause symptoms
Breast cancer is the most commonly diagnosed cancer among women in Canada. The Canadian Cancer Society estimates that 32,400 women will be diagnosed with the disease in 2026.
Many breast cancers are hormone-receptor positive, meaning hormones such as estrogen help the cancer cells grow. To reduce the risk of recurrence, patients may be prescribed endocrine medications such as tamoxifen or aromatase inhibitors.
Adjuvant endocrine therapy is generally taken for five to 10 years, according to the Canadian Cancer Society.
By blocking estrogen or reducing the amount produced by the body, these treatments can trigger hot flashes, night sweats and disrupted sleep.
Dr. Ellen Warner, a Professor of Medicine at the University of Toronto and a staff medical oncologist at the Odette Cancer Centre at Sunnybrook, said moderate to severe symptoms are particularly common among premenopausal patients receiving ovarian function suppression with tamoxifen or an aromatase inhibitor.
Postmenopausal patients can also experience severe symptoms, particularly if they were using hormone replacement therapy before their diagnosis and had to stop, she added.
Younger patients may feel the effects more abruptly than people going through natural menopause.
“The body normally eases into menopause over years—these women are plunged into it over the span of a few weeks,” Dr. Warner said.
She said symptoms can become severe enough that some patients stop taking endocrine therapy or take lengthy breaks, increasing their risk of cancer recurrence and death.
Menopause hormone therapy is generally not recommended for patients with a history of hormone-receptor-positive breast cancer. Existing non-hormonal options have included medications such as venlafaxine and gabapentin.
“Antidepressants like venlafaxine or drugs like gabapentin work moderately well for some women, little if at all for others, and often have intolerable side effects,” Dr. Warner said.
How Lynkuet works
Lynkuet targets the NK-1 and NK-3 receptors involved in regulating body temperature.
When estrogen levels decline because of menopause or cancer treatment, certain neurons can become overactive. By blocking signals to those receptors, the medication is intended to reduce hot flashes and night sweats.
The expanded authorization was supported by OASIS-4, a Bayer-funded Phase 3 randomized, placebo-controlled study involving 474 women between the ages of 18 and 70 across 16 countries.
Participants were receiving endocrine therapy for hormone-receptor-positive breast cancer or its prevention and experiencing at least 35 moderate to severe episodes each week.
At the beginning of the study, participants experienced an average of more than 11 episodes per day.
By week four, those taking elinzanetant had an average reduction of 6.5 episodes per day, compared with a reduction of three among those taking a placebo. At week 12, the reductions were 7.8 and 4.2 episodes per day.
The findings also showed improvements in sleep and menopause-related quality of life.
Of the 474 participants, 395 completed the full 52 weeks. More than 91 per cent of those who finished chose to continue taking the medication through an optional two-year extension.
The most common side effects included headache, drowsiness, joint pain, nausea and diarrhea.
Who may be a candidate?
Dr. Warner said patients should generally try lifestyle changes and established medications such as venlafaxine or gabapentin before considering Lynkuet.
She would treat it as a next-line option when those approaches do not provide enough relief or cause intolerable side effects. Dr. Warner said she would not combine Lynkuet with another hot-flash medication at this point because their interactions are not yet known.
Patients should speak with their health-care provider about whether the medication is appropriate for them. Dr. Warner said it should not be given during pregnancy or to patients with a history of seizures.
She also advised patients to watch for daytime sleepiness, avoid grapefruit and grapefruit juice, and ask a pharmacist about possible interactions with other medications. Blood tests are also required to monitor for potential liver damage.
The OASIS-4 study demonstrated symptom relief but was not designed to determine whether Lynkuet reduces breast cancer recurrence, improves survival or increases long-term adherence to endocrine therapy.
“All those questions remain unanswered,” she said. “It might improve breast cancer outcomes if it increases adherence to endocrine therapy.”
Cost could limit access
Despite the authorization, access remains a concern. Bayer told The Canadian Press that Lynkuet is not currently publicly funded in Canada and did not disclose its Canadian price.
“Unfortunately, as with many medications in our ‘free’ health-care system, at least initially the drug may only be available to very wealthy patients or to those with a good drug plan that will cover most or all of the cost,” Dr. Warner said.
She hopes the medication will eventually be covered through public programs such as Ontario’s Trillium Drug Program.
Health Canada’s authorization allows Lynkuet to be prescribed for the expanded indication, but it does not guarantee that provincial drug plans will cover its cost.
