CLINICAL QUESTION

Is elinzanetant (Lynkuet) safe and effective for the treatment of vasomotor symptoms caused by endocrine therapy for the treatment of breast cancer?

BOTTOM LINE

Elinzanetant was more effective than placebo and reduced vasomotor symptoms by approximately two-thirds. The effect was sustained, and the medication was generally well tolerated. The drug is approved by the US Food and Drug Administration and is marketed as Lynkuet, with a cost of approximately $500 per month. (Level of Evidence = 1b)

SYNOPSIS

Endocrine therapy for breast cancer (ie, tamoxifen or an aromatase inhibitor, such as anastrozole, with or without a gonadotropin-releasing hormone analogue such as goserelin) reduces mortality in patients with hormone receptor–positive breast cancer but can cause vasomotor symptoms that may be severe, especially in younger women. Hormone therapy for vasomotor symptoms is contraindicated in these women. The researchers identified 474 women who were taking tamoxifen or an aromatase inhibitor with or without a gonadotropin-releasing hormone analogue for the treatment or prevention of breast cancer. The women's mean age was 51 years, 88% were White, 90% had stage I or II breast cancer, and all had at least 35 moderate to severe vasomotor symptoms per week. Tamoxifen was used by 56% of the participants and 44% used an aromatase inhibitor. Groups were balanced, allocation to groups was concealed, and analysis was by intention to treat all randomized participants. The women were randomized in a 2:1 ratio to receive elinzanetant, a nonhormonal treatment for vasomotor symptoms, or placebo. The primary outcome was the change in vasomotor symptom episodes from baseline to 12 weeks; at that time, participants were unmasked and all were given elinzanetant. A clinically meaningful reduction in episodes is 50% or more. The change in episodes in the elinzanetant group decreased from 11.4 per day to 3.6 and 11.5 to 7.3 episodes per day in the placebo group (mean difference = −3.4 episodes per day; 95% CI, −4.2 to −2.5). From 12 weeks to 52 weeks, the number of episodes remained stable at approximately 4 per day for all participants. Adverse events were generally similar between groups, although discontinuation of the study medication was more common in the elinzanetant group (7.3% vs 2.5%).