About two thirds of breast cancers are classified as “hormone receptor positive” disease. These cancer cells express a group of proteins that bind to hormones, including estrogen and progesterone, which help cancer cells grow.
Women with hormone receptor positive breast cancers commonly receive endocrine therapy, treatments that block hormones from binding receptors on the cancer cells, thus preventing growth. In addition, some women at high risk of developing breast cancer may be prescribed endocrine therapies as a preventative measure.
While endocrine therapies have good efficacy in treating and preventing breast cancer, many women experience vasomotor symptoms, such as hot flashes and night sweats, which can significantly impair quality of life. Elinzanetant, a drug that blocks the receptors in the brain that regulate body temperature, reduces vasomotor symptoms in women during menopause.
A team of researchers wondered if elinzanetant could also provide relief to breast cancer survivors experiencing vasomotor symptoms as a side effect of their cancer treatment. They recently published the results of their phase three study (NCT05587296) in the New England Journal of Medicine.
The trial enrolled 474 women who developed moderate or severe vasomotor symptoms after endocrine therapy for hormone receptor positive breast cancer treatment or prevention. Participants assigned to the treatment group received a daily dose of elinzanetant for one year. Women assigned to the placebo group received a daily placebo for 12 weeks, followed by a daily dose of elinzanetant for 40 weeks. The research team monitored the frequency of vasomotor symptoms over the first 12 weeks of treatment.
Before treatment, moderate-to-severe vasomotor symptoms occurred at an average of 11.4 episodes in participants in the treatment group and 11.5 episodes in the placebo group. Four weeks into treatment, women in the treatment group experienced an average decrease of 6.5 episodes per day while those in the placebo group experienced an average decrease of only 3 episodes per day. By 12 weeks, an average decrease of 7.8 episodes occurred in the treatment group, compared to a decrease of 4.2 episodes in the placebo group.
The data suggests that elinzanetant can significantly reduce the frequency of vasomotor symptoms in women receiving endocrine therapy for breast cancer. These findings, consistent with the data established in populations of postmenopausal women taking elinzanetant, shows improvements in breast cancer-related quality of life.