A Study to Assess the Safety and Tolerability of Fezolinetant in Women Seeking Treatment for Relief of Vasomotor Symptoms (VMS) Associated With Menopause

This study is for women in menopause with hot flashes. Menopause, a normal part of aging, is the time of a woman’s last period. Hot flashes can interrupt a woman’s daily life. The purpose of this study is to find out how safe it is for these women to take fezolinetant long term (up to 52 weeks). To do that, the study will look at the number and severity of the “adverse events.” Those are the side effects that study participants have while they are in the study. The study treatment is fezolinetant (1 tablet of fezolinetant) once a day. The study participants will take study treatment for 52 weeks. At weeks 2 and 4 and then once a month, the study participants will go the hospital or clinic for a check-up. They will be asked about medications, side effects and how they feel. Other checks will include physical exam and vital signs (heart rate, temperature and blood pressure). Blood and urine will be collected for laboratory tests. At some study visits, study participants will complete questionnaires that are about their quality of life. Study participants who still have their uterus will have 2 more tests done at the first and last study visits. One of the 2 tests is endometrial biopsy. This test involves removing a small amount of tissue from the inside lining of the uterus. The tissue is then checked under a microscope. The other test is transvaginal ultrasound. It uses sound waves to create pictures of the organs in the pelvis. The sound waves are transmitted by a probe (transducer), which is placed inside the vagina. Study participants may have a screening mammogram done at the first and/or last study visit. A mammogram is an x-ray picture of the breasts used to screen for breast cancer. Study participants who did not have this test done in the last 12 months will have it done at the first study visit. They will have it done at the last study visit if they are due for their screening mammogram and their own doctor agrees. The last check-up at the hospital or clinic will be 3 weeks after the last dose of study treatment.