A study to find out if fezolinetant helps reduce moderate to severe hot flashes in women going through menopause - 2

This study is for women in menopause with moderate to severe 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 study treatments are fezolinetant low dose (1 tablet of fezolinetant and 1 placebo tablet) once a day, fezolinetant high dose (2 tablets of fezolinetant) once a day or placebo (2 tablets) once a day. (Placebo is a dummy treatment that looks like medicine but does not have any medicine in it.) The study will compare fezolinetant and placebo after 4 and 12 weeks of dosing. The study will see if fezolinetant reduces the number of hot flashes. And the study will see if fezolinetant reduces the severity of the hot flashes.

Women in the study will receive an electronic handheld device at the first study visit. (It is similar to a smart phone.) Each day of the study, study participants will use this to record their hot flashes. Their record for the 10 days before the start of study treatment will be checked. They can remain in the study if their record shows 7 or 8 moderate to severe hot flashes per day (50 or more per week). Next, they will be picked for 1 of the 2 study treatments (fezolinetant or placebo) by chance alone. It is like flipping a coin.

The study participants will take study treatment for 52 weeks. The first 12 weeks of study treatment are “double-blinded.” That means that the study participants and the study doctors do not know who takes which of the study treatments (fezolinetant low dose, fezolinetant high dose or placebo) during that time. The last 40 weeks of study treatment are “noncontrolled.” That means that each study participant and the study doctors know which study treatment that study participant takes during that time. Women who take fezolinetant during the first 12 weeks will continue to take the same dose. Women who take placebo during the first 12 weeks will start taking fezolinetant. Their dose will be either low dose or high dose fezolinetant.

At weeks 2, 4, 8, 12, 14, 16 and then once a month, the study participants will go to 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. Study participants will complete questionnaires that are about how hot flashes affect their daily life. Study participants who still have their uterus will have the following 2 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. This test 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.