NCT06206408: Starlight 2

A Study to Confirm if Fezolinetant Helps Reduce Hot Flashes in Japanese Women Going Through Menopause

Completed Phase 3 Last updated 23 December 2025

What this trial tests

Phase 3 trial testing Fezolinetant in Hot Flashes in 410 participants. Completed in 18 December 2025.

Timeline

16 February 2024

Primary endpoint
22 October 2025

18 December 2025

Quick facts

Lead sponsor	Astellas Pharma Inc
Phase	Phase 3
Status	Completed
Study type	INTERVENTIONAL
Allocation	randomized
Design	parallel
Masking	triple
Primary purpose	treatment
Enrollment	410
Start date	16 February 2024
Primary completion	22 October 2025
Estimated completion	18 December 2025
Sites	64 locations across Japan

Drugs / interventions tested

• Fezolinetant (FEZOLINETANT) — full drug profile →
• Placebo

Conditions studied

• Hot Flashes — all drugs for Hot Flashes →

Sponsor

Astellas Pharma Inc — full company profile →

Who can join

Adults 40 to 65, female only, with Hot Flashes. Patients with the condition only — healthy volunteers not accepted.

Sponsor's own description

Hot flashes are the most common reason women going through menopause seek medical attention. Hormone replacement therapy, or HRT, is most often prescribed to treat hot flashes. However, HRT can't be used by all women or for as long as may be needed.

Researchers want to find other ways to treat hot flashes. Fezolinetant is a medicine to treat hot flashes in women going through menopause. Fezolinetant is an approved medicine in the US. Further studies are needed before it is available in other regions such as Asia.

This study will confirm if fezolintant helps reduce the number of hot flashes in Japanese women going through menopause.

Women that want to take part in the study will be given an electronic handheld device with an app to track their hot flashes. Some women may be able to use the app on their own smartphone. Before the women are assigned a treatment, they will record information about their hot flashes.

Women will either take a lower or higher dose of fezolinetant, or a placebo. This is decided by chance alone. The placebo looks like fezolinetant but will not have any medicine in it.

The women will take 2 tablets of the study medicine (lower or higher dose of fezolinetant, or the placebo) once a day for up to 12 weeks. They will either take 1 tablet of fezolinetant (higher or lower dose) and 1 placebo tablet, or they will take 2 placebo tablets. The women will continue to record information about their hot flashes on the electronic device or their smartphone.

During the study, the women will visit the study clinic a few times. At each visit they will be asked if they had any medical problems and will use an electronic device at the clinic to answer questions about how the hot flashes affect their daily life. Other checks will include a medical examination, vital signs (temperature, blood pressure and pulse). Some blood and urine samples will be taken for laboratory tests. At some visits, the women will also have an ECG to check their heart rhythm. Women who have a womb (uterus) will also have a test called a transvaginal ultrasound. A probe is gently placed inside the vagina. Sound waves will create a picture of the organs in the pelvis. This will allow the study doctor to look more closely at the uterus and surrounding organs.

The last clinic visit will be 3 weeks after the women take their final tablets of the study medicine (1 tablet of lower or higher dose of fezolinetant and 1 placebo tablet, or 2 placebo tablets).

Publications & conference data

No peer-reviewed publications indexed yet for this trial. Completed trials usually publish results within 12-18 months.