Long-term Safety and Efficacy Study of MT-8554 in Postmenopausal Women With Vasomotor Symptoms

January 5, 2026 updated by: Tanabe Pharma America, Inc.

An Open-label, Long Term Extension Study of MT-8554 in Postmenopausal Women Experiencing Moderate to Severe Vasomotor Symptoms Who Completed Study MT-8554-A01

An open-label, long term extension study of MT-8554 in postmenopausal women experiencing moderate to severe vasomotor symptoms who completed Study MT-8554-A01

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

190

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35209
        • Research Site
      • Dothan, Alabama, United States, 36303
        • Research Site
    • Arizona
      • Phoenix, Arizona, United States, 85032
        • Research Site
    • California
      • Norwalk, California, United States, 90650
        • Research Site
      • Sacramento, California, United States, 94203
        • Research Site
      • San Diego, California, United States, 92111
        • Research Site
    • Colorado
      • Denver, Colorado, United States, 80209
        • Research Site
    • Connecticut
      • New London, Connecticut, United States, 33176
        • Research Site
    • Florida
      • Clearwater, Florida, United States, 33759
        • Research Site
      • Crystal River, Florida, United States, 34429
        • Research Site
      • Fort Myers, Florida, United States, 33900
        • Research Site
      • Hialeah, Florida, United States, 33012
        • Research Site
      • Hialeah, Florida, United States, 33016
        • Research Site
      • Jacksonville, Florida, United States, 32256
        • Research Site
      • Jupiter, Florida, United States, 33458
        • Research Site
      • Miami, Florida, United States, 33176
        • Research Site
      • Miami, Florida, United States, 33185
        • Research Site
      • Orlando, Florida, United States, 32806
        • Research Site
      • Orlando, Florida, United States, 32801
        • Research Site
      • Ponte Vedra, Florida, United States, 32081
        • Research Site
      • Port Saint Lucie, Florida, United States, 34952
        • Research Site
      • Sarasota, Florida, United States, 34231
        • Research Site
      • Wellington, Florida, United States, 33414
        • Research Site
      • West Palm Beach, Florida, United States, 33409
        • Research Site
    • Georgia
      • Sandy Springs, Georgia, United States, 30328
        • Research Site
    • Idaho
      • Idaho Falls, Idaho, United States, 83404
        • Research Site
    • Kansas
      • Hutchinson, Kansas, United States, 67501
        • Research Site
      • Wichita, Kansas, United States, 67226
        • Research Site
    • Louisiana
      • Marrero, Louisiana, United States, 70072
        • Research Site
      • Metairie, Louisiana, United States, 70001
        • Research Site
    • Maryland
      • Baltimore, Maryland, United States, 21208
        • Research Site
    • Michigan
      • Kalamazoo, Michigan, United States, 49009
        • Research Site
      • Saginaw, Michigan, United States, 48504
        • Research Site
    • Missouri
      • Kansas City, Missouri, United States, 64114
        • Research Site
    • Montana
      • Missoula, Montana, United States, 59801
        • Research Site
    • Nevada
      • Las Vegas, Nevada, United States, 89128
        • Research Site
    • New Jersey
      • Lawrenceville, New Jersey, United States, 08648
        • Research Site
    • North Carolina
      • Morehead City, North Carolina, United States, 28557
        • Research Site
      • Winston-Salem, North Carolina, United States, 27103
        • Research Site
    • Ohio
      • Cleveland, Ohio, United States, 44101
        • Research Site
      • Columbus, Ohio, United States, 43213
        • Research Site
      • Columbus, Ohio, United States, 43231
        • Research Site
      • Englewood, Ohio, United States, 45322
        • Research Site
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19114
        • Research Site
    • Tennessee
      • Bristol, Tennessee, United States, 37620
        • Research Site
      • Jackson, Tennessee, United States, 38305
        • Research Site
      • Memphis, Tennessee, United States, 38119
        • Research Site
    • Texas
      • Fort Worth, Texas, United States, 76104
        • Research Site
      • Schertz, Texas, United States, 78154
        • Research Site
    • Utah
      • Draper, Utah, United States, 84020
        • Research Site
      • Salt Lake City, Utah, United States, 84107
        • Research Site
    • Virginia
      • Norfolk, Virginia, United States, 23502
        • Research Site
    • Washington
      • Seattle, Washington, United States, 98101
        • Research Site

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Signed informed consent to participate in this study.
  • Subjects who complete the preceding trial (Study MT-8554-A01) through Week 12.

Exclusion Criteria:

  • Subjects who meet the withdrawal criteria for the proceeding trial (Study MT-8554-A01)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Open Label
MT-8554
Drug: MT-8554
MT-8554 Oral

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Percentage of Subjects With Adverse Events
Time Frame: 52 Weeks
52 Weeks
Percentage of Subjects With Serious Adverse Events
Time Frame: 52 Weeks
52 Weeks
Percentage of Subjects With Clinical Laboratory Tests Abnormalities
Time Frame: 52 Weeks
Hematology, biochemistry, coagulation and urinalysis
52 Weeks
Change in Blood Pressure
Time Frame: Baseline and 52 Weeks
Systolic and diastolic blood pressure
Baseline and 52 Weeks
Change in Heart Rate
Time Frame: Baseline and 52 Weeks
Baseline and 52 Weeks
Change in ECG Parameters
Time Frame: Baseline and 52 Weeks
PR, QRS, QT and QTc
Baseline and 52 Weeks
Change in Endometrial Thickness as Measured by Transvaginal Ultrasound
Time Frame: Baseline and 52 Weeks
Baseline and 52 Weeks
Percentage of Participants With Endometrial Hyperplasia as Measured by Endometrial Biopsy
Time Frame: 52 Weeks
52 Weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Average Daily Frequency of Moderate to Severe VMS
Time Frame: Baseline and 52 Weeks

Subjects were asked to record frequency and severity of VMS in an electronic diary. Severity levels are defined as follows.

Mild : Sensation of heat without sweating

Moderate : Sensation of heat with sweating, able to continue activity

Severe : Sensation of heat with sweating, causing cessation of activity
Baseline and 52 Weeks
Change in Average Daily Severity Score of Mild to Severe VMS
Time Frame: Baseline and 52 Weeks

Baseline VMS severity score : (1xFmi + 2xFmo + 3xFse)/(Fmi + Fmo + Fse)

VMS severity score for a specific week during the open label treatment period :(1xFmi+2xFmo+3xFse)/(Fmi+Fmo+Fse)

Fmi, Fmo, and Fse are the daily frequencies of mild, moderate, and severe VMS respectively.

The severity score of VMS ranged from 0 (lowest severity) to 3 (highest severity).
Baseline and 52 Weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Tanabe Pharma America, Inc.

Investigators

  • Study Director: Head of Medical Science, Tanabe Pharma America, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 18, 2018

Primary Completion (Actual)

November 15, 2019

Study Completion (Actual)

November 15, 2019

Study Registration Dates

First Submitted

March 29, 2018

First Submitted That Met QC Criteria

May 17, 2018

First Posted (Actual)

May 30, 2018

Study Record Updates

Last Update Posted (Actual)

January 23, 2026

Last Update Submitted That Met QC Criteria

January 5, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • MT-8554-A02

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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