A Clinical Pharmacological Study of MT-3921 in Subjects With HTLV-1 Associated Myelopathy (HAM)

A Clinical Pharmacological Study of MT-3921 in Subjects With Human T-cell Leukemia Virus Type 1 (HTLV-1)-Associated Myelopathy (HAM)

The purposes of this study is to assess the safety, tolerability, and pharmacokinetics of MT-3921 in subjects with Human T-cell Leukemia Virus Type 1 (HTLV-1)-Associated Myelopathy(HAM).

Subjects meeting eligibility criteria will enter the 6-month double-blind period. Subjects will be randomized in a 2:1 ratio to receive MT-3921 or placebo in a double blind manner.

Study Overview

• Status: Completed
• Conditions: HTLV-1-Associated Myelopathy (HAM)
• Intervention / Treatment: Biological: MT-3921; Biological: Placebo

• Study Type: Interventional
• Enrollment (Actual): 15
• Phase: Phase 1

Contacts and Locations

Study Locations

• Japan
  • Kanagawa
    • Kawasaki-shi, Kanagawa, Japan, 216-8511
      • St. Marianna University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

Additional screening criteria check may apply for qualification:

• Subjects aged 20 years or older on the day of consent
• Subjects with a confirmed diagnosis of HAM according to the diagnostic algorithm of Practical Guideline for HAM 2019 on the day of consent
• Subjects with an Osame's motor disability score (OMDS) of ≥4 and ≤6 at Screening and on the first day of the Treatment period (predose)
• Subjects with no change in OMDS for at least 3 months before the day of consent
• Subjects with a CSF concentration neopterin of ≥6 pmol/mL at Screening
• Subjects on maintenance oral steroid therapy who have continued to receive the same dose equivalent to ≤10 mg/day of prednisolone for at least 3 months before the day of consent

Exclusion Criteria:

Additional screening criteria check may apply for qualification:

• Subjects who have a history of anaphylaxis or clinically significant allergic reactions due to administration of antibody products
• Subjects exhibiting or with a history of malignant tumor.
• Subjects with adult T-cell leukemia/lymphoma (ATL) or those with positive HTLV-1 clonality test (Southern blot) at screening and suspected of having ATL
• Subjects with spinal cord compression lesions, such as cervical spine disease, disc herniation, and ossification of the yellow ligament
• Subjects with psychiatric disorders, epileptic seizures, or dementia.
• Subjects with suicide attempts or suicidal ideation corresponding to item 4 or 5 on the Columbia Suicide Rating Scale (C-SSRS) at screening and/or on the first day of the Treatment period (predose)
• Subjects exhibiting or with a history of hepatitis B virus (HBV), hepatitis C virus (HCV), or human immunodeficiency virus (HIV) infection.
• Subjects with the novel Coronavirus disease 2019 (COVID-19)
• Subjects with severe illness
• Male or female subjects of childbearing potential who do not agree to use a contraceptive measure from the day of consent to 16 weeks after the last dose of the investigational medical product
• Female subjects who are pregnant, lactating, or may be pregnant
• Subjects who have received anti-repulsive guidance molecule (RGM) a antibody containing this investigational medical product
• Subjects who participated in other clinical studies (including clinical trials) and received drugs (including investigational medical products) or therapy within 12 weeks before the day of consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: MT-3921; Intravenous (IV)	Biological: MT-3921; Solution for infusion; Intravenous (IV); Other Names: Unasnemab
Placebo Comparator: Placebo; Intravenous (IV)	Biological: Placebo; Solution for infusion; Intravenous (IV)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Percentage of subjects with adverse events	36 weeks
Percentage of subjects with adverse reactions	36 weeks
Serum concentrations of MT-3921	PK samples will be collected at predose, 1.5 hours, 2, 4, 8, 12, 20 (predose and 1.5 hours), 24, 36 weeks post-dose.
CSF concentrations of MT-3921	PK samples will be collected at 2, 4, 12, 24 weeks post-dose.

Collaborators and Investigators

• Sponsor: Mitsubishi Tanabe Pharma Corporation
• Investigators: Study Director: General Manager, Mitsubishi Tanabe Pharma Corporation

Study record dates

Study Major Dates

• Study Start (Actual): May 2, 2022
• Primary Completion (Actual): September 14, 2023
• Study Completion (Actual): December 28, 2023

Study Registration Dates

• First Submitted: February 13, 2022
• First Submitted That Met QC Criteria: February 13, 2022
• First Posted (Actual): February 15, 2022

Study Record Updates

• Last Update Posted (Estimated): January 29, 2024
• Last Update Submitted That Met QC Criteria: January 25, 2024
• Last Verified: January 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Central Nervous System Diseases; Nervous System Diseases; RNA Virus Infections; Virus Diseases; Infections; Retroviridae Infections; Hematologic Diseases; Central Nervous System Infections; Myelitis; Deltaretrovirus Infections; HTLV-I Infections; Neuroinflammatory Diseases; Spinal Cord Diseases; Bone Marrow Diseases; Paraparesis, Tropical Spastic
• Other Study ID Numbers: MT-3921-C-101; jRCT2031210616 (Registry Identifier: Japan Registry of Clinical Trials (jRCT))

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No