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

  • End date
    Dec 26, 2023
  • participants needed
  • sponsor
    Mitsubishi Tanabe Pharma Corporation
Updated on 26 May 2022


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.

Condition HTLV-1-Associated Myelopathy (HAM)
Treatment Placebo, MT-3921
Clinical Study IdentifierNCT05240612
SponsorMitsubishi Tanabe Pharma Corporation
Last Modified on26 May 2022


Yes No Not Sure

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
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